[LAD] USB audio interface

[Ralf Mardorf]

PS: You mentioned live usage. If you use a 19" rack it doesn't
matter, if you chose a Presonus AudioBox 1818VSL or a Focusrite Scarlett
18i20 2nd Gen, but if you carry the device in a bag, it might be
important, to be aware that the Presonus is smaller, but it has got an
external power supply. The power supply is also small.
However, the Presonus requires more power via USB, than the Focusrite,
it's within the standard, but some portable computers might need an USB
hub, if they should limit USB power to safe energy.