Absolute Polarity - Anyone else can hear a significant difference?

[Jim Audiomisc]

Jim, did you take the Audiocheck test? I seem to remember that you are using ESLs.

https://www.audiocheck.net/blindtests_abspolarity.php

Not taken that test. But in the past I can't say I've noticed or cared much about polarity provided the source material and system otherwise seemed fine.

FWIW I did put up some info on audio waveform asymmetry some years ago where CD recordings make it clearly present. cf
https://www.audiomisc.co.uk/asymmetry/asym.html

However note the implication/possibility the 'up bow' and 'down bow' may swap the asymmetry sign. 8-]

 

[davidsrsb]

Hmm, so up and down bow would make automatic fixing a lottery. Violins are often recorded from above, which would mess up polarity compared with what you would get next to the conductor and different again for the audience

 

[davidsrsb]

At the top of a mid-woofer range, where cone break up is often a real problem, could the break up be polarity sensitive?

 

[tuga]

Not taken that test. But in the past I can't say I've noticed or cared much about polarity provided the source material and system otherwise seemed fine.

FWIW I did put up some info on audio waveform asymmetry some years ago where CD recordings make it clearly present. cf
https://www.audiomisc.co.uk/asymmetry/asym.html

However note the implication/possibility the 'up bow' and 'down bow' may swap the asymmetry sign. 8-]

I'd be interested in learning whether in the present you notice a different. Not caring is another subject 8^)

 

[tuga]

Not taken that test. But in the past I can't say I've noticed or cared much about polarity provided the source material and system otherwise seemed fine.

FWIW I did put up some info on audio waveform asymmetry some years ago where CD recordings make it clearly present. cf
https://www.audiomisc.co.uk/asymmetry/asym.html

However note the implication/possibility the 'up bow' and 'down bow' may swap the asymmetry sign. 8-]

Hmm, so up and down bow would make automatic fixing a lottery. Violins are often recorded from above, which would mess up polarity compared with what you would get next to the conductor and different again for the audience

At the top of a mid-woofer range, where cone break up is often a real problem, could the break up be polarity sensitive?

I understand why you'd want to find the mechanism, I'd like to know what it is myself.

Overcomplicating theories and second guessing is part of it I guess but the subject of the topic is "Absolute Polarity - Anyone else can hear a significant difference?" (sorry for the lousy English)

Just take the darn test.

 

[davidsrsb]

I have and I cannot hear any difference on headphones. Obviously I have an inferior system or am deaf, but I am wondering if there is a speaker related effect that is polarity sensitive.
I am suspicious that this is the case or it would be most obvious with ESLs and single driver headphones, the two types that do actually reproduce an impulse cleanly.
Most multi driver speakers and presumably multi driver headphones make a complete mess. Some even flip polarity between drivers.

 

[davidsrsb]

I cannot hear a difference on my main system either.

 

[tuga]

I have and I cannot hear any difference on headphones. Obviously I have an inferior system or am deaf, but I am wondering if there is a speaker related effect that is polarity sensitive.
I am suspicious that this is the case or it would be most obvious with ESLs and single driver headphones, the two types that do actually reproduce an impulse cleanly.
Most multi driver speakers and presumably multi driver headphones make a complete mess. Some even flip polarity between drivers.

If you cannot, you cannot. Many seem to and hardly any have ESLs or single-driver speakers/headphones.

It could be in part because you are not attuned to the audible differences. When I took the Philips Golden Ear Challenge they'd train you to pinpoint a few of the issues beforehand and when you felt confident you would then take the blind test.
Training makes a massive difference in these matters, as Harman's research has shown.

As to the why, it is audible so it might make more sense to try put together a theory of why it is audible instead of one which supports the/your view that it cannot be and is just unicorns and audiophiles making babies in the new moon...

 

[davidsrsb]

I am not saying that this does not exist. I am very grateful that I don't hear it as it saves me some paranoia about correcting it and I can just get on with enjoying the music

 

[Colin L]

Tuga,

You started two posts at the same time all about hearing tests. Most of your posts relate to technical issues and approach them from a hard objectivist viewpoint. You are frequently quoting ASR and Archimago, posting charts and graphs and are very “proud” of your technical bias.

Are you trying to turn this site into ASR-lite?

 

[tuga]

I am not saying that this does not exist. I am very grateful that I don't hear it as it saves me some paranoia about correcting it and I can just get on with enjoying the music

I can enjoy the music over my monaural tabletop Tivoli One.
If your system is any better then you are already paranoid. I know you didn't mean it as an insult but it's still not a nice thing to say, and probably the reason why the experimentalists and the rationalists collide so often...

 

[cooky1257]

I have and I cannot hear any difference on headphones. Obviously I have an inferior system or am deaf, but I am wondering if there is a speaker related effect that is polarity sensitive.
I am suspicious that this is the case or it would be most obvious with ESLs and single driver headphones, the two types that do actually reproduce an impulse cleanly.
Most multi driver speakers and presumably multi driver headphones make a complete mess. Some even flip polarity between drivers.

Yes exactly, expressing a positive polarity preference using multi driver loudspeaker begs the question wether a driver in your 2 or 3 way has its polarity inverted and if so why don't you dislike the way it's covering its particular bandwidth? Ie in a 2 way half your preference is actually for inverted polarity.....and that's before we even get to multi track recordings...

 

[Tony L]

Yes exactly, expressing a positive polarity preference using multi driver loudspeaker begs the question wether a driver in your 2 or 3 way has its polarity inverted and if so why don't you dislike the way it's covering its particular bandwidth? Ie in a 2 way half your preference is actually for inverted polarity.....and that's before we even get to multi track recordings...

Also what is “correct” phase? If one considers a initial pressure wave from say a drum hitting a microphone that causes an inward deflection of the mic diaphragm, therefore ‘correct’ phase would be an inward/backward movement of the loudspeaker. IIRC this was the Tannoy argument and why their drivers are wired the way they are: bass unit in phase with the mic diaphragm, compression unit time-aligned (phase reversed) with the bass unit.

PS Most multi-driver speakers are an absolute mess when it comes to phase and time alignment. The more drivers and larger the baffle the more the resulting mess!

 

[Alex M]

It's not just a switch that is needed. The signal needs to be inverted which means including an additional inverter stage in the amplifier to correctly invert the phase. This active stage needs to be switched in and out for "in" or "out" of phase. Therefore to invert the phase properly the signal ends up going through another amplifier stage in the signal path. You could do it with a transformer, but that also means more components in the signal path and the corresponding degradation. Swings and roundabouts really. This topic isn't new, it was raised over 25 years ago and was much talked about in the USA on Audiogon. My US distributor at the time started pushing me to fit a phase switch to satisfy his clients and help increase his sales. In a matter of months it was all forgotten about until some other fad or flavour of the month topic came up. In reality, no one could put up with the faff of labelling their music indicating which phase they preferred. This topic is very similar to LP equalisation and what record companies did, or didn't fully adopt the RIAA standard post 1954 and corresponding modern phono stages, offering several different EQ's for users to choose which one they prefer the sound of...

You don't need an extra stage to invert the signal if your input stage is differential to start with. Allen Wright worked out a neat way to eliminate any extra switching as well with his differential Realtime Preamplifier - double up the choices on your source selector switch to include a choice of polarities for each source.

Having said that, I have never really experimented with the polarity options with my RTP3C - you really need either a remote to switch both channels at once from the listening seat, or a willing and patient assistant to stand by the preamp and switch polarities at random.

Alex

 

[paulfromcamden]

Can someone explain in simple terms why inverse phase would be a problem if it's across both channels?

I understand Tony's example of miking a drum kit - it's fairly common for example to invert phase on the under snare mic for example (or even manually time align) to minimise comb filtering. But I'm not sure that's what people are talking about.

 

[Tony L]

Can someone explain in simple terms why inverse phase would be a problem if it's across both channels?

To my mind it only matters on the initial transient of a percussive wave. Think of a kick drum; as the beater on the pedal hits the skin you effectively get a pressure wave accelerating very rapidly upwards from zero Hz (stationary state) and pretty much a DC pulse - an initial push forward of a large diaphragm which pressurises the air in front of it in a pretty visceral manner. For a hi-fi to capture that one would expect the loudspeaker drivers (which need to be large to have even a hope in hell) would kick that initial air-mass forward into the room, not try and suck it out of the room. Obviously I’m only talking about that initial transient and shift of air mass. The note/ringing etc that comes later is just audio frequency AC and phase doesn’t really matter. As such I’d argue absolute phase only applies subjectively to the initial almost DC transient hit of a percussive instrument.

This obviously gets way more complex as soon as we think of mic position, especially multiple mic positions. If you start to think of an instrument as complex as say a grand piano, which is a combination of percussively actuated strings above a horizontal soundboard amplified by a lid acting in part as a horn, where the mics are placed can tell a whole world of different stories when it comes to the initial attack stage of the envelope. That is before we think about the piano mics on stage with a drum kit, sax, electric guitar or whatever. Absolute phase gets real messy real fast if your musical taste expands beyond say a string quartet mic’d with a simple stereo pair.

PS Somewhere on YouTube there is an excellent example of how to record in mono with one ribbon mic the way most classic rock ‘n’ roll or early mono jazz records were done which explains phase and cancellation beautifully. The usual approach was to have the vocalist on one side of the ribbon mic, the band on the other, and the drums at the side in the phase cancellation zone, i.e. the vocals and music are out of phase with one another, and the drums in phase with nothing really just being room reflections! That is just one mic. One’s head soon explodes when trying to think of phase accuracy of multi-mic recordings, and that is before we get to FX etc. My view is audiophiles should forget it. If they want to obsess do so about their loudspeakers, which are almost certainly a total mess phase-wise (unless they are ESL63s, then you get to comment).

 

[paulfromcamden]

@Tony L OK I'll forget it : )

Yes, it's an excellent video that demonstrates polar patterns and phase really well. Plus lots of excellent old gear!

Funnily enough a pair of ribbon mics mounted horizontally over the piano soundboard can be very useful when recording raucous free jazz as the fig 8 null will reduce bleed from that incredibly loud drummer who insisted on setting up right next to the piano... : )

 

[Jim Audiomisc]

If you cannot, you cannot. Many seem to and hardly any have ESLs or single-driver speakers/headphones.

FWIW I've used ESLs for many decades. Maybe that's correlated with my not noticing polarity. Dunno. However TBH

1) I'm too busy with 'non interruptable' tasks caused by 'life' at present to try again. (e.g. now have to make up more 'guddles' for the strange diet I have to eat for 'medical' reasons.)

2) More curious about other things.

 

[Jim Audiomisc]

Also what is “correct” phase? If one considers a initial pressure wave from say a drum hitting a microphone that causes an inward deflection of the mic diaphragm, therefore ‘correct’ phase would be an inward/backward movement of the loudspeaker.

If the drum has an open back then the radiation from one side of the surface will be of opposite polarity to that from the other. 8-]

 

[Jim Audiomisc]

Jim, Don't go breaking my heart, or are you referring to someone's sexuality?

Nope. You've identified what puzzled some AM transmission people in the US.