[Porcupine]

After learning of VMPS and reading the webpage, and also doing lots of general speaker info learning on the web this past month, I was shocked to learn that nearly all speakers wire their drivers in alternatingly reversed polarity.

I tested out my speakers in various ways and came to the conclusion that they all indeed obey that law. My Bohlender-Graebener Z-series speakers, which are essentially 2-way, have positive polarity woofers and reversed polarity tweeters, crossed via a 2nd-order Linkwitz-Riley network. My Infinity Kappa 5.1 Series II speakers are 3-way, have positive polarity woofers and tweeters, but negative polarity midranges. I don't know what kind of crossover they use but I suppose they must have even-order networks of some kind.

I had tried to play all my speakers simultaneously before with the same source signal for fun, but the result was very weird sounding, and so I stopped doing it. This morning though I decided to reverse the global polarity to all my BG-speakers and then try playing them simultaneously with my Infinities...and WOW the difference is humongous!!! As expected, I suppose. Now they play together well. Kind of cheesy but fun I guess.


Now the question for me is: should I leave my BG's in reversed polarity permanently? They are wrong either way...so which way is better? Is it safe to play them that way forever?

The Infinities should definitely be left as intended. Only the couple octaves of the midrange will be inverted which is not too bad. Midrange frequencies tend to be steady sounds anyway (fundamental frequencies of human voice, orchestra string, etc....mellow sounds) so maybe phase information of that isolated driver might be less important (on the other hand it will still be bad when superimposed upon the inverted harmonics coming out of the tweeter). Woofer kickdrums will bang out properly, and metallic clangs and sharp striking notes out of the tweeters will spike in the correct direction.

But I dunno what to do about my BG's. If I want to listen to them with my Infinities I have to wire them in reverse but that's just a gimmick. For serious listening what matters is how they sound alone. Which is more discernible to the human ear? Should woofer kickdrums bang out properly but tweeters suck in....or should the woofer kickdrums suck in and the tweeters clang out?

I am not sure yet if I can tell the difference in global speaker polarity. I *think* that I can,  however until someone blind tests me I can't be sure. I grew up listening to positive polarity tweeters...and that is all that I listen to when I listen to music. I always equalize bass levels as low as I can. So I think I should reverse the global polarity. But will my woofer cones sucking in all their life will cause them damage?

[_scotty_]

Porcupine,a speaker driver does not care if it produces a compression or a rarefaction of the the air if front of it in response to an positve polarity electrical signal.  If it is fed a signal consisting of a waveform with simularities to a sinewave the driver will be reversing it's direction of motion when the
waveform swings the other direction and passes through zero anyway.
  A loudspeaker system if designed with a 2nd order slope crossover may exhibit a 180degree phase shift at the crossover frequency which will mandate that a driver has to be connected with  reversed polarity in order to avoid a suck out in the response curve due to phase cancellation at the crossover frequency.  If your speakers came with one of the drivers connected in reverse polarity from the factory and it has a second order crossover this is why it was made that way. Connecting both drivers with the same phasing will result in degraded frequency response accuracy in the crossover region and worsened lobing errors both on and off axis.
It should also sound worse as well.  
  Technically speaking a loudspeaker should reproduce an exact acoustic
copy of the incoming waveform with zero phase error of any kind.
They should perfectly reproduce a squarewave signal with no error.
Only Dunlavey speakers came close to this standard and only
in an anechoic chamber.  Because we live in an enviroment with
 reverberation the importance of phase accuracy is diluted. We cannot
recover a squarewave from a reverberant enviroment due to the preponderance of reflected and delayed waveforms that modify a phasecoherent waveform via interference
effects before it reaches our ears . Scotty

[Porcupine]

>> I don't know what kind of crossover they use but I suppose they must have even-order networks of some kind.

> A loudspeaker system if designed with a 2nd order slope crossover may exhibit a 180degree phase shift at the crossover frequency which will mandate that a driver has to be connected with reversed polarity in order to avoid a suck out in the response curve due to phase cancellation at the crossover frequency.

Oops, you are right, I forgot that 4th-order crossovers don't need to be polarity reversed because the two drivers phase shift 360 relative to each other at the cross frequency. Only 2nd-order (and possibly 6th-order, 10th-order, etc) ones do.

> Porcupine, a speaker driver does not care if it produces a compression or a rarefaction of the the air if front of it...if it is fed a signal consisting of a waveform with simularities to a sinewave the driver will be reversing it's direction of motion when the waveform swings the other direction and passes through zero anyway.

Thanks for reassuring me that hooking up my speakers in reversed polarity will not damage the woofers. I agree totally with what you said about sinewave signals to the driver and do not fear the effect of reversed polarity steady bass notes or sounds.

But I was worried about possible "humpy" bass signals that make my driver stick out one way more than the other. I worry that kickdrums for example might be a little like that....boomp boomp boomp. Maybe in their lifetime my woofers might be displaced 1% more often to one side than the other from kickdrums or something. In theory that still shouldn't matter but real life things are never perfectly ideal.

> Because we live in an enviroment with
reverberation the importance of phase accuracy is diluted.

Quite true.