I've noticed a significant difference in bass levels from my subwoofer between 2-channel modes (stereo, bypass, upsample) and multi-channel modes - specifically Prologic IIx Music. The bass is significantly louder when playing the same source using Prologic IIx Music mode. I tend to prefer the extra bass as I usually listen at lower volume levels but sometimes it can be a bit much. When I switch to 2-channel mode the bass level decreases significantly - usually too much.

Why is this? Is this a feature of Prologic IIx Music mode? Should this be happening or should the bass levels be relatively the same regardless of using 2-channel or multi-channel modes?

BTW - I've level matched my speakers to 75db at 0 volume level with the sub between 80-81 db. All speakers are small with appropriate cross-overs (60 for fronts, 80 for center/surrounds).

Any thoughts?

Thanks!

Bryan

Bryan,

I've noticed exactly the same problem, except its not just Prologic IIx Music. If I take any two channel source and go multichannel, the bass level is just waaaay too high.

However, remember there is a '2CH SUB OFFSET' option (MAIN MENU > SURROUND CONFIG). See the manual for more info. This offset option is not the problem in my case.

I even have too much bass for the same recording mastered at 5.1 vs 2 ch. Example: Blue Man Group, The Complex Rock Tour Live. Side B has 3 songs mastered in 5.1. 'Above' in 5.1 has too much bass compared to the same song off the 'The Complex' CD. The difference is not subtle.

HD TV and DVDs are fine.

Any thoughts, anyone?

As the pretty princess begged - "Help us, Obi-Gonk Kenobi, you are our only hope."

"Obi-Gonk... That's a name I've not heard since, oh, before you were born..."

I've been mulling over this thread off and on for a day or so, and I'm not sure I have a great explanation for this effect in PLIIx-Music. I have heard similar reports regarding loudness in general (and bass in particular) with 5 Stereo or 7 Stereo mode, which is related to duplicating the stereo signal into additional channels.


This could be a mastering issue - when they made their 5.1 mix, they could have used the .1 channel as an excuse to add some LFE impact relative to the 2.0 mix.

gonk - thanks for the reply.

I agree with your last statement re: Blue Man Group. I think the 5.1 vs 2.0 mix is a mastering issue.

Re: toom much bass in multi-channel modes. Is it possible that the bass management in the 990 is summing the bass frequencies from all speakers below their respective cross-overs in such a way as to cause the bass emanating from the subwoofer to be (relatively) too loud? I'm assuming that the bass frequencies from the original 2-channel source are split and sent to 5 speakers (fronts, rears, center) prior to the bass management - and then bass managed to send the bass frequencies from the 5 speakers to the subwoofer in an additive manner. Would this cause the issue with the bass emanating from the subwoofer being too loud?

Thoughts?

Thanks in advance!

Bryan