Need Help connecting Dual Subwoofers... (1 Viewer)

[Mark Kieckbusch]

I am searching for an answer to a HT question I have. I am in the final stages of completing my HT set-up and need a bit of help (if you have any recommendations). My system consists of an Onkyo Integra DTR-7 receiver, Onkyo DVD player, Mitsubishi 50" RPTV, and DefTech ProCinema 100 Series speakers (4 ProMonitors down to 50Hz, a ProCenter 100, and a ProSub 100TL to 19Hz). I am trying to integrate a second sub into my system and need some hook-up suggestion(s) on how to hook-up the two subs in my system. Currently I have the DefTech set-up for BOTH LFE and Speaker Level connections per DefTech's Owners manuals. They claim that this gives the flexibility needed for both music (speaker level adjustment) and movies (LFE). It seems to be working well. I seem to have better luck for both without the LFE connected, but I am still playing around. My listening ratio is about 30% movies and the rest music and the TV signal. I always use the 5 channel stereo DSP on my receiver when listening to the TV and music, although sometimes I just run the 2-channel with music. How can I connect my second sub (Velo CT100)and what are my options? DefTech recommends connecting the second sub to the rear surround speakers via speaker level, setting them to Large. I have also had a suggestion of dedicating one sub to speaker level for music(fronts) and the other for LFE from Digital sources. My HT room somewhat limits me so that one sub is located front left, and the other will have to be back left/center. Also, why not just hook up my new sub just like my DefTech with both speaker level and LFE like DefTech recommends? If you have any suggestions/comments I would love to hear them. Thanks....

 

[Selden Ball]

Mark,
Don't forget that the low frequencies generated by subwoofers have wavelengths comparable to your room dimensions. This means that the frequencies that match your room dimensions set up standing waves. They'll always be loud at some locations in the room and quiet at others.
The usual solution for this is to find a location for the sub which provides appropriate amplitudes at your primary listening position. Sometimes small position differences can make a significant improvement. Some people also use a parametric equalizer like the BFD -- Berringer(sp?) Feedback Destroyer -- to help compensate at speciic frequencies.
Having two separate subwoofers generating the same sounds at the same time complicates things even more, since that sets up interference patterns. There will be places in the room where their sound waves cancel one another, causing dips in volume that simply can't be eliminated. You can use an SPL meter and a CD with test tones to find out if this is happening at your listening positions.
The usual workaround for this second problem is to colocate the subwoofers: put them in the same place, stacking one on the other if possible. That provides additional low frequency power without the additional complications. Equalizers simply can't boost the sound levels where they're cancelling.
In your situation, I'd suggest using one sub just to extend your main speaker response and the other strictly for LFE effects.
I hope this helps a little.
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Selden