Quote:
Originally Posted by plurn
I think you might be overstating the phase issue. We probably all know the following but I will state it for clarity. Hopefully I get it right.
There is "inverted phase", and there is "out of phase", and they are not the same thing.
Out of phase is when you have the left speaker playing with the opposite phase of the right speaker. This is a very bad situation and causes easily audible aberrations. Everyone that can hear, can hear this easily. No disputes there.
Inverted phase is when you have both speakers with the same phase, but the positive "electrical" signal is going to the negative terminal of the speaker (for both left and right speakers). It is debatable whether inverted phase is easily audible when playing music. Some claim it is, some claim it isn't. Whether it is easily audible or not, it will not change the frequency response, and will not cause "treble emphasis".
Now from what I read, the reviewer had inverted phase (with both main speakers in phase with each other). Initially his subwoofer was out of phase with the woofers of his main speakers, and playing some of the same frequency range (as his main speakers were playing full range), causing "weak bass response" due to cancelation of some bass frequencies due to the subwoofer being out of phase with the woofers of the main speakers. He corrected this issue by setting his subwoofers phase to 180 degrees (inverted phase) to match his main speakers woofers.
Sure he should have inverted the phase of his main speakers and left the subwoofer at zero degrees phase, that would have been preferable. But his chosen solution also works. Either solution would sound pretty much identical when playing music. As I mentioned before, it is debatable wether inverted phase is audible when playing music.
If his left and right speakers were out of phase with each other, that is a whole different story and would invalidate the whole review, but I don't think that is the case here.
Anthony
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Anthony. Do you own a cj preamp?. It is very easy to hear the difference. Somewhat exaggerated treble and lack of bass are side effects of not in phase, let alone the singer breathing in when he is supposed to be breathing out. I purposely play my supertweeters phase reversed as they provide a little more sparkle than wired phase correct.
From the cj et3 manual - its the same on every cj preamp manual.
Absolute Phase
Musical notes are heard through the ear’s response to waves of
alternating rise and fall of air pressure. Musical transients are
almost exclusively positive: that is, the initial effect is a rise in pres-
sure. The ear is capable of distinguishing these positive transients
from the musically unnatural alternative of a negative transient (an
initial fall in air pressure). In terms of your stereo system, these
transients are created by your loudspeakers. If the speakers
respond to musical transients by first moving out, they are creating
a rise in pressure, and the system is said to be phase correct. If
they respond by moving in, they create a fall in pressure and the
system is said to be phase inverting. Each component in the stereo
system either preserves the phase of the incoming signal, and is
said to be phase correct, or inverts the phase and is said to be
phase inverting. It is unimportant whether an individual component
is phase correct or phase inverting, as long as the system as a
whole is phase correct. This will be the case if the number of phase
inversions is even (or zero).
The ET3 Preamplifier is phase inverting. If your system has an odd
number of inversions, (for example, if the ET3 is the only phase
inverting unit in the chain) then you must add one phase inversion.
This is conveniently done by reversing the positive and negative
connections to your speakers (be sure to reverse both channels). If
you are not sure about the phase of every piece in your system,
you can establish correct absolute phase by careful listening.
When the system is in correct phase, transients will be noticeably
cleaner and more sharply defined. The effect is especially apparent
on plucked string sounds. A final warning - not all recordings are
phase correct (including some “audiophile” recordings), so listen to
several before concluding your investigation of absolute phase.