• Registered: 2020-12-19
  • Posts: 59

Topic: Signal Path for Direct Routing

I'm hoping someone could describe the signal path that my BFP-FS and UCX II use when I route, for example, AN1 In to AN1 Out in TotalMix.

I'm doing some timing tests, and it appears (unless I botched my testing setup, which often happens), that the AD and AD are completely bypassed. My timings are coming in at wayyy below the cost of a round-trip through the converters (like 0.3ms rather than around 3.7msec at 48samp/44.1kHz). Is there some Analog-to-analog link going on??

Clint Goss - 2xBF Pro FS, UCX II, UFX II; 3xWin10Pro22H2
WindSynth:Sylphyo Cantabile Ableton Push3S
  • Jeff
  • Jeff
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  • Registered: 2007-05-21
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Re: Signal Path for Direct Routing

There is no analog bypass. The path looks like this: AD -> TotalMix -> DA

You are avoiding the driver and DAW app this way, so there is no buffer latency, etc. Only the AD + DA latency + 3 samples for TotalMix. 0.3ms sounds about right to me.

At 48k sample rate, 48 samples = 1ms, so this 0.3ms latency is about 14 samples.

Regards,
Jeff Petersen
Synthax Inc.

Jeff's Website

3 Reply by ramses (edited by ramses 2021-12-03 22:19:46)

  • ramses
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  • Registered: 2012-10-14
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Re: Signal Path for Direct Routing

Ah Jeff (good evening), we typed at the same time. It's your timezone and you were quicker wink

Each HW output can have an individual submix.
You can route any HW input and SW playback to any HW Output inside of one device.
You mentioned two different recording interfaces and only said AN1 IN to AN1 OUT.
So if AN1 IN and OUT are  on one interface you can route it in near realtime on the recording interface itself.
Otherwise you would need to route it in the DAW and thus have the RTL through USB/FW/TB which is bigger and depends on the ASIO buffersize if your are on a Windows PC.

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub13
  • Registered: 2020-12-19
  • Posts: 59

Re: Signal Path for Direct Routing

Excellent Info! Thank you so much!!

All the numbers line up nicely and the UCX-II and BBF Pro-FS test exactly on your specs. I'm including a summary diagram below, with relevant details following.

One realization: I can incorporate TotalMix as a (very) fast path-routing alternative to my DAW in my WindSynth live rig setup, in pass-through situations. Since TotalMix responds to MIDI, I can switch that routing directly from the DAW with no fuss. Shave 3msec off every time I do this, which is significant to me!!

https://www.Goss.com/img/LatSigPathCG_8A_TotalMixLoopback__2021_1204b_200dpiC10.jpg

Details

Host1: "Shiba" Win10x64, i7-6600U (6th gen), 2 core, 16GB, SSD, 2016 laptop.
Host2: "Husky" Win10x64, i9-9900U (9th gen), 6 core, 128GB, SSD, 2019 desktop.
UCX II: Firmware v37/24/16, RME ASIO v1.212
BBF Pro-FS: Firmware v125 (4May2021), RME ASIO v1.212
All .wav files 24 bit. All digital audio 44.1kHz. USB links are direct to the host.

Thanks for the great support!!

Clint Goss - 2xBF Pro FS, UCX II, UFX II; 3xWin10Pro22H2
WindSynth:Sylphyo Cantabile Ableton Push3S