Re: [Sursound] The BBC & Quadrophony in 1973

[Geoffrey Barton]

> 
> Message: 10
> Date: Tue, 10 Jan 2017 08:42:43 -
> From: "Alan Varty" 
> To: "Surround Sound discussion group" 
> Subject: Re: [Sursound] The BBC & Quadrophony in 1973
> Message-ID: <26495940C1B04DA6B9C600AD83F69931@AlanPC>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
>   reply-type=response
> 
> I think I am correct in saying the BBC (H) and NRDC (45j) decided to
> co-operate rather than have yet another two competing systems on
> the 4-channel scene which at the time already had CD-4, UD-4, SQ and
> QS in the arena.  BBC/NRDC each modified their encoding "towards"
> each other and called it HJ.

As I recall, the BBC were getting bad reviews of the stereo produced by matrix 
H and discussed this with MAG who proposed a compromise. UHJ was a variation 
within the 5 parameters which define an Ambisonic encoding, mainly a reduction 
in the centre front phase shift compared with 45J, based on many listening 
tests. It was known internally as 35JA’, so you can guess there was a whole 
family of small variations. BBC HJ was defined as a set of tolerance zones on 
the locus, mainly defined with reference to pairwise panning, I think it 
coincided with the UHJ locus at four points , so in that sense it was 
compatible; the exact parameters of both variations were defined by MAG. In 
subsequent tests the BBC made, primarily using SFMs, they also used our 
encoders, so I suspect drama productions such as Gilgamesh and Inferno 
Revisited are actually UHJ.

Geoffrey


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Re: [Sursound] Is the LP SV-95002(D) UHJ-encoded?

[Geoffrey Barton]

> 
> Message: 2
> Date: Fri, 8 Jan 2016 12:14:37 -0700
> From: Martin Leese 
> To: sursound@music.vt.edu
> Subject: Re: [Sursound] Is the LP SV-95002(D) UHJ-encoded?
> Message-ID:
>   
> Content-Type: text/plain; charset=UTF-8
> 
> Geoffrey Barton wrote:
> 
>> Yes I was, inasmuch as there was only one recording, which went straight
>> into UHJ 2ch PCM.
> 
> Hi Geoffrey,
> 
> Thank you for this.  If I have understood you
> correctly, the B-Format was not archived (only
> the two-channel UHJ) so there could not have
> been a different mix.

Hi Martin,
yes, sadly that is so.
For commercial reasons eg. no affordable 4 track digitals and the (then) high 
cost of recording on PCM1600, which was a must have for marketing reasons 
('DDD'), apart from some earlier trials, there were no parallel b-formats of 
the Unicorn commercial releases. A similar situation existed at Nimbus for some 
years once they started using the pcm1610.

But Laurie Johnson was influential in the use of UHJ as he like the fact that 
what he heard on the session ended up on the record. He even liked the Meridian 
speakers I used on his sessions and bought some for home.

> 
> Steven Dive wrote:
>> Hi Martin,
>> 
>> The Discogs site has the DKP 9001 version. Is this of any use?
> 
> Discogs.com lists four versions:
> 1.  DKP 9001
> 2.  DKP 9001
> 3.  SV-95002
> 4.  SV-95002 D  (should be "SV-95002(D)")
> 
> I assume 1 and 2 are duplicates.

I think so.

>  I own 4,
> which states on the sleeve:
>   "The finest vinyl in the world (Japanese
>CD-4 type) has been used for the pressings
>..."
> I assume 3, instead, used crappy vinyl :-)

yes, possibly. It was called re-grind. However, John Goldsmith at Unicorn was 
fastidious in doing things as well as possible, so I expect the Unicorn 
versions are as good as you will get.
The danger with unsupervised disc cutting was that there were tools, used 
routinely, which altered the L/R phase at LF to make it easier to cut. This was 
not helpful for UHJ. So, it is quite possible the two pressings do not sound 
the same!

regards,
Geoffrey

> 
> Regards,
> Martin
> -- 
> Martin J Leese
> E-mail: martin.leese  stanfordalumni.org
> Web: http://members.tripod.com/martin_leese/
> 
> 
> --
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Re: [Sursound] Is the LP SV-95002(D) UHJ-encoded?

[Geoffrey Barton]

> 
> Message: 2
> Date: Thu, 7 Jan 2016 13:23:51 -0500
> From: Marc Lavall?e 
> To: geoffreybar...@mac.com
> Cc: sursound@music.vt.edu
> Subject: Re: [Sursound] Is the LP SV-95002(D) UHJ-encoded?
> Message-ID: <20160107132351.1...@hacklava.net>
> Content-Type: text/plain; charset=US-ASCII
> 
> Hi Mr. Barton.
> 
> On Thu, 07 Jan 2016 18:04:53 +
> Geoffrey Barton  wrote:
>> On 7 Jan 2016, at 17:00, sursound-requ...@music.vt.edu wrote:
>>> 
>>> Message: 4
>>> Date: Wed, 6 Jan 2016 16:08:41 -0700
>>> From: Martin Leese 
>>> To: sursound@music.vt.edu
>>> Subject: [Sursound] Is the LP SV-95002(D) UHJ-encoded?
>>> Message-ID:
>>> 
>>> Content-Type: text/plain; charset=UTF-8
>>> 
>>> Hi All,
>>> 
>>> I have recently purchased the 1980 LP "First
>>> Men in the Moon", SV-95002(D) on the
>>> Starlog/Varese Sarabande label.  This is an
>>> original motion picture score, conducted by
>>> Laurie Johnson.  As far as I can tell, this is the
>>> US release of the Unicorn-Kanchana label LP
>>> DKP 9001.  DKP 9001 is UHJ-encoded; is
>>> SV-95002(D)?
>>> 
>>> UHJ is not mentioned on the record or sleeve,
>>> although the sleeve does state that a Calrec
>>> Soundfield microphone was used.  Could
>>> there have been different mixes for the UK
>>> and US releases?  Geoffrey Barton was the
>>> recording engineer on other recordings in this
>>> series, so he probably was for this one as well.
>> 
>> Yes I was, inasmuch as there was only one recording, which went
>> straight into UHJ 2ch PCM.
>> 
>> rgds,
>> Geoffrey
> 
> Which one of these releases are UHJ encoded? :
> http://www.discogs.com/artist/872734-Geoffrey-Barton

Hi Marc,

the short answer is all of them.
A more detailed answer follows:

The Delius (DKP9008/9009) is stereo on side 1. The rest claims to be UHJ (on 
the sleeve notes). I can certainly say the Julian Lloyd Webber tracks are UHJ 
as I recall editing them with him, so I think the sleeve notes are correct.

The HiFi Sound test disc has two UHJ tracks recorded with a MKII SFM.

In addition to the Unicorn releases listed I engineered DKM6001, DKM6002 and 
the Peter Maxwell Davies 'Ave Maris Stella' KP8002 (see the Unicorn-Kanchana 
page on discogs). The latter was recorded 2ch UHJ on 1/2" tape @30ips ATR102; I 
had to take said machine to the cutting room as they did not have 1/2" tape 
machine, I think it was Townhouse or maybe Abbey Road.

There is a second Ruggiero Ricci recording DKP9003 which is not on the discogs 
list. This is UHJ too.

On the Unicorn-Kanchana list DKP9002 is UHJ (me) as are DKP9004, DKP9005 & 
DKP9016 (Bob Auger)


> 
> I have the "North By Northwest" cd.

so do I, Michael Gerzon once presented me a copy of it when he returned from a 
trip to NY.

> 
> Detecting UHJ encoding is the subject of some previous discussions on
> sursound, but I better ask the audio engineer. :-)

Its fairly safe to say, if my name is on it then it is Ambisonic..

(subject to the efforts of the cutting engineer to the contrary :-)

regards,
Geoffrey

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Re: [Sursound] Is the LP SV-95002(D) UHJ-encoded?

[Geoffrey Barton]

On 7 Jan 2016, at 17:00, sursound-requ...@music.vt.edu wrote:
> 
> Message: 4
> Date: Wed, 6 Jan 2016 16:08:41 -0700
> From: Martin Leese 
> To: sursound@music.vt.edu
> Subject: [Sursound] Is the LP SV-95002(D) UHJ-encoded?
> Message-ID:
>   
> Content-Type: text/plain; charset=UTF-8
> 
> Hi All,
> 
> I have recently purchased the 1980 LP "First
> Men in the Moon", SV-95002(D) on the
> Starlog/Varese Sarabande label.  This is an
> original motion picture score, conducted by
> Laurie Johnson.  As far as I can tell, this is the
> US release of the Unicorn-Kanchana label LP
> DKP 9001.  DKP 9001 is UHJ-encoded; is
> SV-95002(D)?
> 
> UHJ is not mentioned on the record or sleeve,
> although the sleeve does state that a Calrec
> Soundfield microphone was used.  Could
> there have been different mixes for the UK
> and US releases?  Geoffrey Barton was the
> recording engineer on other recordings in this
> series, so he probably was for this one as well.

Yes I was, inasmuch as there was only one recording, which went straight into 
UHJ 2ch PCM.

rgds,
Geoffrey
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Re: [Sursound] Is this a questionable statement?

[Geoffrey Barton]

> 
> Message: 1
> Date: Mon, 23 Nov 2015 18:09:10 +
> From: John Leonard 
> To: Surround Sound discussion group 
> Subject: [Sursound] Is this a questionable statement?
> Message-ID: <4c86a959-cf67-4aff-b42a-0e3fe54ba...@johnleonard.uk>
> Content-Type: text/plain; charset=utf-8
> 
> I?ve just looked at the Wikipedia entry for Ambisonics, which contains this 
> statement:
> 
> "Ambisonics was developed in the UK in the 1970s under the auspices of the 
> British National Research Development Corporation.?
> 
> Well, I know they screwed up my little project because of their involvement, 
> but is this really a correct statement of fact?
> 

yes.

Peter Fellgett brought NRDC into the project before filing his patent as, it 
being a university invention, NRDC at that time (since 1948) had first refusal 
to the development and commercial exploitation thereof. It is arguable whether 
he had to do this, but he did.

Geoffrey

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Re: [Sursound] SQ QUAD

[Geoffrey Barton]

>> 
> Message: 5
> Date: Fri, 30 Oct 2015 16:40:08 +
> From: Dave Malham 
> To: Surround Sound discussion group 
> Subject: Re: [Sursound] SQ QUAD
> Message-ID:
>
> Content-Type: text/plain; charset="utf-8"
> 
> Kind of thought it might be that - purely manual,

no

> or was there any signal
> dependent stuff going on?

Very much so, it was a multiband design with much detection logic and VCAs. It 
took up a half width rack box, 7 or 8 boards as I recall.

Geoffrey 
> 
> 
> 
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Re: [Sursound] SQ QUAD

[Geoffrey Barton]

> 
> Message: 4
> Date: Fri, 30 Oct 2015 16:24:23 +
> From: Dave Malham 
> To: Surround Sound discussion group 
> Subject: Re: [Sursound] Sursound Digest, Vol 87, Issue 20
> Message-ID:
>
> Content-Type: text/plain; charset="utf-8"
> 
> Well, I tracked down at least one source for my memory - the pdf of what is
> claimed to be the"original design documents" for the Minim AD7, which can
> be found here - https://sites.google.com/site/minimdecoders/
> Not that it tells you much - just a section (on page 9) on what you can
> expect out of a "Variable Preference Decoder" for "Normal UHJ", "Fwd UHJ"

that's 'variable preference', which is the Minim pro design (I forget the 
number) and the A+D design. Not 'variable  directional preference'

> and "Bkwrd UHJ" In fact, this doesn't seem to relate to the design
> presented - maybe it was included in the scan accidentally.

I gave Martin that part as the bottom of the page refers to the AD7 design.

Geoffrey
> 
> 
> 
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Re: [Sursound] SQ QUAD

[Geoffrey Barton]

> 
> Message: 2
> Date: Thu, 29 Oct 2015 13:44:35 -0400
> From: "Ronald C.F. Antony" 
> To: Surround Sound discussion group 
> Subject: Re: [Sursound] SQ QUAD
> Message-ID: <8831d411-7334-4736-86a5-a450b42df...@cubiculum.com>
> Content-Type: text/plain; charset=utf-8
> 
> On Oct 29, 2015, at 12:22, Geoffrey Barton  wrote:
> 
>> On Oct 29, 2015, at 04:41, Dave Malham  wrote:
>> 
>>> Going back to this old theme, something which slipped under my radar but
>>> reappeared when I was re-reading the Integrex decoder articles was
>>> Michael's throw-away statement on page 3 that "...a fully fledged ambisonic
>>> 'variable matrix' design is under development for (such) specialist
>>> applications". Does anyone (Geof Barton, Peter Craven, Peter Carbines,
>>> Richard lee...) remember this or know anything about it - certainly nothing
>>> remains in my memory, even if it was there in the first place.
>> 
>> Certainly. It was called the 'VDP' decoder, 'Variable Directional 
>> Preference'.
>> 
>> Michael and I had great fun with that; it revealed all sorts of detail in 
>> stereo recordings played through it, quite apart from the effect on UHJ.
>> I believe that, some time after I left the Cybernetics dept, to quote Peter 
>> Fellgett, 'a student destroyed it by connecting 240v into the 5v supply'.
> 
> Any relation to what Meridian calls ?SuperStereo??

no


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Re: [Sursound] SQ QUAD

[Geoffrey Barton]

> 
> Message: 4
> Date: Thu, 29 Oct 2015 20:07:59 +
> From: Peter Lennox 
> To: Surround Sound discussion group 
> Subject: Re: [Sursound] SQ QUAD
> Message-ID:
>   
> <28f33490c302424e98cc6dc2531b2048010969e41...@mkt-mbx01.university.ds.derby.ac.uk>
>   
> Content-Type: text/plain; charset="Windows-1252"
> 
> or does it bear some relationship to variable order panning (I remember my 
> colleague Bruce Wiggins's  work on higher order ambisonic panning for 
> decoding to 5.1)?

no, it is purely a decoding technique, mainly for 2 channel material. In 1977 
it was very hard to do

Geoffrey
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Re: [Sursound] SQ QUAD

[Geoffrey Barton]

> 
> Message: 3
> Date: Thu, 29 Oct 2015 18:58:34 +
> From: Dave Malham 
> To: Surround Sound discussion group 
> Subject: Re: [Sursound] Sursound Digest, Vol 87, Issue 20
> Message-ID:
>   
> Content-Type: text/plain; charset="utf-8"
> 
> Hi Geofrey,
>Thanks for the info - now you mention it, VDP strikes a faint chord in
> my memory, I wonder if maybe either Michael or Peter mentioned at some
> point when we talking all those years ago.
> 
> Of course, you know what's going to happen next - someone is going to ask
> for design info.

I think we wrote an AES about it. 

but the clue is in the name. Start with the 'preference' bit, usually 'forward 
preference', now allow it to point in any direction over 360 degrees (indeed 4∏ 
steradians :-)



Geoffrey


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Re: [Sursound] Sursound Digest, Vol 87, Issue 20

[Geoffrey Barton]

> 
> Message: 1
> Date: Thu, 29 Oct 2015 08:41:25 +
> From: Dave Malham 
> To: Surround Sound discussion group 
> Subject: Re: [Sursound] SQ QUAD
> Message-ID:
>   
> Content-Type: text/plain; charset="utf-8"
> 
> Going back to this old theme, something which slipped under my radar but
> reappeared when I was re-reading the Integrex decoder articles was
> Michael's throw-away statement on page 3 that "...a fully fledged ambisonic
> 'variable matrix' design is under development for (such) specialist
> applications". Does anyone (Geof Barton, Peter Craven, Peter Carbines,
> Richard lee...) remember this or know anything about it - certainly nothing
> remains in my memory, even if it was there in the first place.

Certainly. It was called the 'VDP' decoder, 'Variable Directional Preference'.

Michael and I had great fun with that; it revealed all sorts of detail in 
stereo recordings played through it, quite apart from the effect on UHJ.
I believe that, some time after I left the Cybernetics dept, to quote Peter 
Fellgett, 'a student destroyed it by connecting 240v into the 5v supply'.

rgds,
Geoffrey



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Re: [Sursound] DeWolfe Library Music - Ambisonics confusion

[Geoffrey Barton]

On 4 Dec 2013, at 17:00, sursound-requ...@music.vt.edu wrote:
> 
> 
> Message: 14
> Date: Wed, 4 Dec 2013 07:02:01 -0700
> From: John Abram 
> To: s...@mchapman.com, Surround Sound discussion group
>   
> Subject: Re: [Sursound] DeWolfe Library Music - Ambisonics confusion
> Message-ID:
>   
> Content-Type: text/plain; charset="utf-8"
> 
> On 4 December 2013 04:31, Michael Chapman  wrote:
> 
>> I would say "ambisonics" is a 'dictionary word'  (though I haven't looked
>> in any dictionaries).
>> 
> 
> I found this in the Dictionary Application on my mac:
> 
> ambisonic |?ambi?s?nik|adjectivedenoting or relating to a high-fidelity
> audio system that reproduces the directional and acoustic properties of
> recorded sound using two or more channels.noun ( ambisonics) [treated as
> sing. ]ambisonic reproduction or systems.ORIGIN 1970s: from Latin ambi- ?on
> both sides? + sonic .
> 
> -- 
> with best wishes, John

Peter Fellgett was instrumental in achieving the first inclusion of 'ambisonic' 
in, AFAIR, the Collins dictionary and argued that it was generic, just as 
'stereo' is. NRDC tried to register 'ambisonic' in the 1970s but this was 
refused, probably because it was already seen as generic, due to PBF's 
influence. They did register 'ambison', but this was dropped at some stage, or 
maybe passed to Nimbus with the rest of the portfolio.

Of course anybody can try and register any word and, just like a patent, it 
stays valid until somebody successfully contests it, if it is allowed to start 
with.

Geoffrey

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Re: [Sursound] Super Stereo emulation (UHJ)

[Geoffrey Barton]

Larry Gruber wrote:

> 
> <https://sites.google.com/site/mytemporarydownloads/Ambisonic_stereo_decoding_equations_1981.pdf?attredirects=0>Ambisonic_stereo_decoding_equations_1981.pdf
>  
> 
> 
> Kindly provided by Dr. Geoffrey Barton  (1/26/2011).
> 
> 
> K1 & K2  are the two frequency magnitudes for the shelf filters
> 
> K1  <  800 Hz.
> 
> K2  >  800 Hz.
> 
> p  is the degree of "phasiness" (e.g. 0.0 to 0.25) which, in a note from 
> Geoffrey, relates to the degree of accuracy of the phase difference networks.

not from me, it is incorrect. Nothing to do with the phase shifter accuracy; a 
perfect phase shifter will not give zero phasiness. The phasiness is the 
manifestation of the fact that you do not quite have enough directional 
information to decode to that order, ie. the difference between BHJ and 
B-format. 'Forward preference' is MAG's term for reducing the subjective effect 
in the forward direction at the expense of increasing it at the rear. The Minim 
and A+D Variable Preference design had a pot which allowed this to be, er.. 
varied, including some way back of neutral. This caused MAG some surprise when 
he first played with it, as he was unaware of what I had done.

> 
> My presumption then is that a tighter tolerance phase shifter  ( < 1 degree 
> error from 20 to 20k Hz) reduces the degree of phasiness (which can be 
> "pushed" to the rear with the forward preference control--fed by the 'b' 
> node) and would "allow" for a slightly steeper slope on the shelf 
> filters.  (The WW '77 decoder probably exhibited a significant degree of 
> phasiness, and a tighter tolerance pair of phase shifters will also 
> probably provide better imaging for SS decoding.)
> 

The 77 decoder stereo decode is inferior to those in the later Minim decoders, 
so MAG said. I never really liked any of them on four speakers.

Geoffrey

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Re: [Sursound] Waveplayer - 16 chnl SD-card audio device

[Geoffrey Barton]

> 
> Date: Wed, 11 Jul 2012 10:16:48 +0100
> From: Dave Malham 
> Subject: Re: [Sursound] Waveplayer - 16 chnl SD-card audio device
> To: Surround Sound discussion group 
> Message-ID: <4ffd4480.2090...@york.ac.uk>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> 
> Hi Marc
> On 11/07/2012 02:27, Marc Lavall?e wrote:
>> Hi Dave
>> 
>> Dave Malham  a ?crit :
>>> Hi Marc
>>> 
>>> I've certainly thought about doing that, but not initially since  it
>>> means that
>>> 
>>> (a) you would be limited to passive speakers
>> This limitation is a feature: with less hardware the cost is lowered
>> and the quality is raised. It would be a good choice to create small
>> domestic systems or public installations. It would be adequate with 6
>> or more identical full range speakers.
> Yes - and no. Different markets, I think...
>>> (b) the specs aren't as good as the Analog Devices ADAU1966, the
>>> evaluation board for which is sitting next to me :-)
>> The better spec of the ADAU1966 is rarely matched by amps and
>> speakers... I agree that for professional use it would be perfect. ;-)
> True, but I am thinking about the "professional" market. Don't forget that 
> this project is driven by 
> my thoughts about the kind of jobs I'll be taking on after I retire.
>>> (c) serious levels of hardware design needed for the power amps stages
>> In the example application schematic the D-class amps with PWM inputs
>> are connected directly to the PWM ouputs of the TAS5508C. How easier
>> can it be? The final system could be made in the form of a PCM to PWM
>> decoding board to connect amps with PWM inputs.
> Yes, but given the level of currents (and voltages) concerned, this ain't 
> quite as easy as it seems 
> to get right. Been there, done that, got the burn marks on my fingers :-)
>> 
>>> on the other hand, the TAS5508C has a "Full 8?8 Input Crossbar Mixer.
>>> Each Signal-Processing Channel Input Can Be Any Ratio of the Eight
>>> Input Channels." and "Mixer gain operations are implemented by
>>> multiplying a 48-bit, signed data value by a 28-bit, signed gain
>>> coefficient" so 8 speaker digital decoder, anyone? Only problem
>>> is, no way to implement shelf filtering :-(
>> Interesting!
>> But its only job would be to interface PCM streams to PWM inputs.
> Depends on the computing power of the thing doing the playback.
> 
> Anyway, I will keep this under review.

see if you can get your head around Zetex DDFA.

http://www.diodes.com/_files/free_pages/u_0_lnk_090413235508.pdf

This has very clean amps and some spare biquads, if you can find suitable 
signal paths for shelf filtering.

Geoffrey
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Re: [Sursound] Stonehenge's eerie sounds revived

[Geoffrey Barton]

> 
> Message: 1
> Date: Fri, 27 Apr 2012 13:41:45 -0700
> From: "Andrew Castiglione" 
> Subject: [Sursound] Stonehenge's eerie sounds revived
> To: "Surround Sound discussion group" 
> Message-ID: <008101cd24b6$2faee010$8f0ca030$@com>
> Content-Type: text/plain; charset="us-ascii"
> 
> http://cosmiclog.msnbc.msn.com/_news/2012/04/26/11418090-stonehenges-eerie-s
> ounds-revived?lite
> 
> British researchers conducted experiments at a fake Stonehenge as well as
> the actual 5,000-year-old monument 
> to determine how sounds echoed within the ancient circle of stones - and
> they found that the sounds would have taken on an eerie reverberation.

Being old enough to have walked inside the circle as a member of the public, I 
can tell you there are a few hard reflections but bugger-all reverberation.

Mind you, the wind whistling between the stones is something else.

Geoffrey

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Re: [Sursound] Why Ambisonics Didn't Become A Standard

[Geoffrey Barton]

> 
> Message: 11
> Date: Sun, 15 Apr 2012 21:19:15 -0700 (PDT)
> From: Robert Greene 
> Subject: Re: [Sursound] Why Ambisonics Didn't Become A Standard, OT:
>   Spatial Music; Low Cost Speakers
> To: Surround Sound discussion group 
> Message-ID: 
> Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed
> 
> 
> Interesting indeed, but not new. I think the Unicorn
> Fenby Legacy(Music of Delius), the part that was
> done with the Soundfield mike,

On the vinyl this is sides 2~4; I have never seen the CD version!

As I recall I used a MKII sfm and handmade electronics as JLW preferred the 
sound
..and it was on a PCM1600, the one with drifting barely 16bit ADCs, but after 
the 7k whistle had been fixed.


Geoffrey

> is one of the
> finest of all stereo recordings of an orchestra.
> For naturalness of sound, it is unbeatable and
> hard for anything else to equal in my view.
> Robert
> 

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Re: [Sursound] Can anyone help with my dissertation please?

[Geoffrey Barton]

> 
> 
> Message: 3
> Date: Mon, 2 Apr 2012 09:21:21 -0700 (PDT)
> From: Robert Greene 
> Subject: Re: [Sursound] Can anyone help with my dissertation please?
> To: Surround Sound discussion group 
> Message-ID: 
> Content-Type: TEXT/PLAIN; format=flowed; charset=US-ASCII
> 
> 
> Re marketing
> I am not a marketing expert
> but it seems to me that if anyone
> had really wanted Ambisonics to succeed, there would
> have been
> 1 presentations at shows for example. I have
> over the years encountered exactly one, by Meridian. Period.
> And

Its a question of when you are talking about. There were many presentations in 
the 70's in US and Europe, but at the time there was very little consumer 
surround sound around; Dolby stereo and logic decoders was about it. At the 
time (2 ch UHJ) Ambisonics was criticised for not being like a logic decoded 
Dolby Stereo. By the BBC.

> 2 there would have been low priced or free demo discs
> mixed to 5 channels. Zero on that one.

At the time BTG was promoting ambisonics there were no 5 channel discs!

> 3 Ads for said discs in audio and home theater magazines
> zero on that one
> 4 attempts to get magazines to write about it, The Absolute
> Sound, Stereophile, etc. Pretty much zero on that one, too.

look further back into late 70's, early 80's.

> 
> 5 Demonstrations at shows of Trifield and four speaker frontal
> stereo. Pretty much zero on that one, too, except for Meridian
> occasionally.

Trifield (Productions) has never had the budget to do much of that; audio was 
always peripheral to our business. Our involvement came through my earlier work 
with MAG. I financed his patents on the multispeaker decoder and also built him 
some prototypes and gave him some expenses to go to AES conventions. Meridian 
gave a lot more exposure to 'Trifield' than we could have achieved on our own.

> 
> One really gets the strong impression that the Ambisonics
> community has never seriously tried for public attention,
> and perhaps did not even want it.

Well, you said it, 'community'. As with the hard-core on Sursound now, we all 
come at it from different perspectives. There is no agreement about what we 
want to achieve, and why should there be? In commercial terms it would still be 
uphill to get Ambisonics into consumer equipment. Basically, you have to get 
through a connection called HDMI. This is limited to 8 channels which have 
moronic speaker location predications.

> 
> It is really not too late at least for Trifield. If it is really
> better, people would respond. (Actually at a Meridian demo I heard,
> I thought it sounded worse than stereo. For one thing,
> the speakers were not far enough apart so that it sounded too mono--this 
> sort of thing does not help the cause).

It happens. I remember seeing one very successful Ambisonic demonstration on 
four speakers where one (rear) speaker was later found to be unplugged.

> 
> If this is really a better way to play stereo in the sense that people
> like it better, one could demonstrate. People go to audio shows
> partly looking for interesting new ideas. But Trifield is one they
> practically never encounter.
> 
> This stuff is not hard to set up. It does not even cost very much.
> But it never seems to happen.

It is not easy to do for those who are most likely to appreciate it ie. those 
who normally listen to a system based on two decent speakers fed by a decent 
stereo amp!

Geoffrey
> 
> Robert
> 

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Re: [Sursound] Can anyone help with my dissertation please?

[Geoffrey Barton]

> 
> --
> 
> Message: 19
> Date: Sun, 1 Apr 2012 00:22:21 +0100
> From: Peter Lennox 
> Subject: Re: [Sursound] Can anyone help with my dissertation please?
> To: Surround Sound discussion group 
> Message-ID:
>   
> <28f33490c302424e98cc6dc2531b2048c18acc4...@mkt-mbx01.university.ds.derby.ac.uk>
>   
> Content-Type: text/plain; charset="us-ascii"
> 
> 
> 
> well!
> 
> Cara, you've had loads of responses!
> 
> 
> I hope that the sheer volume hasn't overwhelmed you
> 
> With my dissertation supervisor head on, I'd like to offer the following:
> 
> Your dissertation question clearly touches something important, but lacks 
> focus.
> By that, I mean (in a caring way, possums) that framing the question this way 
> makes it very difficult to elicit clear answers. Proving why something didn't 
> happen is very often impossible - it's like the evolutionery arguments as to 
> why this species made it, whilst that one didn't. The reasons are usually 
> incredibly complex, and intrinsically involve chaotic elements - the toss of 
> a coin, the arrival of this circumstance instead of that, the confluence of 
> these causal items instead of the lack of coincidence of such.
> 
> Having said all that...
> 
> You've clearly struck a nerve - the responses here show that plenty of 
> articulate and knowledgeable people have something to offer on this - and 
> these people won't be around for ever! - clearly, Blumlein has gone, Gerzon 
> has gone, Felgett isn't around.. - BUT: Peter Craven is. I know he is not so 
> active on this list, but look for algol.co.uk.

Can I just point out that Peter Craven, although 'in at the birth' as the 
co-inventer of the soundfield mic, was not directly involved in the development 
of Ambisonics? MAG used to keep people and projects in separate boxes and the 
Reading group was quite separate from the OUTRS activities and MAG always kept 
it that way. MAG worked on Ambisonics with Peter Fellgett and John Wright at 
Reading University. I joined them in 1975.

BTW I agree about the necessity for formulating the question carefully. How do 
you measure success?

If you asked MAG and PBF why they were spending so much time during the 1970s 
on Ambisonics, there was no ambiguity. It was entirely about making a 
technology which could reproduce a realistic simulacrum of a musical 
performance, and that is why I joined them, being like-minded. And under that 
measure, Ambisonics was and remains a success. Mind you, I had difficulty 
convincing PBF of this in his declining years.

Others had other objectives. Once NRDC/BTG became involved, commercial 
objectives, in retrospect maybe unrealistic, were added, and we had to service 
these in order to finance what we really wanted to do.


Geoffrey
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Re: [Sursound] Can anyone help with my dissertation please?

[Geoffrey Barton]

> 
> Message: 1
> Date: Sun, 1 Apr 2012 10:05:18 -0400 (EDT)
> From: newme...@aol.com
> Subject: Re: [Sursound] Can anyone help with my dissertation please?
> To: sursound@music.vt.edu
> Message-ID: <1343c.5791214f.3ca9b...@aol.com>
> Content-Type: text/plain; charset="us-ascii"
> 
> Robert:
> 
>> But I think that using this sort of thing as a way
>> to persuade  people they ought to have 16 channels
>> of playback or something is wrong  headed.
> 
> Of course it is but how about THREE?
> 
> Remember that the most obvious home-playback application of Michael  
> Gerson's mathematical work is *not* Ambisonics but TRIFIELD.
> 
> As I recall, it was the addition of a center speaker that Gerzon himself  
> thought would become the most widely adopted of his inventions -- or did I 
> read  the biography wrong?
> 
> Here, the licensing seems to have gotten in the way.  Did anyone other  
> then Meridian ever implement Trifield for consumers?

yes, but not currently

>  Was it ever (or is it  
> now) available as a *cheap* license, so that it can be put in Japanese or 
> Korean  recievers?

yes it is, but none have shown any interest. The biggest volume implementation 
is in expensive cars. (Jag,Range Rover and McLaren)


> 
> Yes, we know how you feel about "sound-stage" reproduction, but given that  
> the US hi-fi market has largely pursued this goal, did anyone ever 
> seriously try  to tackle the center speaker issue for music?

I think that, because the centre speaker has come from the 5.1 home theatre 
side, historically the centre speaker has been dissimilar, badly located and 
only thought appropriate for 'dialogue'. After all, even film soundtracks do 
not use the centre speaker for music. Personally, I would not want to be 
without Trifield three channel playback for music. Actually four is better.

Geoffrey

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Re: [Sursound] Sursound Digest, Vol 44, Issue 5

[Geoffrey Barton]

On 6 Mar 2012, at 17:00, sursound-requ...@music.vt.edu wrote:
> 
> Message: 6
> Date: Tue, 6 Mar 2012 04:03:47 +0200 (EET)
> From: Sampo Syreeni 
> Subject: Re: [Sursound] Me again - on the H/HJ hunt
> To: Surround Sound discussion group 
> Message-ID: 
> Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed
> 
> On 2012-01-25, Paul Hodges wrote:
> 
>> And given that HJ was defined to include within its tolerance zones 
>> both H and 45J, they could by definition have simply continued using 
>> existing H equipment and labelling the results HJ.

no, 45J predated UHJ.

H would not fit inside the HJ tolerance zone.

The ambisonic part of UHJ, as opposed to the pairwise referenced HJ used by the 
BBC, was and is 35JA'
UHJ was/is not a tolerance zone.

> 
> Yes. And that is one of the funkiest things about ambisonic 
> compatibility codings: you can't say there is just one codec. No, there 
> are encoders and decoders, separately. Because analog electronics 
> compatibility not only allows, but sometimes requires that sort of 
> thing.
> 
> I believe we should implicitly talk about precise encoders, here. 
> Because there is precisely one optimum way to decode what they produce, 
> evenwhile, say, UHJ allows a rather broad decoding band over the 
> Scheiber sphere.

DEcoding?
How do you described decoding on a Scheiber sphere?

If you mean encoding then BHJ has a precise single definition on the energy 
sphere, 5 parameters define the locus.

> 
> (Mind you, it was perhaps the first system in existence to explicitly 
> define itself through a decoder, and a one which wasn't perfectly well 
> defined either. Nowadays every digital codec defines itself that way, if 
> usually in a way which doesn't tolerate errors... ;)
> -

NO, it is precisely defined by the ENcoder, not the decoder.

The kernel (or equivalent B-format) encoding of UHJ was precisely and 
unambiguously defined.


Geoffrey
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Re: [Sursound] Me again - on the H/HJ hunt

[Geoffrey Barton]

On 27 Jan 2012, at 17:00, sursound-requ...@music.vt.edu wrote:
> 
> 
> Message: 3
> Date: Fri, 27 Jan 2012 16:46:59 +
> From: Paul Hodges 
> Subject: Re: [Sursound] Me again - on the H/HJ hunt
> To: Surround Sound discussion group 
> Message-ID: <628e491ec63e5d5f64b57...@octo-133.clinpharm.ox.ac.uk>
> Content-Type: text/plain; charset=us-ascii
> 
> --On 27 January 2012 15:03 + Richard  wrote:
> 
>> I'm surprised that the altered equation used wasn't ever written down
>> anywhere. 
> 
> Was there actually a specific altered equation anyway?  Given that the
> definition of HJ used tolerance zones, how would it be have been
> decided on?

Paul is quite right, the 'compromise' HJ was a set of tolerance zones drawn on 
the energy sphere. It was designed to allow various 'production techniques'  
used by the BBC to still remain within the specification. The version used by 
us, the Reading group, was a kernel specification UHJ (not 45J BTW, actually 
more like 35J) and fell within the zones too.

The IBA only used UHJ per our spec together with their brilliant (JH designed) 
3 channel FM multiplexer for their broadcasts.

Geoffrey


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Re: [Sursound] UHJ decoding and shelf filters

[Geoffrey Barton]

On 15 Dec 2011, at 17:00, sursound-requ...@music.vt.edu wrote:
> 
> Message: 3
> Date: Thu, 15 Dec 2011 14:57:06 +
> From: Fons Adriaensen 
> Subject: Re: [Sursound] UHJ decoding and shelf filters
> To: sursound@music.vt.edu
> Message-ID: <20111215145706.ga29...@linuxaudio.org>
> Content-Type: text/plain; charset=us-ascii
> 
> On Thu, Dec 15, 2011 at 07:19:40PM -, Richard Lee wrote:
> 
>> Fig 3.3 shows them in the form that Ambdec uses; matched gain at LF.
>> 
>> So 'order gain' at LF is 1.0 for both.
>> 
>> At HF, 'order gain' is 
>> 
>> 3.7dB for W
>> and
>> -2.1dB for X & Y
> 
> So what this amounts to is that for normal B-format the difference between 
> the 
> HF gains for resp. W and X,Y is 3 dB, and for UHJ it should be 5.8 dB.
> 
> The actual shelf gains (the difference between LF and HF gain 
> for any component) don't tell the real story. Changing the LF
> or HF gain for all components by the same amount doesn't modify
> the decoding, it just results in some EQ. 
> 
> The Ambdec presets actually normalise for pressure at LF
> and for energy at HF. That means that the shapes of the
> equivalent shelf filters depend on the number of speakers.
> 
> For example, the square decoder has order gains
> +3, 0 at HF, while the octagon first order one
> has +6, +3. In both cases the difference between
> W and X,Y is 3 dB, this makes the decoder max rE.
> 
> The balance between the HF and LF parts (that is,
> the actual slopes of the 'shelf filters') can be
> changed at run time using the LF/HF balance control.
> 
> Ambdec doesn't use shelf filters, it uses crossover
> filters and two independent matrices.


That is still a shelf filter in its composite response!

We used such bandsplitting shelf filters right from the earliest experimental 
Ambisonic decoders in the 1970s as it was much easier to change the cross-over 
frequency this way. I have always built experimental decoders this way. Its 
really only when you seek to reduce costs in analogue implementations that 
shelf filters of the all-pass type become attractive.

Geoffrey

> So all the
> above is assuming that the two matrices are the
> same. They usually are for regular layouts, but
> not in the case of the 5.1 one. This complicates
> matters.
> 
> Looking at the HF order gains for the 5.1 decoder
> it seems the ratio is close to 5.8 dB, but this
> doesn't mean anything as the matrices are quite
> different.
> 
> Ciao,
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Re: [Sursound] Soundfield-type mics: inverting or not?

[Geoffrey Barton]

On 9 Oct 2011, at 17:00, sursound-requ...@music.vt.edu wrote:
> 
> Message: 7
> Date: Sun, 9 Oct 2011 09:39:36 +
> From: Fons Adriaensen 
> Subject: Re: [Sursound] Soundfield-type mics: inverting or not?
> To: sursound@music.vt.edu
> Message-ID: <20111009093936.gb11...@linuxaudio.org>
> Content-Type: text/plain; charset=us-ascii
> 
> On Sun, Oct 09, 2011 at 10:16:22AM +0100, dave.mal...@york.ac.uk wrote:
> 
>> Does anyone know, of the top of their heads, 
>> if a film set type clapper board reliably provides a positive going 
>> leading edge to it's impulse? I can't see it not, but I'd prefer that to 
>> be confirmed by repeatable experiments.
> 
> I wouldn't rely in it. There's some air being squeezed out, but
> that would be a low-F thing. The real 'clap' is the sound of two
> pieces of wood hitting each other - I wouldn't make any guess
> as to the polarity of that wavefront.

With larger clapper boards it is a bit of a mess, especially if you are a long 
way from the mic.

Dog training clickers (search dog clicker on Amazon) work very well; you can 
get a pretty good idea of the frequency response too by an fft as the click is 
quite sharp and short. Drilling a hole in the back of it helps. The one I use 
produces a better click when you release the button than when you press. They 
are hopeless for dog training, our labrador regards it as a cue to grab the 
clicker from my hand and run off with it.

Peter Fellgett used to burst a balloon (compressed air, not helium) at centre 
stage. This always produces positive pressure.

Actually, with speech you can usually see polarity (we speak using positive 
pressure, usually), so just talking to the mic from centre stage is better than 
nothing.

Geoffrey

> 
> If you have a piece of bubble plastic around, making on of the
> bubbles burst should produce a 'positive' pulse...
> 
> Ciao,
> 
> -- 
> FA
> 
> 
> 
> --
> 
> ___
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> 
> 
> End of Sursound Digest, Vol 39, Issue 4
> ***

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Re: [Sursound] Scheiber fundamental paper on matrix quad

[Geoffrey Barton]

On 12 Sep 2011, at 17:00, sursound-requ...@music.vt.edu wrote:
> 
> --
> 
> Message: 1
> Date: Mon, 12 Sep 2011 08:42:57 -0600
> From: Martin Leese 
> Subject: [Sursound] Scheiber fundamental paper on matrix quad
> To: sursound@music.vt.edu
> Message-ID:
>   
> Content-Type: text/plain; charset=ISO-8859-1
> 
> Hi,
> 
> I am trying to update the Wikipedia page on
> Quadraphonic sound, and am looking for the
> Peter Scheiber paper which formed the basis
> for all the quad matrix systems.  What I am
> trying to do is discussed here:
> http://en.wikipedia.org/wiki/Talk:Quadraphonic_sound#Benjamin_Bauer
> 
> I have found two contenders:
> 
> 1.  Analyzing Phase-Amplitude Matrices
>JAES, November 1971, Volume 19, issue 10,
>pages 835 to 839
> http://www.aes.org/e-lib/browse.cfm?elib=2125

I would go with this one. I have not got the journal to hand, its in the garage 
somewhere, but the paper 'Analyzing Phase-Amplitude Matrices'
was presented at the 41st convention and appears in the AES 'Quadraphony' 
anthology. It is also used as a reference in numerous papers by MAG, assuming 
the journal is the same as the bound volume.

Geoffrey
> 
> 2.  Four Channels and Compatibility
>JAES, April 1971, Volume 19, issue 4,
>pages 267 to 279
> http://www.aes.org/e-lib/browse.cfm?elib=2183
> 
> I am not an AES member, so do not have free
> access to these.  Could somebody who does
> please tell me which one I seek.
> 
> Many thanks,
> Martin
> -- 
> Martin J Leese
> E-mail: martin.leese  stanfordalumni.org
> Web: http://members.tripod.com/martin_leese/
> 
> 
> --
> 
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> 
> 
> End of Sursound Digest, Vol 38, Issue 6
> ***

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Re: [Sursound] Sursound Digest, Vol 37, Issue 16

[Geoffrey Barton]

On 24 Aug 2011, at 17:00, sursound-requ...@music.vt.edu wrote:
> 
> Message: 1
> Date: Wed, 24 Aug 2011 05:28:38 -
> From: Richard Lee 
> Subject: Re: [Sursound] Questions regarding a very early 'Ambisonic'
>   LP
> To: 'Surround Sound discussion group' 
> Message-ID: <01CC621F.0240EF60@edgexp>
> 
>> Peter also mentions the Meridian software decoder, which is not 
> available. However there are plenty of software decoders available for 
> download.
> 
> Duu.uuh!  Mr. Elen, could you please provide some links to these.  I've 
> already checked the Unobtainium Software website for software UHJ decoders.
> 
> BTW, though I suggest a way to distinguish between RM & UHJ/45J, I agree 
> with the gurus who suggest it is probably 45J.
> 
> A UHJ decoder will decode Matrix H nicely.  

I disagree, unless you mean press the stereo button (or the mute button). 
Matrix H was designed to be decodable via a modified QS decoder.

Nothing decodes matrix H well and, as such, nothing is the best thing to use.

> If you can tweak it to 45J, 
> even better.
> 
> The "phase amplitude pan locus" for Matrix H is discontinuous but not as 
> badly as the seriously wonky SQ.  45J was designed to be inside the Matrix 
> H spec and would probably give "better" results than "dedicated" Matrix H 
> decoddrs.  

45J was designed entirely without reference to matrix H!
say three hail MAGs for the blasphemy.

> IIRC, apart from the ve...ry early experiments, the BBC used 45J 

not so. They only changed from matrix H into the 'compromise' HJ. An HJ decoder 
was designed to be made entirely from political, rather than electronic, 
components and, as such, was entirely non-causal and was as accurate as you 
imagined it might be.

> and UHJ decoders for all their work.

HJ was compatible with UHJ at maybe four locations. One of them was not RAH. 

However, the only HJ encoders around for b-format encoding got UHJ 
compatibleised by a backend re-design by me.


> 
> GV Malham, is Howard Smith still around?  

sadly, no.

Geoffrey

> I don't think he made the move to 
> AMS.
> 
> 

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Re: [Sursound] Questions regarding a very early 'Ambisonic' LP

[Geoffrey Barton]

On 
> Message: 4
> Date: Mon, 22 Aug 2011 16:16:08 +0100
> From: "Richard" 
> Subject: Re: [Sursound] Questions regarding a very early 'Ambisonic'
>   LP
> To: "Surround Sound discussion group" 
> Message-ID: <5E69167FE4FB4878AA81D91F3BCC8108@richardc7363d4>
> Content-Type: text/plain; charset="iso-8859-1"
> 
> Thanks for the reply. this gets more and more interesting, doesn't it. I 
> thought the NRDC were responsible for the introduction of UHJ/Ambisonics, but 
> then I could be wrong. Am very hazy about what happened when I'm afraid.
> 
> I'd really like to get to the bottom of this, really because I'd like to hear 
> it decoded.
> 
> If you'd like I can scan the relevant parts of the cover for you, it does 
> state 'Ambisonics' a couple of times. But then, your mention of BMX could 
> possibly point the way.
> 
> Still haven't been able to contact Calrec who produced the album.
> 
> Now, if it is BMX then it should be decodable in the same way I decode QS 
> (and SQ) as QS was based on RM
> 
> 


1   it is unlikely to be BMX

2   AFAIK all the guys at Calrec who might have known about it are dead.

3   It is possible that it is 45J

4   Not having any info about the record sleeve, ie. who it is playing, 
where it is, who engineered it, makes it rather guesswork!

5   If the BBC were involved it could be BBC HJ

6   But if it was from a SFM then it is more likely to be UHJ as the BBC 
encoders for B-format were actually UHJ.

You may be able to tell which by measuring the centre front phase shift for a 
centre front source, if there is one. 

UHJ gives you about 35 degrees phase shift. Guess what 45j gives you.

Geoffrey
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Re: [Sursound] Question regarding UHJ Encoding - Decoding

[Geoffrey Barton]

> 
> Message: 14
> Date: 06 May 2011 07:12:21 +0100
> From: dave.mal...@york.ac.uk
> Subject: Re: [Sursound] Question regarding UHJ Encoding - Decoding
> To: Surround Sound discussion group 
> Message-ID: 
> Content-Type: text/plain; format=flowed; charset=ISO-8859-1
> 
> On May 5 2011, Richard Lee wrote:
> 
>>> This sqrt(2) factor is an endless source of confusion. It seems silly 
>>> that W should be divided by sqrt(2) in recoding to restore its value, 
>>> which was multiplied by this in the encode to UHJ.
>> 
>> This sqrt(2) factor is WRONG.  Where do people come up with such myths?
>> 
> 
> I think the problem stems from the early material on Ambisonics in that 
> sometimes the pragmatic engineering decision to use -3dB on W to equalise 
> average channel levels on a recording of a reverberant environment with a 
> large number of distributed sources was rolled into the en/decoding 
> equations and sometimes (in the more "correct", theoretical discussions) it 
> wasn't. I remember being thoroughly confused by that way back in the days 
> of my youth...


I think it more likely comes from there being two versions of the equations, 
one encoding from b-format and the other in kernel form. The casual reader 
tends to confuse the direction cosines with the x and y of b-format, MAG 
usually gave both versions in internal documentation as he worked using the 
kernel form himself.

Geoffrey


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Re: [Sursound] Minim AD7 for sale

[Geoffrey Barton]

> 
> Date: Tue, 3 May 2011 11:03:55 -0700
> From: Aaron Heller 
> Subject: Re: [Sursound] Minim AD7 for sale
> To: Surround Sound discussion group 
> Message-ID: 
> Content-Type: text/plain; charset=ISO-8859-1
> 
> On Tue, May 3, 2011 at 10:14 AM, Fons Adriaensen  wrote:
>> On Tue, May 03, 2011 at 07:15:29PM +0530, umashankar mantravadi wrote:
>>> 
>>> in fact angelo recommended that i arrange the eight speakers as two crossed 
>>> squares. two speakers in front and back, and four speakers mid bottom left 
>>> and right and mid top left and right, the only problem is i do not see a 
>>> readymade decoder
>> 
>> A variation on this is an horizontal rectangle, 1 unit wide and 1.73 deep,
>> and a vertical rectangle in the YZ plane 1 unit high and 1.73 wide.
>> Or the same rotated 90 degrees. Looking from above you see an hexagon.
>> 
>> This somewhat improves the rE for horizontal directions (not much), at
>> the expense of all others. Anything outside the +/- 30 degrees elevation
>> region will become very fuzzy.
> 
> I had one of these set up at home for a couple of days and found it
> better than a horizontal hexagon.  The impression of height is a
> welcome addition to the sense of envelopment.   I had a fader set up
> in Bidule so you could change the Z gain to compare horizontal-only
> with periphonic. The entire listening panel (my son and I) preferred
> having the height info, but the rest of the family didn't appreciate
> having a couple of ladders in the living room.  I also tried it with
> the vertical rectangle in the XZ plane.  That works too.  Contact me
> off list if you want the Ambdec config files I used.

We demonstrated this layout at the London AES in 1980. MAG called it the 
'bi-rectangular'. I have been fortunate to have a version of it at home ever 
since.

It is quite a good rE compromise for first order recordings.

It also gives you a 'home theatre' compatible setup 5.1/6.1 using the 
'hexagon'; the lower of the front vertical pair can be used for the centre 
speaker, thus leaving a large space for the screen. I use 8 KEF HTS3001 
satellites, the upper ones screwed to the ceiling so, with a 2.4m ceiling 
height, fairly usual in the UK, you end up with a screen centre about 1.2m 
above floor level. The upper speakers are fairly inconspicuous, but the dog 
does tend to snuggle up to the lower ones, which are on the floor.

Geoffrey
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Re: [Sursound] Minim AD7 for sale

[Geoffrey Barton]

> 
> Message: 1
> Date: Tue, 3 May 2011 09:51:58 -0700 (PDT)
> From: Robert Greene 
> Subject: Re: [Sursound] Minim AD7 for sale
> To: Surround Sound discussion group 
> Message-ID: 
> Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed
> 
> 
> Here is a post that makes sense in the real world.
> Of course it is intriguing to work out how
> to create the impression of a mosquito circling around
> your head. But it is really not important musically.
> 
> What is wrong with stereo?
> 1 It is all in front
> 2 It is too LITTLE. Real orchestras are 15 meters or so wide, or more.
> And concerthalls are huge compared to home listening rooms.
> 
> What counts for music, real concert music as opposed to music
> constructed for surround(which is a small art form to say the least)
> is to get it to surround you are far as ambience is concerned
> and to get it to sound LARGE and as if in a large place-
> preferrably the large place in which it actually occurred.
> 
> And this is pretty much all that counts to my mind.
> 
> Unfortunately, I have yet to hear any domestic system
> that solved the large size problem. Surrounded yes, orchestra
> 15 meters across, not really
> 
> Robert


I agree with all that. I would only add that depth and height are part of that 
perception, the stuff from behind is almost irrelevant. And in referring to 
height I am not thinking about sound sources from above (there are very few of 
those in any music I would particularly like to listen to anyway :) but more 
about the fact that even solo instruments do not radiate as point sources (or 
even planar sources) towards the listener. The difference between a piano 
recording with a soundfield mic (not TM) played periphonically and only 
horizontally is astounding; the change is of coloration in the instrument. 
Musicians notice this immediately, others tend to hear the stuff coming from 
behind


Geoffrey
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Re: [Sursound] Calrec CM4050 Surround Microphone SN: 502 - solved ! ?

[Geoffrey Barton]

> 
> 
> Message: 2
> Date: Thu, 10 Feb 2011 12:22:47 -
> From: "Steve Higgs" 
> Subject: Re: [Sursound] Calrec CM4050 Surround Microphone SN: 502 -
>   solved !?
> To: 
> Message-ID: <000d01cbc91d$3c00efc0$0200a8c0@OFFICE>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
>   reply-type=original
> 
> Hi Folks,
> Many thanks Geoffery for your detailed reply. I probably now have even more
> questiones than I started with.
> 
> I have been able to regain contact with Bob Harrison (no longer in
> Broadcast), and his memories tie in with yours - I hope diaries can be
> found.

they were not lost, just in storage:-)

It seems the mic in use at the proms in 1978 would have been MKII no 504, as 
505 was in use at Nimbus at the time I went to the RAH with Bob to set up for 
the proms. I had been at Nimbus the previous week and left 505 with them.

In February 1979 I sent a draft eq curve for the MKIII to Clem at Calrec, based 
on measurements they supplied to me from the prototype. I also have notes of 
schematics I sent to Ken Farrar later in the year which subsequently emerged in 
the MKIII control unit. And the MKIII was then used at the proms that year as 
we had surmised.

Incidentally, my diary notes say that the IBA had (two?) MKII sfms down at 
Winchester, it would be interesting to know their serial numbers and where they 
are now; they did not get there via Reading but direct from Calrec. There is a 
note in 1978 that I purchased some capacitors to replace some in those units. 
My recollection is they were coupling capacitors, breaking down due to 
inadequate voltage spec for the 50v phantom.

rgds,
Geoffrey

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Re: [Sursound] Calrec CM4050 Surround Microphone SN: 502 - update

[Geoffrey Barton]

> 
> 
> Message: 1
> Date: Thu, 3 Feb 2011 11:59:36 -
> From: "Steve Higgs" 
> Subject: Re: [Sursound] Calrec CM4050 Surround Microphone SN: 502 -
>   update
> To: 
> Message-ID: <005b01cbc399$d92b3050$0200a8c0@OFFICE>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
>   reply-type=original
> 
> Dear Iluminati
> An rathey practical posting and update as to my investigations into this 
> mic, - it does work, with only a slight modification as to a safe chassis 
> earth to the mains PSU.
> 
> Some more clarification as to its construction. The mic head appears to be 
> just as it left the factory,
> 
> The head cable is remade - now 10meters .
> 
> The mains PSU  is tested and working, it does contain 4 FET/transistor 
> amplifiers - or is that filters. A set of tweaks inside (with amps/filters 
> on a Vero board construction and another 4 multi-turn tweaks accessible from 
> external. So provision for fine tuning - set-up. The polarising voltage 
> measures 52V off load.
> 
> The pair of joined diecast boxes are untested. A mains cable is provided to 
> the bottom box marked 'amplifiers', which also has mono jack inputs for the 
> signals from the above filter?/PSU.
> The top box with I believe PBF's notes written on masking tape contain 2 
> Vero boards mounted on edge connectors, the bottom board has 4 daughter 
> boards with 2 x 8 pin OP amps, the top board has no components - just some 
> wire links (a simple programmer?).
> 
> No passive processing.
> 
> My investigations lead me to Richard Elen's article 'Ambisonics - a BBC 
> Soundfield Experiance', from Studio Sound/Sound International from Oct 1979, 
> just 3 years after I joined the BBC. Paragraph 14 is when I started to see 
> daylight. Antony Askew is I'm afraid no longer with us, an I am at the 
> moment out of contact with Bob Harrison. I strongly suspect that this mic 
> and collection of boxes is the prototype MK2 evaluated at the RAH at the 
> Proms in 1979. Jeff Barton might you remember?

Steve,
I think that in 1979 it was a MKIII. As I recall it was John Rushby Smith in 
command, so you might try asking him if he is still around.
I was there at several of the broadcasts, mainly providing moral as well as 
technical support to Bob Harrison, who on a number of these occasions put his 
job on the line in his advocacy for the SFM and Ambisonics.

1978 was probably a MKII, but I will have to dig out my old diaries to check.


> As other readers of this list 
> I am very interested as to what was the (if any) processing provided for the 
> MK1, why did Reading University at some time and trouble construct this 
> control/processing kit, and what was the post microphone processing kit 
> supplied (factory) with a MK2.

No factory processing was supplied for a MKII, the first control box was for 
the MKIII.
That is why we built our own.

The MKI and MKII were part of a research project at the university; we were 
making it up as we went along, so there was no 'factory' processing available.

> 
> It is amazing how things 'come around. I have been closely connected with 
> the surround mic set-up at the proms for HD TV for the last 6-7 years to 
> provide the required 5.1 output - Just the TV output, while all mics are 
> available to both Radio and TV the surround TV (BBC2) output is mixed 
> entirely separately to the Radio output. Unfortunately a Soundfield is not 
> used. A MK5 was again evaluated during the 2009 season and was not found to 
> be satisfactory. Any microphone has got to be 'in the right place' and 
> remote control of it's parameters cannot totally make up for positioning for 
> the highest quality recordings, (I'm sure this can be argued, especially 
> with the very recent advent of digitally processed microphones such as the 
> Schoeps Super CMIT). The RAH is a very - well unique if not difficult place 
> to record, and perform as a soloist, essentially a lack of early 
> reflections - and then the echo.


Absolutely. If you stand centre stage at the RAH and just make a single 
handclap you can hear all the problems.

I think the particular problem with recording with the SFM there is that, if 
you put it in the normal 'stereo' position, behind and above the conductor, the 
recording sounds like you are floating in space, especially played back 
periphonically, this is partly because of the lack of early (floor!) 
reflections. Musically it balances ok, apart from perhaps too much brass. But 
then, that often happens

rgds,
Geoffrey


 
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Re: [Sursound] Why do you need to decode ambisonic/b format signals

[Geoffrey Barton]

> 
> 
> 
> 
> --
> 
> Message: 3
> Date: Wed, 26 Jan 2011 14:26:07 -0700
> From: Martin Leese 
> Subject: Re: [Sursound] Why do you need to decode ambisonic/b format
>   signals
> To: sursound@music.vt.edu
> Message-ID:
>   
> Content-Type: text/plain; charset=ISO-8859-1
> 
> Geoffrey Barton  wrote:
> 
>>> From: Martin Leese 
>>>> From memory, the theory behind Trifield
>>> assumes either Blumlein XY, or pan-potted
>>> multi-track mono.  Perhaps Geoffrey can chip
>>> in, or somebody can look at the paper
>>> (reference below).  ...
>> 
>> It is not essential that the material is Blumlein or pan potted; that is
>> just the way MAG handled a virtual 'test signal' in the paper; other
>> recording techniques work ok too, but with varying results, much as they do
>> over two speakers:-).
> 
> Obviously different recording techniques will
> work with varying results, and all will work to
> some extent.  The theory developed in the
> paper, however, is more restrictive.
> Specifically, MAG stressed the importance of
> the decoder being energy preserving.  But
> there is little point in the Trifield decoder being
> energy preserving when the recording
> technique used is not.  That would be closing
> the stable door after the horse has bolted.
> Blumlein M-S with a cardioid M, for example, is
> not energy preserving.


but the decoder will preserve the energy as recorded.


> 
> While energy preservation is not essential, the
> paper seems to suggest it is desirable.

yes, because it gives the best fidelity to the original musical 'balance'... 
whatever it originally was! The decoder was intended not to have an opinion 
about how the original should sound, unlike some variable matrix decoders :-)

rgds,
Geoffrey
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Re: [Sursound] Why do you need to decode ambisonic/b format signals

[Geoffrey Barton]

On 25 Jan 2011, at 17:00, sursound-requ...@music.vt.edu wrote:
> 
> Message: 8
> Date: Mon, 24 Jan 2011 12:03:11 -0700
> From: Martin Leese 
> Subject: Re: [Sursound] Why do you need to decode ambisonic/b format
>   signals ?
> To: sursound@music.vt.edu
> Message-ID:
>   
> Content-Type: text/plain; charset=ISO-8859-1
> 
> Eero Aro  wrote:
> 
>> J?rn Nettingsmeier wrote:
>>> in theory, you can. in practice, you can't, because you'd have to know
>>> what stereo technique was used during recording
>> 
>> Yes you can.
>> 
>> Just one word: Trifield.
> 
> Steven Dive  wrote:
> ...
>> I understand that Trifield is derived from the same groundwork as
>> Ambisonic, which also gives us ambi superstereo. It's a matter of
>> personal judgement, I think, but do you more knowledgeable theory
>> folks know if Trifield is therefore as flexible in its use as
>> superstereo?
> 
>> From memory, the theory behind Trifield
> assumes either Blumlein XY, or pan-potted
> multi-track mono.  Perhaps Geoffrey can chip
> in, or somebody can look at the paper
> (reference below).  Again from memory,
> SuperStereo assumes some sort of coincident
> mic technique so, in theory, is more flexible
> than Trifield.  I don't know of a reference for
> SuperStereo; this is a gap in Ambisonic
> theory.

It is not essential that the material is Blumlein or pan potted; that is just 
the way MAG handled a virtual 'test signal' in the paper; other recording 
techniques work ok too, but with varying results, much as they do over two 
speakers:-).

The main difference between 'Trifield' and 'Super-stereo' is that the former 
works over a number of speakers >2 across the front sector and the latter seeks 
to use an ambisonic array of speakers all around the listener to lock the front 
in place. There were a number of different alignments of 'Super-stereo' in 
various decoder implementations, but in essence they all sought to bend the 
'washing line' of the in-phase stereo image around the front arc with variable 
width, and anything substantially out of phase generally somewhere else, again 
rather dependent on the source material.

Geoffrey






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Re: [Sursound] Available UHJ encoders?

[Geoffrey Barton]

On 18 Jan 2011, at 17:00, sursound-requ...@music.vt.edu wrote:
> 
> 
> --
> 
> Message: 7
> Date: Mon, 17 Jan 2011 22:34:52 +0100
> From: f...@kokkinizita.net
> Subject: Re: [Sursound] Available UHJ encoders?
> To: Surround Sound discussion group 
> Message-ID: <20110117213452.GC4090@zita2>
> Content-Type: text/plain; charset=us-ascii
> 
> On Mon, Jan 17, 2011 at 08:46:04AM +, Geoffrey Barton wrote:
> 
>> UHJ needs all the help it can get, and the analogue design Dave referred to 
>> is 6 pole/zeroes in each of the 0 and 90 degree sections, designed for a 
>> phase ripple of <1degree 20~20k. Too much ripple gives blurring and 
>> mis-location in the images. IMHO 4 degrees is way too much.
> 
> I very much doubt it is. If such small errors matter that would imply
> that the UHJ coefficients themselves are very critical or that the
> encoding/decoding matrices are ill-conditioned, but they are not.

How do you justify that assertion? Phase shifts changing with frequency also 
translate into amplitude errors when the phase shifter chains are summed. You 
need to maintain the asymptotic behaviour outside the band too. These things 
are audible on critical material and, especially in an encoder, should 
therefore be as accurate as possible. Not having to use analogue now makes this 
easily possible with a good design, and at reasonable mips cost. Why accept 
less?

Geoffrey
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Re: [Sursound] Available UHJ encoders?

[Geoffrey Barton]

> 
> 
> Message: 5
> Date: Sat, 15 Jan 2011 19:44:05 +0100
> From: f...@kokkinizita.net
> Subject: Re: [Sursound] Available UHJ encoders?
> To: Surround Sound discussion group 
> Message-ID: <20110115184405.GA4117@zita2>
> Content-Type: text/plain; charset=us-ascii
> 
> On Sat, Jan 15, 2011 at 06:19:33PM +, d...@york.ac.uk wrote:
> 
>> problem with Fon's code is that the filter poles are pre-optimised
>> for a limited range of sample rates (44.1/88.2 and 48/96) and I'd
>> like more even more choice.
> 
> 192 kHz ???
> 
>> It shows a little bit more phase
>> difference variance at the higher frequencies than the CSound
>> implementation but unless I am missing something it is only a four
>> pole per leg implementation, as opposed to CSounds (and Geoffrey's)
>> 6 poles per leg.
> 
> Yes, 2 second order sections in series.
> 
>> In both cases, however, the low end (under a
>> hundred Hz) becomes problematic at the higher sampling rates,
> 
> Are you sure ?
> 
> I measure +/- 4 degrees error in the range 20Hz .. 20kHz, even
> at 96 kHz. Below 20Hz it gets worse of course.


UHJ needs all the help it can get, and the analogue design Dave referred to is 
6 pole/zeroes in each of the 0 and 90 degree sections, designed for a phase 
ripple of <1degree 20~20k. Too much ripple gives blurring and mis-location in 
the images. IMHO 4 degrees is way too much.

rgds,
Geoffrey
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Re: [Sursound] Available UHJ encoders?

[Geoffrey Barton]

On 14 Jan 2011, at 17:00, sursound-requ...@music.vt.edu wrote:
> 
> Message: 7
> Date: Fri, 14 Jan 2011 08:52:17 +
> From: Dave Malham 
> Subject: Re: [Sursound] Available UHJ encoders?
> To: Surround Sound discussion group 
> Message-ID: <4d300ec1.7080...@york.ac.uk>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> 
> 
> 
> On 14/01/2011 01:54, J?rn Nettingsmeier wrote:
>> 
>> under linux, you can run jconvolver with the uhjenc plugin, sounds very 
>> good, but introduces 2048 
>> samples of latency.
>> and fons has recently added an IIR-based uhj encoder to the AMB plugin set 
>> (with zero latency but 
>> likely some compromises in sound quality), i haven't had the chance to test 
>> it carefully, but a 
>> quick run-through showed it does the job, although i prefer the sound of the 
>> convolution one.
> 
> D*mn, I'm just finishing off a (VST/AU) encoder myself using an IIR filter 
> set based on the analogue 
> all pass filters in the original Calrec unit (as designed by Geoffrey)- 

Nice to know something I did 30 years ago is still worth ripping off :-)

These are probably ok at 96 or 192, but at 44.1/48 I think they will wander off 
at high frequencies due to warping.
A better approach is to look for a solution which is symmetrical about fs/4. 
That version is only about 20 years old :-)
Used with backwards dubbing gives partitioned convolution a run for its money.

rgds,
Geoffrey
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Re: [Sursound] Calrec CM4050 Surround Microphone SN: 502

[Geoffrey Barton]

On 15 Dec 2010, at 17:00, sursound-requ...@music.vt.edu wrote:
> 
> Message: 2
> Date: Tue, 14 Dec 2010 12:37:42 -0500
> From: Daniel Courville 
> Subject: Re: [Sursound] Calrec CM4050 Surround Microphone SN: 502
> To: Sursound 
> Message-ID: 
> Content-Type: text/plain; charset="ISO-8859-1"
> 
> Le 10-12-13 16:54, J?rn Nettingsmeier a ?crit :
> 
>> now remains the question: whose are the mysterious initials on that
>> controller box?
> 
> RL = Richard Lee ?
> 

Could be. The controller module is from a MKIII control box and is not 
contemporary with the microphone.

G
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Re: [Sursound] Calrec CM4050 Surround Microphone SN: 502

[Geoffrey Barton]

On 14 Dec 2010, at 17:00, sursound-requ...@music.vt.edu wrote:
>> 
> 
> Message: 3
> Date: Tue, 14 Dec 2010 08:56:23 +
> From: Dave Malham 
> Subject: Re: [Sursound] Calrec CM4050 Surround Microphone SN: 502
> To: Surround Sound discussion group 
> Message-ID: <4d073137.1090...@york.ac.uk>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> 
> Many thanks for the correction, Geoffrey - hopefully this will all get 
> written up one day!
> 
>  Dave
> 

Further thoughts; maybe it is a MKI. I think the numbering started at 501, and 
we had two MKI at Reading. I am pretty sure that the first MKII we had was good 
old 504 (probably in a skip somewhere courtesy of a Fellgett child).
It should be pretty obvious as the MKI had a spherical windshield and thicker 
stem than a MKII. 
NOPQ was one of the conventions PBF used, so the preamp may have come from 
Reading.

regds,
Geoffrey
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[Sursound] Calrec CM4050 Surround Microphone SN: 502

[Geoffrey Barton]

On 13 Dec 2010, at 17:00, sursound-requ...@music.vt.edu wrote:
> 
> Message: 1
> Date: Sun, 12 Dec 2010 17:53:44 +
> From: Tim BC 
> Subject: [Sursound] Calrec CM4050 Surround Microphone SN: 502
> To: sursound@music.vt.edu
> Message-ID: <4d050c28.5000...@btopenworld.com>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> 
> I have been fortunate to be the steward of a Calrec CM4050 microphone 
> and related accessories for the last 18 months or so. Sadly I have not 
> been able to do much with it, partly due to a lack of adequate time and 
> partly due to a slight mistrust of the mains power supply. I am about to 
> return it to its rightful owner.
> 
> From its appearance and low serial number (502), I suspect that it is a 
> prototype particularly as the pre-amp is covered in handwritten notes on 
> masking tape and the connectors are RCA phonos and TS 6.35mm jacks. The 
> connector on the base of the microphone is a 6-pin male XLR. The 
> connecting lead is a 6-pin XLR-F to four TS 6.35mm jacks and is about 
> 1m80 long. This lead is connected to a pre-amp with coarse and fine gain 
> switches and then to what would appear to be an A-format to B-format 
> converter, the outputs of which appear on 2 sets of 4 RCA phono sockets 
> marked NOPQ. I have not had the courage to open the cases to investigate 
> their contents. The mic-preamp is mains powered and I suspect provides 
> the polarisation voltage for the capsules. The A/B converter appears to 
> be passive.

I think what you are describing is a MKII SFM, as 504,505 and 506 were MKII 
development mics we used on the Ambisonics project at Reading Univ in the late 
1970s. The 6 pin xlr is four capsule feeds,50v phantom and gnd. 

regards,
Geoffrey
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Re: [Sursound] Early tetrahedral experiments

[Geoffrey Barton]

On 5 Dec 2010, at 17:00, sursound-requ...@music.vt.edu wrote:
> 
> - Original Message 
> From: John Leonard 
> To: Surround Sound discussion group 
> Sent: Sat, December 4, 2010 6:35:30 AM
> Subject: Re: [Sursound] Early tetrahedral experiments
> 
> More importantly, are there competing bidders on this list? If someone want 
> to 
> get hold of this for historical reasons rather than as a personal possession, 
> care needs to be taken that list members don't force the price up between 
> them 
> by constantly counter-bidding. If no-one else is interested, I may consider 
> bidding with a view to finding a way for this to be preserved somehow. It's a 
> shame that the plexiglass clamp isn't part of the sale, but I'm sure one 
> could 
> be fabricated.
> 
> My concern is that many on this list are at academic institutions and may 
> take a 
> break from their email over the weekend.
> 
> Anyway, I'll keep an eye on the auction and see how it progresses. If the 
> price 
> goes past my limit, which it's not far off now, I'm afraid it'll go elsewhere.
> 
> Regards,
> 
> John

As far as I was aware, the only example of this SFM version (a very early one) 
was at Peter Fellgett's house and I was hoping this and other Ambisonics 
memorabilia would eventually find a place in a museum somewhere. I have 
contacted his family to ask if they still have this array. I certainly never 
saw it dismantled and separate from the perspex collar as it is in the photo, 
so maybe it is a different one. Apart from PBF's family, I cannot think who can 
have it legitimately, unless Calrec had one (if so I never saw it in Hebden 
Bridge).

regds,
Geoffrey
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