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Home » Hardware » +DSP » So.... Multi-device DSP seems to be NOT shared across units? (Curiosity / frustration with DSP allocation when using multiple ULN-8mkIVs)
So.... Multi-device DSP seems to be NOT shared across units? [message #88437] Tue, 06 December 2022 08:50 Go to next message
adingley is currently offline  adingley
Messages: 2
Registered: June 2022
Location: Philadelphia
Junior Member
Perhaps this is a really nit-picky thing -- but I'm a little surprised by this.

I just received my second ULN-8mkIV (it's tricky to come by them these days with the current supply chain woes) but I have two units now, and I'm thrilled about having more inputs & DSP. I've been especially excited about a 2nd unit after reading this passage from the MIO manual's DSP Implementation Guide: (pg. 341)

  • All plug-in processing within the 3d Mixer occurs in the shared DSP/FPGA engines of the Metric Halo 3d hardware, completely independent of your Host computers' processor. The more 3d boxes you connect to your MHLink domain, the more processing power you have.

The above does seem to indicate that the DSP/FPGAs are "shared", and that someone with multiple units is going to have and increased ability to process DSP plug-ins in their MIO mixer.

My actual experience is not quite what I was hoping for, though, "technically", I suppose it holds true.

What I'm seeing happen is:

• ALL DSP for inputs of box #1 seems to be handled SOLELY by the DSP/FPGAs in Box #1.
• ALL DSP for inputs of box #2 seems to be handled SOLELY by the DSP/FPGAs in Box #2.
• IF I max out the DSP on box #1, I still get digitally-garble audio through my outputs... there's no "overflow" method in place that allows my "shared DSP/FPGAs" (from box #2) to intelligently handle the signal processing for signals flowing into Box #1.

I'm posting this because:
A) I'm not sure if there's a setting that I'm missing, and perhaps something I could do would change this behavior. -- If anyone knows what switch to flip, I'd be thrilled to have the DSP/FPGAs actually be "shared" as it seems to indicate in the manual.
B) I feel like that section of the manual could maybe be more explicit (if this behavior that I'm seeing IS the expected behavior).

* as I write this, I'm starting to think that maybe it is the default/expected behavior, and it probably has to do with maintaining low latency signal paths, as maybe the MHLink system is fast enough to route real time audio, but not fast enough to route real time audio + offload DSP resources for that same real time audio in a bi-direction fashion while maintaining sample accurate sync, etc.
Re: So.... Multi-device DSP seems to be NOT shared across units? [message #88455 is a reply to message #88437] Tue, 03 January 2023 16:08 Go to previous message
Mike_DM is currently offline  Mike_DM
Messages: 9
Registered: December 2022
Location: Vienna, Austria
Junior Member
I have experienced the same issue with a mk4 ul8, Uln8 3D and Lio 8 4p.
To get by on a schedule I lowered the sample rate which helped a bi... sometimes even restarting the interface helped... but really that seemed like voodoo from 1998.
Ide love to see this improved with the next update.

Freelance Audio Engineer
Recording - Mixing - Live
Based in Vienna, Austria
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