0

DAC+ DSP - Volume Control Options

Hi

I'm currently working on a project and after a LOT of wandering around I think the DAC+ DSP may be the missing link to get everything i need working. But I would appreciate any feedback / thoughts / logic checks!

Issue

I need volume control (Ideally up/down/mute/set but also set to specific level ideally) of a S/PDIF optical source.
Control interface is the excellent Bitfocus Companion software running on a Pi400 (only units in stock ...)

Option 1 - Mounted on the Pi

S/PDIF Audio In
Analogue Audio Out
Control using shell commands (can be tied to a Streamdeck button) eg amixer -c 0 set HDMI 5db+

I already have the control side working - I presume I will just need to change some of the options so that I'm controlling the hifiberry rather than onboard...
I have seen conflicting posts about this i/o path working - but I think from what I have seen the DAC+DSP possible...

The biggest issue is that I am also using the Pi to control a Waveshare 8 Channel relay board https://www.waveshare.com/product/raspberry-pi/hats/motors-relays/rpi-relay-board-b.htm

The default setup there are definitely some pin conflicts - but the setup of the waveshare board means that I think I can patch around them.

But having all of this on the one board / PSU is making me a ... little twitchy ... So ...

Option 2 - Standalone

Could I use the DAC+DSP in standalone setup but take control from the PI's GPIO into the DSP Analogue inputs to change the volume using commands from the Pi/Streamdeck/Companion Software ....

Or is there a better way ....

Bigger picture - in case it's helpful - The plan is for these units to drop into the teaching and rehearsal room systems that we have built at work. The CompanionPi will take over control duties from the PC that is also in the rack but also add the option hard power down / reset devices in the racks via the relay baord. The Hifiberry setup it to create a single common way of getting in room volume control over the system - at the moment we use RS232 commands to the in room displays and take the audio out from the displays to the in room speakers. This means each room has a customised setup and really starts to complicate things. Additionally some rooms don't have RS232 control for the displays and some don't have audio out - and some have ... dubious audio out quality ....
The system also has an Atem Mini for 4 way video switching / capture and audio control - and a analogue audio mixer that takes the in room mics, the de-embedded audio from the atem video mixer and presents it back to the PC as a USB input for capture in zoom / teams etc.
The HDMI de-embedder gives an analogue output for the Audio Mixer but it also has a digital S/PDIF output.
I want to give local volume control to the rooms that doesn't affect the stream volume- hence the split and slightly complicated setup ...
We currently have 18 of these systems very few have exactly the same config ....Its a ... bit of a headache to maintain ...
Simples .....

0 comments

Please sign in to leave a comment.