Hiss, hum bad for speakers?

I've got some kind of hiss/hum going on here. Not sure if it is feedback from the high-level connection from my amp to my REL sub or just from connecting multiple amps into wall sockets. The question is, is this hum, hiss, high wine bad for my speakers and gear?
hiss/high hat, hum/ bass note or synth, whine/flute. I doubt the speakers know the difference. DO you have one of those dimmer equiped halogen lights on the circut? they will make all kinds of racket through the lines.
No dimmers or halogen lights. My Bryston amp has a ground lift switch, but this doesn't seem to make a difference.

I have the same problem: constant low level hiss/hum coming through my speakers as long as my REL subwoofers (Ihave 2) are on and connected to my amp, even when my amplifier is off. If I turn my RELs off, the hiss/hum goes away. My entire system is on one circuit, so I don't think the problem is ground loop, and I have tried cheater plugs to no avail. Perhaps we should discuss this off line, if no response appears here that turns out to help us both. Maybe we compare notes and figure out a solution.

R. Yee
Are you talking about a clearly audible (loud) hum, or is this something where you have to place your ear close to the speaker to hear? It's a rare system that doesn't produce some of the latter, but the former should be addressed. It's probably not hurting anything, but it certainly won't help your enjoyment of music. I suggest you check the REL connections at the amp and make sure your power cords aren't touching any signal carrying cables.
In my experience, a hum is almost universally associated with a ground loop. Do you have a cable TV or satellite system hooked up to your system? Have you tried to drive your REL from the preamp instead of using the high level connections at the amp?
No cable or satellite hookup, just DVD and CD. I could run the REL from the preamp, but that would activate the bass management and would not be true analog. And yes, the hum/hiss is loud enough to hear from my sitting position. The high level cable from the REL is not really touching any power cords.
How do you connect your sub ? from preamp using RCA terminated cable(s) ? Or from amp using speaker cable(s)?

Either case, replace them with the shielded one.
The REL sub is connected using the supplied high level cable that attaches to both positive terminals on the amp and one ground terminal on the amp. I did this following the REL manual instructions. It is the only way to get proper 2ch music use out of the sub without going through the digital processor. I believe the high level connection is shielded.
I have a REL Strata III hooked to a Rotel RTC-965 preamp and an Adcom 7400 amp using both high and low level connections. I also have a (quiet) hiss. However mine is actually originating from the preamp. The only reason I say this is because you may be looking in the wrong place. Hope this helps.
I too have a REL sub, but no hiss or hum problems. The REL-supplied high level cable is not shielded, but this should not be a problem since speaker level voltages are going down it, and these should not be susceptible to RFI.

Does the hiss / hum go away when the REL is switched off ? How about when the REL is disconnected ? Do both go away or just the hum ? Is the hiss / hum the same regardless of which source you select ? What if you switch all your equipment off one by one ... does the hum or hiss go away at any point ? How about disconnecting major appliances around the house (maybe even isolate by switching off breakers one by one)? These are the steps I'd go through.

Hum is usually a power supply problem (e.g. earth loop). Hiss : I'm not sure : could be any number of reasons. Some amps are quieter than others, some are more / less susceptible to RFI. Shielding is much more important on interconnects than speaker level cables.

So long as both are well below the normal listening level of your music (as I assume they are or it would be more than a minor problem) I can't see why it would cause any problems with the speakers, but I'm no expert in these matters.
After trying cheater plugs on each of a dozen components and then taking them out of the system one at a time, I've recently changed the interconnects from Nordost SPM to Kimber KS1020. The audible hum is now gone!

It's unshielded vs shielded that eliminated the hum in my system. My preference is the faster SPM but the tradeoff to eliminate the hum was worthy of the change. Change the interconnects.
The speaker cable or ICs might be the cause. I will change them out when I get the chance and see if this helps. Thanks.
I have two Rel Stentors. One older model and one newer. When I hooked up the second one recently I had a bad hum problem that I didnt have in the other one. It turned out to be a ground loop problem. I recommend eliminating the chance of it being a ground loop.

I dont know what makes the newer models more seceptable to the hum but the high current cable is a little different in the newer models.
I would say you have a ground loop somewhere. I use 2 Stadiums, no hum at all. All on one curcuit. One time while changing speaker cables, there was a very noticable hum from one of the Stadiums. The ground wire was not connected yet and i forgot to unpower the subs while connecting the new cable. The amp and pre was off of course but the REL was on. After unpowering the sub and connecting the cables and powering up the system, back to normal, no hum. This told me a ground loop caused the hum. I would ck that all connections are secure and in order first. Maybe redue the connections from amp to REL and be sure no loose strands of wire are free. Ck your internal house line connected to the REL for a possible ground problem. Maybe connect the setup to a completly different curcuit to eliminate any possible ground problem in the curcuit. Disconnect one component at a time to isolate the culprit and see if the hum ceases. Hum is usally a ground loop or transformer interferring like mentioned above from others. Call REL and explain the problem, they should be able to help. I think you can call Sumiko in CA, Sumiko is the US distributor for REL. The hum you describe is not normal and should be eliminated. Good Luck!!
Dont forget to check your cable tv for the ground loop also.
I will redo all the connections this weekend and report back. Thanks.
Okay, after pulling out all the cables (and my hair) and redoing them, I have a theory. First, the hum has noticably decreased after reorganizing the wires. This led to an extensive removal and plugging in over every single cable, starting with the setup in straight 2ch audio and then growing the entire home theater around it. What I noticed was that that hum is always present, just quieter. The more connections I add, the louder it gets, until it is just barely audible from the listening position. Then, just out of curiousity, I changed the preamp setting from 2ch direct to dolby pro-logic. Walla, part of the high ringing (the annoying part) dissappeared. Now here is the disturbing part. I do not think that the pre-amp is truly "causing" the ring/hiss/hum. I think that during 2ch mode it is just so sensitive that it is picking up the darned video noise (it still broadcasts that stupid gray screen to the TV even in 2ch direct mode). Madrigal will be getting some irate-customer-email shortly, however, I don't think this is a fixable problem. The unit works fine. It just picks up the extra noise in the system. The unit is quieter during DVD movies, but if I pause the DVD I can actually hear the electonic cycling going on in the DVD player through the speakers until I hit play again. In all honesty, I am talking about a barely discernable noise that I cannot hear during music or movie listening. But after going from my 2ch only system where even the slightest noise was like a 3 alarm fire I guess I am a little picky. Thanks all for the advice.