Nice system EJ!

I would recommend installing the firmware update on the 990. It makes life a lot easier both for setup and regular use. And a question, did you make sure the 25 and 50 Hz settings are zero on the Descent? If either is too high, this would definitely cause booming.

As it says in the Descent manual try either letting the 990 do all the bass management or use the standard 2-channel hookup between the Aeons and Descent. What you are doing is mixing the two, and as Gonk recommends it is good to avoid double sets of crossovers.

If you let the 990 do the bass management just make one connection from the 990 sub output to the LFE input on the Descent. According to the Descent manual this bypasses the internal Descent crossover settings but still allows you to shape the bass with the 25 Hz and 50 Hz level controls. Again start these at zero. You could even use a balanced connection for this.

The other option is to use the Descent crossover by doing the 2-channel hookup between the Descent and the Aeons as described in the Descent manual. If you do you need lots of long cable runs. Then you configure the 990 with NO SUB and the fronts as LARGE. The 990 will divert the bass from the center and surrounds to fronts, and the Descent's crossover will handle splitting it appropriately between the Aeons and the Descent. Again you can use still the 25 & 50 Hz levels to control deep bass and boominess.

Between you and me, I would try the first set up consistently before you give up on it. Adjusting the sub levels and settings with knobs on the sub is very tedious -- you need a friend to sit by the sub and turn the knobs and switches while you listen and measure.

Thanks wolverine.....I'll give it a try.

Let us know how you work it all out.

The AVIA Gudie to Home Theater DVD has a good subwoofer set up section with test tones. I used it to set phase and the sub level (while keeping the sub outpt on the receiver at 0 dB). You don't need the AVIA to set up the other speakers but I found it invaluable for the sub (and for the TV). It's $38 on amazon.com, which may be less than the sub cable that you use and will probaby do more for the sound

Ok Gonk, I took your advice and went with the connections you recommended; 990 Sub Out to ML LFE in, bypassing the ML crossover.

New 990 Settings:

Fronts = Large @ 40hz
Surrounds = Small @ 120hz
Center = Small @ 120hz
Sub = LFE Only

Sub Settings

1. Phase @ 0
2. Low Pass Filter is now disabled
3. Level @ 5
4. 25hz Level @ +3

I just made the change so not allot of listening time. I did briefly listen to a few of my favorite regular and SACD's and I have to say the immediate experience wasn't pleasant. I did play with the 25hz level a bit and successfully got rid of the "BOOM" but I can't find that quick, tight, disappearing bass I used to have....its there though....just needs a little more tweaking. Maybe a need to reposition the sub....?

Threw in a couple movies and immediately I could hear the difference in the dialog and mids. I actually had to go into the 990 and dial them down a bit because they were now so prominent. "That was pleasing!" The low end response remained almost as quick and transparent as the previous setup but I had to adjust the 25hz level to get the umff I wanted.

Only because I was impressed by the video sound reproduction will I live with this setup until I've done some real critical audio listening. Audio playback is a very important part of my HT, so this has to work.

Any suggestions ?

With the fronts set to large, two-channel sources played back in stereo should have no subwoofer present. Obviously if a surround mode like PLIIx is used, that changes things.

I'm starting to wonder if you don't have some room problems - the fact that you get "boom" and/or start having problems integrating sub and speakers as soon as the sub starts reproducing anything about 40hz really seems out of place. My SVS 25-31PCi gave me a little grief in this regard at our old house (crossed fronts at 40Hz so the sub wouldn't intrude when listening to music in two-channel), but it was better behaved in our new house (although the LFM-1 blended better still, as I mentioned in my LFM-1 review) and it wasn't as bad as what you are describing. You're just having way too much trouble getting the sub to play nicely with the rest of the system, and the most likely explanation at this point is room effects. Fixing it acoustically (sub placement, bass traps, and other acoustical treatments) is an ideal approach, but it's tricky business. You might actually want to consider something like an SMS-1 at this point (in which case I strongly recommend Outlaw's SMS-1 Guide to walk you through setting it up optimally).

So besides your assumption of needing acoustical treatments, you think changing the fronts to small would improve bass response in audio playback?

Yeah, I think setting the fronts to small would probably help with bass response for two-channel playback.

Another question (possibly been asked before and dismissed for some reason I can't remember)... Have you tried a lower crossover for the center and surrounds? The Cinema i is rated to 80Hz and might perform well with a crossover of 100Hz (maybe even 80Hz), and the Monitor Audio Bronze surrounds can get down to 65Hz (which might work well with an 80Hz crossover).

Gonk, once again you were right. Changing the fronts to small (this forces the 990 sub trim to "yes") made a significant difference in 2-chnl audio playback. I like it! Good thing I tried all these new settings before moving anything around!! That would've been a nightmare. Now I'll try tweaking the center and surround crossovers as you suggested. I'll let you know this evening how it goes.

Thanks again.

I am glad you finally got things all worked out. This is actually what I meant above by but I should have added to set the fronts to small. Sorry!

I agree with Gonk about trying lower crossover settings for the center and surrounds. Listen to some 2-ch source that should have a centered bass guitar with PLIIx, change the center crossover and see if the bass player is centered or appears to move over toward the sub.

Also, you can also adjust the 2-channel subwoofer offset which changes the sub level if there is too much or not enough bass in stereo compared with multichannel.