Re: [Sursound] Core Sound Announces OctoMic - First 2nd-orderAmbisonics Microphone

[Fernando Lopez-Lezcano]

On 03/28/2018 04:23 AM, Len Moskowitz wrote:

Stefan Schreiber wrote:


At first sight I could not tell anything about the difference between
an OctaThingy and Octomic capsule mount.



Even not at second...

Could you give me/us  some hint?


Eric's OctaThingy is based on a tetragonal trapezohedron.
OctoMic is not. It's based on another geometric solid.


Which one exactly?


The angles are different.


I presume you mean the elevation angles, right? I don't think Eric's 
paper includes the actual elevation angle he used for his design. What 
is the elevation angle in the Octomic?


Aaron (Heller) did 3D print some Octathingy arrays and his code 
(https://bitbucket.org/ajheller/mic-arrays/, predates mine) uses 
atan(sqrt(1/2)) for the elevation (same as a tetrahedral microphone).


Eric writes that the design is based on the tetragonal trapezohedron, 
but I always found it easier to visualize it using its dual, the square 
antiprism (with the capsules mounted in its vertices):


https://en.wikipedia.org/wiki/Square_antiprism

Changing the side triangles from equilateral to isosceles (ie: 
stretching it vertically) creates a family of shapes, most interesting 
among them would be the equilateral square antiprism (equal angles 
between capsules) and the one where the vertical elevation angles match 
the ones of a tetrahedral design. I always had both choices in my 3d 
models, but others are possible. Different vertical elevation angles 
will optimize the array differently, but the underlying geometric solid 
is the same.


-- Fernando

PS: I first asked about what could be done with eight capsules in July 2015:

On 07/24/2015 09:34 AM, Aaron Heller wrote:

If you want to try something, there's what we've been calling "the octathingy". 
  Four capsules up, four down, with the down facing ones rotated 45 degrees.  See 
attached photos.


I 3d printed my first "proof of concept" in November 2015 (see picture) 
but it took a long time to get a full working prototype (I did the 
tetrahedral design first). Always working on too many projects... :-)

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Re: [Sursound] Core Sound Announces OctoMic - First 2nd-orderAmbisonics Microphone

[umashankar manthravadi]

I was showing off a second order brahma microphone at the AES los angeles in 
2016, I had two versions (I think I took only one) one is a standard octagon, 
the other was an octagon with the top half rotated 45 degrees, which looks 
remarkably like Eric Benjamin’s Octathingy. Both used 14 mm capsules. I have 
since  built two other designs. One is a tetrahedron surround by a ring of 
four, and the other similar, but the ring is tangential capsules. I will 
probably end up using only the octathingy style. But in the meantime, I have 
been seduced by all digital MEMs based second order microphone outputting 
directly to USB. MEMs are Omni, so I am flush mounting them on a polished 
acrylic sphere 1.5 cm radius. I will post photographs on my facebook Brahma 
page soon.



By the way I visualize the octathingy as two tetrahedron superposed, one 
rotated 180 degrees.



umashankar







Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=550986> for Windows 10




From: Sursound  on behalf of Len Moskowitz 

Sent: Wednesday, March 28, 2018 4:53:15 PM
To: Stefan Schreiber
Cc: Sursound List
Subject: Re: [Sursound] Core Sound Announces OctoMic - First 
2nd-orderAmbisonics Microphone

Stefan Schreiber wrote:

> At first sight I could not tell anything about the difference between
> an OctaThingy and Octomic capsule mount.


> Even not at second...


>
> Could you give me/us  some hint?
Eric's OctaThingy is based on a tetragonal trapezohedron.
OctoMic is not. It's based on another geometric solid. The angles are
different.

Len Moskowitz (mosko...@core-sound.com)
Core Sound LLC
www.core-sound.com<http://www.core-sound.com>
Home of TetraMic and OctoMic
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Re: [Sursound] Core Sound Announces OctoMic - First 2nd-orderAmbisonics Microphone

[Len Moskowitz]

Stefan Schreiber wrote:

At first sight I could not tell anything about the difference between 
an OctaThingy and Octomic capsule mount.




Even not at second...      





Could you give me/us  some hint?

Eric's OctaThingy is based on a tetragonal trapezohedron.
OctoMic is not. It's based on another geometric solid. The angles are 
different.


Len Moskowitz (mosko...@core-sound.com)
Core Sound LLC
www.core-sound.com
Home of TetraMic and OctoMic
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Re: [Sursound] Core Sound Announces OctoMic - First 2nd-orderAmbisonics Microphone

[Stefan Schreiber]

Citando Len Moskowitz :


Ambisonic guru Eric Benjamin wrote:

I'd like to point out that I am the inventor of the second order  
microphone array called by Core-Sound the Octomic. I published the  
design six years ago at the 133rd AES Convention in preprint 8728.


Actually, we're not using Eric's OctaThingy capsule mount design.


https://ccrma.stanford.edu/~nando/publications/sphear.pdf

Fig. 5, second mike

At first sight I could not tell anything about the difference between  
an OctaThingy and Octomic capsule mount.


Even not at second...      🤔

Could you give me/us  some hint?

Best,

Stefan

We (Fons and I) came up with OctoMic's geometry independently. It  
has slightly different angles than Eric's OctoThingy. It's based on  
a different geometric solid.


still not clear...

After we designed OctoMic's capsule mount, I happened across Eric's  
AES paper, and was pleased that we came up with something that might  
be as good.




 There are very few great minds in the ambisonic world - Eric is one of them.





 Len Moskowitz (mosko...@core-sound.com)

 Core Sound LLC

 www.core-sound.com[1]

 Home of TetraMic and OctoMic



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Re: [Sursound] Core Sound Announces OctoMic - First 2nd-orderAmbisonics Microphone

[Len Moskowitz]

Ambisonic guru Eric Benjamin wrote:

I'd like to point out that I am the inventor of the second order 
microphone array called by Core-Sound the Octomic. I published the 
design six years ago at the 133rd AES Convention in preprint 8728.


Actually, we're not using Eric's OctaThingy capsule mount design.

We (Fons and I) came up with OctoMic's geometry independently. It has 
slightly different angles than Eric's OctoThingy. It's based on a 
different geometric solid.


After we designed OctoMic's capsule mount, I happened across Eric's AES 
paper, and was pleased that we came up with something that might be as 
good.


There are very few great minds in the ambisonic world - Eric is one of 
them.



Len Moskowitz (mosko...@core-sound.com)
Core Sound LLC
www.core-sound.com
Home of TetraMic and OctoMic

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Re: [Sursound] Core Sound Announces OctoMic - First 2nd-orderAmbisonics Microphone

[Fernando Lopez-Lezcano]

On 03/27/2018 12:58 PM, Eric Benjamin wrote:

I’d like to point out that I am the inventor of the second order microphone 
array called by Core-Sound the Octomic. I published the design six years ago at 
the 133rd AES Convention in preprint 8728. I purposefully did not patent the 
invention to allow entrepreneurs to use the design.  But I would like a little 
bit of credit! I realize that Core Sound put in significant effort in making 
their product.


Yes! And the "Octathingy", which is part of the SpHEAR[*] project, is 
also a physical realization of Eric's eight capsule design (thanks and 
kudos!).


Two of them are already functional, the first one since 6/2017 (lowres 
picture attached), and the current encoder (which is generated Faust 
code) outputs WXYZSTUV.



I made the microphone utilize only eight channels because I only can record 
eight channels.


That was the attraction of the design for me as well. I have been using 
it with a Zoom F8.


Thanks again, Eric!
-- Fernando

[*] https://cm-gitlab.stanford.edu/ambisonics/SpHEAR/



From: Jörn Nettingsmeier
Sent: Tuesday, March 27, 2018 12:09 PM
To: sursound@music.vt.edu
Subject: Re: [Sursound] Core Sound Announces OctoMic - First 
2nd-orderAmbisonics Microphone

On 03/27/2018 03:59 PM, Len Moskowitz wrote:

core-sound.com/OctoMic/1.php


Sweet! A resounding "me too" to Stefan's question about the matrix,
since you're one channel short :)
Looking at the geometry, I guess you sacrificed the second-order
rotationally symmetric component (FuMa R or ACN 08), which seems to be a
good choice to me.

What's that disclaimer about third-party PPAs? I mean, your PPA seems to
be an integral part of the mic, given that it produces unbalanced
signals. Is there any other magic going on there?

I wonder if you can get ZOOM to include an octomic firmware in the F8
eventually, as Sennheiser did with their Ambeo mic, that one's mighty
handy. (Not that I'm holding my breath, I wouldn't be surprised if there
were some exclusive deals at play...)

Can I assume that there is an updated version of TetraProc for the
followers of the penguin?

And looking at the shop, I don't see the Rycote lyre listed yet - is it
a generic one that can be had from them, or something custom-made and
not quite ready yet?

I'm trying to come up with a good business case to order one asap, and
since I'm good at fooling myself, it might just happen :-D


All best,


Jörn





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Re: [Sursound] Core Sound Announces OctoMic - First 2nd-orderAmbisonics Microphone

[Stefan Schreiber]

https://cm-gitlab.stanford.edu/ambisonics/SpHEAR/

"3D models

The 3D models currently include the TinySpHEAR, a four capsule first  
order Ambisonics microphone, the Octathingy, an eight capsule second  
order design by Eric Benjamin and Aaron Heller and preliminary designs  
for 12 and 20 capsule designs (the BigSpHEAR_12 and BigSpHEAR_20  
models). The models will be expanded as testing proceeds."


So let's not forget to mention your colleague Aaron (Heller), too?

Best,

Stefan

P.S.: I would see the Octathingy as reduced "Platonic body" design.

This doesn't mean it could not be an invention. Even then the  
spherical array microphone has been invented before. The invention  
would be to design a microphone for order 1.x?


I am just speculating, because there has to be some specific feature  
to be claimed. 


-

Citando Eric Benjamin :

I’d like to point out that I am the inventor of the second order  
microphone array called by Core-Sound the Octomic. I published the  
design six years ago at the 133rd AES Convention in preprint 8728. I  
purposefully did not patent the invention to allow entrepreneurs to  
use the design.  But I would like a little bit of credit! I realize  
that Core Sound put in significant effort in making their product.




 I made the microphone utilize only eight channels because I only  
can record eight channels.




 Eric Benjamin



 From: Jörn Nettingsmeier

 Sent: Tuesday, March 27, 2018 12:09 PM

 To: sursound@music.vt.edu

 Subject: Re: [Sursound] Core Sound Announces OctoMic - First  
2nd-orderAmbisonics Microphone




 On 03/27/2018 03:59 PM, Len Moskowitz wrote:


core-sound.com/OctoMic/1.php[1]


Sweet! A resounding "me too" to Stefan's question about the matrix,

 since you're one channel short :)

 Looking at the geometry, I guess you sacrificed the second-order

 rotationally symmetric component (FuMa R or ACN 08), which seems to be a

 good choice to me.



 What's that disclaimer about third-party PPAs? I mean, your PPA seems to

 be an integral part of the mic, given that it produces unbalanced

 signals. Is there any other magic going on there?



 I wonder if you can get ZOOM to include an octomic firmware in the F8

 eventually, as Sennheiser did with their Ambeo mic, that one's mighty

 handy. (Not that I'm holding my breath, I wouldn't be surprised if there

 were some exclusive deals at play...)



 Can I assume that there is an updated version of TetraProc for the

 followers of the penguin?



 And looking at the shop, I don't see the Rycote lyre listed yet - is it

 a generic one that can be had from them, or something custom-made and

 not quite ready yet?



 I'm trying to come up with a good business case to order one asap, and

 since I'm good at fooling myself, it might just happen :-D





 All best,





 Jörn









 --

 Jörn Nettingsmeier

 Tuinbouwstraat 180, 1097 ZB Amsterdam, Nederland

 Tel. +49 177 7937487



 Meister für Veranstaltungstechnik (Bühne/Studio), Tonmeister VDT

 http://stackingdwarves.net

 ___

 Sursound mailing list

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Re: [Sursound] Core Sound Announces OctoMic - First 2nd-orderAmbisonics Microphone

[Fons Adriaensen]

On Tue, Mar 27, 2018 at 12:58:08PM -0700, Eric Benjamin wrote:

> I’d like to point out that I am the inventor of the second order microphone
> array called by Core-Sound the Octomic. I published the design six years
> ago at the 133rd AES Convention in preprint 8728.

That is absolutely true. That preprint is indeed the first published description
and analysis of the capsule geometry as used by the OctoMic.

Ciao,

-- 
FA



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Re: [Sursound] Core Sound Announces OctoMic - First 2nd-orderAmbisonics Microphone

[Eric Benjamin]

I’d like to point out that I am the inventor of the second order microphone 
array called by Core-Sound the Octomic. I published the design six years ago at 
the 133rd AES Convention in preprint 8728. I purposefully did not patent the 
invention to allow entrepreneurs to use the design.  But I would like a little 
bit of credit! I realize that Core Sound put in significant effort in making 
their product.

I made the microphone utilize only eight channels because I only can record 
eight channels.

Eric Benjamin

From: Jörn Nettingsmeier
Sent: Tuesday, March 27, 2018 12:09 PM
To: sursound@music.vt.edu
Subject: Re: [Sursound] Core Sound Announces OctoMic - First 
2nd-orderAmbisonics Microphone

On 03/27/2018 03:59 PM, Len Moskowitz wrote:
> core-sound.com/OctoMic/1.php

Sweet! A resounding "me too" to Stefan's question about the matrix, 
since you're one channel short :)
Looking at the geometry, I guess you sacrificed the second-order 
rotationally symmetric component (FuMa R or ACN 08), which seems to be a 
good choice to me.

What's that disclaimer about third-party PPAs? I mean, your PPA seems to 
be an integral part of the mic, given that it produces unbalanced 
signals. Is there any other magic going on there?

I wonder if you can get ZOOM to include an octomic firmware in the F8 
eventually, as Sennheiser did with their Ambeo mic, that one's mighty 
handy. (Not that I'm holding my breath, I wouldn't be surprised if there 
were some exclusive deals at play...)

Can I assume that there is an updated version of TetraProc for the 
followers of the penguin?

And looking at the shop, I don't see the Rycote lyre listed yet - is it 
a generic one that can be had from them, or something custom-made and 
not quite ready yet?

I'm trying to come up with a good business case to order one asap, and 
since I'm good at fooling myself, it might just happen :-D


All best,


Jörn




-- 
Jörn Nettingsmeier
Tuinbouwstraat 180, 1097 ZB Amsterdam, Nederland
Tel. +49 177 7937487

Meister für Veranstaltungstechnik (Bühne/Studio), Tonmeister VDT
http://stackingdwarves.net
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