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In Reply to: RE: More about Absolute Polarity posted by Dawnrazor on December 16, 2008 at 21:47:28
I don't think that anyone will be able to hear polarity issues. Take two 1k sine waves, invert polarity on both channels, they will be the same I betcha. Phasing is different. Revers polarity on one channel. If the wave cancels, you have a properly set up system. If not, you have improper speaker placement and/or system issues.
Follow Ups:
If you have sine waves they will sound the same in either polarity, as the waveform of an undistorted sine wave is completely symmetrical. If you want to try detecting polarity with constant tones, you can mix in 2nd harmonic distortion at various phases. This can be done easily using audio editing software which has waveform generating features. You can create a mixture of fundamental and second overtone at any amplitude and phase you wish. Detection results will be best if tones are well below 1 kHz as that is pushing the range at which the auditory nerve fires synchronously with the acoustic waveform. Above a cutoff only amplitude information makes it to the brain, according to the research that I have read. I have had better results detecting absolute polarity when listening to music rather than test tones.
It is equally convenient for me to adjust playback polarity as volume. I use both controls about the same amount when adjusting playback so that a given recording sounds at its best. However, most of the recordings that I listen to are minimally miked Classical and Jazz recordings, which tend to show up polarity much more than multiple miked complex mixes.
After trying both polarities with many different Classical and Jazz recordings, if you still don't hear differences it may be that your speakers aren't phase coherent enough. Try playing back through a single driver speaker setup. It need not be fancy. A cheap table radio should do just fine.
I have found it best not to listen to the tone of the instruments, just the general ambiance. If you can achieve a Zen mind it will be easier to detect polarity differences. Over time you will gain experience and be better able to hear polarity right away and predict whether the sound is likely to improve if you reverse the polarity. However, at least in my case, this ability varies from day to day.
Enjoy. It is a fun game to play and a cheap tweak.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
Right.
What I was getting at is that if the speakers by design have the tweeters connected with reverse polarity (phase???) relative to the mids or the bass, then that sinewave will be at different polarity at the different drivers making it impossible to hear.
Now lets say I have a single full range driver, are you saying that I cant hear reverse polarity?
You may be hearing an effect of the filter. But if you were to do a double blind test, there would be no beneficial obvious difference.
but not true with actual music which contains many overtones. The relationship of the fundamental tone to the overtones will be changed, and one obvious aspect easily heard is excessive sibilance.
Stu
Uhhhh. Sine waves are harder for gear to reproduce than music. Harder for digital and analog. Do you know what a sine wave consists of?
Music with its complex overtones and harmonics are much harder to reproduce accurately. IM starts to rear its ugly head along with TIM distortion in the case of amps with slow transient response. Typically you do not get those issues with a pure sine wave, particularly in the 1KHz range.
But perhaps I am not understanding the scope of your question. Perhaps you ought to elaborate a bit more.
Stu
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