inverting (both) speakers polarity : any audible difference ? any danger for speakers ?

[amanieux]

hi audio friends, if i invert speaker wires on both sides, is there any audible difference ? (tried inverting audio in audacity and i could not hear any difference) - is there any danger for speaker longevity ?

 

[MaxwellsEq]

hi audio friends, if i invert speaker wires on both sides, is there any audible difference ? (tried inverting audio in audacity and i could not hear any difference) - is there any danger for speaker longevity ?

There is no danger of damaging the speakers.

You will be inverting the absolute phase. For sine waves, there should be no audible differences. But music is often made up of impulses, such as a drum beat. Also, some instruments generate sounds where the positive part is a different shape to the negative part. These will be reproduced differently. Whether you can hear a difference is not clear. I believe I can hear a difference when there is applause at the end of a live classical feed. But I might be imagining it.

 

[DSJR]

Depending on the speaker and it's bass performance, you *may* hear a difference in absolute phase. Most times you won't because the music played is all over the place phase-wise anyway

The other thing is that no passive crossover to my knowledge is totally symmetrical. Heybrook in their early (Peter Comeau designing) days used to put the series components in line with the return rather than hot connection (I think I have it right), but whether it actually made any difference I have no idea and of course forty five or so years later, no idea if he continues with that line of thought with his current and successful designs for IAG.

 

[sergeauckland]

Some thoughts on the matter:

Firstly, some amplifiers (like QUAD) invert the signal anyway, as do some pre-amps, so depending on what equipment one uses, the polarity of the signaal going to the loudspeakers may already be inverted.

Secondly, air is linear to a very high degree, so at normal listening levels, there is no non-linearity in positive or negative air pressure changes in the sound waves. At very high levels, such as rocket motors, air is non-linear as one can compress the air by any amount but only rarefy it by 1 Bar.

Thirdly, I don't know of any mechanism in human hearing that is polarity sensitive and can't think of any reason why one should evolve.

Finally, although there's a standard for polarity from microphone right through to loudspeakers, there's no guarantee that any recording follows that. Microphone polarity is essential, whether multi-mic multi-track mixes or purist single pair recordings, and what happens afterwards in mixers/recorders/mastering etc should similarly be controlled, but there's no guarantee it has been.

As to damage, no not possible due to polarity inversion.

S.

 

[BeerBear]

With some music, inverted phase produces an audible difference. I'm attaching an example.

Firstly, some amplifiers (like QUAD) invert the signal anyway, as do some pre-amps

Why do they do that?

Finally, although there's a standard for polarity from microphone right through to loudspeakers, there's no guarantee that any recording follows that. Microphone polarity is essential, whether multi-mic multi-track mixes or purist single pair recordings, and what happens afterwards in mixers/recorders/mastering etc should similarly be controlled, but there's no guarantee it has been.

A microphone recording is pretty much never left untouched during production. All the later stages still shape the sound and there can be phase changes too, if that helps to make a song sound better... Those are, to some extent, creative decisions.
But once a song is finished, any playback equipment doing its job properly should not be inverting polarity.

 

[fpitas]

Inverting both speakers creates a time vortex where the recording gets pulled back into the media and sent to the recording studio.

/Honest!

 

[Mnyb]

For multichannel record i can imagine that phase is all over the place with some source channels inverted and others not

 

[amanieux]

There is no danger of damaging the speakers.

You will be inverting the absolute phase. For sine waves, there should be no audible differences. But music is often made up of impulses, such as a drum beat. Also, some instruments generate sounds where the positive part is a different shape to the negative part. These will be reproduced differently. Whether you can hear a difference is not clear. I believe I can hear a difference when there is applause at the end of a live classical feed. But I might be imagining it.

i do not hear difference even on clappings, where i hear a difference is when speakers are out of phase (one speaker inverted, the other not) this is very unpleasant on speakers but oddly enough on iems i prefer when it is out of phase, it has more depth, you can experience this for yourself here :

 

[AdamG]

Inverting both speakers creates a time vortex where the recording gets pulled back into the media and sent to the recording studio.

/Honest!

Ahh, the old Backdoor path to earning unearned royalties. Sweet

/lies, pure!

 

[DVDdoug]

Someone did some research once and they determined that the polarity in commercial recordings/productions tends to be "random". (I don't know how they did that.) With multi-track recordings there's a good chance that at-least one voice or instrument is inverted.

A lot of mixers have an "invert" button for each input and sometimes that can help to minimize feedback in live productions. (It's just a 50/50 thing depending on the distance between the speakers & microphone and the frequency of the feedback oscillation.)

A single stage of transistor or MOSFET amplification usually inverts, so if there is an odd number of amplification stages you'll have an inverting amplifier. With op-amps it's easy to make an inverting or non-inverting amplifier, but there are some circuits that are easier to build one-way or the other. It's also easy to add another op-amp inverter to re-invert if desired.

 

[tomtoo]

no,no.

 

[MaxwellsEq]

where i hear a difference is when speakers are out of phase (one speaker inverted, the other not) this is very unpleasant

That's true for everybody.

 

[sam_adams]

Really?

 

[sergeauckland]

With some music, inverted phase produces an audible difference. I'm attaching an example.


Why do they do that?


A microphone recording is pretty much never left untouched during production. All the later stages still shape the sound and there can be phase changes too, if that helps to make a song sound better... Those are, to some extent, creative decisions.
But once a song is finished, any playback equipment doing its job properly should not be inverting polarity.

Because there's no reason not to in a replay amplifier.

S.

 

[Zoomer]

I don't know of any mechanism in human hearing that is polarity sensitive and can't think of any reason why one should evolve.

In case you've missed that article on Polarity Sensitivity of Human Auditory Nerve Fibers .

 

[sergeauckland]

In case you've missed that article on Polarity Sensitivity of Human Auditory Nerve Fibers .

I can't see how a study of nerve fibres with cochlear implants is relevant to reversing loudspeaker leads.

S

 

[krabapple]

Don't do it. The music will sound upside-down.

 

[Speedskater]

OK, let's assume that some musical instruments when recorded with some microphones and some mic techniques can have audible polarity differences when played back thru some loudspeakers.
But:
a] instruments can be recorded with different mics and/or techniques, sometimes on the same album.
b] some recording consoles have individual mic channel polarity switches.
c] some recording processors can invert polarity.
So overall polarity will be rather random.

 

[BeerBear]

I think that microphones and recording techniques are completely irrelevant in the context of audio playback. Because whatever was done with polarity during production, that's the product they were happy with, so that's what needs to be played back.
For proper playback, all that matters is that your speaker pushes the woofer forward for waveform peaks and pulls it back for troughs. If it does that, it's working correctly. If it does the opposite, it's working incorrectly. That obviously goes for the speakers used in production too, because we want consistency.
This speaker behavior can be easily checked with an audio editor and a very low frequency square wave.

 

[sergeauckland]

I think that microphones and recording techniques are completely irrelevant in the context of audio playback. Because whatever was done with polarity during production, that's the product they were happy with, so that's what needs to be played back.
For proper playback, all that matters is that your speaker pushes the woofer forward for waveform peaks and pulls it back for troughs. If it does that, it's working correctly. If it does the opposite, it's working incorrectly. That obviously goes for the speakers used in production too, because we want consistency.
This speaker behavior can be easily checked with an audio editor and a very low frequency square wave.
View attachment 314650

Regardless of what is 'correct', there's no credible evidence I've seen that inverted audio is in any way audibly different from 'correct' polarity. As long as both stereo loudspeakers (all loudspeakers for multichannel) are of the same polarity, then it doesn't matter what the polarity is.

It may be noted that many loudspeakers invert the polarity of the tweeter with respect to the woofer, so even if the amplifier has correct polarity, it may not be so in the air at higher frequencies.

S