Been playing with the 990 b.m.
Read all I could find on the subject, Gonk's nice pages included.

Using "normal" processing (DD, Prologic or Stereo), can I switch the crossover off?
Do I effectively accomplish that by setting all speakers to LARGE ?
I would prefer the crossover inside the SMS-1.

Using the 7.1 input, am I correct to assume that BM settings can only be applied with at least one speaker set to small?

In fact all my speakers go down to 40 Hz (the floorstanding fronts go even lower).
What should sound better- set them all to SMALL and let the SMS1 + Sub handle everything below the crossover?
Any opinions ?
Or set only the smaller ones to SMALL like center and surrounds?

My toys:
Fronts: KEF Reference 203 (biamped)
Center: KEF Reference 202c
Surrounds: KEF Reference 201
Subs: REL Strata or Q2 (a German dipole sub)
Final amp: Arcam P7 7*150W
Processor: 990
DVD/SACD 5.1: Marantz DV-9600
SACD 2.0: Jungson Magic Boat
Front Low Channels: Behringer EQ
Sub EQ: SMS1

If to switch the crossovers off, you'll need to set the speakers to LARGE. Likewise, the bass management will only be applied to the 7.1 input if you have at least one speaker set to SMALL (of course, if all speakers are set to LARGE then you aren't getting bass management with any other inputs, either).

I'm not sure what you mean by letting the SMS-1's crossover handle the bass management. The SMS-1 can apply a low-pass crossover to the subwoofer's signal, and if you route your left and right pre-amp outputs through the SMS-1 then you can apply an 80Hz analog high-pass crossover to those two channels. The SMS-1 will provide no bass management for the center or surrounds, and if those speakers are set to LARGE at the 990 then there will be no data redirected from them to the subwoofer output for the SMS-1 to even use.

According to KEF's site, the -3dB point for your Ref203\'s is 55Hz, with -3dB points of 65hz for your Ref202c and 58Hz for your Ref201\'s . The -6dB points are lower (40Hz, 50Hz, and 46Hz respectively), but by the time you're -6dB down it's really past time to be steering data to the sub. Based on those figures, I'd probably start out by setting all speakers to SMALL in the 990, setting the crossovers at 60Hz for the fronts and 80Hz for the center and surrounds, and disabling the low-pass crossover in the SMS-1. Obviously you can tweak crossovers from there, or even switch the mains to LARGE to compare their performance alone vs. their performance with the SMS-1+sub picking up the low stuff.

barend,
here is a quote from:
www.Audioholics.com on bass management.

OK, I Get It But My Speakers Really Are LARGE!

For some, your main speakers may actually extend down to 30Hz or lower, especially if they include 10” or 12” side-firing low frequency drivers. The temptation will be to set these speakers to LARGE., The setting is there so there must be a place for its use, right? Actually, we recommend setting almost all speakers to SMALL, even if they are physically large floorstanding speakers. Here’s why: Even though those floorstanders have a low extension, they won’t necessarily go down to the lowest range of your subwoofer as linearly and free of compression (unless your main speakers have more piston area and box volume than your sub – but we won’t address that here) The problem with the LARGE setting is: the ultra low frequency information will not be heard if the speaker cannot reproduce it. Well if by some chance you were able to get your main speakers bass extension flat down to 20Hz, then adding the subwoofer on top of that would yield too much (up to 6dB) of bass output at the frequencies both are producing. Hence integration between the loudspeakers and subwoofer will be poor and the bass may be overpowering, sloppy and/or boomy.



As a practical example, Reference System 3 has a pair of RBH Sound 1266-LSEs which extend down to 32Hz. I have them set to SMALL and I set my crossover frequency to 60Hz. Because of this, the subwoofer handles everything up to 60Hz that would otherwise go to my front speakers. The front speakers are now freed up to concentrate on only 60Hz and up. The result is no lost information, less distortion, more headroom and a better overall sound.

for the entire story:
http://www.audioholics.com/techtips/setup/loudspeakers/bassmanagementbasics.php

this is just an expansion of 'Gonk' point.

Another argument in favor of small speakers and a conservative crossover setting is that the SMS-1 can only provide equalization for the subwoofer. Starving the sub with low crossover points lessens the opportunities for the SMS-1 to do it's "thing."

Thanks guys,
A lot of food for thought and experimentation, as always.
This is going to be a nice weekend (raining anyway).
What a nice forum we have here!

Ok. after months of being frustrated about not being able to get the Auto Calibrate set on my 990.. finally today.. i got it to work.

Like someone said in another thread... to turn on tone defeat. i don't even know what that is. can anyone explain that to me?

I also as i did before set all speakers to small, crossover at 120 instead of 80 and away I went. it actually worked correctly this time.

After the auto calibrate was finished.. i checked the settings.. and it set all speakers to large. which is ok with me.. i have a big center and floorstanders for fronts. and my surrounds are semi small 5 1/2 in drivers set in bi pole setting.

Bonus! It also fixed my "other" problem i was having with the lip sync being out of whack.

I work in television.. so I notice right away when there is a lip sync problem if the video and audio don't match up.

Very happy that both problems have been solved.. i can return to watching and enjoying the HT again without worry.

Glad to hear that you got it working! Tone Defeat is a setting that will simply "override" any tone adjustment settings (the bass and treble controls) when turned on. I think of it as a "bypass" mode for bass and treble adjustments.