Sub interference?

[murl]

Mods feel free to move this if it isn't in the correct place, I am new here!

So I have always left my Kenwood powered sub beside the TV and stand right up front, well I got married, moved, took it with me and my wife decided she wanted it beside the couch. I procede to move the sub beside the couch no problem right? I run the single RCA cable under the woodwork with a surround wire, I got the cable from monoprice.com, just the 25ft single M/M cable. I tried to post the link but I have to have more post to do that. So if you want to see the exact cable I bought I can post it in a reply.



I plug everything in and the sub is humming. The cable was obviously picking up some interference from somewhere..........I had bought two of those 25ft. cables which I only used one. There are no couplers in line nothing one 25ft cable. I grabbed the brand new 25ft cable plugged it in the sub ran it straight across the living room floor where I could see it, plugged it into the receiver and still had the interference. So then I grab the sub from behind the couch sit it back in front of the TV plug the 6ft RCA in that came with it and no interference.

Could it really be just the cable, the length, any other ideas?

Any solutions?

I really appreciate the help.

 

[EJ1]

You might try a ground loop isolator. Maybe others will chime in.

 

[murl]

I had thought about that, I didn't know if that would be the correct thing in this situation, or if it would fix the problem. I used one in a car for alternator noise. If it will work here I will go get one tmrw. Do they usually fix the problem?

Thanks for the advice

 

[murl]

Ground loop isolator didn't work, any other ideas on cables or anything? It really needs to fit under the woodwork.

 

[phlakvest]

I assume your also plugging the sub in on the other side of the room?

Can you run an extension cord from where you previously plugged the sub in.
See if the hum goes away. If it doesn't then you just ruled the outlet.

Your sub probably isn't grounded through the power outlet so it probably wont make a difference, but its worth a try.

 

[murl]

I assume your also plugging the sub in on the other side of the room?

Can you run an extension cord from where you previously plugged the sub in.
See if the hum goes away. If it doesn't then you just ruled the outlet.

Your sub probably isn't grounded through the power outlet so it probably wont make a difference, but its worth a try.

I did try that, and no the sub is not grounded. I thought that could be it but I ran the extension cord today.

 

[ninja12]

I did try that, and no the sub is not grounded. I thought that could be it but I ran the extension cord today.

Have you tried an XLR Cable? Since you have a long run, you might need to switch from RCA to XLR. XLR Cables are good for long runs.

 

[mtrycrafts]

Ground loop isolator didn't work, any other ideas on cables or anything? It really needs to fit under the woodwork.

Where did you connect the ground loop isolator?
I bet you may have the cable TV somehow connected to your audio system, even if it goes to the TV only but you have something from the audio system also going to the TV?
You indicated under the woodwork. Is that in a crawl space? Any 120V wiring nearby, less than 1ft?

 

[murl]

I connected one end of the ground loop isolator to the RCA and the other end to the sub, the isolator was about 6" from the sub. The only thing I have hooked up to the TV right now or the Receiver is a DVD player via HDMI to TV and digital coaxial to receiver. When I say under the woodwork I mean under the baseboard right below the carpet. Keep in mind that the sub hummed while it was sitting in the middle of the floor, it wasn't next to the wall, plugs, anything, the rca was also in the middle of the floor.

 

[TLS Guy]

Mods feel free to move this if it isn't in the correct place, I am new here!

So I have always left my Kenwood powered sub beside the TV and stand right up front, well I got married, moved, took it with me and my wife decided she wanted it beside the couch. I procede to move the sub beside the couch no problem right? I run the single RCA cable under the woodwork with a surround wire, I got the cable from monoprice.com, just the 25ft single M/M cable. I tried to post the link but I have to have more post to do that. So if you want to see the exact cable I bought I can post it in a reply.



I plug everything in and the sub is humming. The cable was obviously picking up some interference from somewhere..........I had bought two of those 25ft. cables which I only used one. There are no couplers in line nothing one 25ft cable. I grabbed the brand new 25ft cable plugged it in the sub ran it straight across the living room floor where I could see it, plugged it into the receiver and still had the interference. So then I grab the sub from behind the couch sit it back in front of the TV plug the 6ft RCA in that came with it and no interference.

Could it really be just the cable, the length, any other ideas?

Any solutions?

I really appreciate the help.

I think that is too long for a high impedance unbalanced cable run.

What happens of you use the cable you had before, with the sub close to the receiver?

Please post back and let us know.

 

[mtrycrafts]

I connected one end of the ground loop isolator to the RCA and the other end to the sub, the isolator was about 6" from the sub. The only thing I have hooked up to the TV right now or the Receiver is a DVD player via HDMI to TV and digital coaxial to receiver. When I say under the woodwork I mean under the baseboard right below the carpet. Keep in mind that the sub hummed while it was sitting in the middle of the floor, it wasn't next to the wall, plugs, anything, the rca was also in the middle of the floor.

Next question: do you have cable TV connected to the TV in any shape or form?

Where you placed the isolator is the wrong place. Such isolators are placed in the cable TV line at the wall as the cable TV is what causes most of the ground loops.