I run bi-amped mains and JRiver is my crossover; I also wrote the sticky on speaker correction at the top of this subforum
Here are some tips on how to do what you want in JRiver:
1) Regarding the output format I probably have to use 7.1 to make use of all outputs of my sound card?
So how/where would I best configure the Downmix of multichannel sources (5.1 / 7.1)?
Normally the way to handle downmixing is to look in JRiver's output format module and use one of the "x channels in a 7.1 container" options. The first number is the downmix target, the second number is the total number of channels available to work with. There isn't currently a "4 channel in a 7.1 container" option, though, so I'd recommend using "5.1 in a 7.1 channel container," but you'll need to do a little custom downmixing from there. At that point, you'd have the rear and side channels already downmixed correctly, so you'd just need to mix in the center and LFE into the fronts in PEQ. Given that you only want the LFE in the fronts, that's actually a bonus not a detriment. This config would also potentially capture your upmixing needs as well (all audio would be mixed to 5.1 by JRiver, and then custom downmixed to 4 channel by PEQ).
As far as I can see, I could use the Room Correction plugin to do the correct bass management but for moving the Center to the Fronts and especially doing the digital XO (plus assigning the correct sound card outputs to Low/Mid/High) will I have to use the PEQ or can all this be done in Room Correction?
What about correctly Upmixing Stereo to 4.0? JRSS will introduce silent channels (e.g. for a subwoofer) that I'll have to overwrite with the XO setup?
Basically all bass should go to the low end of the Fronts, so LFE to both, bass end of the rears to respective front (though I can also keep the rears full-range).
As between the two, you will need to do most of your routing in PEQ, not room correction; room correction offers no way for you to split out, say, your HF from your midrange, you need to do that in PEQ. It's pretty intuitive using the filter options under "mix channels," basically you'd
add LFE and center to left and right with appropriate reductions in gain, then
copy front left and front right to the blank channels, and apply your crossovers from there. The only thing you might want to use Room Correction for is to redirect the rear/side channel bass to the fronts, but you mentioned that wasn't a super high priority. If you have any specific questions about putting together a filter bank, I'm happy to help.
2) To correct the speakers, especially the Fronts, I wanted to measure and correct each driver near field with REW, subsequently correct the whole speaker from a little distance and finally do an overall room correction at/around the listening spot.
I could specify a 8 ch convolution filter config to achieve the first (and possibly second) step, but how would I achieve an additional overall room correction?
Using an expensive software like Acourate or Audiolense would enable me to combine all individual filters step-by-step with an overall correction into one filter for each speaker or a multichannel WAV file, but can this be done using free software like REW or possibly DRC? Of course I could go the overall route fromt he beginning but I'd like to have a corrected active speaker first (similar to a regular passive one) in case I'll change postions or the like int he future.
The thread pinned to the top suggests this is possible (at least for one speaker at a time?) when combining the individual corrections in HOLM? JRiver by itself cannot apply mutiple filter-WAVs to the same channel, right?
I wrote the sticky thread at the top, and the secret (in my opinion) is to do most of the speaker correction in PEQ and then only use convolution for phase fixing/room correction at the end. JRiver can (using the convolution config file system) apply multiple different convolution filters to different channels; I'm not sure if it can apply multiple convolution filters to the
same channel (I've never tried, but that's because I'm not sure it would work)
If you want to do speaker correction separately from room correction, the stickied thread tells you more or less exactly how I would suggest doing it. The only difference when working on an active speaker is that you should treat each element (at first) as though it were an entirely separate speaker. Take the three measurements described in the guide for each stage, but don't try to stich them together in Holm. Use REW to generate the filters needed to get each stage flat in the frequency band of interest, copy those filters into JRiver's PEQ, and then work out your crossovers.
So for example, with my speakers I measured the LF section at 3 inches, 12 inches and 1 meter in Holm, exported the measurements to REW as described in the guide, averaged them, auto-calculated the EQ to get them flat from 30Hz to 1000Hz, and then copied the filters into JRiver's PEQ. Then I did the same thing for the HF stage. Once they were both flat in their pass bands (and a little beyond), only then did I start taking "whole speaker" measurements to work out my crossovers and delay settings. Then, I took another whole system measurement in Holm at 1 meter and used that to figure out what kind of phase correction I might need, etc. Doing it that way makes getting the crossovers aligned much easier, and results in flatter overall system response.
3) What is the correct order for the plugins in the end?
Bass management and downmix/upmix of the input should probably come first, so I would move Room Correction up the list?
What about the speaker distance? Is it better to configure it per speaker or per driver (output)?
The latter is preferable from a time- and phase-alignment standpoint but this could also be accounted for in the filters themselves.
The order of operations is going to depend on whether you use convolution or PEQ for channel routing, but channel routing should come first; everything else can happen in almost any order. If you're going to be measuring the system anyway, I'd recommend setting delay in PEQ (or in convolution), rather than using distance in Room correction (which is a coarse adjustment).
4) What about convolution/XO of external sources? For things played by MC or through the loopback method, everything should work as set up.
I can also play back the input of my soundcard, but in this case, and also for the loopback sources, the neccessary video delay cannot be taken care of, right?
So I'd have to set up a "TV" and "external" zone that takes the sound from the input or loopback and uses minimal phase corrections (maybe just through PEQ) to achieve minimal delay with video?
Yes, PEQ processing is more than fast enough for av sync if you're routing audio back through loopback or JRiver's new WDM driver. Convolution filters (unless very short) may or may not fast enough for that. That's one advantage of doing everything possible in PEQ and then only using convolution for things which require convolution (i.e. phase correction).
I use my active XO speakers for web video, video games, for any kind of audio you can get out of a computer. If my system required convolution to function, that would be harder to manage with some of my hardware (I would have to either give up optimal correction or acceptable lipsync).
5) If I want to be able to quickly switch to a headphone output (I think the Xonar uses the front channels for this) I best setup a dedicated zone without XO/convolution etc. and just downmixing to stereo?
Yep, I have a separate zone for headphones, that's the easy answer.
My current approach to above topics would be to enable 7.1 output, do mixing/bass management and XO in the PEQ and use individual filters in convolution.
Different setups (external Sources, Headphone output, etc.) via other zones.
But maybe there is a better and less error-prone way? Especially regarding correct mixing and bass management?
Your approach is (given your system goals) a good approach; my advice would be to try and push as much of the correction as you can into PEQ (and out of convolution) for the reasons outlined above, but that is definitely more labor intensive so I understand if you'd prefer a more convolution-focused approach. If you're using REW, that makes things easier as REW will tell you exactly what filters compose it's convolution filters, so it's easy to migrate them to PEQ.
On the mixing issue, unfortunately there isn't a 4 channel in a 7.1 channel container option, so there is no less "error prone" way to do the down/upmixing (JRiver's built in mixing is very good). You'll need to do your own mixing at least to some extent. As noted above, the 5.1 in a 7.1 container setting will at least reduce the difficulty somewhat by handling the Rear and Side channel downmixing for you.
I'm sorry if all those questions are answered somewhere already but I could only find individual setups/solutions regarding either mixing+XO or multichannel-convolution etc. but not all of those combined correctly.
As the whole setup is pretty much 50% music 50% home theater, things like bass management and correct channel mixing/routing are really important to me vs. a simple Stereo-XO approach that would be sufficient for music (although I like 5.1 music too).
If Acourate is the way to go I might bite the bullet and buy it, but as JRiver offers a solution to all of the above I'd like to at least avoid external convolvers, XO software and the like that would even more overcomplicate things.
I don't have too much personal experience with Acourate; as mattkhan said, it may fit your bill perfectly. That said, I think everything you want can be achieved using JRiver and freeware, it'll just take some effort to get it right.
I spent quite a lot of time getting my own DIY active setup configured in JRiver, and there's no reason you should have to work it all out by trial and error. These issues are not perfectly covered on the forum, and I've been meaning to write a guide to active crossovers in JRiver, but got sidetracked by life.
Point being, don't feel as though you need to work through all of this on your own, I'm happy to answer any questions you have. Just post 'em here. Active XOs can be a daunting process and there's no reason you shouldn't be able to learn from our collective trial and error
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Topic: Downmix/Upmix + Digital XO + Convolution + Room Correction (Read 9426 times)