Help with Cornwall 3's and my RT 12D Subwoofer

[link]

I just hooked up my new cornwalls. I was using in wall surround speakers before. I notice that my subwoofer (rt 12D) at the same setting doesn't put out any bass. What do I need to adjust. I imagine the cornwalls are making up much of the bass but I still would like to get more out of my subwoofer then just turning up the volume more. Maybe that's all I should do. I use a Pioneer Elite VSX 59txi receiver with one single wire coming out to the subwoofer. Thanks for any advice.

[wuzzzer]

The Cornwalls are probably affecting the phase setting of the subwoofer. I would assume that since your sub is Klipsch's current top of the line Reference sub that it has some sort of phase adjustment.

Best way to adjust the phase is to sit where you normally listen to bass, play some music that has very low, steady bass and have someone adjust the phase setting back and forth slowly until the bass sounds the loudest.

Its possible you might also need to turn up the gain on the sub, as I can't imagine any in-wall surround speaker being anywhere close to the efficiency of a Cornwall.

[DrWho]

Maybe you might find this helpful:

Dial in a Subwoofer by ear

But I agree - it's likely the case that you have some phase-cancellation occuring now that your mains are playing down into the same range as your subwoofer. A quick google search on "phase cancellation" might help explain it further.

[colterphoto1]

I know it may sound like sacriledge, but you could set your CW's to SMALL and choose a very low crossover point. That would lessen the overlap and therefore help minimize any phase problems. (after you get it into phase as good as possible)- follow Doc's Sub Cheat Sheet.

[link]

Great article, thanks Dr. for passing it on and thanks to all for your response. I'll try a few things suggested and see what sounds best......

[Jay L]

keep in mind the RT's have more delay than subs without DSP. you'll have to account for that in your processor.

[colterphoto1]

Can you expound on that Jay? Do you mean that the built in processor has lag time?

If someone used an automated system for delay/speaker distance, it would automatically take that into account, yes?

But if you used a physical measurement, the sub would appear to be 'farther' time wise than it actually was..but it would be miniscule wouldn't it? And most processors only give you increments of .5 feet or so.

M

[DrWho]

Yes, an automated system (when working properly) should take the DSP

lag time into account, or any other delays in the signal path

(including the time the sound takes in the air, which is the major

thing it's trying to account for). Would Klipsch happen to have the

true or average processing delay time for the sub? Sounds like an

important spec to advertise...When ya gonna be privvy to this info mr.

colter dude? []

I mention it in the article that you can adjust the phase of the

subwoofer by changing the distance setting for the sub in the

receiver...and I have always noticed that it sounds better to put the

sub further away than closer, even when both are achieving the same

phase rotation (by using the polarity inversion switch). I don't want

to draw a direct correlation, but I wonder if it doesn't have to do

with the group delay inherant with "small" drivers playing low

frequencies. (setting the sub further away causes the signal to arrive

earlier). Anyways, the point being that it seems the sub sounds better

when you favor "too early" versus "too late".

[Jay L]

its about 20ms delay right around the supposed threshold where delay can be detected. i tested the heck out of the RT for a long time. i think its fantastic for movies, but i couldnt get it to jive easily in 2 channel. my denon was set to max distance before i was happy with it.

[Jay481985]

20 ms is not bad. but now this makes me think about 2 channel.....

[JetJockey]

This is how my system is set up.

Yamaha RXV 2500, Klipsch Rf83,RC62, Paradigm PW2200, Mirage Omni 260 rears.

Set sub Xover to max(full clockwise), set phase to min(full counterclockwise), set speaker to small for movies, large for music. Set sub level to 10 or 11 oclock position. set bass out on receiver to both, set Xover on receiver to 80 or 90 HZ( experiment with this with a good bass song playing that you know). Lower xover settings tend to make the sub boom and you can tell where the sub is located(directional, it should not be!) this of course all depends on your rooms acoustics and equipment. Finally run the auto setup and fine tune as you go.

This is just what has worked for me, good luck.