Help! Subwoofer Newbie Problems!

I've had several subs and have quite a bit of experience with integrating them.  There is definitely something to the claim that having multiple sets of interconnects can mess up the sound.  It isn't always a problem but I've found that my benchmark dacs can't drive both the amplifier and a sub.  The bass quality is surprisingly degraded.  On the other hand, my Bryston pre can drive both amp and sub with no problem with no noticeable change in quality. 

I hate to say it but after having my systems in 5 different houses the best way to integrate a sub is to have your system in a large room in a house that has fairly lightweight construction.  I've had my system in multiple basements, smallish rooms in brick houses, medium rooms in frame houses, smallish plaster rooms in frame houses, and now in large rooms in a frame house.  I've also bought digital equalizers, made over 2 dozen bass traps and gone through extensive measurements with a measurement mic, real-time analyzer and various tone generators and discs. 

If I were you I'd buy the behringer ultra-curve and measurement mic (or something similar).  Get a tone generator.  This will let you do a direct comparison of the signal being fed to the system vs the actual volume that is present at the microphone.  If you do this it will give you a sense of proportion that I don't think you'll get any other way.  If you have a 12db peak at 60hz and a 12db null at 45 this will let you hear it and know what you're hearing.  You'll be able to completely squash the peak, although you'll probably be a little surprised at how deep of a cut you have to make to actually get rid of the bloat. 

Once you quantify what you're hearing you will be able to decide what you want to do about it.  You can make huge cuts to completely get rid of the peaks but in my opinion this won't sound right.  It seems to kill transients.  You can make a bunch of bass traps and that can help with the peaks without doing as much harm as huge eq cuts but it's either very expensive or a lot of work to get enough of them to really make a big difference.  In my experience it's impossible to completely fix a bad room, although the problems can definitely be reduced.  I haven't tried the processors that do processing in the time domain as well as frequency and I haven't tried making any sort of resonator.  I'd like to try it someday just to see how it works.  Sadly, I've got systems in really good rooms now and I don't have troublesome resonances that are bothering me. 

Great responses, thanks!

snapsc,

I like my Conrad Johnson tube preamp/amp too much to switch to solid state.  Every time I've tried SS I've run back to tubes.  Learned my lesson.  (I believe the crossover I'm going to use will pass along the character of my pre-amp ok).

Jon,

Your experienced input is valuable.

The ability of my CJ preamp to drive the signal over long runs of interconnect are a bit questionable.  That's one way adding the JL CR-1 crossover helps, which will drive things no problem.

My listening room was designed with the help of a acoustician, so it has treatment, trapping, sort of "built in."  It's a great sounding room (and a wide opening to one side into the hall seems to stop a lot of bass room-node wave build up - the big Thiel 3.7s for instance sound perfectly even in the room).  I won't be adding any more room treatments.

I've considered going with a good mic and computer software to read the room, but I'm trying to make this as user friendly as possible.  So I'd first probably go to items like my Velodyne SMS or an Anti-Node, to dsp the subwoofers.

I'm still curious if subwoofers can actually be added in a way that doesn't alter the general tonal character of the main speakers.  After all, adding frequencies anywhere does tend to have a psycho-acoustical effect in how we perceive the sound.   As mentioned, my bigger Thiel 3.7s go lower than the 2.7s, and preserve the Thiel sonic character I'm looking for.  Except they are aesthetically larger than I want in the room.

I added a sub (B&W PV1d) to my Quad 2805 speakers, and it did not change the sound of the main speakers, but just added to it. In my case the larger Quad 2905 were simply too large from an aesthetic point of view and adding the sub turned out to be a good alternative. Without the Antimode 8033 integration was less than perfect, with quite a bit of boom, even in a large room. With the Antimode, it is much better, even if I have decided a second sub should improve matters even more, and add extra power. My (quite inefficient) Quads are now driven by a 2x140 watt Quad 606-2 amplifier (earlier I had a 2x45 watt Quad 303 and that was not quite enough). The extra 400 watts from the sub gave even more power for a cleaner sound, but I can use yet more for dynamic music like symphonic music.

Good info about the anti-mode, willemj.

I've heard that it's not quite transparent enough for some people when used over the entire system, but works well on just the sub signal.  Sounds like that set up worked for you.