# 2.0 amplifier ( how to connet a sub? )



## djloui (Nov 10, 2014)

Hello everyone! I have this JBL Pro Speaker that I bought on christmas. I have it running with a two channel amplifier. The speaker sounds wonderful with good highs and lows. However, I would like to add extra bass to it but my amp is 2.0, meaning that it doesnt have a sub output. So I want to add an underpowered subwoofer I have laying around in my house. How could i connect this sub to the other channel of the amplifier? Is it there something I could put along with the subwoofer such as a Crossover Or Capacitor? tried to connect it but the mids filters.


http://www.amazon.com/gp/aw/d/B00CY...tDescription_secondary_view_div_1452297216400

Thanks


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## ajinfla (May 10, 2009)

Hi djloui, it will be near impossible and impractical to do this passively.
Your best bet is to make the sub active with a sub amp, such as these: http://www.parts-express.com/dayton-audio-sa70-70w-subwoofer-plate-amplifier--300-784
http://www.mcmelectronics.com/product/MCM-CUSTOM-AUDIO-50-6269-/50-6269
They have speaker level ins/outs for hookup. Or, depending on the "unpowered" sub you did not specify, it might make $ense to just buy an active unit.

cheers


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## Wayne A. Pflughaupt (Apr 13, 2006)

Your post if a bit vague, dj. It sounds like you have a single JBL speaker (I assume the one linked) connected to one channel of a stereo amplifier. An “underpowered” sub sounds like one with its own built-in amplifier (aka an “active” sub).

So with all that, it sounds like you want to connect the active sub to the other channel of the stereo amp? That can’t be done. You’ll have to connect the sub to whatever source you have feeding a signal to the stereo amp.

Regards,
Wayne


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## fbov (Aug 28, 2008)

Is Wayne correct that you have one speaker, powered by one channel of your amp? And that you'd like to wire a subwoofer to be powered by the other channel of the amp, but you're hung up on the low-pass filter for the subwoofer? 

This is very unusual, but there is a way to do it, if the amp has a "Tape in/out" and "Tape Monitor" functions. 

Get a "Harrison FMOD" in-line, low-pass filter for the frequency where you want the sub to start. 
http://www.parts-express.com/cat/in-line-crossovers/405

The idea is to run the signal out of the amp, then back in, with one channel low-pass filtered for the subwoofer. You'll need two RCA cables.
- On the speaker channel of the amp, connect Tape Out to Tape In
- on the subwoofer channel of the amp, connect Tape Out to FMOD, and plug FMOD into Tape In. 

If you listen in normal mode, you'll hear the speaker and the sub running full range. 

If you listen in Tape Monitor, you should hear the speaker with a filtered sub. Balance is sub level. 

This works because the Tape Monitor allows the signal to loop back into the receiver, and we can modify the signal before it loops back in. It's the same way you would add an equalizer to an integrated amp. 

Assuming, of course, that you have Tape Monitor and the in/outs required....

Have fun,
Frank


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