mat6066
Joined: 21/01/08
Posts: 18
Loc: Nottingham
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Phase checking my monitoring
#1018702 - 15/11/12 01:32 PM
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Hi,
I've been using Alan Parson's 'Sound Check 2' CD to check my monitoring. On
the CD there are some pink noise tests for checking the phase between one's monitors;
there is a 'phase check' signal, and then subsequent signals both in and out of phase
broken into different frequency bands.
Whilst my monitors phase cancel
perfectly when running the 'phase check ' signal and also the signal between 0-200 hz
band, I can still hear a (much reduced) sound when running the pink noise tests in the
bands ranging from 200 hz up to 15 khz.
Is this something that should concern
me?
If it is, what are the solutions please?
Cheers,
Mat
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Richie Royale
Joined: 12/09/06
Posts: 3350
Loc: Bristol, England.
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Re: Phase checking my monitoring
[Re: mat6066]
#1018714 - 15/11/12 02:42 PM
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At a guess this is comb filtering from reflective sufraces in your room, such as the desk
or walls. Do you have any acoustic treatment in the room?
-------------------- http://soundcloud.com/richie-royale
http://www.mixcrate.com/richieroyale
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Hugh Robjohns
SOS Technical Editor
Joined: 25/07/03
Posts: 18348
Loc: Worcestershire
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Re: Phase checking my monitoring
[Re: mat6066]
#1018716 - 15/11/12 03:04 PM
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Quote mat6066:
Whilst my monitors
phase cancel perfectly when running the 'phase check ' signal and also the signal between
0-200 hz band, I can still hear a (much reduced) sound when running the pink noise tests
in the bands ranging from 200 hz up to 15 khz.
The wavelength of sound below 200Hz is very long and slight
movements of the head or measurement mic won't make much difference to the relative
ephasing of the signals, and so won't affect the depth of cancellation significantly.
At higher frequencies the wavelengths are much smaller and small differences in
distance can have a big effect.
Clearly, there is still a substantial amount of
cancellation going on since what you hear is much reduced.
your results may
also be influenced by local HF reflections diluting the effect.
hugh
--------------------
Technical Editor, Sound On Sound
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mat6066
Joined: 21/01/08
Posts: 18
Loc: Nottingham
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Re: Phase checking my monitoring
[Re: mat6066]
#1019078 - 17/11/12 10:24 PM
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Thanks Hugh for the information and to both of you for the tip on HF reflections. I have
a got sound treatment in the room but perhaps I could increase the amount of HF absorption
- much of my budget has gone on bass trapping.
Cheers,
Mat
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DC-Choppah
Joined: 20/07/12
Posts: 166
Loc: MD, USA
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Re: Phase checking my monitoring
[Re: mat6066]
#1019106 - 18/11/12 04:28 AM
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This test also stresses your monitors phase matching.
You need identical
speakers to phase match over a wide band. Nothing does that perfectly, but you can really
tell the difference between the high end monitors vs el-cheapos with the phase match test.
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