[Alex]

A thread about phase alignment reminded me of another question:
Does speaker connection polarity (+/-180 degrees of phase) make any
difference?

I remember in my young years we experimented and sort of came to a
conclusion that the correct phase is when the cones of the speakers suck in
with the first beat of a big drum. The sound was "deeper" this way. However,
the difference was marginal and barely perceplible. Personally I did not
hear any difference.

What is the modern take on that? Do manufacturers of the top-end CD players,
amplifiers and speakers specify their gear as "inverting" or non-inverting"?
(I believe they do not) Do the recording studios observe "polarity" from the
microphone to the digital values actually recorded on CDs? (Probably not)

Regards,
Alex

[Patrick Turner]

Alex wrote:

A thread about phase alignment reminded me of another question:
Does speaker connection polarity (+/-180 degrees of phase) make any
difference?

I remember in my young years we experimented and sort of came to a
conclusion that the correct phase is when the cones of the speakers suck in
with the first beat of a big drum. The sound was "deeper" this way. However,
the difference was marginal and barely perceplible. Personally I did not
hear any difference.

What is the modern take on that? Do manufacturers of the top-end CD players,
amplifiers and speakers specify their gear as "inverting" or non-inverting"?
(I believe they do not) Do the recording studios observe "polarity" from the
microphone to the digital values actually recorded on CDs? (Probably not)

Regards,
Alex

When a drum is beaten, the skin is forced down creating a suction wave.
Meanwhile a compression wave is created out the bottom of the drum.

The two waves sum together and the mic records the pressure changes then
the signal is processed in the studio gear and recorded onto CD maybe
and sent to the record cutting head amp to make an LP.

Its anyone's guess which way the initial drum bang is phased. In
amplifiers at home there may be several stages of amplification and
maybe the signal gets inverted or maybe not.

I don't know what importance is given to phase when recordings are made.

The initial bang of a drum consists of a large number of sine wave
harmonics which start together but with all rapidly decay in amplitiude.
Most people would not notice if all or some of these wave forms were
phased oppositely to others; we would merely groove along with the
obvious bang of a drum and all the more so if there is a suitable rythym
of drumming.

If we recorded an explosion then you'd expect to be hit by a blast of
blowing air rather than a sudden suction towards the source of the
explosion sound. A hand grenade let off in a living room will make a
hell of a bang which may rupture both your ear drums. It'd be impossible
to recreate the sound with a normal hi-fi sound system. Both sucks or
blows of serious magnitude would be perceived as awful noise. Music is
carefully arranged noise which is meant to have use muse, and be
delighted, and distracted from the world or work and troubles. I have
two 12" bass reflex drivers in reflex speakers capable of going down to
20Hz, and the Fb is about 30Hz, and just what phase reversals occur is
something I have either forgotten or never measured. At below about 40Hz
the sound comes from the port of the box. But In perceive the bass to be
quite excellent and very much like bass heard from bass instruments or
large drums. I just spent another pleasant evening listening to music at
a friend's place where he has a sub-woofer and bass speakers also
capable of going down to 25Hz. I built all the amps and speakers and the
sub and when I set up the sub position I wanted to get maximum flatness
of response at the listening chair and so we tried the sub in many
positions and with reversal of speaker leads at the sub amp to get the
best flat response with minimal peaking and troughing due to phase
adding and cancelations. The sub amp filter is has only 50 degrees of
phase shift at the -3dB point but then has a much increasing rate of
attenuation. Some filters might have a huge phase "turnover" at the -3dB
point, making the integration of sub and existing bass speakers very
hard to achive without unwanted peaks and troughs in the response.

I like bass I get with my two bass units which cover 20Hz to 250Hz with
perhaps a slight broad lump in the low bass response. Perhaps the drum
sound I get is better than what my friend has, but its hard to say
because our rooms are different. I've been to some loud rock music gigs
wearing ear plugs because ot the SPL and found my chest heaving with low
bass and the boom chucka boom. I never bothered to ask myself is my
chest being compressed at each drum beat or stretched; you just feel
pummelled by the sound anyway.

The transition reponse between bass and midrange and how the filter
crossovers are set up will affect the perceived transient sound quality.
Sometimes one has to reverse phase connect mids relative to bass, then
treble relative to mids, depending on the response. Its a very tricky
business to set up speaker drivers for minimal phase change and yet
achieve a smooth response through the crossover regions without a big
peaks each side of the crossover F or two or a big trough where each
driver tries to cancel the sound at the trough.

I think getting the smooth response with rapid cut offs at least
12dB/octave away from the Xover F is the most important thing to get
right.
This means a slightly over damped second order filter. Big old woofers
meant to be cut off at sat 250Hz may need much more steep filtering
beyound 500Hz lest the transients muddy the sound meant to be handled by
the smaller midrange driver.

Patrick Turner.

[Eeyore]

Alex wrote:

A thread about phase alignment reminded me of another question:
Does speaker connection polarity (+/-180 degrees of phase) make any
difference?

If you want some bass, it makes a spectacular difference.

Graham

[Eeyore]

Patrick Turner wrote:

Alex wrote:

A thread about phase alignment reminded me of another question:
Does speaker connection polarity (+/-180 degrees of phase) make any
difference?

I remember in my young years we experimented and sort of came to a
conclusion that the correct phase is when the cones of the speakers suck in
with the first beat of a big drum. The sound was "deeper" this way. However,
the difference was marginal and barely perceplible. Personally I did not
hear any difference.

What is the modern take on that? Do manufacturers of the top-end CD players,
amplifiers and speakers specify their gear as "inverting" or non-inverting"?
(I believe they do not) Do the recording studios observe "polarity" from the
microphone to the digital values actually recorded on CDs? (Probably not)

When a drum is beaten, the skin is forced down creating a suction wave.
Meanwhile a compression wave is created out the bottom of the drum.

The two waves sum together and the mic records the pressure changes then
the signal is processed in the studio gear and recorded onto CD maybe
and sent to the record cutting head amp to make an LP.

Its anyone's guess which way the initial drum bang is phased. In
amplifiers at home there may be several stages of amplification and
maybe the signal gets inverted or maybe not.

I don't know what importance is given to phase when recordings are made.

In the past very little probably but designers such as myself always strive to
keep all ins and outs on say a mixing desk in the same polarity ( phase is really
the wrong word ).

Apologies for my flippant response to my misunderstanding of your question
elsewhere.

I doubt even the CD standard has a polarity requirement.

Graham

[Staring at old audio chassis as a hobby :)]

On Apr 25, 4:59�pm, Eeyore
wrote:

Apologies for my flippant response to my misunderstanding of your question
elsewhere.


Hi RATs!

You're a better man than I am, Gunga Din.

Happy Ears!
Al


PS The relative phase of the listener's space to the original space is
something some folks study and expound on to display their dedication
to Truth, or Honesty or something. It may be possible to enjoy
listening to Music without such effort. Life is so unfair

We can only hope Death is more even handed ...

[Alex]

"Patrick Turner" wrote in message
...


Alex wrote:

A thread about phase alignment reminded me of another question:
Does speaker connection polarity (+/-180 degrees of phase) make any
difference?

I remember in my young years we experimented and sort of came to a
conclusion that the correct phase is when the cones of the speakers suck
in
with the first beat of a big drum. The sound was "deeper" this way.
However,
the difference was marginal and barely perceplible. Personally I did not
hear any difference.

What is the modern take on that? Do manufacturers of the top-end CD
players,
amplifiers and speakers specify their gear as "inverting" or
non-inverting"?
(I believe they do not) Do the recording studios observe "polarity" from
the
microphone to the digital values actually recorded on CDs? (Probably
not)

Regards,
Alex

When a drum is beaten, the skin is forced down creating a suction wave.
Meanwhile a compression wave is created out the bottom of the drum.

The two waves sum together and the mic records the pressure changes then
the signal is processed in the studio gear and recorded onto CD maybe
and sent to the record cutting head amp to make an LP.

That is how we set that experiment.
Firstly, we checked with an oscilloscope which polarity the first drum bang
signal wave was at the amplifier output.
Then we visually found out, using a DC voltage (battery cell) which polarity
corresponds to which direction of the speaker cone movement.
Then we inserted a 4-pole double throw relay to simultaneously reverse
connection polarity of both speakers from time to time. We also blocked
their ports off. As an indicator to the "expert audience" a lamp would light
up in case the relay is energised.
Then the "experts" (several uni students) were sitting listening to sseveral
passages of music with distinctive drums, trying to find any difference
between "Lamp on" and "lamp off" positions. The listeners did not know in
advance which position corresponded to which polarity, but only they knew
which position it was at any moment. The "experts" were making notes in
their notepads, voting for one or the other position for different pieces of
music.
Then their votes were counted. It turned out that there was a marginal
preference towards "cone pulled in on the firs bang" position. Personally I
did not perceive any difference.

Regards,
Alex

[Patrick Turner]

Alex wrote:

"Patrick Turner" wrote in message
...


Alex wrote:

A thread about phase alignment reminded me of another question:
Does speaker connection polarity (+/-180 degrees of phase) make any
difference?

I remember in my young years we experimented and sort of came to a
conclusion that the correct phase is when the cones of the speakers suck
in
with the first beat of a big drum. The sound was "deeper" this way.
However,
the difference was marginal and barely perceplible. Personally I did not
hear any difference.

What is the modern take on that? Do manufacturers of the top-end CD
players,
amplifiers and speakers specify their gear as "inverting" or
non-inverting"?
(I believe they do not) Do the recording studios observe "polarity" from
the
microphone to the digital values actually recorded on CDs? (Probably
not)

Regards,
Alex

When a drum is beaten, the skin is forced down creating a suction wave.
Meanwhile a compression wave is created out the bottom of the drum.

The two waves sum together and the mic records the pressure changes then
the signal is processed in the studio gear and recorded onto CD maybe
and sent to the record cutting head amp to make an LP.

That is how we set that experiment.
Firstly, we checked with an oscilloscope which polarity the first drum bang
signal wave was at the amplifier output.
Then we visually found out, using a DC voltage (battery cell) which polarity
corresponds to which direction of the speaker cone movement.
Then we inserted a 4-pole double throw relay to simultaneously reverse
connection polarity of both speakers from time to time. We also blocked
their ports off. As an indicator to the "expert audience" a lamp would light
up in case the relay is energised.
Then the "experts" (several uni students) were sitting listening to sseveral
passages of music with distinctive drums, trying to find any difference
between "Lamp on" and "lamp off" positions. The listeners did not know in
advance which position corresponded to which polarity, but only they knew
which position it was at any moment. The "experts" were making notes in
their notepads, voting for one or the other position for different pieces of
music.
Then their votes were counted. It turned out that there was a marginal
preference towards "cone pulled in on the firs bang" position. Personally I
did not perceive any difference.

Regards,
Alex

I recall reading an old 1970s Scientific American article about 14 years
ago and their conclusion was that human hearing is unable to detect the
phase of sound. However, nature evolved living creatures to have TWO
ears and TWO eyes probably because with twin sensors you could afford to
loose one and still survive. Not only that, with two hearing sensors
**the phase difference** at each ear allows critters to determine the
direction of the sound, and where their next feed is positioned, or
where a threat is located. Two eyes means stereo vision which is better
than mono vision. As the millions of years went by the ears and eyes got
better and encouraged the brain to develop.

But we have never needed to know exactly what the phase of a signal is
so nature didn't allow us that capability. Yet when we try to sing in
tune with music we know exactly when we are in tune, and "in phase" with
another singer or a piano.

Other critters hear a lot better than humans do.

Patrick Turner.

[Don Pearce[_3_]]

On Mon, 27 Apr 2009 14:56:47 GMT, Patrick Turner
wrote:

But we have never needed to know exactly what the phase of a signal is
so nature didn't allow us that capability. Yet when we try to sing in
tune with music we know exactly when we are in tune, and "in phase" with
another singer or a piano.

This is just wrong. Neither do we have the slightest idea of when we
are in phase with a musical instrument, but nor can we sing a steady
enough note to remain that way. Somewhere near the same note is the
best anybody can do.

And what phase would we synchronize with anyway? A piano tuner offsets
the tuning of the triples slightly to fatten the sound, which means
that the net phase of the note is sliding around as it decays.

No, we have no phase perception - the only way we can get to it is by
the indirect method of hearing an amplitude variation when two signals
at the same frequency reinforce or cancel each other.

d

[Dave]

Eeyore wrote:

Patrick Turner wrote:

Alex wrote:
A thread about phase alignment reminded me of another question:
Does speaker connection polarity (+/-180 degrees of phase) make any
difference?

I remember in my young years we experimented and sort of came to a
conclusion that the correct phase is when the cones of the speakers suck in
with the first beat of a big drum. The sound was "deeper" this way. However,
the difference was marginal and barely perceplible. Personally I did not
hear any difference.

What is the modern take on that? Do manufacturers of the top-end CD players,
amplifiers and speakers specify their gear as "inverting" or non-inverting"?
(I believe they do not) Do the recording studios observe "polarity" from the
microphone to the digital values actually recorded on CDs? (Probably not)
When a drum is beaten, the skin is forced down creating a suction wave.
Meanwhile a compression wave is created out the bottom of the drum.

The two waves sum together and the mic records the pressure changes then
the signal is processed in the studio gear and recorded onto CD maybe
and sent to the record cutting head amp to make an LP.

Its anyone's guess which way the initial drum bang is phased. In
amplifiers at home there may be several stages of amplification and
maybe the signal gets inverted or maybe not.

I don't know what importance is given to phase when recordings are made.

In the past very little probably but designers such as myself always strive to
keep all ins and outs on say a mixing desk in the same polarity ( phase is really
the wrong word ).

Apologies for my flippant response to my misunderstanding of your question
elsewhere.

I doubt even the CD standard has a polarity requirement.

Graham



Positive pressure on the diaphragm cause a positive voltage on XLR pin 2.

[[email protected]]

PS The relative phase of the listener's space to the original space is
something some folks study and expound on to display their dedication
to Truth, or Honesty or something. It may be possible to enjoy
listening to Music without such effort. Life is so unfair

We can only hope Death is more even handed ...

it's called "absolute polarity" and it IS very important, under
certain conditiona, and others it does not make any discernible
difference.

[[email protected]]

wrote:
But we have never needed to know exactly what the phase of a signal is
so nature didn't allow us that capability. Yet when we try to sing in
tune with music we know exactly when we are in tune, and "in phase" with
another singer or a piano.

This is just wrong. Neither do we have the slightest idea of when we
are in phase with a musical instrument, but nor can we sing a steady
enough note to remain that way. Somewhere near the same note is the
best anybody can do.

And what phase would we synchronize with anyway? A piano tuner offsets
the tuning of the triples slightly to fatten the sound, which means
that the net phase of the note is sliding around as it decays.

No, we have no phase perception - the only way we can get to it is by
the indirect method of hearing an amplitude variation when two signals
at the same frequency reinforce or cancel each other.

"Phase" refers to two different signals, always. One sine wave by
itself does not have phase in free space. It DOES have polarity in
three axes with respect to any fixed plane.

We humans are VERY sensitive to phase between two signals, we are NOT
sensitive to POLARITY in free space.

We do not listen in free space.

Most musical or sound signals are asymmetrical, they are not sine
waves and they are not center referenced to "ground" .Also, we are in
an atmosphere which can be compressed to infinite pressure but which
can only be "expanded" to an absolute vacuum.

For this reason, absolute polarity does matter as a documentary
issue. It matters in practice under some specific conditions and not
others. For example, if you have a singer singing vocals along with
him- or herself, flipping the PHASE 180" will screw the singer up
royally. It has been proven time and time again in cinema ADR and in
tracking harmonies.

A good preamp like the Marantz 7 or Mc C22 will allow one to flip L
for R, but flipping plus for minus is not easily done in a n
unbalanced environment, except at the speakers. A big argument for
balanced chains, that.

[GregS[_3_]]

In article , "Alex" wrote:
A thread about phase alignment reminded me of another question:
Does speaker connection polarity (+/-180 degrees of phase) make any
difference?

I remember in my young years we experimented and sort of came to a
conclusion that the correct phase is when the cones of the speakers suck in
with the first beat of a big drum. The sound was "deeper" this way. However,
the difference was marginal and barely perceplible. Personally I did not
hear any difference.

What is the modern take on that? Do manufacturers of the top-end CD players,
amplifiers and speakers specify their gear as "inverting" or non-inverting"?
(I believe they do not) Do the recording studios observe "polarity" from the
microphone to the digital values actually recorded on CDs? (Probably not)


Some people can detect absolute polarity of an impulsed sound.
There is no single frequency on most instruments or music
in general. Its lows and highs. The bass is going to lag the highs because the
woofer takes longer to travel if its trying to produce the same frequency.
Its funny, a woofer also cannot reproduce very low frequencies well below resonance without
lagging behind. The flexible membranes have a stickiness to them.

greg

[jim greg]

"dave" wrote in message
...
Eeyore wrote:

Patrick Turner wrote:

Alex wrote:
A thread about phase alignment reminded me of another question:
Does speaker connection polarity (+/-180 degrees of phase) make any
difference?

I remember in my young years we experimented and sort of came to a
conclusion that the correct phase is when the cones of the speakers
suck in
with the first beat of a big drum. The sound was "deeper" this way.
However,
the difference was marginal and barely perceplible. Personally I did
not
hear any difference.

What is the modern take on that? Do manufacturers of the top-end CD
players,
amplifiers and speakers specify their gear as "inverting" or
non-inverting"?
(I believe they do not) Do the recording studios observe "polarity"
from the
microphone to the digital values actually recorded on CDs? (Probably
not)
When a drum is beaten, the skin is forced down creating a suction wave.
Meanwhile a compression wave is created out the bottom of the drum.

The two waves sum together and the mic records the pressure changes then
the signal is processed in the studio gear and recorded onto CD maybe
and sent to the record cutting head amp to make an LP.

Its anyone's guess which way the initial drum bang is phased. In
amplifiers at home there may be several stages of amplification and
maybe the signal gets inverted or maybe not.

I don't know what importance is given to phase when recordings are made.

In the past very little probably but designers such as myself always
strive to
keep all ins and outs on say a mixing desk in the same polarity ( phase
is really
the wrong word ).

Apologies for my flippant response to my misunderstanding of your
question
elsewhere.

I doubt even the CD standard has a polarity requirement.

Graham



Positive pressure on the diaphragm cause a positive voltage on XLR pin 2.

Not only of the speakers....
This maxim is a standard set by the-powers-that-be to coordinate manufacture
of micropones with their XLR3M termination, ahead of their being used by
mixing or
summing their outputs.
Using one mic alone in circuit creates neither a phase nor a polarity
problem, as these are 'relative' terms;
bipolar mics have in-phase and anti-phase faces.
The same convention is supposedly observed by the industry for, say, cone
loudspeakers and earphones when driven by dedicated amps.
2 speakers in dual-mono mode need to be wired in phase [or observing same
polarity] to prevent differential cancellation of soundwaves in air.
Active modules and the like are placed in a [linear] chain so that the
finished
product at all take-off and test points as well as at the speakers/cans] are
designed to be in
phase with the audio input to the first stage, spared from intrusive
response-shaping gizmos [which serve to ruin any prior integrity].
The same care applies for audio transformers, whose phase-angle error
between source and its secondary/ies should be
minimum at 800Hz.

The ear-trumpet routine: while live sound relay in small rooms benefits from
maintaining absolute phase (but kept well short of that point where acoustic
feedback howls), IMO 'absolute' phase of retrieved/reproduced material is a
lot of hype and phooey....
It's just an historical acoustic illustration.
Jim

[Eeyore]

GregS wrote:

There is no single frequency on most instruments or music
in general. Its lows and highs.

It's the fundamental plus harmonics for tuned instruments.


The bass is going to lag the highs because the
woofer takes longer to travel if its trying to produce the same frequency.

********.

Graham

[[email protected]]

On Apr 28, 2:50 am, flipper wrote:
On Mon, 27 Apr 2009 18:19:41 -0700 (PDT), wrote:

wrote:
But we have never needed to know exactly what the phase of a signal is
so nature didn't allow us that capability. Yet when we try to sing in
tune with music we know exactly when we are in tune, and "in phase" with
another singer or a piano.

This is just wrong. Neither do we have the slightest idea of when we
are in phase with a musical instrument, but nor can we sing a steady
enough note to remain that way. Somewhere near the same note is the
best anybody can do.

And what phase would we synchronize with anyway? A piano tuner offsets
the tuning of the triples slightly to fatten the sound, which means
that the net phase of the note is sliding around as it decays.

No, we have no phase perception - the only way we can get to it is by
the indirect method of hearing an amplitude variation when two signals
at the same frequency reinforce or cancel each other.

"Phase" refers to two different signals, always. One sine wave by
itself does not have phase in free space. It DOES have polarity in
three axes with respect to any fixed plane.

We humans are VERY sensitive to phase between two signals, we are NOT
sensitive to POLARITY in free space.

We do not listen in free space.

Most musical or sound signals are asymmetrical, they are not sine
waves and they are not center referenced to "ground" .Also, we are in
an atmosphere which can be compressed to infinite pressure but which
can only be "expanded" to an absolute vacuum.

For this reason, absolute polarity does matter as a documentary
issue. It matters in practice under some specific conditions and not
others. For example, if you have a singer singing vocals along with
him- or herself, flipping the PHASE 180" will screw the singer up
royally. It has been proven time and time again in cinema ADR and in
tracking harmonies.

I don't follow your example. Do you mean a singer singing along with a
prior made recording of themselves? Or do you, as I suspect, mean a
singer hearing their own voice 'live', like in an earpiece or
headphones?

In the 'live' case, that would be a matter of the 'playback' phase
relative to their own head (bone conduction). I.E. Constructive or
destructive interference.

Singing along with themselves, overdubbing harmonies or ADR, or with
other harmony singers. Throws them off horribly.



That's different than an audience listening for a 'better drum beat'
because they have no 'in their head' phase relationship to the sound.

A good preamp like the Marantz 7 or Mc C22 will allow one to flip L
for R, but flipping plus for minus is not easily done in a n
unbalanced environment, except at the speakers. A big argument for
balanced chains, that.

Inserting an inverting stage does it simple enough even with
'unbalanced' chains.

Not saying that's preferable, just that unbalanced doesn't make it
'impossible'.

Yes, you'd have to insert or remove a stage, which has to be unity
gain and the two need to be identical. Balanced is just a lot better
all the way around. We have unbalanced hi-Z in modern audio as a tube
holdover even though 1) only a percent or so of commercial hi-fi is
tubes and of that that is 2) they more and more like having
transformers.