[HiFiSoundGuy]

  How many have tried this and liked it better? Reverse the phase at both sides at the amp outputs only and at the source output only.

[Wayner]

I don't get what your trying to do. You reversed the polarity of both speakers, so that's no big deal, but then you reversed the ........and then there you lost me. Do you change the wires in the interconnect, say from a CD player so that the signal went to the shield and vise-versa?

Wayner 

[Haoleb]

if you reverse the phase at the speakers and the source output you just end up back where you were to begin with...

[Gordy]

He's referring to Clark Johnson's book, The Wood Effect.  "The Wood Effect. Discovered by Charles Wood at the Defense Research Laboratory in 1957, it was first reported in 1962 in the Journal of the Acoustical Society of America."  An article about it from Positive Feedback

[dyohn]

The wood effect... isn't that what happens if you take Viagra then get unexpectedly called in to work?
 

[HiFiSoundGuy]

I don't get what your trying to do. You reversed the polarity of both speakers, so that's no big deal, but then you reversed the ........and then there you lost me. Do you change the wires in the interconnect, say from a CD player so that the signal went to the shield and vise-versa?

Wayner 

   At the amp side you reverse the way you hook up the speaker cables and at the speaker hook ups end you (do not) reverse them. Did you all know that some recordings were recorded this way? I do all my Interconnects on the outputs side this way and even do this in my tape loop on my Integrated amp too. 

[opaqueice]

 At the amp side you reverse the way you hook up the speaker cables and at the speaker hook ups end you (do not) reverse them. Did you all know that some recordings were recorded this way?

What do you mean, "some recordings were recorded this way"?  Recordings are usually made with many channels recorded by many mics at different positions (and therefore different relative phases).  Mics often have a phase switch, and when the channels are mixed the engineer can again reverse the phase as well as adding time delay, phase response aberrations from filters, etc. etc.

Anyway, absolute phase is almost totally inaudible to humans (phase in general is very hard to hear, fortunately for us).  The exceptions are special test tones and a few specific natural sounds, sometimes, if you listen _very_ carefully.

[HiFiSoundGuy]

 At the amp side you reverse the way you hook up the speaker cables and at the speaker hook ups end you (do not) reverse them. Did you all know that some recordings were recorded this way?

What do you mean, "some recordings were recorded this way"?  Recordings are usually made with many channels recorded by many mics at different positions (and therefore different relative phases).  Mics often have a phase switch, and when the channels are mixed the engineer can again reverse the phase as well as adding time delay, phase response aberrations from filters, etc. etc.

Anyway, absolute phase is almost totally inaudible to humans (phase in general is very hard to hear, fortunately for us).  The exceptions are special test tones and a few specific natural sounds, sometimes, if you listen _very_ carefully.

                                                                        Your Wrong! Absolute Phase is Very Audible with Horn Type Speakers........

[Wayner]

I must be dense, but please restate what you are doing. Are you just flipping the positive and negative on the speaker terminals? That would put the signal (in the electronics) and the speakers 180 degrees out of phase (relative to the original signal)....Is this what you mean?

Wayner 

[HiFiSoundGuy]

I must be dense, but please restate what you are doing. Are you just flipping the positive and negative on the speaker terminals? That would put the signal (in the electronics) and the speakers 180 degrees out of phase (relative to the original signal)....Is this what you mean?

Wayner 

Yes but only on the amp side (both sides) where you hook up the speaker cables... on the other end of the cables where you hook up to the speakers you (do not) reverse positive and negative

[Wayner]

Ok. So the theory is that when I do my first breath into the microphone, I push the diaphram in making a (positive?) voltage. Now if I'm listening to the band, the positive "push" makes the speakers go outward, as the audience would expect to hear it. So, If I reverse the phase of the speakers, then the first breath into the microphone makes the diaphram go inward (like always) but this time the speakers go inward. So which side of the microphone are you on, the performers or the audiences? (I did humor this idea and flipped the dual banana jacks and tried to think about the theory, but I noticed no different effect).

Wayner

[*Scotty*]

opaqueice,Wrong Again,the difference in absolute phase can be easily detected when listening to Sheffield Labs Direct to Disc recordings. The effect is best demonstrated when these recordings are played back through phase coherent loudspeakers,that is, speakers that can pass a recognizable 1kHz square wave. If you doubt this,try an experimental listening test.
I have also heard a difference when absolute phase was changed in the digital domain. I was able to do this when I owned a Mike Moffat's Frankenstein CD player which was the predecessor to Theta Digital's first commercial product. The effect was more subtle and I could not have told you which polarity was the more correct one. No longer having the means to easily switch the phase for each recording by flipping a switch, I have not concerned myself with which direction is the correct one for years. I suspect it may matter when a simple microphone array is used in which the absolute phase intergrity is maintained.
Scotty

[Wayner]

I'm not saying the theory is completely full of shit, but I didn't notice any change. The other problem I have with this is that the studio recording techniques probably place microphones pointing in all kinds of different directions so the ambient sound they pick up on the rebound may blurr any pure positive or negative signal. There are also lots of electronics involved that have a shot at inverting the signal. Unless it's a pure 2 channel, 2 microphone recording, I really doubt the ear could sense the inversion. But I will ponder on this for awhile. I have done lots of live recording with my old Revox A77 reel to reel.

Wayner

[opaqueice]

opaqueice,Wrong Again,the difference in absolute phase can be easily detected when listening to Sheffield Labs Direct to Disc recordings.

I'm not sure what exactly you think I'm "wrong again" about, but I'll let it pass.  I've never heard those recordings so I can't comment.  But color me skeptical.

The effect is best demonstrated when these recordings are played back through phase coherent loudspeakers,that is, speakers that can pass a recognizable 1kHz square wave.

Actually, in my experience by far the easiest way to hear it is through headphones.  That might be related to the fact that headphones (at least mine) have no crossover and should be reasonably phase coherent - much more so than just about any speaker.

If you doubt this,try an experimental listening test.

I have.  I spent some time investigating this a while back, including generating my own custom test-tones that let me hear the effect relatively easily (although only with a little practice - even then it's subtle).

One thing you should be aware of is that hearing a difference when you flip the phase actually does not prove that you can really hear the difference in any meaningful way.  The reason is that all speakers are at least somewhat asymmetric in their response to positive and negative voltages (perhaps with the exception of some planar speakers).  So you might just be hearing the non-linear response of your system.  That possibility has to be eliminated before you can conclude anything.

I was able to eliminate that possibility with headphones in (what I thought was) a clever way, proving that human hearing really can distinguish, but that was with my special test tones, not with music.  It's really not easy to hear with natural sounds.  Basically, no one needs to worry about it for music.

[HiFiSoundGuy]

opaqueice,Wrong Again,the difference in absolute phase can be easily detected when listening to Sheffield Labs Direct to Disc recordings. The effect is best demonstrated when these recordings are played back through phase coherent loudspeakers,that is, speakers that can pass a recognizable 1kHz square wave. If you doubt this,try an experimental listening test.
I have also heard a difference when absolute phase was changed in the digital domain. I was able to do this when I owned a Mike Moffat's Frankenstein CD player which was the predecessor to Theta Digital's first commercial product. The effect was more subtle and I could not have told you which polarity was the more correct one. No longer having the means to easily switch the phase for each recording by flipping a switch, I have not concerned myself with which direction is the correct one for years. I suspect it may matter when a simple microphone array is used in which the absolute phase intergrity is maintained.
Scotty

  I agree, this tweak is great for the digital domain. It also works great on your car stereo too. I did this tweak on my Bose Acoustic Wave series 2 and was amazed at the difference!

[Bill Baker]

 If not sure, it is an easy enough test to perform but it does not apply to all systems.

[Brown]

I find the polarity switch a Gods send. Some Cds and Lps are recorded out of phase. Furthere we have noticed the bass on LPs is out of phase to the program material.
   Would have a tough time listening without the polarity reversal option. When phase is correct you will hear a better defined bass, less sibilance and a deeper soundstage.
   Unfortunately not all listeners are able to detect phase. Lucky you. Its simple then. For me and many others, because of the program material we need that switch.

[macrojack]

This comes under the heading of looking for trouble. If you don't hear it, don't try to. You'll just create problems for yourself.

[Eric]

In other words don't go looking for a bullet with your name on it. You will find it every time

[HiFiSoundGuy]

 I was looking around and found this ... http://www.6moons.com/industryfeatures/polarity/polarity.html .. And this.. http://www.stereophile.com/asweeit/988awsi/index1.html