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[Mikkel]

Dear everyone,

In regard to the latest confusion on how to handle the LFE and low-pass signal to ensure proper bass-reproduction I have been left in complete confusion.
So in hoping someone could finally sort this out for me, I ask for your help, please.

Purpose: I want to ensure the LFE-signal is compensated for the -10db reduction from the mixing while ensuring that my low-pass signal from all other channels to the sub remains at the correct sound pressure level.

My setup:
7.1 using JRSS
REW-generated filters for all 8 channels entered into a convolver config-file. No pass management (rerouting) is done within the convolver.
Room Correction set to move all bass below 200hz to the sub.
All channels level-matched to output 75db within Room Correction.

The problem: With this setup, if I understand you all correctly, I will have a proper low-pass signal level (e.g. 75db) while the LFE-signal is 10db too low (65db).

The question: How do I get 75db for the low-pass signal and 75db for the LFE-signal without also increasing the low-pass signal (resulting in a 75db LFE-signal but an 85db low-pass signal)?

Thx for your help and patience - and hoping this will be the end of my spamming this forum with bass-management questions.


Best regards,

Mikkel

[mojave]

Because you are doing bass management within Room Correction, all your levels are correct when you level match to 75 dB. The issue that arises is when an external program such as Audiolense or Acourate is performing the bass management and isn't compensating for the LFE channel being -10 dB. Since you aren't doing that, then your levels are fine.

I'm more concerned with your methodology. Your REW filters have information for frequencies below 200 Hz that are generated from the speaker locations. You are then moving those filters to the subwoofer by using bass management. The filters are now no longer valid and you could be causing a lot of problems. The filters have to be run after bass management, not before. Otherwise the levels, delay, and EQ are totally different.

Let's say your mains have a peak at 125 Hz of 12 db. The REW filter does a correction of -12 dB. Now you move that correction to the subwoofer which has a dip of 6 db at 125 Hz. Now the mains info routed to the sub will be down 18 dB at 125 Hz!

[Mikkel]

Hello mojave,

And thank you for your reply/help :-).

I don't think you need to worry about the filters. For all other channels than the sub I have only eq'ed above the cross-over (200hz). The sub-signal is then eq'ued from 20-200hz. So everything should be alright. The RTA-measurements in REW seems to confirm this.

If you still believe something is wrong, don't hesitate to tell me.


Best regards,
Mikkel

[Matt]

To state this simply, Media Center handles bass levels properly in all known cases.

To calibrate levels, this is our recommended approach:
http://wiki.jriver.com/index.php/Audio_Setup#Room_Correction

Some third-party convolution packages do not handle bass levels properly when they are used for bass management instead of JRiver's Room Correction.  We've been talking with the authors of these packages, and hopefully any problems will be solved soon.