Axiom Home Page Forums General Discussion Technical Questions Sub Settings for a 2-Channel System

Have a sub on loan with no manual. Would appreciate any advice/info regarding the proper settings for the sub on a 2-channel system using a pair of M-60's. I would like the 60's to continue to run full-range. I am running the sub out of a pre-out on my amp, into the line-inputs on the sub. The settings in question are as follows:

Line Input: Normal or LFE?
Phase: 0 or 180 degrees? (the sub is placed in left-corner of my room beside one of the M-60's)
Frequency Cross-Over: Dial runs from 50 to 150Hz?

I believe the freqeuncy response of this sub is rated 40 to 150 Hz? Is this an appropriate sub to use with M-60's...is the low-end low enough to enhance or add bass beyond what the 60's can reproduce on their own?
Thanks!

Joe

Joe, it would have been helpful to identify the sub, but just from the 40hz limit you report it would seem that this might not be a suitable addition to the M60s. I checked back and see that you're using Cambridge Audio two-channel amps. Since they have no built-in crossover for a sub, you would have to use the internal crossover in the sub. Since the LFE input bypasses the sub crossover, you'd have to use the "Normal" input. Since the sub is close to the M60 the 0 phase setting is probably better, but check the 180 to see if it gives stronger bass. Since running the M60s full-range means that the sub will be used just to reinforce the lowest bass(maybe not much with this sub),the cross-over should be set at or just above the 50hz mark(which may or may not be accurate).

Appreciate the info John.

The sub is a Dahlquist QX125S (10" woofer, 125 watts). I've set the sub as per your advice. In tweaking the volume control, I find that I have to turn it just below the half-way point to hear enhanced bass from my 60's...I may be able to notch it down a little lower after more extensive listening. Is this OK, or should I be considering a sub with a lower low-end frequency spec? I should add that I am not a bass "fanatic"...don't need to hear/feel the nether-world region to the nth degree. I use my system primarly for music, and was just looking to enhance the bottom-end of the 60's.

A final question, should the sub always be left powered on, or does it matter? (I believe this sub goes into a stand-by mode if the power is left on and no signal is being transmited to it, LED indicator changes from green when active to red when no signal).

Thanks again.

Joe

Joe, I looked at the Dahlquist site, and yes, they do claim only 40hz for the QX125S. Unusual for sub makers, this may be conservative. If it gives you what you're looking for, fine, but I note that the Audioshop site shows that Marc has an attractive $650Cdn sale on the Axiom EP350. Marc also sells the QX125S at a similar price. I would think that for the money the EP350 would give you more bass extension, but you might ask Marc for his opinion. On this board Chesseroo has reported good results with running his M60s full-range and supplementing the lowest bass below 50hz with his EP350.

It's common to use the auto on/off feature on subs unless it causes problems with premature shutoffs, so it should be left on "auto" or whatever Dahlquist calls it.

Appreciate your time and comments. Thanks again John.

Joe