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Stupid Question Alert! Re: Subwoofers

post #1 of 14
10/24/05 at 2:36pm
Thread Starter 
What is necessary to add an active subwoofer to your speaker system?

Should there be a subwoofer-out on a multi-channel player?
Or is there a subwoofer-out on preamps?

If I have a strict two channel stereo setup, is it even possible to add a subwoofer without swapping out or adding components?
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post #2 of 14
10/24/05 at 3:38pm
Quote:
Originally Posted by insomniac
What is necessary to add an active subwoofer to your speaker system?

Should there be a subwoofer-out on a multi-channel player?
Or is there a subwoofer-out on preamps?

If I have a strict two channel stereo setup, is it even possible to add a subwoofer without swapping out or adding components?
Yes its easily doable.

I'm not sure how to do it with your system, because your running Paradigm Studio 40 Actives right? Using a pre-amp?

What are you using for that? You don't need sub line-out as long as your subwoofer has line-level inputs. Just run speaker wires to it as you normally would from your amp. You might also be able to run inputs from the pre outs, what are you using exactly?

If your pre-amp your using now won't work for this, you can buy a sub-woofer preamp module that can do the job, usually around $100 depending on features.
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post #3 of 14
10/24/05 at 3:43pm
depends on the subwoofer.

some subwoofers only have line in/xlr connections (low level), while others have speaker wire connectors (high level).

So if it has high level inputs/outputs, you basically plug amp -> speaker wire -> sub -> speaker wire -> speaker -> speaker wire -> amp and you're set. If it only has low level, then you need to output something from your amp... If it doesn't have line out/sub outputs, you're basically screwed. Some will probably say that you can use tape out, but the problem is that the signal does not vary depending on the volume, so depending on the volume of your amp, you would have to constantly be adjusting your sub volume....

AS for outputs on pre-amp/integraded, well that depends on each amp model...
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post #4 of 14
10/24/05 at 5:16pm
Thread Starter 
Thanks for the input, guys.

If I'm understanding correctly, there is no way I can currently add a sub to my 2 channel setup because...
I'm currently running CD-Player => ICs => Stereo Preamp => ICs => Active Speakers.
There are no speaker wire terminals or subwoofer line-outs to be found in my system.

One question I have remaining is, if I purchased a source with multi-channel outputs, I wouldn't want to directly connect the sub to the source, since there would be no volume control, correct?

EDIT: One more question - what is a crossover?
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post #5 of 14
10/24/05 at 5:28pm
insomniac:

It'd be pretty easy to add a sub into your current setup. Get a couple of RCA Y splitters and hook them up to your preamp RCA outputs. Run a set of ICs from the splitter to your active speakers, and another set from the splitter to the RCA inputs on your subwoofer. Make sure that the RCA inputs that you're using on your subwoofer have a low pass filter, and aren't the unfiltered ones.
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post #6 of 14
2/9/06 at 12:13am
Thread Starter 
Resurrecting an old thread. Not specific to my situation (as I'll be overhauling my speaker rig), is there any optimal set-up for adding a sub to a 2 channel rig. For example, should I be targeting only subs with high level connections?
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post #7 of 14
2/9/06 at 12:43am
Almost all powered sub will have both high and line-level connections. Generally, you'd connect your pre-amp to the sub using an audio cable. However, you could also connect your system to the sub using speaker cables (a method recommended by British sub specialist REL).

One reason you want a sub is to take away the bass frequencies to the left/right speaker and redirect the bass to the sub. Have you consider Paradigm's crossover units?
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post #8 of 14
2/9/06 at 12:47am
Thread Starter 
Quote:
Originally Posted by soundboy
Almost all powered sub will have both high and line-level connections. Generally, you'd connect your pre-amp to the sub using an audio cable. However, you could also connect your system to the sub using speaker cables (a method recommended by British sub specialist REL).

One reason you want a sub is to take away the bass frequencies to the left/right speaker and redirect the bass to the sub. Have you consider Paradigm's crossover units?
If the sub takes up the the speaker binding posts on the amp, what do the speakers connect to?
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post #9 of 14
2/9/06 at 12:51am
Just connect the speakers to the subwoofer if they're active. Otherwise, put an amp inbetween if the speakers are passive.

cdp => cables => (preamp => cables =>) active subwoofer => cables => active monitors

or

cdp => cables => active subwoofer => cables => preamp / amp => cables => speakers

Some active subwoofers have an output signal that covers the entire frequency range so your monitors should have a filter where you can cut out the lower frequencies. Otherwise you'll have unwanted overlapping frequencies. More sophisticated woofers have crossovers that split the input signal into low and high frequencies at a specified frequency (e.g. 80 Hz), so can use any main speakers.
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post #10 of 14
2/9/06 at 12:56am
Crossovers in subs are usually not very high-end (depends on the sub of course). You can do the crossingover on the line-out signals by using a high quality external crossover. In my speaker rig I used the Outlaw Audio ICBM, specially for multichannel SACD. But it can be used perfectly with stereo as well. It is a great device, and not expensive (~$250):

http://www.outlawaudio.com/products/icbm.html
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post #11 of 14
2/9/06 at 12:57am
If the sub takes high level input, it will have high level outputs to hook the speakers up to.

Using the high level inputs for subs is generally not recommended though. Usually the circuitry for the high pass filter on the speaker connections are of inferior quality. Also, certain amps, Tripath ones in particular, can be damaged if the grounds of the sub high level inputs are tied together.
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post #12 of 14
2/9/06 at 11:34am
Quote:
Originally Posted by marvin
If the sub takes high level input, it will have high level outputs to hook the speakers up to.
Many subs have high level inputs but not outputs
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post #13 of 14
2/9/06 at 11:48am
Example of what a sub can possibly have (courtesy of hifi-forum.de):

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post #14 of 14
2/9/06 at 1:52pm
Thread Starter 
Quote:
Originally Posted by saint.panda
Example of what a sub can possibly have (courtesy of hifi-forum.de):
Picture really is worth a thousand words. Thanks, saint.panda.
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