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[bobkatz]

Currently the latency of my convolution filter is too large to handle lip sync so I'm trying to set up a simpler, low latency system to play back videos.

I've got 8 channels of DACs going, LF/RF, C/LFE, SL/SR and then the two subwoofers, in that order, so channels 7/8 need to be routed to low pass filters and the stereo subs.

Is the parametric equalizer capable of routing and crossing over a 5.1 source signal to stereo subs, routing the left front low end to the left front subwoofer and so on and so forth? Tonight I've tried many combinations of output format and parametric equalizer functions and have not found the magic formula to do it all. I just succeeded in getting pink noise to the subs, but only by making output format be "5.1 channels in a 7.1 channel container" and then magically by also reordering so that the extra channels (7 & were first in the order. I've also tried the user 1 and user 2 channels, first by removing sound from them as mentioned in one post by Matt, then sequentially adding signals to them and then doing the filtering, but nothing comes out of the subs when I'm done.

It's a little like rolling dice, I can't quite decode JRiver's way of thinking about this (probably student pilot error). Or perhaps stereo subs are not possible with the current routing and mixing facilities in the DSP studio. Anyone? 

Many thanks.

[Matt]

The default audio chain in JRiver is going to think of a subwoofer as mono, not stereo.  That means JRSS can only build a mono subwoofer, Room Correction bass redirection only talks to a mono subwoofer, etc.

However, you can use Parametric Equalizer to low pass any channel and route the result to any other channel.  So you could lowpass, Linkwitz, etc. L to channel 7 and R to channel 8.  Explore the 'Mix Channels' and 'Channel Order' filters for the routing.

This will get a little complicated when you play content that has a native LFE channel (like a 5.1/7.1 movie).  Because in that case it wouldn't be good to build the subwoofer from L / R low-passes.  You could always add the native 0.1 channel using 'Mix channels' to 7/8 after building from the L/R, and then tell JRSS to leave the 0.1 channel empty (so it would only be filled when playing native 5.1 / 7.1 content).

Does that help at all?

[mojave]

I use stereo subs for music, but mono for movies.

Matt explained it pretty good. In "5.1 in a 7.1 container" the channel order is L, R, C, LFE, RL, RR, SL, SR so you need your surrounds connected to channels 7 & 8.

Here is what I would do.  In Parametric Equalizalizer I would add two Mix Channels. The first one copies Left to Rear Left and the second copies Right to Rear Right. Then I would add a high pass filter for both Left/Right and Low Pass Filter for both Rear channels.

[bobkatz]

Dear Matt:

That's the concept that I worked from last night for hours and hours trying to configure the various options in the parametric equalizer. Maybe the problem is I'm using output channels 7/8, which are pre-defined as right rear and left rear, for the two subwoofers. Whatever it is, I can't crack the code to get the parametric to split and route the channels properly.

BK

The default audio chain in JRiver is going to think of a subwoofer as mono, not stereo.  That means JRSS can only build a mono subwoofer, Room Correction bass redirection only talks to a mono subwoofer, etc.

However, you can use Parametric Equalizer to low pass any channel and route the result to any other channel.  So you could lowpass, Linkwitz, etc. L to channel 7 and R to channel 8.  Explore the 'Mix Channels' and 'Channel Order' filters for the routing.

This will get a little complicated when you play content that has a native LFE channel (like a 5.1/7.1 movie).  Because in that case it wouldn't be good to build the subwoofer from L / R low-passes.  You could always add the native 0.1 channel using 'Mix channels' to 7/8 after building from the L/R, and then tell JRSS to leave the 0.1 channel empty (so it would only be filled when playing native 5.1 / 7.1 content).

Does that help at all?

[bobkatz]

I use stereo subs for music, but mono for movies.

Matt explained it pretty good. In "5.1 in a 7.1 container" the channel order is L, R, C, LFE, RL, RR, SL, SR so you need your surrounds connected to channels 7 & 8.

Here is what I would do.  In Parametric Equalizalizer I would add two Mix Channels. The first one copies Left to Rear Left and the second copies Right to Rear Right. Then I would add a high pass filter for both Left/Right and Low Pass Filter for both Rear channels.

Thanks for coming in on this, Mojave! Thanks for cracking the code on "5.1 in a 7.1 container." I think that's the formula I need to use to get my stereo subs, using RL and RR as the subwoofers. Assuming that the names RL and RR carry through, what do you think would happen if I use channel order as the last activity in the parametric to reroute the RL and RR signals (now low passed) out to my channels 7/8 and the SL and SR signals (surround) out to my channels 5/6? I've tried various combinations of that last night to no avail, but I strongly suspect it's because I didn't crack the code on how "5.1 in a 7.1 container" is organized.

By the way, true stereo subs work great for movies, too, Mojave. It gives an additional sense of envelopment for the uncorrelated bass (especially in orchestral) music which is likely sent full range to the front left and front right speakers. The degree of envelopment depends a lot on how much the motion picture sound engineer redirected low frequency information to the LFE, which would dilute the envelopment factor of the uncorrelated bass. If you have a good, reasonably large room when playing well-recorded orchestral scores, you will hear an improvement in envelopment in the bass region with true stereo subs.

Best wishes,


Bob

[bobkatz]

The default audio chain in JRiver is going to think of a subwoofer as mono, not stereo.  That means JRSS can only build a mono subwoofer, Room Correction bass redirection only talks to a mono subwoofer, etc.

However, you can use Parametric Equalizer to low pass any channel and route the result to any other channel.  So you could lowpass, Linkwitz, etc. L to channel 7 and R to channel 8.  Explore the 'Mix Channels' and 'Channel Order' filters for the routing.

This will get a little complicated when you play content that has a native LFE channel (like a 5.1/7.1 movie).  Because in that case it wouldn't be good to build the subwoofer from L / R low-passes.  You could always add the native 0.1 channel using 'Mix channels' to 7/8 after building from the L/R, and then tell JRSS to leave the 0.1 channel empty (so it would only be filled when playing native 5.1 / 7.1 content).

Does that help at all?

Yes, thanks. I've been thinking along those lines. I'm confused about your JRSS recommendation since JRSS comes in the first module in the chain always. If I tell JRSS to leave the 0.1 channel empty, then how does the 0.1 information get to my parametric where I'm going to construct a route to get my LFE to my subs?

[Matt]

You can also select '7.1' instead of '5.1 in a 7.1 container' and then just overwrite the extra channels.  It will work the same, but be a little less efficient since you may build channels only to throw them away.  One thing to remember is 7.1 uses a default line order of: L, R, C, SW, RL, RR, SL, SR (RL, RR come before SL, SR), which is different than 5.1.  I think this is confusing, but it's the standard.

As for leaving the 0.1 empty, JRSS is only used to up and down mix.  If the input already has a channel, like the case of a 5.1 movie playing to a 5.1 output, JRSS leaves the 0.1 alone.

[mojave]

Bob, I'm using Audiolense for two channel sources and haven't yet spent the time to integrate my whole surround system with Audiolense. Despite many objections in other forums, I've always liked stereo subs better. I'm experimenting with Audiolense on the octave width of my crossover. Audiolense puts my mains -3 dB down at 16 Hz and my subs play up to 400 Hz. Maybe I should just let my mains be completely fullrange for movies.

I use JRSS a little different than Matt in that I always have the subwoofer set in Output Mode to "Silent" and use Room Correction or Paramentric EQ to define how I want my bass routed.

[tgundo2003]

Bob, I'm using Audiolense for two channel sources and haven't yet spent the time to integrate my whole surround system with Audiolense. Despite many objections in other forums, I've always liked stereo subs better. I'm experimenting with Audiolense on the octave width of my crossover. Audiolense puts my mains -3 dB down at 16 Hz and my subs play up to 400 Hz. Maybe I should just let my mains be completely fullrange for movies.

I use JRSS a little different than Matt in that I always have the subwoofer set in Output Mode to "Silent" and use Room Correction or Paramentric EQ to define how I want my bass routed.

Wow, taking your mains out to 16Hz and only 3dB down... What are they?

[bobkatz]

Bob, I'm using Audiolense for two channel sources and haven't yet spent the time to integrate my whole surround system with Audiolense. Despite many objections in other forums, I've always liked stereo subs better. I'm experimenting with Audiolense on the octave width of my crossover. Audiolense puts my mains -3 dB down at 16 Hz and my subs play up to 400 Hz. Maybe I should just let my mains be completely fullrange for movies.

I use JRSS a little different than Matt in that I always have the subwoofer set in Output Mode to "Silent" and use Room Correction or Paramentric EQ to define how I want my bass routed.

Impressive, Mojave. Let me know if you have any success making a low-enough latency filter that's good for surround video lip sync.

Even my JL woofers start rolling off at 20 Hz, but that's pretty good for a 12"  :-). I think they drop like a rock, on purpose, below 20, I'll have to look at the curve to see what they measure at 16....

Sorry, Matt, but I also have JRSS turned off, I can't see any need for the extra routing, but I'm glad you provided it for people who need or want it.