phasing

Posted by: J. B.

phasing - 03/09/14 08:42 AM

a few days ago i installed a new amp for my 2 front speakers.

when the installation was finished, i realized that the speakers were not
in phase, so i inverted the connecting wires at one of the speakers' connector.

all was fine until the time came for Audyssey calibration.
Audyssey said my front speakers were out of phase. i ignored the advice and went on with the calibration, knowing they were in phase.

what i would like to know is the reason this is happening; that Audyssey says one thing and my ears tell otherwise.
could it be that phase is inverted in the amplifier?
the amp is bridgeable, and i think that when an amp is bridged, one of the channels' phase is inverted; but the amp, as used, is not bridged.
it's used in stereo mode, and the only filter used is a 33Hz hi-pass.

anyone can enlighten me about this? i find it quite puzzling.
Posted by: casey01

Re: phasing - 03/09/14 03:39 PM

Originally Posted By: J. B.
a few days ago i installed a new amp for my 2 front speakers.

when the installation was finished, i realized that the speakers were not
in phase, so i inverted the connecting wires at one of the speakers' connector.

all was fine until the time came for Audyssey calibration.
Audyssey said my front speakers were out of phase. i ignored the advice and went on with the calibration, knowing they were in phase.

what i would like to know is the reason this is happening; that Audyssey says one thing and my ears tell otherwise.
could it be that phase is inverted in the amplifier?
the amp is bridgeable, and i think that when an amp is bridged, one of the channels' phase is inverted; but the amp, as used, is not bridged.
it's used in stereo mode, and the only filter used is a 33Hz hi-pass.

anyone can enlighten me about this? i find it quite puzzling.


That is why I am not a particular fan of calibration. A few months ago I bought a brand new Yamaha CX-A5000 Pre-pro, great unit, however, when I did the calibration, it read that all but 1 pair of speakers(9.2)were out of phase which is ridiculous. It had me rechecking everything in my set-up including the cabling between the Pre-pro and amps, but, in the end, being pretty meticulous when I connected the new unit, and I hadn't changed any connections between the amps and speakers anyway, I knew there was nothing wrong.

My usual checking method(if you want to be 100% sure) is run a test tone just in the L/R speakers and when sitting in the sweet spot between the two and the tone is in the middle then you know everything is OK.
Posted by: exlabdriver

Re: phasing - 03/09/14 06:04 PM

Audyssey found that my 'Rears' were out of phase with the other speakers & indeed they were hooked up wrong on Axiom's powered wall mounts.

My fault, but Audyssey was correct in that case...

TAM
Posted by: J. B.

Re: phasing - 03/09/14 06:25 PM

i checked my wiring again, and found out that everything was ok before i did the calibration.

i'm getting quite old, and after about 8 hours work on the new setup, i was very tired and out of breath and a mistake slipped by which i did not see when i checked all the connections again just to be sure all was right.
i had also checked on a TV station where the sound was mono...

so now everything is fine and working properly; i just had to reverse a connection on one of the speakers.

so, we just forget about this and go listen to some good music...

thanks to you both for the comments and help. :-)
Posted by: exlabdriver

Re: phasing - 03/09/14 06:35 PM

Getting old & developing dim vision - I hear ya!!

TAM
Posted by: Socketman

Re: phasing - 03/09/14 07:11 PM

I hear ya, I am still looking for the truck that ran over me last time I was working behind my system.
Posted by: SirQuack

Re: phasing - 03/09/14 09:45 PM

Trust Audyssey smile
Posted by: JohnK

Re: phasing - 03/09/14 10:15 PM

Okay Jacques, but just to answer something you asked about, yes some amplifiers do invert polarity, but this would affect all its channels equally, so the connected speakers wouldn't exhibit a wrong polarity issue.

Of course some "audiophiles" imagine that absolute polarity is also necessary, but testing doesn't support such a theory. It isn't unusual for polarity to be reversed several times in the electronics of recording studios.