## Tested sound cards
We typically run the sound system with 48000 Hz sampling rate and
periods of 2 ms (96 samples). The measured hardware delay (combined
input and output), as caused by block processing, USB BUS protocol and
anti-aliasing filters is given below. Please note that the values for
USB devices may vary slightly between jack starts and sound-card
reconnections:
| | period size | delay | delay |
|------------------------------------|-------------|-------------|---------|
| | | | |
| Focusrite Scarlett Solo 3rd gen | 96 | 429 samples | 8.9 ms |
| | 48 | 238 samples | 5.0 ms |
| | 24 | 136 samples | 2.8 ms |
| | 12 | 94 samples | 2.0 ms |
| | | | |
| Audient EVO16 [[1]](#1) | 96 | 284 samples | 5.9 ms |
| | 64 | 196 samples | 4.1 ms |
| | 48 | 164 samples | 3.4 ms |
| | 32 | 120 samples | 2.5 ms |
| | 24 | 104 samples | 2.2 ms |
| | 16 | 82 samples | 1.7 ms |
| | | | |
| TASCAM US-2x2 | 96 | 518 samples | 10.8 ms |
| | 48 | 316 samples | 6.7 ms |
| | 24 | 210 samples | 4.4 ms |
| | 12 | 165 samples | 3.4 ms |
| | | | |
| TASCAM US-100 | 96 | 510 samples | 10.6 ms |
| | | | |
| TASCAM US-16x08 | 96 | 623 samples | 13.0 ms |
| | 48 | 327 samples | 6.8 ms |
| | | | |
| Behringer u-phoria UMC22 [[2]](#2) | 96 | 512 samples | 10.7 ms |
| | 48 | 320 samples | 6.7 ms |
| | | | |
| Mackie Onyx 2-2 | 96 | 587 samples | 12.2 ms |
| | 48 | 364 samples | 7.6 ms |
| | 24 | 262 samples | 5.4 ms |
| | | | |
| Presonus Audiobox USB | 96 | 593 samples | 12.4 ms |
| | 48 | 364 samples | 7.6 ms |
| | | | |
| Superlux E205U | 96 | 618 samples | 12.9 ms |
| | 48 | 372 samples | 7.8 ms |
| | | | |
| ConnectAUDIO 2/4 [[3]](#3) | 96 | 652 samples | 13.6 ms |
| | 48 | 620 samples | 13.0 ms |
| | 144 | 844 samples | 17.6 ms |
| | | | |
Also the HiFi Berry ADC+ Pro (and probably other HiFi Berry devices as
well) can be used if after installation the instructions documented
[here](https://www.hifiberry.com/docs/software/configuring-linux-3-18-x/)
are followed.
[1] Seems to be unstable on Raspberry Pi. On Desktop
PCs, block sizes of 48 samples at 48 kHz are no problem.
[2] Also supports 32 kHz which is very useful in case
of low upstream bandwidth.
[3] Seems to be unstable on Raspberry Pi, and with
short buffers also on Desktop PCs.
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