Help with installing subwoofer.

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Maxx2008

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Jan 11, 2008
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I took my 5.1 speaker system from my "home cinema" (was rarely used) and hooked it up to my computer. The 5 speakers are working fine however I don't know how to connect my subwoofer to my PC. It's a BBK FSW-120. The manual says I can hook it up to an amp. Of course my Kenwood KR-V6080 has 2 speaker output classes: A and B. However I can only use 1 of those classes if I am to use any of the 5.1 modes. But I can't fit the speakers and the subwoofer into 1 class...

It used to be connected directly to a DVD player, so I'm thinking maybe I could connect it directly to my computer? I don't see where. I have an M-Audio Audiophile USB soundcard. There is only 1 free output jack left - the S/PDIF output, but that doesn't work for my sub.

That's about it... Help please.
 
Normally you'd hook up the sub up to your LFE output (RCA connector) but your receiver is so old (and/or cheap) it doesn't appear to have one.

So I'd say you'd have to run the front left/right speaker wires to your sub and use the subs crossover and speaker outputs to handle divvying up the low/high frequencies. But if your sub is of the same age and/or quality as the receiver it may not be capable of this. What connection options does your sub have? Anything thats labelled as output? Sounds like it might be of the variety that doesn't have anything but speaker level inputs.

When I search for your subwoofer almost all the results appear to be in Cyrillic. Not a good sign. If your sub doesn't have an internal crossover and speaker outputs then I don't think there's going to be any way to do it that doesn't involve buying newer equipment.
 
Nicolaskl said:
Normally you'd hook up the sub up to your LFE output (RCA connector) but your receiver is so old (and/or cheap) it doesn't appear to have one.

So I'd say you'd have to run the front left/right speaker wires to your sub and use the subs crossover and speaker outputs to handle divvying up the low/high frequencies. But if your sub is of the same age and/or quality as the receiver it may not be capable of this. What connection options does your sub have? Anything thats labelled as output? Sounds like it might be of the variety that doesn't have anything but speaker level inputs.

When I search for your subwoofer almost all the results appear to be in Cyrillic. Not a good sign. If your sub doesn't have an internal crossover and speaker outputs then I don't think there's going to be any way to do it that doesn't involve buying newer equipment.
Click to expand...

Firstly thanks for helping.

Yes, my sub has only inputs, no outputs. The Google search results are in Cyrillic probably because I'm in Eastern Europe. :) I guess the product is oriented towards this part of the world.

So what happens if I try to run the front left/right speaker wires to the sub?
 
Maxx2008 said:
The Google search results are in Cyrillic probably because I'm in Eastern Europe. :) I guess the product is oriented towards this part of the world.
Click to expand...

Well, that solves that mystery.

So what happens if I try to run the front left/right speaker wires to the sub?
Click to expand...

Was it hooked up to a your DVD player via RCA cables?

http://en.wikipedia.org/wiki/Image:High-quality-RCA-connectors-VDH.jpg

If so and if that's the only input then hooking it up to speaker level wires would most likely do bad things to it.

If it is designed to take speaker wire then you could try hooking it up to the same output as the speakers (at the same time) but your receiver might not like the change in resistance, so do so at your own risk.
 
You could get some supporting hardware to combine the amplified front speaker channels to provide one unamplifed output for the sub to use.

This solution is actually very good, you will configure the sub bass frequencies to go to the front speakers which will then feed them to the sub.
This allows the bass to remain closely in phase with the bass from your front speakers and also helps prevent/reduce any frequency response holes between the sub and the front speakers as the front speakers will also respond to the low level frequencies they can handle.

My sub works in this fashion as it has its own inputs that take a direct feed from the amplified front speaker outputs from my main amp.
You will need to combine the speaker output sources into a single channel and feed that to the subs amplifier.
(note you should use opamps or other circuitry to isolate both channels from each other and the sub, and reduce the voltage when using an amplified feed)


An alternative and the simplest solution is to use the line level (non amplified) output to one front speaker and feed it to the subwoofers amplifier.
There are many ways to do this but only one controlled by your amplifers volume control will be want you want.
If your amp has connections to allow another amp to be fed (ie your current amp acts as a pre-amp), that output can be fed directly to the subs amp, allowing you to use your amps volume conrol with the sub as well.

Using any method that takes its bass from either or both of the front speaker channels will require you to disable the LFE channel in Windows.
This doesnt disable LFE, it feeds them to the other speakers.
If you like to drive your speakers to their absolute max, this might blow your front speakers but if you dont push your cones to the edge, this should not be an issue.

If you have no means of allowing your amplifiers volume control to be used, you can just feed the subwoofer directly using the line level subwoofer channel on your soundcard.
To make this most effective you will need to set your main amplifier to a usable volume level and leave it there permanently.
Then set the subwoofers own amplified volume to match and use the volume controls in Windows to change the overall volume.

I've no doubt not explained it too clearly so if you want further info, pls ask.
 
Nicolaskl said:
If it is designed to take speaker wire then you could try hooking it up to the same output as the speakers (at the same time) but your receiver might not like the change in resistance, so do so at your own risk.
Click to expand...

Yup, it can take speaker wire. Not sure I'm going to try to hook it up to the same output as the speakers yet though...

Nenu said:
You could get some supporting hardware to combine the amplified front speaker channels to provide one unamplifed output for the sub to use.
Click to expand...

Hm, might work, but exactly what hardware do you have in mind?
 
If it can take a single amplified speaker output as an input to the sub, thats probably your easiest solution.
The input stage to your sub will be very high impedance so will not load the amplifier and should not affect the sound from your front speaker.

Its rare that sub bass is ever directional as by the definition of the way it works, it sets up a standing wave in your room that envelopes where you you sit and your speakers, using your walls like one big loudspeaker box.
It is non directional.
So all speakers should be fed the LFE channels bass if you dont use a separate LFE channel.


As for the electronics you would use to combine 2 amplified speaker outputs, build something that reduces the voltages to line levels and then combines the channels to feed a single channel at line level.
This is only useful for line level input.
 
found that pic of the sub
edd8a76718.jpg


looks like it has speaker level inputs and outputs so you can pass trough the speaker signal.

so if your sub looks like this, run the speaker wire from the amp to the sub inputs and from the subs outputs to the speaker.
 
shadowlord said:
looks like it has speaker level inputs and outputs so you can pass trough the speaker signal.

so if your sub looks like this, run the speaker wire from the amp to the sub inputs and from the subs outputs to the speaker.
Click to expand...

Only inputs, no outputs. Yes, that looks like my sub.
 
assuming that the m-audio usb has rca outputs the cheapes solution would be to buy two rca Y-slitter like this http://www.casecooler.com/rcasplitcab1.html and connect both, your amp and sub to the soundcard. then match the volume with the sub and amp volume controls and set your listening volume via windows like nenu already suggested.

or you could try to stuff your speaker cable and some speaker cable to the sub into the main speaker outlets of your amp. connecting them in parallel shouldn't harm your equipment. but thats the not so smart solution imo.
 
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