Connecting the Sub

[Hi Ho]

My new home theater reciever just came and I am going to set it up. However I am a bit confused on how to connect the sub woofer. My Polk sub has an input for left and right. In the manual it says to use a splitter if the reciever has a single subwoofer out. I have a splitter lying around somewhare but I can't find it. I don't get why I would have to have a stereo input to a subwoofer. Can't I just connect it to the left input on the sub?

[mr_spider3]

yeah you can but the wattage and all that might split making the right one louder, well seem louder because the left one will be half a loud. try it see what happens, i could be wrong.

[Hi Ho]

There is no left and right sub. There is only one. The reciever, like most recievers, has a single monural output. My sub, however, has a stereo input. That is what I cannot figure out. I find in the manual that hooking it up to both will bypass the cut-off control in the sub. I have it hooked up with one input right now and it is working fine. The only problem is a noticable hum that emits from the sub whenever it is on. It is probably due to the cable I made out of lamp wire. Any suggestions on a decent quality, low cost cable?

[mr_spider3]

i wouldnt use lamp wire, use speaker wire! when does the hum occur? is it when u just turn it on or is it always there? i'll look for some wire thats not to expensive.

[mr_spider3]

i found some, i would recommend either 12 gauge or 8 gauge. they have both and there prob. the cheapest you'll find anywhere. http://www.partsexpress.com/webpage....&WebPage_ID=40

[SonicVanguard]

The Polk design is simply maximizing it's amplifier. It's not stereo, but the speaker is being fired by two rather than one amp. That allows the unit to run cooler and have more headroom.

As for your speaker wire, you can use lamp cord (zip cord), that's all speaker cable is -nothing more and don't ever let someone tell you different. We use zip cord for multi-million dollar audio/video installations all the time. You'll hear all this talk about dielectically injected this and that - what a crock. No one, and I mean no one, can hear the difference from basic vip cord to say Monster ZR cable.

The one problem with creating your own cables is the connections - if they are not terminated properly, you could introduce noise or hum. Of course your hum could be associated with a poor ground or uncommon ground. I doubt the sub or reciever have ground pins, but they certainly should have safety plugs (one plug is wider than the other). Make certain they are plugged into the same source - that will take care of any uncommon grounding that may occur.

As far as the cables, I'd just head over to BestBuy and grab a 1 male to 2 female splitter and two 12ft Acoustic Research sub cables. They've heavy duty so they'll take abuse, and they don't cost a ton. just don't let them talk you into Monster cable - they just aren't worth it.

Dave.

[not important]

Your getting the hum because only one channel is hooked to the sub. If the manual says hook both channels, or use a Y-Adapter, then it needs both L+R input to perform correctly.

[Hi Ho]

I know the Monster Cables aren't worth it. I have always used lamp wire because I know that "speaker wire" is the same thing. By the same source, do you mean the same curcuit? The sub is on the right wall in the middle of the room about 10 feet from the receiver. They are both on the same curcuit. There is a turtle tank with a filter pump and a flourecent light that the cable runs past but turning those things off doesn't help. I had read that shielded coaxial cable is better for a sub. Is that what I need? Neither the sub or the reciever have ground plugs. I guess I will have to buy another splitter even though I know I have wone somewhere. It seems that things lay around forever when I don't need them but as soon as I need them they dissapear.

[Hi Ho]

Bump.... Glc pushed this way down with the flood of posts he made yesterday.

[SonicVanguard]

Originally posted by Hi Ho By the same source, do you mean the same curcuit? ... I had read that shielded coaxial cable is better for a sub. Is that what I need?

Same source = same circuit.

Just a decent sub cable will do - Acoustic Research's sub cable is shielded.

If your reciever is plugged into a powerstrip, try plugging the sub into the same strip. There is also a cahnce that your home's wiring has RF interference - it's not uncommon. If that's the case, look at the lower cost power regulators. This is one place Monster does shine - thier power supplies are great, even the $80 ones. They clean the line of RF and EM interference.

Dave.

[Hi Ho]

I did some more trouble shooting and thought I had found the source of the hum. I had turned off the reciever and the sub was still humming. I turned off the turtle tank filter pump and the humming stopped. However, the next day I tried to do it again with the reciever off and the humming did not stop. I do not remember if the computers were off the first time or not. They are on the other side of the house. I don't remeber if the fridge was running either. I will buy a cable and see if that helps.

[Hi Ho]

I did more troubleshooting. When the sub is turned on, the pump and light are on, and the reciever is off there is very little hum. When I turn the reciever on the hum get very noticable and annoying. I don't think a shielded cable would help. Would it? It's hard to plug the sub into the same power strip because the sub is 15 feet away.

[SonicVanguard]

Sounds like a grounding issue (uncommon or messed up ground) or RF interference.

I know it's difficult, but the sub really should be plugged into the same strip as the reciever. That should give them a common ground. But if the florecent light is on the same circuit, you still could be SOL. If that's the case, you'll need some way to isolate either the light, or your audio equipment. The easiest way to do that is some form of power center that can contain or isolate the noisy circuit from your other equipment. Beyond a power center, isolating the circuit can be a bear. We did a rather large audio/video system in a church about three years ago that had the same annoying hum. We found the culprit to be one room the church never had converted from florencent lighting - and it was on the other side of the church from the audio gear. But it still caused us a day of finding the problem and them combating the problem.

Good luck.

Dave.

[Hi Ho]

I plugged the sub into the same power strip and it did not help so I put it back where it was. I am certain that the ground is common and not messed up. I used a curcuit tester to make sure. Turning the flourecent light off makes no difference. When I turn the reciever off the hum gets much quieter.

[SonicVanguard]

Unless there are other flourecent lights on in the house, my guess is RF interference or a serious shielding issue.

Or, the sub is just bad. Can you try the sub/receiver combo outside of the house somewhere (a friend's maybe)?? That would tell you if it's something in your house (wiring, RG or EM interference).

Dave.

[Hi Ho]

Well now that I think about it, almost all of the lights in my house are compact flourecents. The only regular on eis on the turtle tank. Do compacts effect a curcuit as much as a regular? I still have yet to try a sub cable. That will be my next step. The sub did not hum when I had it hooked up to my old reciever but it was right next to the reciever and kooked up with a very short piece of speaker cable through the "speaker level inputs".

[Hi Ho]

I bought a fiber-optic cable to hook up the DVD player and I cannot believer how much of a difference it made. The sound is so clear and much more defined. Another thing it did was almost completely eliminate the hum in the sub. When I switch it to "digital input" the hum goes away. What does that mean?

[SonicVanguard]

That would indicate that there is some sort of interference in your analog input - most lilkely RF interference. But it could be EM as well. Digital lines (fiber or toslink and coax) are not going to be effected by RF or EM interference.

Dave.