but since this is just AD, then what are these 8 outputs of Micstasy for? what signals are they sending out? are these digital signals?
The Micstasy is - besides a high-end mic preamp - an 8-Channel AD converter. The XLR outputs on the back carry the analog preamp signals (8 x analog line outputs with up to +27 dBu level).
With the MADI option card installed, the Micstasy provides the ability of 8 channels being used as digital return path, sending audio via the MADI output to the Micstasy's ADAT and AES outputs. For example stage and studio monitors can be fed digitally from the Micstasy. Or you can connect an 8-channel DA converter (like the QSM) to the digital outputs. In this case the Micstasy + DA converter can work as 8-channel AD/DA solution.
if I give up getting a summing box, and get ADI-8QS and Micstasy, How could I connect studio monitors and headphones?
With both you can use the summing box. The analog D-sub25 output of the QS (8-channels) connects perfectly to the d-box input (8 channels). If you choose the RayDAT, the AES/EBU or SPDIF output can deliver the signal for the headphone output of the d-box.
Even without the summing box, the QS already delivers all outputs for main and headphone monitoring.
For the PCI express card:
- HDSPe MADI FX (390 channels), 3 x MADI I/O + AES/EBU I/O (d-box monitoring) + analog stereo monitoring
- HDSPe MADI (128 channels), 1 x MADI I/O + analog stereo monitoring
- HDSPe RayDAT (72 channels), 4 x ADAT I/O (d-box monitoring) + AES/EBU + SPDIF
- HDSPe AES (32 channels), 8 x AES/EBU I/O
A combination of Micstasy + QS + HDSPe MADI (FX) + summing box would be the most powerful setup, but also the most expensive one. E. g. the german Principal studios using this combination. MADI cards in every computer, Micstasys for recording and QS for monitoring. Mixing is done nearly completely in-the-box.
The setup with RayDAT + Micstasy + QS + summing box comes a little bit cheaper. The cabling is done with ADAT.
best regards
Knut