Old Sub, New System

[jmtb02]

Hello,

I have a non-powered subwoofer that takes speaker cable (+/-) in, and an amplifier that takes one RCA-style connection in (Pre-out, it says). I have already tried buying a cable that has two speaker cables on one side, and one RCA connector on the other, but I am not getting any sound.

Does anyone have any suggestions? The receiver is an AVR 146 Harmon Kardon, and the speaker is some LG system that came with a all-in-one.

Thanks for your help -J

 

[MDS]

If the sub also has speaker level outputs you'd wire the front left and right speakers to the inputs of the sub and then connect the front speakers to the outputs of the sub. The receiver would then power the sub but that is a heavy load for it to drive.

If the sub does not have speaker level outputs you'd have to wire the front speakers to the A terminals and the sub to the B terminals. That is also very hard for the receiver to drive.

The last option would be to buy an amplifier (or use another receiver) and connect the sub pre-out of the HK to the amp and the subwoofer speaker terminals to the amp.

 

[mtrycrafts]

Hello,

I have a non-powered subwoofer that takes speaker cable (+/-) in, and an amplifier that takes one RCA-style connection in (Pre-out, it says). I have already tried buying a cable that has two speaker cables on one side, and one RCA connector on the other, but I am not getting any sound.

Does anyone have any suggestions? The receiver is an AVR 146 Harmon Kardon, and the speaker is some LG system that came with a all-in-one.

Thanks for your help -J

Need a bit more info to help better.
You have a passive sub.
You have an amp. Is that a power amp? A stand alone amp or part of a receiver, or what?

If you have a stand alone amp, you need an interconnect cable with RCA type plugs on both end, one into the LFE/sub out from the receiver/processor to one channel of that stand alone amp. On that same channel of that amp, standard speaker wire to the sub, no RCA plugs on either amp, just bare wire, banana plug or spades.

 

[jmtb02]

Need a bit more info to help better.
You have a passive sub.
You have an amp. Is that a power amp? A stand alone amp or part of a receiver, or what?

If you have a stand alone amp, you need an interconnect cable with RCA type plugs on both end, one into the LFE/sub out from the receiver/processor to one channel of that stand alone amp. On that same channel of that amp, standard speaker wire to the sub, no RCA plugs on either amp, just bare wire, banana plug or spades.

Sorry, I misspoke. It's a Harmon Kardon receiver, no amplifier anywhere.

Non-powered Subwoofer has: Red Speaker Wire in, Black Speaker Wire in.

Receiver has: Preamp Subwoofer In (RCA style single connector).

I bought: A black and red speaker wire to single rca cable.

 

[whitestone]

If I understand this right, you need a sub output from your reciever to an amp. Then the amp output to your passive sub.

 

[Adam]

jmtb02, just to make sure that it's clear, you can't power the sub through the RCA subwoofer output from your receiver. The RCA jack sends out a very low power signal, so when you connect that to your subwoofer, you won't hear anything. The cone in the subwoofer needs to be powered just like your other speakers. So, like the others have said, you'll need to use an amplifier.

You can run it from your receiver (which contains amplifiers), but I don't think that you could control the frequencies going to your subwoofer versus your speakers doing it that way, so it might not sound right. A separate amp would be best, and using an old receiver (like MDS said) is a nice, inexpensive option if you have one around. I'm actually powering a sub using an amp from a set of computer speakers, but that required me to modify some wiring inside of the box...an option if you're good at that kind of stuff.

 

[no. 5]

I bought: A black and red speaker wire to single rca cable.

The reason that you aren’t getting any sound using that cable is because the RCA jack it’s plugged into (the subwoofer pre-out) is line level, it’s not meant to and can not drive a speaker; its maximum output is around two volts.

If you are intent on keeping the subwoofer from the LG system, you would need a amplifier to power it; something like this could work.

 

[whitestone]

The reason that you aren’t getting any sound using that cable is because the RCA jack it’s plugged into (the subwoofer pre-out) is line level, it’s not meant to and can not drive a speaker; its maximum output is around two volts.

If you are intent on keeping the subwoofer from the LG system, you would need a amplifier to power it; something like this could work.

Good find no.5 but do you think the LG sub could handle the power?

 

[no. 5]

Good find no.5 but do you think the LG sub could handle the power?

The more applicable question may be "can the AudioSource handle the impedance".

I have no idea what the power handling of the LG sub is, but even if it can’t handle that much, I don't think it will be a big problem - as long as the volume isn’t too high.

 

[whitestone]

True enough.

 

[jmtb02]

Thanks for all the help, and thanks to everyone else for their input as well. At this point, my LG subwoofer is not even worth getting that amplifier for, and I might as well just get a new compatible subwoofer and sell the old LG subwoofer. I knew very little about recievers, speakers, and subwoofers before venturing here... thanks for all the help and knowledge .