Topic: Feature Request: mixing two sources (USB + SPDIF)
I have been using the ADI-2 DAC for over a year and I am very happy with this product. It is very rare for me to use such a refined product with so many amazing features
I would like to suggest adding one very missing feature: the ability to mix two music sources (USB + SPDIF) at once.
I'm using a DAC with two sources: a USB connected computer and a Sonos Connect music streamer with SPDIF output. Sometimes I listen to music on studio monitors from a computer over USB, but sometimes I listen to music throughout the house on many Sonos speakers - then the source is the Sonos Connect streamer over SPDIF. Sonos system ensures that music playback on many devices in many rooms are synchronized in time to milliseconds.
Unfortunately, automatic source switching in the ADI-2 DAC in this situation does not work. Sonos Connect regardless of whether it plays music or does not always send a signal over SPDIF. The ADI-2 DAC does not distinguish the lack of PCM data in the SPDIF signal (silence) from the full stream with PCM data. You cannot power off Sonos Connect or force it to not send SPDIF signal.
The mixing function would solve this problem - then regardless of which source played the music - would be to listen on the studio monitors.
It would also solve the problem of audibility of system sounds / applications played by the computer while listening to music from Sonos. Currently, even if you manually switch the music source to SPDIF, the ADI-2 DAC does not disconnect from the computer via USB - as a result, the computer sends audio via USB to the DAC (instead of the built-in speaker in the monitor). Switching every time the audio output of the operating system manually in audio settings is very awkward.
The mixing function can have restrictions - e.g. that both sources have the same parameters (like 44.4 KHz 16 bit PCM) and the same volume controls as well as other parameters set in the ADI-2 DAC. This mixer mode may be available as further modes of input selection in the ADI-2 DAC (USB + SPDIF optical, USB + SPDIF via coax cable).