Axiom Home Page Forums General Discussion Home Theater Subwoofer hum

The power useage is not so much determined by the amp but the signal the amp in given. They have to have a wide range on the gain because of the different signal levels of different sub (pre) outs.

Ok.I think I understand. So the signals coming from the pre-out are not fixed. That would explain it. I was thinking that there would be a standard output level, eg. +/- 5 miilivolt. My background is in chemical engineering so this signal processing stuff is not my bag

Pretty much. Not only from the sub pre outs but from the speaker level inputs and regular pre outs from stereo pre amps.

A line conditioner would most likely solve the problem. But 60Hz noise should never enter the amplifier circuits. It's a result of poor filtering and/or lay-out and/or too few layers on the printed circuit boards.

Try turning down your sub volume -5 db and see what happens...see if the humming is related to the volume setting on the receiver...

Any recommendations here? I have seen that APC sells one but it looked to be $300. But this had more than I need. Do they sell just line filters that can be plugged in or are they hard-wired?

When the sub volume is lower, the receiver does add some hum but only at extremely high levels of volume nearly 0 dB on my HK.

This amount of hum is way less than when I crank up the sub volume at normal receiver volume.

I think there it is either AC noise that is passed through or some noise creeping in from the receiver through the rca cable connectors. I need to get an AC filter and Maybe I'll buy the Axiom or Hsu sub cable? But the Monster cable I use now should work fine. it doesn't seem to be interference because I have pulled the receiver out (temporarilly) and moved the sub cable all by itself with 2 feet of space between it and anything else. That did not help at all.

Mark, yes there's a recommendation: since you've reported no hum at a more normal setting on the sub level control and that it sounds "fantastic", there's no need to do anything, including spending money on any expensive magic power conditioning items.

Exactly. Hammer, SVS even notes that receivers give out sub line-out distortion at higher levels and recommends to set the sub volume at -5 in the receiver, then calibrate for that.

So, I'd pass that recommendation to you, set the "woofer" level to -5 and that will reduce the distortion hum you are getting.

Good idea. And that is just what I'll do...

So if I understand correctly-- you don't recommend going to Mapleshaderecords.com?

BTW-- I like you sig.