Axiom Home Page Forums General Discussion Technical Questions Scratchy Sound Problem - Please Help!

I am having a problem with my new home theater setup. I am running 5 Axiom speakers (VP 150, M22, QS8's)with a SVS sub and a HK525 all connected with RCA 14 guage wiring with gold connectors. The problem I have is that I get a scratchy sound on the diologue when someone is yelling in the media content (peak sounds). Now I thought it was a problem with the reciever so I got a replacement from J&R and still have the same problem. I also thought it was a problem with the speaker so I switched my center with one of the front surrounds and still get the same noise. I also tried new speaker wire and that didn't help. This noise happens on all sources, regular cable (analog) and DVD (digital coax). I am running out ideas on what it could be. The only things I can think of are dirty power fromt the wall or that the replacement reciever is bad as well. What do you guys think? I was thinking about buying a power conditioner and seeing if that fixes it. I can probably get another reciever fron J&R but I am only going to request it as a last resort. I am running out of time on the replacement window (10 days) so any quick help would be appreciated. Thanks everyone!

Most of us read all 5 of the boards. Please don't cross post!


Does this happen at all volumes? It's possible the receiver is clipping (design flaw or inability) or that your second one is bad as well.

When you listen in stereo, do you hear clipping on the dialog? That could indicate something as well, although I can't think what at the moment ;-)

It might be because the VP150 is a 6-ohm speaker (although the 525 should be able to handle it).

What I'd try doing is forcing the receiver into stereo mode (onlt the L,R, and sub channels active) to see if the crackling still occurs when you watch DVDs.

Sorry about the cross post, here is an update. I tried the monster power conditioner - no help. Next I tried putting it in stereo mode - no help. After that I tried another reciever - no help. Tried another optical cable - no help. Then I tried another reciever, wire, DVD player and speaker, basically a new system and still get that noise. My test sound is in Lord of the Rings Two Towers, Chapter 9 where everyone on horses surrounds the 3 men. The guy on the horse asks them who they are and the dwarf replies, "Give me your name horse rider and I shall give you mine." In that line I get a scratchy sound twice. Once after Give and the other after "I". If any of you have this movie and can go to that part and tell me if it is common I would appreciate it. I picked that scene cause I remember it is the first time I heard distortion. Some movies are bad and some movies I can barely hear it. One movie that was bad was Identity, lots of yelling. I don't know what to do now.

lets back track a bit....

The speakers and sub are calibrated using an SPL meter? How does it sound with music?

-curtis

Is the scratchy noise heard only on the center channel? Or is it from all 5 channels? When you sufficiently turn down the volume knob, does the noise go away even at the "problematic" peak passages?

I would also make sure that there is nothing in your room that rattles when exposed to a loud sound. This sounds dumb, but it actually happens and sometimes those rattling things give you an exact impression of distorted sound quality.

Sounds pretty good with music as far as I can tell. The sound happens from the center only because that is where the voices come from. When I switch to stereo mode it also comes from the frond surronds. I have not noticed a distortion in the rears. It only happens when someone is yelling in a movie (peak noise). All the levels are calibrated correctly with an SPL and the volume is not excessivly high. There is nothing in the room that can rattle.

poltergeists...

In all seriousness, this is pretty baffling. All the ideas I have as to the cause have already been suggested and ruled out. Hmmm...

I'm also puzzled CM. Forget "dirty power", essentially a myth which would affect all channels if it existed. One thing I don't understand is "RCA 14 gauge wiring". Are you using a coaxial cable to the sub and regular bare speaker wire to the speakers?

I just meant it was RCA brand Speaker cable. Just regular speaker cable. The only thing I can think of is some type of interference. Is that common?

Okay. Next, any unusual form of external interference should affect all sources and all channels equally and at all times. Just to further clarify, you have the speakers directly connected to the 525, not in any way through the sub, and you're using a coaxial cable to the low level sub input from the 525's sub output?

I can't help thinking that the scratchy sound originates from your source. You mention: "This noise happens on all sources, regular cable (analog) and DVD (digital coax)" but you haven't described what you are using. If you are talking about a CD or DVD player and you have tried hooking it up both ways, then that is the first place I would look.

Speakers are conneceted straight to the reciever. The content I am using are DVD's to test. I even tried a second DVD player.

cmuajp,

You haven't answered one question: When you sufficiently turn down the volume knob while going through the problematic passage, does the noise/distortion still persist?

I will try that this evening and let you all know. Again thanks for all the help is it nice to know that this board is so responsive.

I had what sounds like the same problem. I ended up finding a CD that played a bunch of the right frequency and would cause the scratchy, buzzing noise at loud volumes. It had been happening only a once or twice during a movie if at all.

It ended up that the top midrange driver on my M22 needed to be tightened down a bit more because after I got my allen wrench out and tightened it up a bit, it went away.

Hope this helps.

I will try tightening the drivers tonight. Someone on another board said that by changing the speakers from small to large fixed the problem for him. Do you think this is a good long term fix if it works?

I don't see how the speaker size setting on the receiver could help. The only difference between small and large is the frequencies sent to the speaker. If anything, I'd expect it to help the other way around (by setting it to small instead of large).

No flames please.....but have you tried different speakers?

-curtis

I tried changing it to large and had no sucess. I have tried changing the center with the front left and I still get the same distortion. Last night I was watching Digital Cable and heard distortion on some parts (scratchy noise). I haven't tried tightening the drivers yet but it is worth a shot. It really does sound like the tweeters are not working correctly but the chances that both the center and the FL are bad are slim.

Ask a friend to temporarily lend you a receiver/amp/pre. Attach all your same devices and check for the scratchy stuff. If you still got it ... its one of your components...if not the 2nd receiver is a dud.

I actually meant try different speakers all together.

My wildest, long-shot guess is, Curtis is suggesting another brand such as, perhaps, Ascend.

Not really, but they would be a fine choice. But just try anything and see what the results are. It seems to me that the options are running out.

CM,since you said that the distortion appeared from the main speakers rather than the center when you switched to stereo, it's pretty clear that the speakers aren't the problem(Curtis's comment was tongue-in-cheek, of course)since there would have to be multiple defects. A somewhat unlikely, but far less remote possibility is that both samples of the 525 are in fact distorting on center channel material. As Sat suggested, if you can possibly borrow a different receiver you could check that.

John,
Actually I was more serious than not. He does say in the thread that it also comes from the other channels, it is just more noticeable in the center because of dialogue.
-curtis