I was calibrating my new Axiom's using the AVIA disk. I have M60's for fronts, VP150 for a center and M22's as rear surrounds. These speakers are being run from a older Sony STR-DB940 A/V receiver. When I run the test which compares the left front with the center, it sounds as if the center is accentuating more of the upper bass than the left M60. It sounds rather like the VP150 is in a hole or something...not horrible but definitely noticeable. I was under the impression that the timbre of these speakers would be very similar especially in the higher frequencies...I have run a Real Time Analysis program on a laptop using the above tones supplied on the AVIA disk, using a cheap Sound Blaster mic and recorded the tones reproduced by the speakers. There is a noted difference in the frequency response graph between the left and the center...peaks in the upper bass from 60 to around 500 Hz or more occur in the center.
I thought it may be affected by my having the 150 on the shelf under my Sony KV36XBR800 TV. The Sanus Video stand on which the TV sits has a front center post adding support to the center of the top shelf holding the set (which weighs in at approx. 235 lbs) and therefore the speaker is two or three inches back from the front of the shelf. As an experiment, I put the 150 on top of the set and ran the AVIA test again...I noticed that the comparison between the two speakers (left and center) still has that difference of the center sounding like it is in a hole.
I performed another experiment this morning. I switched the speaker connections on the receiver between the center and the right front (making the left front and right front speakers identical...both M60's). I then ran the tone set again from AVIA comparing left front and center and the right front exhibited the same issue as the center does when the center is connected to the center's speaker connections.
Also, the standard individual level tones used to set all five speakers level also exhibits the "in a hole" effect for which ever speaker is connected to the center output...using this test, upon switching the connections (VP150 connected to the right front output), the center sounded more like it was supposed to (at least what I was expecting...more treble response) than when connected to its correct set of center speaker posts. Has anyone heard of any situations where the output to the center channel on a specific receiver was tonally different from the other speakers? Could this possibly be an issue with the signal on the AVIA disk for that specific test or an issue with the center output on the receiver?
This is something that I "can" hear...I tried recording it with the mic I had available just to see if it heard (and recorded) what I was hearing and that my mind was not "making it up...". I have no other "effects' turned on...no DSP of any kind except for the standard Dolby Digital decoding of the AVIA disk...
Anyone...anyone?
WhatFurrer
