LOUD hum in RSW-15

[FrankD]

Hi ya'll. I just bought a brand-new RSW-15. There is a Significant hum from the driver, 60 cycles. Really, it is loud as all hell, scary even.

I have never had any problem with bad grounds, the rest of the system is as quiet as you can imagine... I have searched the boards for hum, etc, and I know the following things:

1) The unit ships with a 2-prong plug, so the cheater plug is no help.

2) No matter what outlet in the apartment I plug into, it is still humming.

3) The power cord is well away from the line-level cables

4) The Subwoofer line-level cable is a brand-new cable.

5) The pre-amp is the Aragon Soundstage, so I wouldn't expect a problem there. Menu settings on the pre-amp have no effect.

6) The hum persists when Everything in the apartment is turned off (lights, PC, Amps, you name it)

7) The only thing that affects it is to turn the crossover level below 60 Hz (as you can imagine)

8) The gain knob on the side of the unit has no effect on the hum

I am so ready to answer questions on this.... I have run out of things to try.

Thanks all, in advance.

F

[FrankD]

Just a little more, in terms of data points (I have been mucking about with it for a while now...)

I remove the Line Ins, and power it up with no inputs, and there is still a hum (albeit not as loud.) This does not seem to be right to me At All.

Further, I have been all over the websites of Klipsch and other manufacturers, but (strangely) the same text keeps popping up ....

"Usually this hum is caused by a "ground loop". This is a problem that is sometimes created when connecting two or more electrical components together. Most times the problem does not lie in any one particular unit, but in how they're connected.

If your subwoofer is connected to a different wall outlet than your system, move the subwoofer plug to the same outlet. This may require an extension cord just for the trial. If it works, you can permanently move the sub or use an extension cord. Please be sure to use a heavy duty UL approved extension cord."

I thought that was strange.

[Stephen328]

Man ,thats awful, I know how annoying subwoofer humm can be, especially in movies. I'm not sure how much help this will be, but here's how I fixed my subwoofer humm problem: When I first noticed the humm (very annoying), I immediatly did most of the checks you did, My primary suspiscion was the computer, but after turning it off the humm persisted. So I gave up for a while. Then on night there was an electrical storm, so I thought it best to unplug the old computer. Later that night, wow no humm. I rejoyced. Anyway, after playing around with my computer power connection, I found it to be the grounder. Whenever I plugged the third plug (the grounder) in, the humm persisted. I understand that other devices, other than computers can do the same thing. Now I just unplug my computer when I want to listen to anything at a high volume. Not the most convenient fix, but i'm happy.

[skonopa]

I don't know if this is the solution to your specific problem, but it does bring up a question that I have. Does having all your HT gear on a dedicated circuit help with eliminating hums? I have never had problems with things humming in my system (I had now gone through 3 systems). I did not realize this at first, but only found out recently when I had to cut the power to the upstairs to replace a broken fire alarm. The ciruit breakers where not labeled very well and when I cut them off one at a time to determine which did what, I noticed that my HT gear had its own dedicated circuit. I then remembered that the folks that lived in this house before me had a pretty big, kick-butt setup themselves (although I have no friggan idea exactly what they had, but I remember seeing it briefly when I was initially checking this place out to buy it - I do remember that they did have one of those huge 8 foot satellite dishes, which they took with them when they moved out).

I still have to figure out where those in-wall speaker hook ups I found down in the game room go to. I may have a set of in-wall speakers down there and not realize it, although I cannot seem to find what would resemble speaker grills on any of the walls down there. But I digress....

[TheEAR]

FrankD,

As I read what you tried may I ask is the BUZZ(noise)still present when you disconect your inteconnect cable from the subwoofer?

Sometimes even shielded cables can have a HUGE effect on audible buzz you hear from amps or amplified subs.

Try with subwoofer cable placement(yes as strange as it sounds)it can sometimes work.It worked for my two ATI 1505 and 2505 power amps!I had a loud buzz as soon as the amp was on,I tried even $2000 AC conditioners,$500 power cables and High-End speaker cables...NO EFFECT.After by pure luck I moved my right front and right rear speaker cable and NO MORE BUZZ!

I placed both cables in an 8 type loopand the buzz is no more! Try it

If all fails contact Klipsch,my RSW10 is silent when it needs to be.As silent as my best powered subs.

Good luck

[FrankD]

Ok... round about 4 AM (after trying cheater plugs on everything I own, individually) I discovered that a cheater plug on the main power distribution (the Isobar) itself, was the trick. I am not sure how comfortable I am with everything cheated, but there you go, the noise is greatly lessened.

Ear, to your question, with the interconnects disconnected, there is no noise. When I discovered this, I moved them Well away from the speaker and power cables. No effect. Anything that was attached to the sub via that cable (or any others) would hum. (Did I mention how loud the hum is?)

I stands to reason that sub manufacturers would be able to detect a 60 cycle constant signal, and notch filter it out. Would it be so difficult to determine the difference between arrived-at 60 hz "music" and constant 60 Hz "noise". The more I think about that, it seems like this could only happen with some processing of the sound coming in, resulting in a delay.. hmm. maybe not so possible...

[TheEAR]

Yes I know just how loud this hum can be,its almost hike a bee hive.Imagine now two pairs of RF-7's and the RC-7 buzzing!

In my case the problem resided in wires,in some cases only cheater plugs cure the problem.

[boa12]

" Does having all your HT gear on a dedicated circuit help with eliminating hums? "

skop, i've been thru all the wringers on this before & i'll just say that on my main sys i have a dedicated 20 amp circuit & i still had ground loop hum. it was from the cable tv box which of course had a ground different from my electrical system. that's the usual suspect for a ground loop - cable tv or dss attached to the sys in some way or another.

& w/ all my various tv/cable attachments to my sys, the only practical way for me was to use the cheater plugs on all components w/ safety grounds (3 prong plugs) & to float all those grounds (except for the cable tv which of course has its own ground). despite the safety issues.

i'm no electrician, but in a nutshell the dif grounds will cause voltage to run along the interconnect shielding & hence that nasty buzz or hum. i couldn't even find an electrician that could figure it out.

[boa12]

& btw, yes I did try ground loop isolators & they worked some but not enough to my liking.

if you have cable tv or dss hooked up to the receiver/prepro in some way, you may want to try disconnecting that & see if it eliminates the noise. if it does enough to your liking, & if you don't like using the cheater plug(s), you way want to get a ground loop isolator like the mondial magic box.

[skonopa]

Fortunatly, I have never encountered any ground loop humming problems in my setup, and I do have a DSS reciever in the mix. I was just curious about having the HT on a seperate circuit, which I would imagine helps eliminate interferance from other things in the house.

I still remember living in PA, whenever somebody turned on the garbage disposal in the kitchen, the TV would go all "funny" and an annoying buzz would come out of the then high-tech Sony HT we had. Same thing when my mother decided she needed to vacuum the floor somewhere in the house. It was really annoying when trying to watch TV, or more especially while playing video games on the venerable Atari 2600 we had at the time.

[boa12]

skop, yeah for that a dedicated circuit would be good. i believe there that's emi trasmitted directly over the circuit. anyway i better shut-up or i'm going to get clobbered by the guys that really know electricity.

right now i'm only getting some rf from the radio station a few blocks away over my surround speaks (long cable runs). need to call those engineers at the station again & see if they have some of those clamp-ons for speaker cables. i've found those guys are real sensitive to noise complaints (& avoiding contact from the fcc).

[FrankD]

I had not even considered that proximity to radio stations might be a problem. I live right in Boston, and am surrounded by hundreds of those little college stations, I bet. I also have a few 40-50 foot cable runs to the rear speakers.

Hmmm. I am interested in the things you mentioned that you could get for your cables? Could you briefly expound on them?

Thanks

F

[boa12]

F, if you're getting rf from the long speaker cable runs then you'll only hear it on those speaks. & it should sound much dif than what you're describing which sounds more like a ground loop. should be much higher frequency. in my case i can hear the station out of both rear speaks' tweeters just like its a radio though not real loud.

if you just want to pick up some of those devices for rf noise, I heard Radio Shack carries 'em & they don't cost much. i haven't looked into them yet - i was going to contact the engineers at the station 1st.

i saw a post by Justin where he mentioned a few/sources & their cost. maybe he or somebody else could help find 'em...

[Guest BobG]

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