As long as you haven’t used the option card slot on the Si expression, you have several options for connecting to a ME-1 system.
1. Use Dante or MADI (64×64 audio paths), or A-Net (limited to 16×16 audio paths), option cards on the Si Expression
– if you don’t have a card slot available, you can use your analog outputs to feed an Aviom AN-16/i. Obviously, the major limitation in the AVIOM protocol is that it only supports 16 channels of audio.
2. Connect to an Allen & Heath ME-U. The default I/O card accepts Allen & Heath ACE or Dsnake, or AVIOM A-Net
3. If you want to maximize channel count, buy a Dante or MADI option card from A&H for the ME-U
4. Connect up to 10 ME-1s to the ME-U, You can also connect a ME-U port to an approved POE switch to feed additional ME-1s.
Be aware that ME-1s will not receive channel names from your non-Allen & Heath mixer.
Daniel