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[maglevrabbit]

I am trying to use the convolution facility within the DSP studio of JRiver to make an active crossover. I am using an Asus Xonar U7 MK2 7.1 USB sound card as output. I have no problem using the parametric eq's and IIR filters in JRiver to create a six channel system (two subs, two mid-woofers, two tweeters).

Now I am trying to do the same using convolution and FIR filtering. The tweeter and sub parts pose no problem, using only a single filter operation, but trying to create the band pass filter for the mid-woofer, which requires both a high and low pass filter to be applied, is not working using separate filter operations, but will work if I generate a combined high-pass, low-pass filter into a single WAV file and then apply it ias a single filter operation. I am using a config file (see below).

I cannot seem to find any decent, complete and thorough documentation  on the convolver web site or indeed anywhere else to describe what is meant by input channel and output channel, or indeed anything else, and how these channels map to JRiver channels, and am doing almost everything by trial and error (mostly error).

Combining the low pass and high pass filters in a single file, and applying them to channels 0 and 1, which seem to correspond to "left" and "right", works fine, as follows:

44100 2 8 FF
0 0
0 0
F:Documents\JRiver\rephase\mid-fir-hplp.wav
0
0.0
0.0
F:Documents\JRiver\rephase\mid-fir-hplp.wav
0
1.0
1.0

Applying the low pass then high pass filters in separate operations, again to channels 0 and 1,  does not:

44100 2 8 FF
0 0
0 0
F:Documents\JRiver\rephase\mid-fir-hp.wav
0
0.0
0.0
F:Documents\JRiver\rephase\mid-fir-hp.wav
0
1.0
1.0
F:Documents\JRiver\rephase\mid-fir-lp.wav
0
0.0
0.0
F:Documents\JRiver\rephase\mid-fir-lp.wav
0
1.0
1.0

Strangely, applying a single filter to the same channels 0 and 1 does work:

(HIGH PASS)

44100 2 8 FF
0 0
0 0
F:Documents\JRiver\rephase\mid-fir-hp.wav
0
0.0
0.0
F:Documents\JRiver\rephase\mid-fir-hp.wav
0
1.0
1.0

OR (LOW PASS)

44100 2 8 FF
0 0
0 0
F:Documents\JRiver\rephase\mid-fir-lp.wav
0
0.0
0.0
F:Documents\JRiver\rephase\mid-fir-lp.wav
0
1.0
1.0

Can anyone explain what is going on here, and just what "input channel" and "output channel" actually mean?
For example, can channels 4 and 5, which seem to map to REAR LEFT and REAR RIGHT, be an output to one operation, and then an input to another?

Hope someone can help.

Thanks!   

Phil T.

[mattkhan]

See https://wiki.jriver.com/index.php/Convolution

Multipass filtering is not supported so you do have to have a single filter per "path". The page above states what features of the cfg file format are supported.

Your experiments on what works and doesn't are likely to be influenced by the cfg file reloading bug, as far as I know this has never been fixed though I haven't tested it myself in quite a while.

[maglevrabbit]

See https://wiki.jriver.com/index.php/Convolution

Multipass filtering is not supported so you do have to have a single filter per "path". The page above states what features of the cfg file format are supported.

Your experiments on what works and doesn't are likely to be influenced by the cfg file reloading bug, as far as I know this has never been fixed though I haven't tested it myself in quite a while.

Many thanks for that info. Saves me wasting a lot of time trying to find a way round it.