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[mdav]

I've started to try bass management and room correction within MC 21. I'm trying that with my desktop to figure out what's happening and then maybe apply it on my main system. 

Desktop: Speakers 2.1, fronts 200 kHz
              Audio Codec Realtek ACL 887
              Source music 2.0 

DSP Studio -> Output Format:
1)  Channels -> 2.0 and no choice in Subwoofer available (as expected)
or
2)  Channels -> 2.1 and Subwoofer ->
     a) Silent
     b) Any JRSS lowpass Hz

For the configuration above (no up-mixing), 1) = 2a) = 2b), correct?

And now to DSP Studio -> Room Correction -> Left (and right speaker) -> Bass Management:

3) Crossover -> 200 Hz and Routing -> Move bass to subwoofer

4) Crossover -> 200 Hz and Routing -> Copy bass to subwoofer

I thought I should choose 3) as I don't want to to bother my small fronts with any bass, but I don' get any bass out from the system including the subwoofer. However, when I choose 4) I get bass out from system, why?

Thanks!

[mdav]

And what's the difference between "remove bass below crossover" and "move bass to subwoofer"?

[mattkhan]

up/down mixing and redirection to a subwoofer are two different things

downmixing is taking content from x channels and mixing it down to y channels  where y < x, typically this is 7.1 down to 5.1 or any multichannel down to 2.0
bass redirection is the .1 side of things and this can be applied to any content, it is not downmixing as such though it often happens in the context of downmixing when you are downmixing to stereo

so 1 & 2 are different things though I suppose they might have the same result in practice in certain situations

have you read https://wiki.jriver.com/index.php/Mixing ? I am not familiar with a jrss subwoofer so can't comment specifically on how it is implemented, I suspect it is intended for stereo use and/or was superceded by the room correction module but not 100% sure on that.

as to your 2nd post

remove bass below crossover == don't redirect it to a sub == throw it away
move bass to subwoofer == redirect the bass to a sub == don't throw it away

[mdav]

Thanks for the link. Searching around the forum indicates there is a lot of confusion about what "Output format" and "Room Correction" do with bass management, see https://yabb.jriver.com/interact/index.php?topic=81795.0 and https://yabb.jriver.com/interact/index.php?topic=75497.0. Subwoofer in Output Format is the "old way" and Room Correction is the "new way". This is confusing and could be more clear in MC, I think.

I tested both 1) (no upmix + bass management) and 2) (upmix + bass management) according to the Wiki, but the problem with no bass from the subwoofer remains except for the choice "copy bass to subwoofer". Maybe I get it wrong, but for me:

Crossover -> 200 Hz and Routing -> Move bass to subwoofer (recommended) => no bass < 200 Hz to front speakers, but played by the subwoofer (which is preferable as the fronts are very "small")

Crossover -> 200 Hz and Routing -> Copy bass to subwoofer => bass < 200 Hz to be played both by front speakers and subwoofer (which is not preferable as the fronts are very "small")

I also tested:

Crossover -> No crossover (play all frequencies) -> Copy bass to subwoofer => same as 200, which is expected as the bass is copied.

As I run WASAPI, Windows (Realtek) shouldn't screw anything up, or?

[mattkhan]

I don't understand

your 1st option sounds like it works and is the correct behaviour

Crossover -> 200 Hz and Routing -> Move bass to subwoofer (recommended) => no bass < 200 Hz to front speakers, but played by the subwoofer (which is preferable as the fronts are very "small")

but then you say before that

the problem with no bass from the subwoofer remains except for the choice "copy bass to subwoofer".

which seems to contradict your test results

[mdav]

Sorry I was unclear. That was a description of what I think should happen with different options, but it didn't.

So I believed that it would work like this:
Crossover -> 200 Hz and Routing -> Move bass to subwoofer (recommended) => no bass < 200 Hz to front speakers, but played by the subwoofer (which is preferable as the fronts are very "small")

Crossover -> 200 Hz and Routing -> Copy bass to subwoofer => bass < 200 Hz to be played both by front speakers and subwoofer (which is not preferable as the fronts are very "small")

but I only get bass for this option:
Copy bass to subwoofer.

[mattkhan]

Ok I see. Can you post some pics of the relevant DSP windows?

[mdav]

Please see attached pictures. The choice (no mixing or mixing with JRSS ) in output format doesn't matter as expected. The choice that gives different results are move bass and copy bass.

[mattkhan]

perhaps I'm being dim but you show 2 different views of 2 different screens so it's not clearly *exactly* which combinations you have tried?

i.e. there are 4 combos

jrss on + copy bass = ?
jrss on + move bass = ?
jrss off + copy bass = ?
jrss off + move bass = ?

pls report what happens in each case.

[mdav]

jrss on (subwoofer silent) + copy bass = bass from sub
jrss on (subwoofer silent) + move bass = no bass from sub
jrss off + copy bass = bass from sub
jrss off + move bass = no bass from sub

I have now also tested:

jrss on (subwoofer silent) + room correction disabled = bass from sub
jrss on (subwoofer send all freq) + room correction disabled = bass from sub
jrss on (subwoofer any lowpass Hz) + room correction disabled = bass from sub

Well, that raised more questions. Why does jrss on (subwoofer silent) + room correction disabled give me bass from sub?

[mattkhan]

tbh I don't know why that's not working

what happens if you select the output format as 2.0 and then use room correction to "move bass"?

[mdav]

it doesn't matter what I choose under Output Format (Source number of channels, 2.0, 2.1 or JRSS mixing or not). The bass from the sub directly disappear when I choose Move bass under Room correction. So something seems to be screwed for Move bass or in my desktop system.

[mattkhan]

So something seems to be screwed for Move bass or in my desktop system.

well move bass certainly works as I've used it in the past. It's not obvious how your system configuration could be the problem if copy bass works for you though. What is the signal chain here? from PC down to the subwoofer I mean. You mentioned realtek so I guess onboard audio of some kind?

[mdav]

Unfortunately I can't test on my main system with HK AVR 7550HD as my house was struck by lightning and fried my AVR. That's why I'm looking for alternatives with bass management in MC so I eventually can replace it with a power amp instead.

Yes onboard audio in my desktop system:

MC Audio Device Realtek HD audio Wasapi -> Line Out port -> Acoustic Energy Aego M 2.1 active speaker system

[mdav]

I found this

There are currently two DSP's that have bass management settings:  Output Format and Room Correction.

The Conflict
First, people see bass management settings in Output Format and don't realize that the settings that actually affect 5.1 or 7.1 content are under Room Correction.

Second, if Room Correction is set for Move Bass, like I assume most will use for 5.1 or 7.1 content, then these settings won't work right for upmixed 2.0 content. I suggested a method of integrating both settings earlier in this thread.

I have however no idea what "won't work" mean, but adding .1 channel is as you said not upmixing.

[mattkhan]

I have however no idea what "won't work" mean, but adding .1 channel is as you said not upmixing.

.1 in used in different contexts, on the output side it is used to refer to the presence a subwoofer and on the input side it is used to refer to a source that has an LFE channel. Creating a .1 output is usually called bass management (or redirection) and bass management != upmixing.

I skimmed that thread and it seems the "won't work" might be referring to the 10dB difference in the LFE channel, it's hard to say as the thread is about the development of a feature so hard to say what is right *today*.

It would probably help if someone like mwillems, mojave or Matt commented. I don't really use the jriver room correction module so am not familiar with *exactly* what it is doing and when it does or doesn't work as expected.

[Matt]

This comment is in the code:

// if the subwoofer is already filled by JRSS, we will do no bass redirection (so 'Move bass' will become 'Remove bass')
// since the subwoofer channel already contains clean data at the proper output level

Could it explain what you're seeing?

[mattkhan]

I think that does explain it.

My interpretation is that "move bass" is specifically designed to operate on a .1 input channel. This means you need one of;

- a source with a .1 channel (typically the LFE channel on a BD/DVD)
- you need to have mixed a .1 channel in a DSP stage before the room correction stage (i.e. a PEQ block, convolution or JRSS)

The OP is listening to a stereo source and is not creating a .1 input channel (because he has subwoofer set to silent in JRSS) then there is no bass to move and hence no output unless he/she goes with "copy bass" (aka double bass).

Solution .... mix a .1 input channel if you want to use room correction "move bass"

[jjkale]

Gurus,
I apologize for being dense, but I still don't understand the best way to go from 2.0 to 2.1 in JRiver.
Would it be to set 2.1 in Output Format, set JRSS mixing, set silent  AND then in Room Correction set your crossovers?
OR
Would it be to set 2.0 in Output Format, no mixing AND then Room Correction...?

Also can you please explain what the second line, Routing, in Bass Management is indicating?  I understand the first drop down, remove/move/copy is doing, but is that second slope for?  How is that slope different than the slope above on the crossover line?
Thanks very much for your help.

[mattkhan]

Would it be to set 2.1 in Output Format, set JRSS mixing, set silent  AND then in Room Correction set your crossovers?

this one

Also can you please explain what the second line, Routing, in Bass Management is indicating?  I understand the first drop down, remove/move/copy is doing, but is that second slope for?  How is that slope different than the slope above on the crossover line?

a crossover is the combination of 2 filters, a high pass filter is applied to create the L or R output channel and a low pass filter is applied to create the subwoofer output channel. The 2 dropdowns let you control the slope of each filter independently, I think the top one is the high pass and the bottom one is the low pass. IIRC they are both butterworth filters but don't quote me on that.

[jjkale]

Thanks mk.
One followup if you don't mind.
Can MC make the change 5.1--2.1--5.1 on the fly without any further configuration, or, do I need to establish zones and use ZoneSwitch?
Thanks for your help.

[mattkhan]

Can MC make the change 5.1--2.1--5.1 on the fly without any further configuration, or, do I need to establish zones and use ZoneSwitch?

when, or why, do you want it to switch?

[~OHM~]

Would it be to set 2.1 in Output Format, set JRSS mixing, set silent  AND then in Room Correction set your crossovers?

this one

no matter what i change channels to it reverts back to 2 channels (stereo)

[mattkhan]

Would it be to set 2.1 in Output Format, set JRSS mixing, set silent AND then in Room Correction set your crossovers?

yes that should work

[jjkale]

when, or why, do you want it to switch?

Thanks again mk.
I would like it to switch because I have both 5.1 tracks and 2.0 tracks on my NAS.  Currently I have them segregated in different libraries, but I would like to combine them in to one and be able to shuffle/play any of them without changing libraries.
Thanks.

[mattkhan]

Thanks again mk.
I would like it to switch because I have both 5.1 tracks and 2.0 tracks on my NAS.  Currently I have them segregated in different libraries, but I would like to combine them in to one and be able to shuffle/play any of them without changing libraries.
Thanks.

the playback system/device is not changing though right, i.e. you want 2.1 or 5.1 depending on the content? If so, that's what the checkbox in the output format screen is for (something like mix stereo to 2.1)

[harlington]

I recently did this: 7.1 with JRSS mixing and using jriver bass management. When playing a stereo 2ch flac file, jriver shows '2ch converted to 8ch'. I then select stereo on my Avr to play 2.1 thru it.  Is this how jriver handle playing a 2ch source with bass routed to subs? I really just want to be able to play 2ch source with bass routed to my subs and since I must set speakers to large in order to use jriver bass management, if I don't use up mix and only choose 'source number of channel', I only get sound to my front l/r speakers, subs do not play. Thanks.

[jjkale]

I would like to submit to the group that possibly the creation of a 2.1 configuration from stereo may not be operating quite the way it was intended to.  I base this on comments from replies 26, 24,22 and 14, etc.  All these posters seem to have some knowledge (and most likely very good equipment) of how JRBM should work.  Yet all seem to be having similar issues implementing it.
Is it possible to get one of the developers to investigate and then provide a straight-forward guide on the creation of 2.1 from 2.0, i.e. basic bass management?
Yes it could be accomplished downline in a pre-pro, but particularly if employing room correction (or in a desktop setting), BM should be accomplished in MC.
Thanks again

[mattkhan]

As far as i know, JRiver saying it converts to 8 channel means it has 8 output channels available not that it puts content into all 8 channels. I.e. it is the output format not the result of jrss mixing.

Are you saying that you have configured it as discussed in this thread but you get 2.0 up mixed to 5 (or 7).1? If not, what are you saying?

[mattkhan]

I ran a quick test to confirm and it works as I posted earlier;

- audio path states the physical output format (how many channels it can output) not the mixing output (how many channels it is actually sending content down)
- setting output format = 5.1, sub = silent, stereo sources to  2.1, jrss mixing + room correction/move bass == 2.1 output

if any of the posters in this thread find this isn't working for them then post pictures of your DSP chain to illustrate exactly how you have it configured and what the output looks like.

[jjkale]

Ok, great.  Thanks mk.
I am away from home today and tomorrow, but I will confirm this asap.
May not seem like it, but the last two replies are more specific.
I'm sure this will work and I will report back. 
Thanks very much.

[harlington]

I ran a quick test to confirm and it works as I posted earlier;

- audio path states the physical output format (how many channels it can output) not the mixing output (how many channels it is actually sending content down)
- setting output format = 5.1, sub = silent, stereo sources to  2.1, jrss mixing + room correction/move bass == 2.1 output

if any of the posters in this thread find this isn't working for them then post pictures of your DSP chain to illustrate exactly how you have it configured and what the output looks like.

Yes it works as you described and that is how mine is set up except my output format=7.1.  According to my Denon Avr info, it shows input as 7.1 even though source is flac stereo 2.0. So it seems jriver actually up mixes the 2.0 source, not just stating how many channels are available.

[mattkhan]

Yes it works as you described and that is how mine is set up except my output format=7.1.  According to my Denon Avr info, it shows input as 7.1 even though source is flac stereo 2.0. So it seems jriver actually up mixes the 2.0 source, not just stating how many channels are available.

this is the behaviour I've described, jriver *is* in a 7.1 output format so the physical output device is showing up as 7.1 but only channels 1,2,4 have anything other than silence.

What is the problem with this? is it that your prepro/avr does not allow per input configuration of what processing is applied?

[harlington]

^^ there is no problem with this as far as I know. I was just curious of how jriver handles 2.0 source if I want to play bass thru my subs for a 2.0 source.  If you say only channel 1,2,4 are playing even my Avr shows 7.1 input, that is exactly what I need to know. Thanks.

[harlington]

Matt, I read your post somewhere but don't remember you showed how to measure jriver dsp with REW. I am using asio4all driver in REW and been measuring my subs and speakers with REW. I added a LSF in jriver along with a HPF and running jriver bass management (Avr speakers setting to large for all). I am using wasapi audio device in jriver MC21, What is the easiest way I can measure those jriver dsp with REW?  Thanks.

[mattkhan]

Ok that's good (that it is working). Using the wdm driver is probably the easiest way to measure so you would put REW to use the Java driver, select your input device as normal, output to the default device. Configure the jriver audio device as appropriate (if you set it as 7.1 in the windows device panel then you should get the rew measurement signal down every channel so add a peq block to mute the channels you don't want OR use fewer channels and use peq to mix the signal to where you want to measure) and measure away.

[harlington]

You lost me when you said peq block. Can you list a step by step in REW, jriver, Window,etc...please? Thanks.

[mattkhan]

PEQ block = one of the sections in jriver DSP studio which lets you do things like mute a channel, move channels around, copy them

I don't have time to write out a full guide for this atm, sorry. There are threads around with examples though so do some research and try it out yourself. Post back if you get stuck detailing your specific problem.

[jjkale]

mk, matt:
Is there a guide for setting the LFE trim level in Room Correction?
I am uncertain exactly how to do this.  I calibrate at 75 dB  so would I use gain on the sub to set 85 on my RS meter?  Or use the RC trim or both?
I just got new speakers, which prompts this question, Revel F208s plus the center and surrounds.
Will bass manage as well.
I will also employ Dirac Live after setting up Room Correction properly.
If you can point me to a reference, I would be grateful.
Thanks, jjk43

[mattkhan]

Can you clarify what your intended signal is exactly? Is this all on the PC going straight to an amp or some other device is downstream of the PC?

[jjkale]

Yes, thanks.
NAS--Broadwell NUC/JRiver--Dirac--Oppo 105D MCH DAC--Emotiva PreAmp--W4S MCH Amp--Revel 5.1
I am concerned about music only.  Movies and DirecTV follow another path.

[mattkhan]

Yes, thanks.
NAS--Broadwell NUC/JRiver--Dirac--Oppo 105D MCH DAC--Emotiva PreAmp--W4S MCH Amp--Revel 5.1
I am concerned about music only.  Movies and DirecTV follow another path.

tbh I'm not sure anyone external could advise in detail given the pretty long signal chain. You need to bear in mind that there are 2 distinct things here, one is maintaining a clean signal (no clipping) throughout signal processing in jriver & dirac and the other is getting gain structure right as you pass through the analogue side of your signal chain (oppo -> emo -> w4s).

[Hilton]

Here's my findings using MC DSP room correction bass management on LFE for 2.1 music and 5.1 music vs 5.1/7.1 Movies in 2 different zones.
The 7.1 zone is set for movies and multi-channel Audio.
The 2.1 zone is for all stereo sources.

Use the MC21 built-in 5.1/7.1 volume level calibration first on the 7.1 zone and check for the speaker with the lowest level.
You want to trim all other channels down to the lowest level channel so you don't introduce clipping.

Set the level on your lowest measured channel so the meter reading is 75db and then use either PEQ offset or Room Correction offset to get the other channels down to match your lowest channel reading on the meter.

After Dirac or EQ adjustments you'll need to come back and re-check volume level again to trim channels down to the lowest speaker reading on the meter.

For the 5.1/7.1 zone all channels should read 75db on the meter including the LFE when using the built-in MC21 Volume 5.1or7.1 channel Level Calibration.

Keep in mind:
Digital level adjustment should always be down as a preference where possible to avoid clipping further down the signal chain.
You should also turn the SUB AMP volume up on the SUB if LFE level is too low so you don't push MC21 into clipping protection.
Baseline LFE meter reading before correction can be upto 10db over your mains without any digital correction (trim) because you can always pull the LFE back down with trim.

You may need to play around with Room Correction Bass redirection crossover slopes and frequencies between stereo and 5.1/7.1 zones to match the characteristics of your main speakers with the Sub(s).  Changing the slopes and crossover region will create different peaks and nulls.
In theory the same cross over slopes and frequencies should work for both 2.1 and 5.1 but I found that not to be the case.

I recommend experimenting with the built in MC21 tones for the bass region from 20hz to 200hz to check the best blend of main to sub to find the right crossover point and slope. This will take quite a while.
If you have the luxury of moving your SUB (or SUBs) around the room you should check for the spot with the flattest SUB response for each SUB before tuning overall levels.
If you cant defeat the SUB built-in crossover, you should turn it upto it's highest frequency (usually 200hz) so that it doesn't interfere with JR bass management cross overs.
You should also set your AMP LFE cross over to it's lowest setting (or large speakers) to avoid interference with the MC crossover settings.
For example my Sony AVR is set to 40Hz LFE crossover with speakers set to large.


Now you have 5.1/7.1 tuned you can move on to tuning the 2.1channel stereo zone.
I copied my 7.1 zone to a new 2.1 zone to start from there.
If your lucky all you'll need to do is check the tick box in DSP studio for convert stereo to 2.1 on you stereo 2.1 zone and your levels will all be good for the test tones from 20hz to 200hz.

To check 2.1 channel stereo calibration I create a PEQ block to mute all channels except left and SUB and then run MC21 built in test tones to check frequency blend and level from 20hz to 200hz. Do the same for right channel.
PEQ-mute by Hilton, on Flickr


Unfortunatley some AMPS and Pre-AMPS handle LFE processing and level differently with multichannel PCM or analog inputs vs decoding DTS or multichannel in the AMP/Pre-AMP.

This may mean you need to do some level adjustments for the SUB in 2.1 stereo mode.

Because we can set upto 10-15db higher sub level in the multi-channel zone, if the sub levels are too low in 2 channel zone, we have the room to bring the sub level back up without clipping by just setting the SUB offset back to 0.

If you're experimenting with different crossover slopes and frequencies between 2channel and multichannel you may need to go back and forth between each zone and adjust levels.  The goal is to always have the Sub over-level in multichannel so you can bring it back down to 0 offset in 2 channel mode. (and bring it down with -10 offset in multichannel)
(usually 10db)

Having just moved house and retuned my system it took me a few days and several hours per session to finish the job.
I have nice phat bass that's not too overpowering in movie mode and multi-channel music mode and clean tight bass in 2.1 stereo mode.

Your mileage may vary, but that's how I've approached it.  I'm open to comments and feedback if anyone thinks there's a better way.
In the end I have NO PEQ frequency adjustments, only level adjustments to match mains and Sub levels.
PS. I have -3db in 2 channel on sub probably because I have dual mono SUBs. ie same signal for LFE to both subs and mono bass redirection to both subs. (amp and sound card are both only mono sub output)
I also have the luxury of having matched floor standing full range speakers for my 6 channels with a matched centre channel so my crossover points and slopes are the same for each channel.

7.1 zone output
7.1zone-output by Hilton, on Flickr

7.1 zone room correction for SUB
7.1zone-room-sub by Hilton, on Flickr

7.1 zone room correction for Left
7.1zone-room-left by Hilton, on Flickr

2.1 zone output
2.1zone-output by Hilton, on Flickr

2.1 zone room correction for SUB
2.1zone-room-sub by Hilton, on Flickr

2.1 zone room correction for Left
2.1zone-room-left by Hilton, on Flickr