Multi-Sub Configuration

[baristaboy7]

For two years now i have paired my RSW-12 with a SVS 25-39+ and have been quite pleased with the results. I recently took another leap and purchased a Fathom 112 based upon very positve reviews. The challenge i know have is to configure the Fathom with one of the other subs which JL Audio does not recommend. The Fathom 112 has XLR output connections and both of the other subs have RCA connections. I have used the SVS as the master sub in a configuration and ran the RCA cables back to the Fathom but it does not seem to have the depth and response i am looking for. Should i be running an XLR cable from the Fathom to the SVS using connectors for the desired results? I feel i should be getting much better results than what i have heard so far. Any thoughts and suggestions as always are much appreciated.Thanks........Don

[fastlane]

Sorry, but does this mean the RSW might be for sale? Where are you located?

[baristaboy7]

I have to determine if this new sub will perform in tandem with one of the others. Once i have done this then i will be selling one of them. I do have great affection for the RSW -12 as it is a great performing sub. I live in Ontario, Canada.

[sivadselim]

I have used the SVS as the master sub in a configuration and ran the RCA cables back to the Fathom but it does not seem to have the depth and response i am looking for. Should i be running an XLR cable from the Fathom to the SVS using connectors for the desired results? I feel i should be getting much better results than what i have heard so far.

Are you certain the SVS's line-level ouptuts are unfiltered? Why don't you simply use Y adapters? This is actually considered to be a better option than daisy-chaining.

Connecting multiple subs of disparate capabilities is problematic. As an example, let's consider 2 hypothetical subs. One subwoofer has a low-end capability of 18Hz. The other sub has a low-end capability of 30Hz. To calibrate both of these subs properly requires calibrating each one individually, first, then level-matching them properly by lowering the level of each one an equal and appropriate amount to compensate for their additive effect. Once this is done, both subs will end up calibrated properly, more or less, over the range of frequencies that they share (30Hz+). But the range of the more capable sub from 18Hz to 30Hz will now be calibrated at too low a level. You definitely don't want your low-end capability to be calibrated to too low a level. But if you 'turn up' the more capable subwoofer to compensate for the low-end being calibrated too low, you will now end up being calibrated too 'hot' over the range that the 2 subwoofers share (30Hz+).

That said, you should do what you want to do. If you're happy with the results, that's all that matters.

[Bret_Salyer]

Once this is done, both subs will end up calibrated properly, more or less, over the range of frequencies that they share (30Hz+). But the range of the more capable sub from 18Hz to 30Hz will now be calibrated at too low a level.

It sounds to me in this scenario he benefits a little because now he has atleast a little bit of rumble below 30Hz.

What if he set it up a different way and had one sub crossed over or EQ'd to handle 30Hz + and the sub with more extension to handle 30 Hz and below? Might be worth a try.

[sivadselim]

Once this is done, both subs will end up calibrated properly, more or less, over the range of frequencies that they share (30Hz+). But the range of the more capable sub from 18Hz to 30Hz will now be calibrated at too low a level.

It sounds to me in this scenario he benefits a little because now he has at least a little bit of rumble below 30Hz.

The sub-30Hz material would be reproduced at a lower level than if he simply calibrated and used the sub that is capable of sub-30Hz reproduction, alone. When two identical subs are utilized and calibrated properly, they are each run at a level that is ~3dB (this number can vary depending upon placement) lower than the level either individual sub would be run at. Same with two subs of disparate capability. You run each sub at a lower level so that the combined volume will be correctly calibrated. In doing so, the range covered at the bottom-end by the more capable sub ends up being calibrated ~3dB too low.

What if he set it up a different way and had one sub crossed over or EQ'd to handle 30Hz + and the sub with more extension to handle 30 Hz and below?

That's, of course, different. And is definitely possible although it is harder to implement properly than it sounds.