Today I tried experimenting with multichannel streaming to the AV7704, but unfortunately Roon can only AirPlay to the device (stereo only, of course).
The Roon partners page: https://roon.app/en/partners/105/marantz lists the device as Roon Tested, but the Roon application itself shows this device as Roon Ready but uncertified, so it will not let me add it as an endpoint.
I don’t suppose there’s anything I can do about this, right? I doubt Marantz is going to go and certify this preamp since it is so old.
Until any certification happens, there is no way to know. But, even if it becomes RoonReady it still might not do multi-channel. It all depends on how Marantz implements it.
Multichannel is only supported by HDMI connection from a PC, HEOS does not support multichannel for music streaming. Roon currently only works via Airplay over the Network (uses HEOS ability here) , Roon Ready is coming later this month according to rumours from the web in next HEOS update. But Even then you wont get Multichannel as HEOS doesnt support it, this is a hardware limitation and nothing Roon can do about it same on all Denon/Marantz range multichannel is via HDMI only.
Some info regarding the U33 update (not yet finalized)
Though select HEOS devices are now Roon Ready, there are some limitations of our hardware
that will not support the full Roon RAAT Technology:
• Roon RAAT supports 32bit 768 kHz PCM files, but none of our HEOS devices support that
file resolution. Roon will still allow users to stream 32/768 PCM files to our HEOS
devices, but it will not be at its full resolution.
• Roon RAAT offers multi-channel playback, but HEOS streams music in stereo. In the case
of multi-channel music, Roon will downmix to 2 channels so that the file can be played
back on our HEOS devices.
o Note: Denon Home Soundbar 550 takes surround signals via HDMI for multi-
channel playback, or simulates surround sound of music streams.
• Roon RAAT supports 2-way communications for volume, mute, convenience switching,
metadata displays, standby controls, and other commands so that you can control your
Roon Ready devices in the Roon App. However not all of our devices will have all of
these controls. For example, Denon Home does not have a power button, so you
wouldn’t be able to turn a Denon Home speaker on and off through the Roon app.
However, the Roon app would have volume and transport controls.