Want to confirm, subwoofy making humming noise - volume dependent.

kettlecorn

Read quite a few article and threads but this being my first system and being short on the do-re-mi, I want to confirm before i go out to Radioshack and buy an expensive cable, adapter or what have you.

I recently bought the Polk Audio PSW10 and Polk Monitor 30 speakers. The 2.1 setup is plugged into my Denon home theater receiver. Everything works great in terms of sound and power but there is this low buzzing and humming sound coming from my subwoofer. I had to try really hard to figure out where it was coming from but now I realize it's the sub. It is volume dependent. If I turn up the volume (sub vol knob) higher, the noise gets louder. The noise is ONLY present when my receiver is ON and making an active connection to the subwoofer, making me think that this is a grounding issue or interference type of issue (if that is such a thing). I don't have cable tv or satellite so it is not that signal and changing the input on my receiver from DVD, CD, AUX, etc. does nothing to get rid of the sound. Changing the bass to -12 db and the SW volume levels on my receiver to -12db also has no effect.

What gets rid of the noise - Turning off the receiver. Muting the receiver. Disconnecting the RCA cable in my receiver "SUB OUT" port to the Polk PSW10's InputLEFT (or RIGHT) port. Using "Headphone mode" only. Turning off "Subwoofer" to "NO" in System settings. These all get rid of the sound. Which I think is pretty clear that it has something to do with the RCA connection between the receiver and sub. Can anyone chime in here to confirm?


The connection: I am using a cheap red RCA cable (part of the red, white, yellow cable combo I found in the garage originally for my DVD player). I didnt buy a "dual shielded" (whatever that means) subwoofer cable cause I read it's a waste of money but now I think I'm reading that i may need one for the grounding issue making this noise?


Another thing to note is that when I plug the RCA cable into my receiver and then plug the other end into my subwoofer, the minute the RCA cable connection touches the sub's InputLEFT or InputRIGHT, it sends a signal or something to the sub and the sub makes a big bass BOOM for a second as the connection occurs. I thought i wasn't a good idea cause it could blow the sub out or something but the audio quality was fine so i just left that connection.



Based on all this, I am thinking I need to get a better cable to connect my receiver's LFE out to the PSW10's input OR get a Monster Y-splitter OR both. Any advice here?

The polk PSW10 doesn't have an LFE port, it has TWO audio inputs, one Audio In (L) and one Audio In (R) and the manual says that either 1 will work.
Not sure if this humming/grounding problem is due to the splitter issue or a bad cable or both.

Glowrdr

The sub making noise when being connected is normal. This is just the sub getting grounded while being plugged in. i wouldn't worry about it (Well, I wouldn't keep plugging it in while on, but the noise itself is normal for the situation)

If you're not in any hurry - I would just get a cable from Monoprice.com. Should run you roughly $5-10 depending on the price you need. A high price cable is not the final answer to the worlds problems - but you definately need something more (sub)stancial than the video cables that you got from the garage. That's where I would start, then you can go from there. I'm not ruling out the possiblity of a hardware issue, but the simple fix would be to get a dedicated sub cable. It's a fairly sensitive piece of equipment that warrants it's own cable if you ask me.

In a pinch though, you should be able to find something for roughly $20 at best buy. Just don't rush out and buy some $100 Monster sub cable and expect the world to be a better place.

tonyb

Toss those red yellow white cables in the garbage, go over to a Radio shack,Home depot, Walmart, and get a basic sub cable, while your there, pick up a 2 dollar cheater plug. Thats a plug that takes the 3 prongs on the power cable to the sub and turns it into 2. That will help with any hum you may get. Let us know how your doing on setting it up in the receiver too.

kettlecorn

Okay cool, I'm going to order some sub cables on Amazon. Either this one http://www.amazon.com/Mediabridge-Ultra-Shielded-Subwoofer-Connectors/dp/B003FW0WIK/ref=sr_1_1?s=electronics&ie=UTF8&qid=1323039891&sr=1-1

or this one http://www.amazon.com/Belkin-PureAV-AV20500-25-25-Foot-Subwoofer/dp/B0001XGQTA/ref=sr_1_2?s=electronics&ie=UTF8&qid=1323039891&sr=1-2

Both should work fine right?


Regarding my connection to the receiver, the RCA is connected to my receiver's SUBOUT/LFE out and going to my PSW10's InputIN LEFT. I tried both left and right side and they yield same problem.

I should note that when the subwoofer is turned on and the RCA cable is disconnected from my receiver (with the other end still hooked up to my sub), there's some loud feedback like big buzzing noise like you hear when you place your speakers next to cellphone. I think this crappy cable could be the problem. I'll go out and get some quality cables and report back.

Glowrdr

Either of those will work. Otherwise, here is a 25 footer for $3.42 - http://www.monoprice.com/products/product.asp?c_id=102&cp_id=10236&cs_id=1023601&p_id=621&seq=1&format=2

kettlecorn

Glowrdr wrote: »

Either of those will work. Otherwise, here is a 25 footer for $3.42 - http://www.monoprice.com/products/product.asp?c_id=102&cp_id=10236&cs_id=1023601&p_id=621&seq=1&format=2

Damn wish I saw this earlier. Well the Mediabridge sub cable came and I haven't been able to try it fully yet cause my receiver is airing out in the garage ,but I'm happy to say that there is no feedback or booming when plugging in the cable, even if it's just on one end. Super clean, silence.

Glowrdr

Got rid of the antenna you were using before. lol