Hi, I have similar needs but a bit moire complex.
I whould like to do 2.2 from a simple stereo file but with 2 stereo sound cards for output (because I use 2 high quality external dacs taking only stereo inputs) :
Stereo flow =>
=> stereo flow with low pass on output card 1
=> stereo flow with high pass on output card 2
Other questions :
How to manage frequency cuttoff setup ? If I put same on both high and low pass, I will have a bump at that freq, right ?
How to add phase and delay management ?
Hehe .. Quite complex. Thanks !
You may run into troubles syncing those two external DACs, unless they allow for an external sync. How are you controlling the two external DACs (And what kind of DACs are they)? If it's a USB interface, unless the DACs will allow you to master/slave them or you have a wordclock, they will probably not sync correctly. If you're using SPDIF outputs on the first DAC to drive the second DAC, it may sync, you just need to find a way to output to those SPDIF outputs in JRiver. If that's what you're doing I can provide some additional advice.
As to your other questions:
1) Yes if you just use the default low pass and high pass you will have a "lump" at the crossover point because they are butterworth filters. If they're symmetrical and even order, it will be a 3dB lump. The easy way around that is to cascade two highpasses or lowpasses of the same order in parametric equalizer to create a higher order linkwitz-riley crossover, which sums flat at the crossover. Two 6dB lowpasses will create a second order linkwitz-riley lowpass on the sub channel, which would then sum flat with two 6dB highpasses set to the same crossover point on the speaker channel, etc. For more info on butterworth v. LR, see
http://www.rane.com/note160.html2) Delay is easy, parametric equalizer has a "Delay" module, and you can dial in exactly how many milliseconds you need and on which channels.
3) Phase adjustment is harder and, long story short, requires using convolution to really do it. All of JRiver's parametric EQ fitlers are IIR filters (i.e. minimum phase filters), so they cannot change frequency response without also adjusting phase and vice versa. To do frequency response-neutral phase adjustment you need to use an FIR filter, which JRiver supports through convolution. But you'll need to create FIR filters in other software, and it's a complicated subject. Search the forum for "convolution" and you'll find many threads, here's a recent one where a user discussed his method for creating FIR filters:
http://yabb.jriver.com/interact/index.php?topic=84252.0