On Thu, Dec 17, 2020 at 03:08:54PM +0100, David Kastrup wrote: > just got an UMC22. Its codec is a Burr-Brown (TI) PCM2902. Looking > up its specs, it's USB1.1 full speed and sports stuff like > > • Stereo ADC > – Analog Performance at V BUS = 5 V > – THD+N = 0.01% > – SNR = 89 dB > – Dynamic Range = 89 dB > – Decimation Digital Filter > – Pass-Band Ripple = ±0.05 dB > – Stop-Band Attenuation = 65 dB > – Single-Ended Voltage Input > – Antialiasing Filter Included > – Digital LCF Included > > "Not recommended for new designs" (currently the card is being sold > new everywhere), an USB1.1 (and USB is half-duplex, so this is > certainly responsible for part of the latency) 48kHz design with a > 16-bit ADC specified for slightly above 14bit of precision. > > And that's the naked codec, without being impacted by any circuitry > around it. > > It's more compact for sure than my current solution at one ensemble > member (mic input into a Mackie Onyx 400F with dead digital circuitry, > out via the plugin jack into the mic input of a laptop). > > For -p64 (without --sync) I get > > 464.320 frames 9.673 ms total roundtrip latency > extra loopback latency: 272 frames > use 136 for the backend arguments -I and -O > > (the -O and -I values are independent of -pxx I think). > > For comparison: with my Alesis iO|14 (Firewire, a lot more inputs and > outputs) I get 81 for the backend arguments regarding additional > loopback latency. With a Hammerfall DSP (PCMCIA card via expresscard > adapter, so routed through a PCI to PCIx converter) it's 31 if I > remember correctly. Yes, this is a bit disappointing from the UMC22. Thank you for taking the time to post the specs & test results, though! >> I need to ask the exact model of Behringer that my one orchestra >> colleague got. That one's performance (regarding latency/dropouts) >> did not really appear to improve upon my stone-age Tascam US-122L > > I think it might be that model but I haven't asked back yet. OK, will be interesting to know. -- A: When it messes up the order in which people normally read text. Q: When is top-posting a bad thing? () ASCII ribbon campaign. Please avoid HTML emails & proprietary /\ file formats. (Why? See e.g. https://v.gd/jrmGbS ). Thank you. _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx https://lists.linuxaudio.org/listinfo/linux-audio-user
