ezkcdude Wrote:
Do you know how polarity is being switched internally, and what
component are you talking about? Maybe it's not the polarity itself
that you hear, but some extra circuitry that does the inversion.
Most high-end equipment, with the exception of valve gear, preserves
correct
P Floding Wrote:
I'm polarity switching my sound (via remote) as I type this, and there
is no question in my mind that the change is very audible (in my
system).
Hi P Floding, I'm going to try to explain why there is such skepticism
about this. Perhaps what I'm saying here is obvious to
opaqueice Wrote:
Hi P Floding, I'm going to try to explain why there is such skepticism
about this. Perhaps what I'm saying here is obvious to you - if so I'm
sorry - but it's become clear to me in this discussion that there's a
basic lack of communication here, so maybe this will help.
ezkcdude Wrote:
Do you know how polarity is being switched internally, and what
component are you talking about? Maybe it's not the polarity itself
that you hear, but some extra circuitry that does the inversion.
ok, I think I understand what you are asking now!
In this particular case the
Yeah, that's what I was getting at. I am assuming you do hear a
difference, and I just don't buy the fact that it is really only the
absolute polarity that has changed. So, just to get this straight, it
is your Tact preamp that inverts the polarity?
--
ezkcdude
SB3-Derek Shek TDA1543/CS8412
tom permutt Wrote:
If there is really much interest in this, I will write the software and
collect, analyze and report results from several listeners.
I would be happy to volunteer as a listener.
If we did this, it would be interesting to include some artificially
generated sound files
P Floding Wrote:
I would love to establish facts, but I also know how big an effort that
would be.
Why is it a big effort? If there is a button for that on your remote,
with the help of a friend you could check this is literally ten
minutes. Or even without the help of a friend, if it
I would go with changing the polarity of the wav/flac file, because then
at least you rule out hardware issues anywhere downstream.
--
ezkcdude
SB3-Derek Shek TDA1543/CS8412 NOS DAC-MIT Terminator 2
interconnects-Endler Audio 24-step Attenuators (RCA-direct)-Parasound
Halo A23 125W/ch
I've two observations to contribute:
1) I remember a demo by Linn in the mid 80's where they reversed the
polarity of the speaker cables to demonstrate the effect on perception
of surface noise from vinyl. I had to agree it made a noticeable
difference to how bad the pops and clicks sounded. It
opaqueice Wrote:
Why is it a big effort? If there is a button for that on your remote,
with the help of a friend you could check this is literally ten
minutes. Or even without the help of a friend, if it turns out
pressing the button many times fast produces a random result. You've
spent
tom permutt Wrote:
Unlike most of the mysteries of the audio universe, this one can be
tested by anyone with a SqueezeBox and a computer, without additional
equipment, without a helper, and without the possibility of confounding
by extra switches and wires in the signal path.
Take a WAV
Actually this is rather interesting. IF absolute phase is audible on
normal music, there must be a reason that is to do with something in
the replay chain. I don't believe that it is an empirical constant,
simply because there is no correct absolute phase on 99.99% of
recordings. So, if it's
Phil Leigh Wrote:
I've two observations to contribute:
1) I remember a demo by Linn in the mid 80's where they reversed the
polarity of the speaker cables to demonstrate the effect on perception
of surface noise from vinyl. I had to agree it made a noticeable
difference to how bad the
opaqueice Wrote:
I think this could be simulated easily with a WAV file editor - wouldn't
that just be adding a constant level to every sample? You would want to
first rescale the levels with an overall multiplier to avoid clipping.
However just because there's a DC offset, there isn't
My point is that the speaker is designed and engineered to be operating
symmetrically about its mid-point. (imagine a car that always pulls to
the left - it's harder to drive...OK that might be a rubbish analogy).
The point is that a speaker in a cabinet which has a resistive loading
(air in
Another thought - which I can't test for myself - is that electrostatics
might be less sensitive to absolute phase effects given the bipolar
nature of their construction?
--
Phil Leigh
Phil Leigh's Profile:
P Floding Wrote:
Good power amps either block DC at the input using a capacitor, or have
a DC servo (better) that removes any DC component of the signal.
Assuming that speakers are as good as you assume seems like one
assumption too far. The whole point was that it was a possible
Just to be clear - I can't hear the absolute phase switch on my system
today - but I did hear the pops and clicks thing on vinyl...
I'd like some example CD's where a clear difference can be heard and a
description of what the difference sound like so I can experiment
further.
--
Phil Leigh
Phil Leigh Wrote:
I'd like some pointers to example reference CD's where a clear
difference can be heard and a description of what the differences sound
like so I can experiment further.
I saw a reference somewhere to a test CD with some asymmetric test
tones which supposedly displayed
opaqueice Wrote:
And from Dr Floyd Toole:
It turns out that, within very generous tolerances, humans are
insensitive to phase shifts. Under carefully contrived circumstances,
special signals auditioned in anechoic conditions, or through
headphones, people have heard slight differences.
P Floding Wrote:
Phase shift?
I believe we are talking about phase REVERSAL now. Not time shift (same
as phase shift).
Anyway, MANY people claim to hear vast improvements when phase
linearity is established (I have never had that pleasure myself).
I thought we went over that before. A
Phil Leigh Wrote:
Just to be clear - I can't hear the absolute phase switch on my system
today - but I did hear the pops and clicks thing on vinyl...
I'd like some pointers to example reference CD's where a clear
difference can be heard and a description of what the differences sound
P Floding Wrote:
That is not really a valid thought-experiment.
The skin of the bass drum is not a window into all sound you hear. Not
from the band, and not even from that particular drum.
Except there's no way it's possible to hear this absolute phase except
(maybe) for very low
opaqueice Wrote:
Except there's no way it's possible to hear this absolute phase except
(maybe) for very low frequency sounds like a bass drum. The more I
think about this the more silly this seems. Even if you could hear the
difference it won't have anything to do with the original sound.
P Floding Wrote:
I found this, which seems a good start:
http://www.audioauctionhouse.co.uk/acoustic_polarity.htm
From that article:
There you have it, ladies and gentlemen. No one who performed these
experiments ever seems to have evaluated the audibility of reversal of
direction
opaqueice Wrote:
From that article:
Sorry, but this guy is a total nutjob...
It seems to have escaped you that the guy contradicting him was equaly
convinced about wire directionality, as are many others in the high-end
industry. I agree, however, that particular guy wasn't the most
P Floding Wrote:
It seems to have escaped you that the guy contradicting him was equaly
convinced about wire directionality, as are many others in the high-end
industry.
Actually, what amazed me (and caused me to stop reading) was that they
agreed on that...
In any case, this demonstrates
P Floding Wrote:
It seems to have escaped you that the guy contradicting him was equaly
convinced about wire directionality, as are many others in the high-end
industry. I agree, however, that particular guy wasn't the most
well-rounded character (most free-thinkers seem to be a bit
opaqueice Wrote:
Actually, what amazed me (and caused me to stop reading) was that they
agreed on that...
In any case, this demonstrates rather nicely that not only are absolute
phases inaudible in music, so are _relative_ phases, which one might
have expected to actually matter (note
No, of course, that's true. The point is that the vibrations traveling
through air are tiny (in water even moreso), and even though we can
hear them because our ears are very sensitive, the change in absolute
pressure is very small. The change in pressure you make by waving your
hand in front of
ezkcdude Wrote:
No, of course, that's true. The point is that the vibrations traveling
through air are tiny (in water even moreso), and even though we can
hear them because our ears are very sensitive, the change in absolute
pressure is very small. The change in pressure you make by waving
I happen to agree with this last post from PF. However, aside from a
simple bass drum and the infamous garage door slam, you'll never hear
the effect in practice, because aside from these sort of sounds with a
distinctly directional 0Hz or DC initial transient impulse
everything else to do with
Phil Leigh Wrote:
I happen to agree with this last post from PF. However, aside from a
simple bass drum and the infamous garage door slam, you'll never hear
the effect in practice, because aside from these sort of sounds with a
distinctly directional 0Hz or DC initial transient impulse
Aren't inverting op amps mostly to blame for reversing polarity?
--
ezkcdude
SB3-Derek Shek TDA1543/CS8412 NOS DAC-MIT Terminator 2
interconnects-Endler Audio 24-step Attenuators (RCA-direct)-Parasound
Halo A23 125W/ch amplifier-Speltz anti-cables-DIY 2-ways + Dayton
Titanic 10 subwoofer
ezkcdude wrote:
Aren't inverting op amps mostly to blame for reversing polarity?
Only in badly designed circuits.
One would usually use them in pairs to preserve polarity.
R.
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audiophiles mailing list
audiophiles@lists.slimdevices.com
P Floding Wrote:
I don't think any RCL circuit will actually invert any signal.. (Again I
think time delay is being confused with polarity inversion. The fact
that time delay is measured in degrees at a certain frequency seems to
be the reason for this confusion.)
I'm not sure anyone is
You know, the gravitational field of the moon and planets in our solar
system act on the earth's atmosphere. The effect is similar to tides:
if a planet is directly over our heads the atmosphere will be slightly
less dense than if it is off to the side. When the atmospheric
pressure is lower,
opaqueice Wrote:
I'm not sure anyone is confused by this, except possibly you. It's not
a coincidence that time delays are measured in degrees - it's usually
much more convenient to use that notation. Polarity inversion, as you
call it, is simply a 180 degree phase shift across all
opaqueice Wrote:
You know, the gravitational field of the moon and planets in our solar
system act on the earth's atmosphere. The effect is similar to tides:
if a planet is directly over our heads the atmosphere will be slightly
less dense than if it is off to the side. When the
P Floding Wrote:
Why don't you just leave the Audiophile forum alone, instead of
trolling? I don't think you or anyone else here has the right to try to
restrict the scope of the idéas discussed here.
That was intended as a joke... I was only trying to insert a little
humor into the
opaqueice Wrote:
That was intended as a joke... I was only trying to insert a little
humor into the discussion. I sincerely apologize if it offended you.
Yeah, I'm starting to understand that :-). Meanwhile, I at least have
learned a lot from parts of this discussion, and thanks to
P Floding Wrote:
Apology accepted.
Anything can be joked about -but these kind of jokes are wearing a
little thin nowdays -especially when coming from a sceptic after a long
exchange. I'm usually fairly patient, and if anyone has even a glimmer
of a doubt about the measurement is king
I'm so confused... by absolute phase reversal, you mean multiplying the
analogue waveform on both channels by -1, is that right? In other words
the same thing as reversing both speaker cables?
If so, what could account for an audible difference? Can the speaker
cone response be somehow
yes that's right - same as reversing the speaker cables. There was a
theory that we could detect the phase polarity of the initial transient
(ie when you hit a bass drum, the skin moves out first then in as it
springs back - and that the speaker cone should move the same way so
that the initial
Phil Leigh Wrote:
yes that's right - same as reversing the speaker cables. There was a
theory that we could detect the phase polarity of the initial transient
(ie when you hit a bass drum, the skin moves out first then in as it
springs back - and that the speaker cone should move the same
opaqueice Wrote:
So I would guess that relative phases between different frequencies get
totally messed up - is that wrong for some reason? If it's right, why
do people worry about phases introduced by equalizers?
Capacitors have frequency dependent phase response. That's why you
don't want
opaqueice Wrote:
Wow - I never cease to be amazed by audiophiles
It seems to me before you should worry about that, you should first
build an exact replica of the room the music was recorded in, with a
speaker with a perfectly flat response in the exact position of every
sound
Now, just for the sake of completeness, I would like to note that there
is one factor that has not been brought up here, and that is the
following: If there is some amount of DC offset in the signal. I
imagine that is a possibility, and most likely, there is always some DC
offset. If the speaker
well DC offset at the output stage could introduce a non-linearity
because the electrical and mechanical null-crossing points are
different...
You really don't want noticeable (ie more than a few tens of millivots)
of DC across your speaker coils.
--
Phil Leigh
Phil Leigh Wrote:
Chortle, chortle - so some people still think there is anything more
than a 50% chance that absolute phase was preserved through the
recording/manufacturing chain?
There's a hell of a lot of outboard studio gear (and desks) that are
inverting...
I possess 1 CD (out of
opaqueice wrote:
So I would guess that relative phases between different frequencies get
totally messed up - is that wrong for some reason? If it's right, why
do people worry about phases introduced by equalizers?
Equalizers typically totally mangle frequency dependant phase.
Really, really
pfarrell Wrote:
I've seen people argue that the first half cycle of a bass drum kick
should come towards the listener to be correct unless you want
it to sound like it does to the drummer.
To me, that argument only makes sense if you think you can hear direct
current. Last I heard, *sound*
ezkcdude Wrote:
You can't hear phase.
I think I agree it's very unlikely you could hear an absolute phase in
music. But is it totally obvious you can never hear it?
Imagine the following - suppose someone increases the air pressure in
the room you're in, then decreases it. Clearly you
pfarrell Wrote:
Equalizers typically totally mangle frequency dependant phase.
Really, really expensive ones do less damage than affordable ones.
Yeah - certainly the simplest equalizer I can think of (a bunch of RLC
band pass filters) will totally destroy the phases.
[QOUTE]
I believe
pfarrell Wrote:
I've seen people argue that the first half cycle of a bass drum kick
should come towards the listener to be correct unless you want
it to sound like it does to the drummer.
Even if this _is_ possible to hear, who cares? As I said before - if
you went to a live
opaqueice wrote:
Yeah - certainly the simplest equalizer I can think of (a bunch of RLC
band pass filters) will totally destroy the phases.
Right, and even fancy parametric eqs are just combinations of RLC nets.
I'm happy to accept that, but I'm asking why don't all the other elements
in
pfarrell Wrote:
I'm not following you here,
Any sound is a pressure wave. The first half cycle of a wave is going
to
cause the speaker cone to move either towards you or away from you.
The
second half cycle will, naturally, move it the other way. For a 40Hz
signal, it moves towards
ezkcdude Wrote:
You just made my point for me. You can't hear 0 Hz!
I think you're missing his point here, ekzdude - I think this is _not_
impossible in principle (although maybe in practice). See my earlier
post about pressure.
--
opaqueice
pfarrell Wrote:
You bet. That is why there is a whole branch of audiophiles who are
into
single speaker systems, i.e. http://www.lowtherloudspeakers.co.uk/
And I believe that is why quads and electrostatics sound so good to my
ears -- no crossover.
OK, that's interesting.
One of
opaqueice Wrote:
You're saying if the frequency response is flat, so is the phase
response is that the case? That would answer my question.
Frequency response can mean Amplitude vs. Frequency or Phase vs.
Frequency. One does not necessarily imply the other.
--
ezkcdude
SB3-Derek
opaqueice Wrote:
I think you're missing his point here, ekzdude - I think this is _not_
impossible in principle (although maybe in practice). See my earlier
post about pressure.
So, are we talking about listening to music or fanning ourselves (in
one direction) with our speakers?
...
Geez,
ezkcdude Wrote:
Frequency response can mean Amplitude vs. Frequency or Phase vs.
Frequency. One does not necessarily imply the other.
That's what I was asking - whether flat amplitude vs. frequency implies
flat phase vs. frequency. Before I was thinking the answer is no, but
now I'm confused
opaqueice Wrote:
That's what I was asking - whether flat amplitude vs. frequency implies
flat phase vs. frequency. Before I was thinking the answer is no, but
now I'm confused by pfarrells response.
:-). Fair enough!
Do yourself a favor, and pick up The Art of Electronics. It's not
ezkcdude Wrote:
Do yourself a favor, and pick up The Art of Electronics. It's not
about audio per se, but I guarantee it will make you think more
rationally about all that is audiophilia.
I already have a copy, thanks - and have for about 15 years :-).
--
opaqueice
This is very informative:
http://www.ethanwiner.com/phase.html
First, to answer my earlier question: flat amplitude-frequency response
does NOT mean flat phase-frequency reponse; see the section titled TIME
OFFSET AUDIBILITY.
Second, phase changes by themselves are _not_ audible, according
ezkcdude Wrote:
Frequency response can mean Amplitude vs. Frequency or Phase vs.
Frequency. One does not necessarily imply the other.
I thought I had answered that already.
--
ezkcdude
SB3-Derek Shek TDA1543/CS8412 NOS DAC-MIT Terminator 2
interconnects-Endler Audio 24-step Attenuators
a - this started off as a nice little discussion about absolute
phase and its significance in modern society and now its got all
technical...
passive x-overs in speakers will mess up phase response big time whilst
trying to correct frequency/amplitude response. This is ONE of the
reasons
opaqueice Wrote:
Even if this _is_ possible to hear, who cares? As I said before - if
you went to a live performance and the drummer had his bass drum turned
around, would the sound quality be worse? I think that shows how
ludicrous the idea that reversing polarity can improve sound
To my ears 6.2.2 and its included firmware restores the SB to its former
glory, gets rid of the tinny highlights and allowd me to start using
ReplayGain ahead...
So for me, this is the 'approved firmware' - anyone else agree?
--
bossanova808
Whichever change it was that made the volume scale better is where I
liked it. Past then, I haven't heard any difference at all soundwise
in firmware... but the rescaling of volume made a huge difference.
--
snarlydwarf
I wouldn't, the networking in 35 is much improved over 28. I found that
the SB interface was much snappier and tended not to skip when
navigating. Oh, and there's the new VUs :-)
--
Morbo
Morbo's Profile:
Actually, the version most identified as the preferred for audiophile
use is 15! If you go to either audiocircle or audioholics and check the
SB threads you'll find a number of them that say 15 is still better than
28. I haven't done a test yet, but I wonder how far back you can go
before the FW
I think it's silly to run with firmware 15.
--
dwc
dwc's Profile: http://forums.slimdevices.com/member.php?userid=1892
View this thread: http://forums.slimdevices.com/showthread.php?t=22118
tonyptony Wrote:
Actually, the version most identified as the preferred for audiophile
use is 15! If you go to either audiocircle or audioholics and check the
SB threads you'll find a number of them that say 15 is still better than
28. I haven't done a test yet, but I wonder how far back you
I'm not sure about this, but I think the attraction of v15 is because it
reversed absolute phase. Now some of you may pooh-pooh the absolute
phase issue but in my experience people can have quite different levels
of tolerance to phase anomolies, and it is important to some. And the
reason why
Jenks Wrote:
I'm not sure about this, but I think the attraction of v15 is because it
reversed absolute phase. Now some of you may pooh-pooh the absolute
phase issue but in my experience people can have quite different levels
of tolerance to phase anomolies, and it is important to some.
My ears are a kind of pinky colour, but current 6.2.2 and 6.5b1
nightlies are good. IIRC the released 6.2.1, isn't.
--
Patrick Dixon
www.at-tunes.co.uk
Patrick Dixon's Profile:
Patrick Dixon Wrote:
My ears are a kind of pinky colour
haha Patrick. I'd vote for a receent 6.2.2 release, and I'm running fw
28 and it sounds fine.
--
dwc
dwc's Profile:
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