Using a passive subwoofer with my stereo?

Question

I have a new stereo reciever but I dont have a powered subwoofer rca output OR a subwoofer crossover, I tried hooking my passive subwoofer into the "Speaker B" terminals and it played not only the bass but the entire frequency range! what do I need to be able to hook up my passive sub to my stereo?

Answer 1

If you only have 2-channel and not Dolby Surround/Prologic then you have the same signal going to A and B alike. You are not going to be able to control the B outputs to sound different. You may also have impedance matching problems that could harm your amp!

If you DO have a multichannel amp, such as 5.1 there is bound to be a channel for it andyou may not understand how to use it.

If you have some plastic thing from Wal-Mart that's already operating with 6 ohm speakers likely or otherwise then use one of the RCA outputs (tape/aux out).

If you have none of these, you should have bought a more capable receiver, that is all there is to it.

Always ask many questions before buying and you will thank yourself later.

Answer 2

Your situation with "speakers B" indicates that there is no crossover network inside your subwoofer. That's unusual  these days. It was more common in the distant past.

You can try going to Radio Shack and purchasing lowpass filters (capasitors) that roll off at about 120 hz. You'll have to solder them onto your speaker wires.

Or, you can buy a crossover network designed to run a subwoofer. This one is inexpesive: $8 http://www.fcsurplus.ca/shopping/shopexd...

You can s***w it onto the back of the sub, or even inside!

GKK's amplifier module from MCM Electronics is overkill. You cannot use the amplifier since you have no line-level out of your receiver. I'd still suggest the $8 crossover network as the easiest, most affordable solution.

Edit:

Let me try this again...

A subwoofer amplifier has two things inside: An amplifier and a crossover network. If your input is line level, the signal is sent through the crossover and the various stages of the amplifier and off to the driver. If you connect an external amplifier, such as an amp inside a stereo receiver, to the speaker level (high current) inputs, the signal goes through the crossover and off to the driver, bypassing the amplifier.

So, it's not bad that there is an amplifier inside the subwoofer amplifier box. It's just that you won't be using it. What you need in that box is the crossover network. My point is, why pay (around $80) for an amp and a crossover when all you will be using is the crossover? You can buy a crossover for less than $10.

Answer 3

Is this only one subwoofer with one voice coil? If so, your best bet would be an add on subwoofer only amplifier module.  They come pre made up and have speaker level inputs as well as line level inputs so you can hook them up to your speakers since you don't have line level output on your stereo.

http://www.mcmelectronics.com/product/50...

Another possibility - especially if you have dual voice coil subwoofer would be a passive low pass filter.

This link talks about filters and gives information about how low pass filters work.

http://www.the12volt.com/caraudio/cross....

edited ...

the poster below me is incorrect.  I suggested the amplifer because it HAS speaker level inputs.  I would not have suggested it if it did not have them.

edited once more.

subwoofer amplifier speaker level inputs do not bypass the amplifier.

http://www.crutchfieldadvisor.com/S-ImI4...