I have installed sampmlerbox (downloaded it from a dutch website)
I connected a usb midi keyboard and was able to get some sound out of it but when I use an usb sound interface, I have noticeable latency. I measured it and I get 15 to 20ms. When I use the integrated output of the RPI the latency is way shorter and it's not noticeable.
I tried to use an I2S DAC (cjmcu-5102) but didn't manage to get it work.
I don't know how to solve this issue. (I tried two different usb audio interface)