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Help troubleshooting McCormack separates?

I've been trying to lick a persistent electrical-souding buzz that comes and goes in my rig, and recently downloaded Ethan Winer's test tones from the RealTraps website to see how much of the problem was real, and how much of it was psychosis.

When playing the 300Hz sine wave I was able to hear a not unpleasant "tubular bells" sort of note, accented by a much drier, less pleasant overtone about a half-step below the main note in pitch -- rather like the sound that animation studios use to simulate a housefly. If I raised the volume, both the tubular-bell note and the overtone would decrease in pitch, and if I lowered the volume they would both increase in pitch (I know that sounds crazy, but I replicated the effect several times).

Also, the overtone briefly got louder if I adjusted the volume in either direction, then returned to its previous volume, relative to the main tone. The effect occurred equally when using my Arcam CD-player or my Oppo DVD player, to play the tone.

My question for the group: is this enough evidence for me to conclude that I'm facing a service issue with the McCormack stuff, or could all of these results be the combined effect of how the test-cd was burned, room interactions, dirty power (specifically, un-grounded outlets), normal performance of the test tones, and unadulterated psychosis, and/or stupidity on the part of the operator?
dog_or_man
caesar148's avatar
caesar148
9 posts
 
Try moving the speaker to different position in the room. If it persist, try a different speaker. Ruptured cone or panel have been know to resonate at a certain frequency and produce the characteristics you mentioned. Sometimes it can be a loose wire hitting the cone.

You didn't mention which amp you are having trouble with but it is very unlikely to be an electronic problem. If the problem persist, the best bet would be to bring it to a service technician.
dog_or_man OP
68 posts
 
Well I've got a problem than I'm relatively confident can't be explained by speakers or room-response, most notably because it's intermittent.

I've had this persistent difficulty in the behavior of my gear for some time, now, and it's bad enough that non-audiophiles can hear it. I haven't been using the test-tones for long enough to say any of the following things about them, specifically, but with regular source material the problem has been...

a) unpleasant enough that my girlfriend can tell the difference
b) sometimes absent after powering-down and re-connecting everything
c) global to different source components
d) global to a different house, a friend's speakers and wall outlet
e) neither more or less likely during the day or night
f) not invokable by any known means if not already present by itself

At someone else's suggestion I just tried to run the test tone with two different pairs of speakers, and couldn't get any of the pathologies described in my OP to happen, with the original pair on which I'd been hearing all the problems yesterday.

A member of another forum also thinks that electronic explanations are unlikely, so I certainly don't mean to come across as having rejected that advice -- I just don't know how to reconcile what's been happening with any other "class" of possible explanations.
audphile1's avatar
audphile1
4,169 posts
 
is it buzzing or humming? it is unclear from both of your posts what exactly the problem is.

You may have something as simple as a ground loop. have you tried cheater plugs or ground loop isolator? do you have a cable tv near your system or on the same circuit?
what are your components? all of them including the non-McCormack gear. What have you attempted to fix the problem?
Provide more detail. your description is not really clear.
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