Comment 19 for bug 785939

Out of interest, I just tried getting Mixxx to work on Windows, and ran into similar issues. Scratch Live now comes packaged with ASIO drivers for the Rane TTM57SL, so you can use it with software other than Scratch Live. Unfortunately, by default, the driver is configured to output the post-fader signal for both channels, and there doesn't appear to be a way to configure the driver directly through Windows.

However, I found a thread on the Serato forums (http://serato.com/forum/discussion/110139), which explains how to configure the ASIO driver via Ableton Live. By following these instructions, I was able to select the pre-fader signals for both channels. This configuration is persistent, so I can then close Ableton Live and open Mixxx, and Mixxx will receive the pre-fader control signal, so it is able to track the position of the vinyl even when the crossfader is closed :)

Sadly, this is still limited to a single-turntable setup, since the mixer must be explicitly set to output the analogue control signal, otherwise Mixxx won't hear it (unlike Scratch Live, which is somehow able to listen to the analogue signal even when the mixer is set to output the digital overlayed audio).

This would seem to confirm that the problems experienced under Linux are indeed due to driver issues, and that Scratch Live isn't communicating with the mixer over USB to tell it which signals to output.