What to do if you have an issue with the …

Fan Control

Your Raspberry PI device needs cooling. If you want to make music, a quiet fan is useful. Thus, we are supporting an automatic fan control to your Fastmusic device. It is based on the ArgonOne enclosure. If you have an issue here, you are probably using none or a different enclosure.
If you decided not to use the ArgonOne but do have a decent alternative, you can add the file ‘/mnt/goodfan.txt’ to remove the error message. Do you so, connect both screen and keyboard the FMB, open an terminal with “alt-ctrl-t”, and run the command

touch /mnt/goodfan.txt

Or, remove the microSD card, plug it into your PC, look for the large partition which typically contains the mp3 files from recording (not the boot partition), and create a file called ‘goodfan.txt’ here. The content of the file does not matter.


hardware.fan_control ArgonOne

Hardware model

Currently, only the “Raspberry Pi 4 Model B Rev 1.1” model is supported, because it is fast than the previous Raspberry PIs. If you have an issue here, you are probably using the wrong hardware, e.g. a PC.

hardware.model	Raspberry Pi 4 Model B Rev 1.1

Serial number

Each Raspberry PI has its own serial number, which is displayed here. It is used as a unique WLAN SSID and to communicate with the update server. If you have an issue here, you are probably using the wrong hardware, e.g. a PC.

hardware.serialnumber 10000000ea120fdc

Temperature of device

If the Fastmusic device gets too hot, it will not work anymore. Please ensure that proper cooling is in place, e. g. air ventilation.

hardware.temperature 48 °C

Linux kernel version

The Fastmusic device used a real-time Linux kernel as the core of its software. The kernel is updated automatically.


kernel.version 4.19.71-rt24-v7l+

CPU load

The Raspberry PI has four CPU cores. The CPU load shows, how much of them would be required to serve the current computational demand. For example, during the first minutes after startup, the CPU demand is quite high because your device is updated. During normal operation, to limit the CPU load, please close the browser window (with ALT-F4) or reduce the number of media connections.


os.cpu.load 51 %

Free space on the user data directory

The mini SD card has two partitions. One with the Fastmusic software and this one. It is used for your data, e.g. music recordings. If full, please remove the SD card, plug it into your computer (or mobile phone), and remove your files that you do not need anymore.


os.free.data.space 13105 MB

Free OS space

The mini SD card has two partitions. If you have an issue with this entry, please contact the support.


os.free.os.space 8388 MB

Automatic update errors

Sometimes, the update process does not work with any errors. For example, it the device was not used for a long time. Then, rlease reboot the FMB and wait whether the errors disappear. If they persist, please contact us.


os.update.errors 0

Automatic update, last check

At this time, the Fastmusic device has checked for recent updates.




You typically have a certification error, if you switch your SD card between devices. Please contact Symonics GmbH for support.



Automatic update, version

We update the FMB frequently to support new features and remove issues. There you see the date of the latest update.


os.update.version 5/22/2020, 11:33:51 AM

Local internet gateway

This is the IP address of your local internet router. If there is a problem here, please check your Internet connection and ensure that the DHCP service is working.



Provider’s internet gateway

The Fastmusic device tries to identify the Internet gateway of your Internet provider, e.g. those routers, which are common regardless of further backbone routing.


gateway.provider and

Network connection of your ethernet connection

These values show the IP address and gateway of your ethernet’s internet connection. If there is an issue, please check your cable connection and DHCP service. Are the LEDs on the RJ45 connector blinking?

interface.eth0 gateway

Wifi IP network

The Fastmusic device offers an unsecured Wifi connection. It allows connection only to the local web page of the Fastmusic device, to soundjack.eu, and symonics.com.


interface.wlan0 no gateway

Number of networking interfaces

The number of available internet connection. If zero, please check your ethernet cable.


networking.interfaces	1

DNS Name of the FMB

Each FMB has a DNS name starting with the ID followed by .soundjack.net. Sometimes, a local Internet router prevents local DNS entries such those for the FMB. This prevention is called DNS Rebinding Protection. It has to be disabled. Please consult the manual of your Internet router on how to do this.

For example, on a FIOS router, this can be done by unchecking “DNS Rebind”:

On a FritzBOX, you must enter the DNS name of the FMB:


networking.dns	 10000000ea120fdc.soundjack.net =

Minimal latency to a DNS server

The Fastmusic device checks the latency to three common DNS services. If the ping times are high here, then your Internet connection is too slow. We recommend you using the Fastmusic device then only on short distances, e.g. within your local network.


ping.DNS.min	17.141 ms

Minimal latency to your local internet gateway

The Fastmusic device pings your local internet gateway. High ping times might be a sign that your local router is overloaded or slow.


ping.local.min 0.616 ms

Minimal latency to your provider’s internet gateway

Fastmusic device pings the routers of your internet providers. High or missing ping times might be a sign that your internet connection has a latency too high. Consider changing the access technology or provider.


ping.provider.min 10.607 ms

Local DNS name of your Fastmusic device

The Fastmusic device announces its DNS name (e.g. soundjack0.local) in the local network. If another Fastmusic device is in your network before you have switched on this one, the number is increased. At most four local Fastmusic devices are supported by soundjack.eu.


zeroconf.localhost soundjack0.local

Number of input/output channels

The number of input and/or output channels used during the current Soundjack session.


fastmusic.audio.channels 2

Frequency of audio sampling loop.

The values measures how often the Fastmusic device queries the USB soundcard. A value of 750 Hz (64 samples) is too high, a value of 512 samples might be too slow. Please set it to 128 or 256 on soundjack.eu.


fastmusic.audio.fps 375 Hz (128)

Using the inputs of your soundcard

If not set to yes on soundjack.eu, the remote partner will not hear you. Please change.


fastmusic.audio.inputs yes

Some internal timing


fastmusic.audio.loop_duration good

Some internal timing


fastmusic.audio.loop_frequency good

Some internal timing


fastmusic.audio.loop_interval bad

Using the outputs of your USB soundcard

On soundjack.eu, please enable the outputs. However, you will not hear the remote side.


fastmusic.audio.outputs yes

Your browser has found the Fastmusic device

If you have not connected your browser to soundjack.eu and if then the browser has not found this Fastmusic device, then you will see an error here. Otherwise, it will display the IP address of the device running the browser.



Your web browser

The Fastmusic device checks, which web browser you are using to connect to soundjack.eu. If you use a browser too old, it will complain. Then please update your browser and use a recent Firefox, Chrome, Safari, Edge, or Opera browser.


fastmusic.browserclient.userAgent Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/73.0.3683.75 Safari/537.36