Sub Question

I also have a sub-woofer (JM Labs SW900) and mains (Acoustic Zen Adagios), but my sub does not have crossover outputs to the main amp. My pre has 2 sets of main outs, I use one to the sub and one to the main amp. Therefore, the full frequency range goes to the main amp/speakers. What is the best way to roll-off the lows to the mains in this situation ?

There is a widespread school of thought that I subscribe to that it is better to run the main speakers full range rather than use a crossover. If you do use one it is better to insert a passive attenuation one in the signal going to the main speaker amp. While rolling off the main speakers will allow you to play them louder the crossover will degrade the sound. This does not bother the HT fans who value dynamic range and think special effects are more critical than music. I would look on the DIY audio sites for advice on constructing a passive attenuation network. They will also have info on who could build one for you.

It's funny but all the responders are correct in their approach. My approach to solve the problem was to have a pair of passive devices made with a (RCA input and RCA output)plugged into the input of the power amp and my interconnect pluged into the device(s). One for R and L channel. This device rolled the speakers off in a controlled manner and you choose the frequency you want it to roll your speakers off. All that is needed is the input impeadance of your amp and what frequency you want your main speakers to roll off. When one of the responders spoke of distortion with the rolling off of the bass from your main speakers it frees the speaker up to produce clearer midrange, mid bass and top end frequencies with better dynamics too.

This can be done on solid state and tube amps but the device is custom to the amp you have it made for. Tom Tutay made mine for my Spica TC 50's and It works well for my TC60's too because they are rolling off around the same frequency. By it rolling off the bottom end of the satellite at say 40Hz the subwoofer takes over from there. Understand that rear ported speakers are harder to blend with a sub than front ported speakers. My subs are acoustic suspension and my TC60's are rear ported. After tinkering and placing them in various positions I have them blending pretty darn good. You have to play with the phasing. Oh, I have two Dali Suite 1.2 12" subs. They are not boomy and are pretty articulate. My TC 50's blend even better than my 60's and they are acoustic suspension. I still prefer the TC60's. This actually gives you more clairty, soundstaging, and depth of sound stage too from your main speakers thus allowing the sub to take over in the bottom range. This is one way to tackle the problem and it is effective. You can call Tom @ 850-244-3041 10am to 8pm CT.

I would never give up my pair of Vandersteen 2Wqs. These subwoofers blend seemlessly with my mains (now Ohms, but previously they blended equally well with my Vandersteen mains). Check my review of these in the review section. Properly executed and set up, a dedicated, powered subwoofer can do things that most full range speakers simply cannot. I suggest you read about them at the Vandersteen web site. Their design is somewhat unique and addresses two major issues of subwoofers: crossover and placement. I got mine used here on Audiogon, but even new, they are a fantastic value for a music-oriented sub (as opposed to home theater), IMHO.

Rythmik Audio in Austin Texas.....Gread