German (Germany) 
English (United Kingdom) You can optionally expand the RoonMatrix with a USB Bluetooth Audio module.
In principle, this is an audio card, which plays music via a Bluetooth radio connection and is connected to a USB port.
What can you use a module like this for? Well, for example, you can pair your much beloved Bluetooth headphones with it and thus send music to a headphone via the RoonMatrix.
The control software on the CPU board is - of course - already adapted.
The best: The Bluetooth Audio Module is recognized by ROON as a WiFi Audio Device. So you can stream the music with Roon directly to the radio module. But that also works via AirPlay 2 with Apple Music. Yes, exactly: the RoonMatrix also supports AirPlay 2.
The Bluetooth Audio Module Avantree DG60P supports all important transmission formats:
- Bluetooth V5.3
- Profiles: A2DP, AVRCP
- Audio codecs: aptx adaptive, aptx-HD, aptX-LL, aptX, SBC
- Sampling rates up to 24bit / 96kHz
Connection to RoonMatrix (standard)
In the RoonMatrix (the large one with 21 LED modules), the connection of the Bluetooth Audio module is associated with a little effort, because the micro USB port is not accessible as standard.
This can be changed if necessary, but is a bit fricked. The micro USB port is tapped off the CPU board with thin copper wire,
and then extended to a small micro USB adapter board. This is screwed into the U profile and leads the micro USB port to the outside.
To do this, three holes must first be drilled into the U-profile. How this is done is described in RoonMatrix Part 3: U-Profile drill processing .
The adapter looks like this:
The pins from 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 is not suitable, i.e. be sure to take the other. For the wiring, 0.15mm thin copper lacquer wire is used.
As the SMD distances are very small, and my eyes are old, I have bought a cheap Max-See USB microscope . This small microscope can connect via WLAN to a mobile phone such as the iPhone. With its help you can then hit the soldering points quite well. You also need a thin soldering tip 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!
A thin copper lacquer wire like this is used for wiring:
After the adapter has been wired, you should glue on both sides of the micro USB adapter with a little Tesa fabric tape, so that it is protected from scratches and damage, as well as the risk of short circuits from the LED modules that will later be mounted above it.
The Bluetooth Audio Module is pressed to the U-profile with a 3M Velcro fastener. You can also take a simple Velcro tape for this.
The 3M Velcro tape is much more durable, stronger, and also does not pull threads over time.
The audio module is connected to the roon matrix with a micro USB OTG cable.
Connection to RoonMatrix Mini
The connection of the Bluetooth Audio module is particularly easy with the RoonMatrix Mini, because all important connections, including the micro USB port, can be reached from the outside.
Here are a few pictures that show 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 don't earn anything about it. It should only make it easier for you to search for suitable individual parts, which were used in this project. These are the original sources that I used in this project.)
1x Conecto micro USB OTG cable, micro USB plug on USB-A socket, 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 extra strong 25.4 mm x 50mm (Amazon)
1x 0.15mm copper lacquer wire (Reichelt)
Component overview
Here are a few screenshots from Roon and Apple Music. In Roon, the Bluetooth Audio module from RoonMatrix is recognized as an audio device.
