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[Mike48]

I am wondering about JRSS Mixing when going from 2.0 to 2.1 channels.

I play stereo files to a 2.1 system. I have crossovers and "routing" enabled in Room Correction, moving bass from both channels to the sub. That seems to work whether or not JRSS is enabled in Output Format, as long as Channels is set to 2.1.

This page http://wiki.jriver.com/index.php/Mixing says it should work either way, but it doesn't say what are the advantages or disadvantages of using JRSS. Anyone?

Thanks!

P.S. MC 19.0.91 on Windows 7/64 Pro.

[mojave]

If you use JRSS for 2.1, then JRiver does the following:

1.  Leaves the mains fullrange
2.  Uses the crossover set in the Subwoofer section of Output Format to copy the bass from the mains to the subs

If you want to use JRSS with a 5.1 system and also want to use Room Correction for bass management, then you set the Subwoofer in Output Format to "Silent".

If you have 2.1 with JRSS and also do bass management in Room Correction, then you are sending double bass to the subwoofer. You should turn off JRSS for 2.1 whenever using Room Correction for bass management.

In my opinion, bass management in Room Correction and moving bass to the subs like you are doing is the best method.

[Matt]

I'm going to disagree with mojave on this one.  I think you'll get the cleanest subwoofer channel letting JRSS build it, especially if you use 5.1 or 7.1.  For 2.1, the results will be mostly the same.

It's fine (and recommended) to also leave bass management on.  When JRSS builds the subwoofer, the "move bass" becomes "remove bass" to avoid double subwoofer.  When the source has a subwoofer (5.1 movie, etc.) then JRSS is not involved and bass management will move bass.

If you have 2.1 with JRSS and also do bass management in Room Correction, then you are sending double bass to the subwoofer.

This is not correct.  See above.

[mojave]

I'm going to disagree with mojave on this one.  I think you'll get the cleanest subwoofer channel letting JRSS build it, especially if you use 5.1 or 7.1.  For 2.1, the results will be mostly the same.

Consider it a special Christmas present from me that I'll choose to agree with you. 

Here is a test Matt did a couple of years ago:

Next, I experimented with how to get the best sounding subwoofer output.

I used the two main approaches we've been discussing:

1) JRSS (using 'Remove bass' in bass management)

I simply love the way this sounds.  Media Center + JRSS + Room Correction delivers the best sound I've ever gotten from any stereo.

I'm able to dial in a very clean subwoofer output in JRSS.  This is especially good with rock music, where it does a nice job of keeping clean bass drum hits on the subwoofer, while keeping drone from bass guitars off the subwoofer.

2)  Redirected bass only (using 'Move bass' in bass management)

This approach is energy neutral, so there's a mathematical purity to it.  But I just couldn't get a bass output that sounded as good as JRSS.  Using the crossovers established above, it put too much high bass on the subwoofer.  Instead of tight punches, it droned and made bass guitars slide around the sound stage.

Moving sound below the 100 Hz crossover from the SL and SR speakers puts frequencies I don't think sound good on the subwoofer because of directionality, inability to exaggerate bass without exaggerating unwanted drone, etc.

Allowing a final (optional) subwoofer crossover might solve some of my problems, although then it's not clear the advantage of using #2 instead of #1.


This is all relevant because we're trying to figure out what to make most prominent in the user interface and what to recommend.  From my testing, the best sound was with letting JRSS fill the subwoofer and using bass management to remove unsupported frequencies (#1 above).

It's fine (and recommended) to also leave bass management on.  When JRSS builds the subwoofer, the "move bass" becomes "remove bass" to avoid double subwoofer.

I completely forgot about that.

16.0.83 (5/6/2011)
2. Changed: In cases where the subwoofer channel is created using JRSS Subwoofer, bass redirection 'Move bass to subwoofer' will be treated like 'Remove bass'.

[Mike48]

Thanks to mojave and Matt for replies! Double that because it's holiday season.

I am hoping for a little more clarification.  I've read all your answers twice, but I'm still missing this: what is different when I turn JRSS on vs. setting Channels to 2.1? 

In both cases, I'm using Bass Management, with a high-pass filter for the mains and Routing (a low-pass filter?) set to "Move bass to subwoofer."

I understand the two approaches (JRSS vs. 2.1) can sound different -- in my case they seem to -- and I'd like to know what they are doing, so I can understand why.

I have used electronic crossovers, and MC seems more flexible than the hardware-based approach, but it's not clear what it's doing behind the curtain.

Thanks!  And all best wishes for the season.

[mojave]

I think JRSS uses a 48 dB low pass on the subwoofer. If you don't select the same low pass in Room Correction, then it could sound different. The low pass is the lower option in Room Correction next to Routing.

Is the Subwoofer setting in Output Format set to the same crossover as in Room Correction or to Silent? This can also cause a difference between your two methods.

Those are the only two "behind the curtain" things I can think of.

You can use the different methods and watch the Analyzer in DSP Studio to see what is going on. For more detail I like to use the free Voxengo Span plugin. Either tool helps you see what various settings do to the mains and to the subwoofer regarding high/low pass filters. You could also use Convert Audio and covert a song using both methods and then run Analyze Audio and see if the Volume Level, Peak Level, and Dynamic Range tags are different between the two conversions. This might give some insight into whether energy levels are the same between both methods. I might try this when I have time.

Like Matt said, JRSS and Room Correction vs just Room Correction will be very similar for 2.0 upmixed to 2.1. When you upmix from 2.0 to 5.1 or 7.1, JRSS is much better than something like Dolby Prologic IIx or even Room Correction since JRSS only creates the subwoofer from the original main channels. DPL IIx creates all surround channels before the mix goes through bass management. This multiple mixing can make the subwoofer not sound as good.

[dean70]

The thing I found with JRSS 2.1 is the subwoofer timing is not correct. For 7.1, I use the speaker distance which gets the timing between sub and mains spot on, but with JRSS 2.1 mode it sounds off.

[Matt]

The thing I found with JRSS 2.1 is the subwoofer timing is not correct. For 7.1, I use the speaker distance which gets the timing between sub and mains spot on, but with JRSS 2.1 mode it sounds off.

Room Correction will apply timing the same for JRSS 2.1 or 7.1.

You might start a new thread and post details if you double-check and still believe there's a problem.