Re: Idea: The ultimate CD/DVD auditing tool (meow)

10 Jul 2003

      "Then your ears are not golden, period."

Harumph!

But you misunderstand what the phase button does. If the speakers are wired 
out of phase anybody can hear that. Actually, it's a quite interesting thing 
to hear...nothing is really localizable.

But the phase button inverts the absolute phase of the signal coming out of 
both speakers. In other words, with a bass drum hit do the speaker cones 
move outward at the initial strike or inward (as they are not supposed to). 
Supposedly this difference can be heard, but my speakers start rolling off 
below 100Hz, so I suspect that's why I have a very hard time discerning the 
absolute phase difference when I hit the button.

-TD
...
From: Jim Choate 
To: 
Subject: Re: Idea: The ultimate CD/DVD auditing tool (meow)
Date: Wed, 9 Jul 2003 23:51:47 -0500 (CDT)
On Wed, 9 Jul 2003, Tyler Durden wrote:
...
Somebody wrote...
...
Yes this is for localization ---clicks are broadband, you need to
identify which freq components are used.  I still think
humans can't discriminate the phase of a tone.
An interesting thing to try is to play with the "phase" button on many
high-end gear. This supposedly matters for low frequencies, but despite 
my
unarguably golden ears, I'm still not convinced I can hear the 
difference.
Then your ears are not golden, period.
A standard test of audio systems in PA's for example is related to
'speaker phase' (ie all the cones move out or in together at the same
time). This is tested by putting a click on the line and then standing
between pairs of speakers. It is quite easy to tell when the speakers are
in phase. The same can be said for music (and no you don't need expensive
high end equipment), garble the phase and things like echo become very(!!!)
wierd. You just have to have the experience to know what to 'look' for.
A very(!) simple test to demonstrate/test your phase sensitivity (using
even very low quality equipment) is to connect a speaker between the R and
L channels (in essence it is driven by diff between the two channels).
This tends to highlight the phase disparity between the two channels
significantly enhancing the 'depth' of the music. Put a switch in there
and then have a friend enable/disable the speaker without your knowledge.
Then indicate what you think is the 'third speaker' setting. If you can't
tell nearly 100% of the time then any money on high end equipment is a
waste of your budget. This trick (was very popular in the 70's, especially
for us Quadraphonic fans) was what eventually led to the sub-woofer we all
know and love today (I do wish somebody would do something about those
damn rattling cars though).
--
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ravage@ssz.com                            jchoate@open-forge.org
      www.ssz.com                               www.open-forge.org
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