German (Germany) 
English (United Kingdom) You can optionally expand the RoonMatrix with a USB Bluetooth audio module.
This is basically an audio card that plays music via a Bluetooth wireless connection and is connected to a USB port.
What can you use such a module for? Well, you can, for example, pair your beloved Bluetooth headphones with it and send music to headphones via the RoonMatrix.
The control software on the CPU board is - of course - already adapted for this.
The best thing: The Bluetooth audio module is recognized by Roon as a WIFI audio device. So you can stream the music directly to the radio module with Roon. This can also be done via Airplay 2 with Apple Music. Yes, exactly: The Roonmatrix also supports Airplay 2.
The Bluetooth audio module used, Avantree DG60P, supports all important transmission formats:
- Bluetooth V5.3
- Profiles: A2DP, AVRCP
- Audio Codecs: aptX Adaptive, aptX-HD, aptX-LL, aptX, SBC
- Sample rates up to 24bit / 96kHz
Connection to RoonMatrix (standard)
With the RoonMatrix (the large one with 21 LED modules), connecting the Bluetooth audio module requires a bit of effort, as the micro-USB port is not routed to the outside as standard.
This can be changed if necessary, but it is a bit fiddly. The micro USB port is tapped from the CPU board with a thin copper wire,
and then extended into a small micro USB adapter board. This is screwed to the U-profile and leads the micro USB port to the outside.
To do this, three holes must first be drilled in the U-profile. How this is done is in RoonMatrix Part 3: Edit U-Profile described.
The adapter looks like this:
The pins of the micro USB port of the Raspberry Zero 2W must be connected 1:1 to the connections on the adapter board. But be careful: The CPU board also has a micro USB port that only supplies it with power. This one is not suitable, so definitely take the other one. For the wiring you use 0.15mm thin enameled copper wire.
Since the SMD distances are very small and my eyes are already old, I got a cheap one Max-See USB microscope granted. This small microscope can connect to a mobile phone such as the iPhone via WLAN. With its help you can then hit the soldering points quite well. You also need a thin soldering tip suitable for SMD work and the right soldering station.
And be careful: after the soldering process, you should definitely check for short circuits with a multimeter!
For the wiring you use a thin enameled copper wire like this one:
After the adapter has been wired, you should stick some Tesa fabric tape on both sides of the micro-USB adapter before screwing it to the U-profile so that it is protected from scratches and damage, as well as the risk of short circuits caused by the LED modules that will later be mounted above it.
The Bluetooth audio module is pressed onto the U-profile with a 3M Velcro fastener. You can also use a simple Velcro strap for this.
However, the 3M Velcro tape is much more durable, stronger, and does not pull threads over time.
The audio module is connected to the RoonMatrix with a Micro USB OTG cable.
Connection to RoonMatrix Mini
Connecting the Bluetooth audio module is particularly easy with the RoonMatrix Mini, as all important connections, including the micro-USB port, are accessible from the outside.
Here are a few pictures showing the connection of the Bluetooth audio module to the RoonMatrix Mini.
The component list:
(Note: The links to the individual parts are no Affiliate links, I earn nothing from them. They are only intended to make it easier to find suitable individual parts that were used in this project. These are the original sources that I used in this project.)
1x conecto Micro USB OTG cable, Micro USB male to USB-A female, gold-plated, 90°, 10cm, black (Amazon)
1x Avantree DG60P – Bluetooth audio adapter, aptX adaptive (Amazon)
1x Exingk 11x16mm, Micro USB adapter board (Amazon, Exing)
1x 3M Dual Lock SJ 3550 CF Velcro tape extra strong 25.4 mm x 50 mm (Amazon)
1x 0.15mm enameled copper wire (Reichelt)
Component overview
Here are a few screenshots from Roon and Apple Music. In Roon, the Bluetooth audio module is recognized by RoonMatrix as an audio device.
