Convolution & Motu Mk5 Ultralite - Channel mapping

I was hoping there may be some users of convolution DSP and multi channel interfaces that could help me correctly set my output channel mask, for a JBL M2 crossover.

My Interface is: Motu Mk5 Ultralite.

State of Play.
No matter what I try I can’t channel map successfully to channel 1,2,3,4 in sequential channel order. I can only get Channel 1,2 then 5,6 for a 4 channel convolution crossover. Its playing havoc with my OCD.

This is my 4 channel convolution cfg file:

44100 2 4 33
0 0
0 0 0 0
M2low.wav
0
0.0
0.0
M2high.wav
0
0.0
1.0
M2low.wav
0
1.0
2.0
M2high.wav
0
1.0
3.0

I have tried every combination under the sun, with channel mask set to 0 etc, but channel 2,3 remain skipped. I honestly don’t understand how to derive this channel mask meaningfully, and I suspect the answer is in understanding how to assign masking correctly. Unfortunately the instructions at best are confusing, and lack detail for a first timer. So any help to understand this would be most appreciated.

http://convolver.sourceforge.net/config.html

Its worth highlighting, I can channel map channels 2/3 perfectly using procedural EQ via Roon… Its worth noting Roon addresses these channels as Center & Low frequency.

…I can also correctly map when using a test 8ch convolution cfg file. Like this:

44100 2 8 0
0 0
0 0 0 0 0 0 0 0
M2high.wav
0
0.0
0.0
M2high.wav
0
0.0
2.0
M2high.wav
0
0.0
4.0
M2high.wav
0
0.0
6.0
M2low.wav
0
1.0
1.0
M2low.wav
0
1.0
3.0
M2low.wav
0
1.0
5.0
M2low.wav
0
1.0
7.0

Any thoughts to channel mapped in sequence for a 4channel convolution crossover?? Any help would be most appreciated.

Hi Stephen

I changed my interface from the Ultralite mk5 before attempting convolution, but I suspect you’re right that the mask is the issue. 33 in hex is the sum of FL (1), FR (2), BL (10) and BR (20). But you want FL (1), FR (2), FC (4) and LF (8) which is F in hex.

Hope this works for you.

1 Like

John that’s amazing, thanks for your help.
Works perfectly now.

I see, so I need to add the channel reference numbers and convert to hexi decimal… Thanks I very much appreciate your help.

Great! Pleased it fixed it. It’s odd that 0 doesn’t work as a mask, since it should. I wonder if there’s some quirk with 4 channels, as multichannel devices and drivers seem to have some favourite numbers, like 2, 6, 8 …

Seems so, as a mask of 0 works perfectly for 8 channels.
Many thanks - I appreciate your help.

6ch doesn’t work with 0 mask either. Needs 3F.

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