In my case, I think of it as reinforced bass rather than double bass, especially for stereo listening. At least for me, I like the way it works. Here's why:

My Paradigm studio reference 40s go down to about 60hz at -2db, and about 40hz at -3 db. If I set them to small and crossover at 60 or 40, it sounds good, but if I set to large with the same crossovers, it sounds better. At a crossover of 60, where the bass on the paradigms is starting to roll off, the sub picks up the slack. And since I have the 2 channel sub mode set to -2 db, it doesn't really double the bass, only adds it back in so that I get a nicely balanced sound without too little or too much bass. If I'd set the paradigms to small, I'm losing bass below the crossover, and even though they can't fully produce down there, they still produce a decent signal and sound better than if it's cut off. The sub helps bring back what's rolled off, and I think it works quite nicely.

This is, of course, with a digital input, and a non-bypass mode. In bypass mode when speakers are set large, there is no sub signal. I suppose it might be nice to have a button or switch to turn on bass management even in bypass mode, but I've found the 990s DACs essentially comparable to my Denon 2910s, so the Stereo mode on the digital input sounds great.

Anyone with these speakers, or similar in range, should definitely experiment with setting them to large. I've found it sounds better.

Mark

I never really understood the double bass issue.
If the issue is that you have the same bass signal delivered to multiple sources and that doubles the content, giving a unrealistic sound, then the only true solution is to have all information below a certian Hz delivered to a single driver in mono, right? I think that I am listening to "double bass" all the time, where the x-overs overlap in each speaker, when the sound is bouncing off the walls, where the recording is using the same information and sending it to the two stereo speakers to produce a centered sound stage, microphones in the sound recording picking up additional information in the studio...

I define double bass this way. Set the front speakers to large. They should get a full range signal and nothing should go to the sub. However, if the surrounds are on and the rears are off, bass goes to the sub even in Stereo mode. If you turn the rears on, the sub gets quiet. If you turn the surrounds off, the sub gets quiet. This is a bug.

That does sound like a bug.

Can you configure the 990 to turn the rear/surrounds or sub off when in stereo mode?

I understand your problem, but to me it isn't a problem. I think of the LFE signal being present as more of an additional crossover to the present speaker system. If the information exists in the signal, even in stereo, why not have the best driver available reproduce it?

Think of it another way. If your Full range speakers reproduced the LFE signal, say each front speaker had an 18" driver in it, would you be concerned that some sound was coming from the larger driver in those front speakers?

Edit - In addition, the sub information should be more sensible then audible. Is it possible that you have a localization problem with the sub placement? As in, if you placed your sub between the L&R front speakers would the double bass affect be reduced/eliminated?

I guess the bottom line is, I may not be comfortable with the functionality, but the sound quality/listening pleasure is not compromised by a double LFE.

You can clearly hear more bass when the (non existant) rear speakers are on then when they are off. You also hear more bass in large mode than in small mode. It is like you have the bass control on and say, that is OK. Well, maybe it is. It is like my wife's car with the sub. They just added the sub. clearly too much bass but she likes it. I, however, don't want my living room soulding like a JBL car system. To me, the LARGE setting is unusable, so I use the SMALL setting.

I have a 5.1 system with C/LF/RF/LR/RR. If I add my non-existant SS speakers will I get more bass? I would love that. Can't get enough bass.

Edit - opps, forgot to add that I am still using the 950. But you probably figured that out.

The reason for my previous posts is because I "kind of" have the reverse problem of wanting MORE bass in stereo mode. And I am interested in seeing if the 990 would provide that.

Another question for the 990 owners: If you have the mute on and use the volume control to reduce the volume does it unmute the system?

I've been meaning to dig deeper into the bass management behavior being discussed here, but time has not cooperated. Maybe in the next week ago...

Yep, it certainly does. Just tried it to be sure.