Multi Channel for Newbies

[Sal1950]

I don't understand.

Pretty sure what he is saying is that the .1 channel (subwoofer) ends up being a compilation of what would be the actual "low freq effects channel" in a movie together with the output of the 5 mains low pass filters signal (everything below 80hz here). Just SOP in all AVR bass management I'm aware of..

 

[Kal Rubinson]

First, in classical, it is extremely rare. I do not change them although, In my NYC system, I do not use bass management but, in my CT system, I do.

I don't understand.

Since the LFE in classical recordings contains no information not already in the main channels (there is no LFE mic channel, afaik), the use of bass management will depend on the equipment in use and personal preference. In NYC, the main channels are, imho, just fine w/o the sub, so I use no BM. In CT, the mains are less capable, so I use BM.

 

[Fitzcaraldo215]

I don't understand.

Sorry I was unclear.

All bass management systems work pretty much the same way in AVRs, prepros and JRiver. There is usually a single, mono .1 discrete output channel that is derived from the sum of two things:

(1.) the .1 input (LFE) channel from the recording (if any)
(2.) the summed result of the low pass side of crossovers for all other input channels. The high pass output of the crossovers goes, of course, individually to the L, R, C, SL, SR, etc.

There are also some bass management systems with more than one subwoofer output channel. Many of those still use the mono summed signal as above, but with separate controls for output level, distance, etc. for each sub. A few may be even more sophisticated.

But, to my point, it makes no difference to me if an SACD is 5.0 (most) or 5.1 (some), since the results for my sub output channel are summed and include the .1 channel whenever necessary.

If I had no sub in my system, I would want to be sure that bass management was mixing the .1 channel on any recordings back into any output channels designated as "full range" or "large" and which therefore have no hi/low pass xovers applied to them.

I hope that is a bit clearer.

 

[dallasjustice]

All bass management systems workpretty much the same way inAVRs, prepros and JRiver. There is usually a single, mono .1 discrete outputchannel that is derived from the sum of two things:

I think it does make a difference tho. The .1 recordings would result in more relative LF SPL as compared with the .0 recordings. Therefore, the relative levels between R,L etc will be different and you'll have different sounding bass. For me, such a combined system would be a problem in terms of low frequency sub integration and DSP.

I believe there will need to be a -10db SPL sub level adjustment for the .1 playback. This can be done in Acourate. I definitely would need two different sets of filters.

 

[dallasjustice]

With multiple mono subs, it will get tricky to figure out how to get a -10db sub adjustment. I'm not sure how to do that except by trial and error with both subs playing LF pink noise at the same time with the source/sink delay already setup.
This is why I always felt that audiolense was defective at calibrating multi mono sub systems.

 

[Fitzcaraldo215]

I think it does make a difference tho. The .1 recordings would result in more relative LF SPL as compared with the .0. Recordings. Therefore, the relative levels between R,L etc will be different and you'll have different sounding bass. For me, such a combined system would be a problem in terms of low frequency sub integration and DSP.

I believe there will need to be a -6db SPL sub level adjustment for the .1 playback. This can be done in Acourate. I definitely would need two different sets of filters.

Maybe so. But, using standardized bass management systems has never yielded a problem for me. 5.0 or 5.1 can sound equally good with no special adjustments, no separate crossovers filters, etc. on my part. Not sure if your assumptions or logic are accurate.

 

[dallasjustice]

Fitz,
It's not a YOU problem. It's a ME problem. If there's only one mono sub, I believe all the AVR systems and Jriver simply attenuate LFE -10db. That's perfect for one sub.

Maybe so. But, using standardized bass management systems has never yielded a problem for me. 5.0 or 5.1 can sound equally good with no special adjustments, no separate crossovers filters, etc. on my part. Not sure if your assumptions or logic are accurate.

 

[Fitzcaraldo215]

Fitz,
It's not a YOU problem. It's a ME problem. If there's only one mono sub, I believe all the AVR systems and Jriver simply attenuate LFE -10db. That's perfect for one sub.

Gotcha, DJ. I knew that. I just did not want others to believe this might be some big unsolved problem they had to contend with. It really is not for most any Mch listener.

 

[dallasjustice]

I think it may be possible now with Roon 1.3.
Roon now has convolution. I could also setup different zones. Interesting.
https://kb.roonlabs.com/Zone

https://kb.roonlabs.com/DSP_Engine:_Convolution

 

[amirm]

Very cool!

 

[dallasjustice]

Very cool!

Maybe they didn't say anything about this feature before because they haven't really tested it that much. It looks like its similar to how Jriver does convolution; using .cfg files. Some folks on the acourate forum said that it works well, which I expect from Roon.