Low hum/buzz with subwoofer

[SangYuP]

Hi, I just purchased the Athena AS-P400 subwoofer(bestbuy floor model for $140) and I noticed that there is a low hum/buzz when the subwoofer is on (green light). My previous subwoofer did not buzz/hum and the athena is hookedup exactly the same way as my previous one. It's in the same power outlet and same cable. There are 2 inputs in the back of the subwoofer. One is "direct input"(this bypasses the subwoofers crossover) and when I hook it up to that, it makes the loudest buzz/hum sound. Changing the volume doesn't do anything. I tried using the other input called "subwoofer input" (this uses the crossover) and the buzz/hum was a little quieter. I had the crossover set to 120 since my receiver is set at 80. Anyway, I noticed that when I lower the crossover, the buzz/hum gets quieter and quieter until it goes away if I lower it almost all the way to 45. Does anyone know what the problem is? Do I have a bad subwoofer? I've tried plugging it into a different power outlet and I've tried using different cables to no avail. The only thing that fixes the buzz is lowering the crossover. Any help would be appreciated. Thanks in advance.

 

[Buckeyefan 1]

Hi, I just purchased the Athena AS-P400 subwoofer(bestbuy floor model for $140) and I noticed that there is a low hum/buzz when the subwoofer is on (green light). My previous subwoofer did not buzz/hum and the athena is hookedup exactly the same way as my previous one. It's in the same power outlet and same cable. There are 2 inputs in the back of the subwoofer. One is "direct input"(this bypasses the subwoofers crossover) and when I hook it up to that, it makes the loudest buzz/hum sound. Changing the volume doesn't do anything. I tried using the other input called "subwoofer input" (this uses the crossover) and the buzz/hum was a little quieter. I had the crossover set to 120 since my receiver is set at 80. Anyway, I noticed that when I lower the crossover, the buzz/hum gets quieter and quieter until it goes away if I lower it almost all the way to 45. Does anyone know what the problem is? Do I have a bad subwoofer? I've tried plugging it into a different power outlet and I've tried using different cables to no avail. The only thing that fixes the buzz is lowering the crossover. Any help would be appreciated. Thanks in advance.

You are experiencing a typical 60 cycle hum. Take a .59 cent 3 prong outlet reducer and plug either your cable box or subwoofer into it, then plug it back into the wall. You have a ground loop issue. You will "lift the ground" of the sub or cable box. That should eliminate the hum. I don't recommend this as a long term solution, but it should help for now.

This will help out in the long run:

www.audioholics.com/techtips/setup/avhardware/groundloopcableTV.php

 

[SangYuP]

Thank you for the help. I don't want to sound dumb, but what is a 3 prong reducer and where can I get one? Thanks.

 

[mulester7]

.....Sang, I was thinking grounding hum the whole time I read your post....Buck was too, and gets up earlier than me here lately, haha....please report what you get......

 

[SangYuP]

Is the 3 prong outlet reducer the adaptor where it takes a 3 prong and makes it into 2 prongs? Also, I plug the subwoofer into the back of the receiver or I could plug it into the power bar. I don't plug the sub directly into the wall outlet. So if I were to use the 3 prong reducer, should I use it on the power bar since that has 3 prongs and plug that into the wall? Will that ground everything that is connected to the power bar thus eliminating the hum? By the way, I don't know if this makes any difference, but the hum ONLY comes from the sub and not the other speakers. Thanks.

 

[Buckeyefan 1]

Yes, that's it. Plug the sub's three prong into the two prong reducer then into it's own socket - not the power strip. If that works, then you can try it on the power strip to protect your sub.

 

[aarond]

Also, I plug the subwoofer into the back of the receiver or I could plug it into the power bar.

DO NOT plug the sub into the back of the receiver! They are almost always a low power outlet, 1 amp or less for a cd or dvd player not another amp

 

[SangYuP]

The sub doesn't have 3 prongs...only 2 prongs...but I will try nonetheless. Thanks for your help!

 

[mulester7]

.....Sang, concerning the power cord from your sub....does it have three prongs on the end that you plug into a socket, or two?....either way, plug it into the wall rather than the back of your receiver to start with, and see what you get....and as to which input of the sub you use to input the signal, use the one that manifests less distortion for you....from what I understand about these surround receivers, if you choose the signal input to the sub that is not variable at sub-level, you can then use the LFE function to cut the signal sent to the sub at receiver-level....

 

[SangYuP]

Okay, I've tried using the 3 prong reducer for the sub even though it only has 2 prongs, but that did not make the noise go away. I even tried to use it on the power bar, and that didn't fix it either. Any other ideas? Thank you for both of your help. I really appreciate it.

 

[mulester7]

.....Sang, try the wall socket and seperate the powering of the sub from your system totally.... and is there any post on the sub to run a seperate ground wire?.....

 

[SangYuP]

Yeah, I tried plugging the sub into a different socket away from the rest of the system, but that did not work. As to the post to ground the sub, I don't think there are any. Could it be that I have a bad sub or is it a ground issue? Like I said, this was a floor model and I don't know what kind of abuse it went through although the outside has no visible damage.

 

[Buckeyefan 1]

Yeah, I tried plugging the sub into a different socket away from the rest of the system, but that did not work. As to the post to ground the sub, I don't think there are any. Could it be that I have a bad sub or is it a ground issue? Like I said, this was a floor model and I don't know what kind of abuse it went through although the outside has no visible damage.

If that didn't work, then it could the the amp in the sub. I had a similar problem with my sub, and called the company and they sent me a new amp. Hooked it up and it worked. Most of the time, though, it's a 60Hz hum from a cable box - believe it or not. Try unhooking your cable box, and turning off any lights or fans in the room controlled by "dials" or reostats -sp??.

 

[mulester7]

.....Sang, as badly as I want to help here, I've about run out of suggestions....if your power cord head has three prongs, try it in the wall without the 3-to-2 adapter if the wall socket will accept three prongs....

 

[SangYuP]

I don't have any cable boxes...only the tv, dvd player, and receiver. I'll try turning off the lights, but it's a regular light switch. Thanks for all your help. I really appreciate it. I guess I'll contact athena and see what they have to say.

 

[mulester7]

.....Sang, one last shot....ground the receiver by a wire out the window attached to a piece of metal and bury it....turn the hose on the spot on the dirt also.....

 

[zumbo]

Does your power bar have a common ground screw?
Does your receiver have a common ground screw?

If they both do, try this. Make sure everthing is unplugged from the wall. Use a 12AWG or 14AWG wire and connect the ground screws to each other. Plug your sub into the power bar along with the other components. This grounds the whole system. Plug the power bar in and hit the juice. This may work. Can't hurt.

 

[mulester7]

.....Zumbo, I'm going to take it one step further....when any part of your system is gounded to the house's electrical wiring by inserting your plug into the wall, the whole wiring curcuit acts as an antennae to pick up interference signals even though it is eventually taking everything to ground....I started a long time ago running a wire, doesn't have to be big, say one strand of 16 ga, out the window to dirt that is connected to Mother Earth....I strip the outside end about six inches of bare showing....I wrap it around a copper elbow and bury it about a foot deep in the back of the flowerbed outside the window....I take the hose and drench the covered-back-up hole....I connect the other end to the ground post on my pre-amp....and let's say receiver....I then carefully inspect all other components of my system for ground posts....I run a wire from the ground post of all the components that have such, and go to the ground post of the pre-amp with them....I then form a rat's nest, haha, with about 5 wires on the ground post of the pre-amp....at that point, virtually ALL of my system is grounded to the best ground possible, with no network of interference in the picture....just one, coated, 16-12 ga. wire......

 

[mulester7]

......Gentlemen, I suggest doing one's homework can make $500 speakers sound like more expensive speakers concerning grounding and interference factors....only Y when absolutely necessary, and ground your system asap to the back side of China....(American soil)....

.....Clint, I tried hard on this thread....you owe me one....I'm gonna' post a picture of Danny's dog I snapped the other night....this dog pick-pocketed my wallet and Danny saw him do it so I got the wallet back quick.....smaaaaaart dog....slick....you'd swear he is smiling too, when he's setting you up....I'll let you guys be the judge and go get it and post it next....

 

[mulester7]

http://pg.photos.yahoo.com/ph/mlester77@sbcglobal.net/detail?.dir=6fb7&.dnm=cb08.jpg&.src=ph