RasPi 1: Recording and Playback in RasPi
Last Updated on July 5, 2020
So let's home recording with your RasPi.
I have USB audio interfaces, behringer's UCA222 and UGREEN's one. The RasPi is 3, and the OS is Raspbian 10 (buster). Recording software is Audacity with QjackCtl.
* Raspbian is renamed to Raspberry Pi OS since May 2020.
In the terminal, command these to install the software;
sudo apt-get update
sudo apt-get install audacity qjackctl alsa-utils
then reboot. The "alsa-utils" includes aplay and alsamixer to be used later.
In the terminal, start QjackCtl and put the process in the background;
then go "Setup" in the GUI.
Go "Advanced" sub tab in "Settings" tab.
Select "Output Device" and "Input Device" from these drop down menus. In this case, it's UGREEN's USB audio interface. You can see many items in the menus. These can be confirmed by commanding "aplay -l" in the terminal.
Go "Parameters" sub tab, then note the value in of "Sample Rate". In this case, the value is 48000.
Back to the GUI of QjackCtl, then push "Start" button.
If you want the playback, Go "Connect" and select "Audio Tab".
DON'T FORGET THE VOLUME OF THE OUTPUT IS ZERO NOT TO LISTEN ALOUD.
Select "capture_1" in "Readable Clients / Output Ports" and "playback_1" in "Writable Clients / Input Ports", then push "Connect" button. One side of the stereo output starts the playback in this case. Test the connection and the volume of the output. If you don't want the playback, just push "Disconnect" button.
In the terminal, start audacity and put the process in the background;
Change the audio bridge from "ALSA" to "JACK Audio Connection Kit" on the upper left corner. Confirm "system" is selected for recording and monitoring on the next of "JACK".
Change "Project Rate (Hz)" on the lower left corner to match with the "Sample Rate" of QjackCtl. In this case, it's 48000.
If you have already installed audacity and used its own software playback (having apparent latency), disable this.
If you want change the volume of the input, right click the speaker icon in the task bar of your desktop (it's on the upper right corner in my desktop), then cursor "Audio Inputs", confirm the device is checked, and click "Input Device Settings".
Click "Capture" tab and control the volume.
"alsamixer" in the terminal also helps the volume change, however using the GUI is preferred.
Guitarix is a virtual guitar amp used with RasPi. To hide the noise from the complexity of the analogue circuit, virtual amps are preferred.
sudo apt-get install guitarix
# Start Guitarix and put the process in the background
In "Connections" in QjackCtl, Select "capture_1" in "Readable Clients / Output Ports" and "in_0" of "gx_head_amp" in "Writable Clients / Input Ports", then push "Connect" button. Make sure that "out_0" of "gx_head_amp" and "in_0" of "gx_head_fx" are connected. For the playback from both sides of the stereo output, connect between "out_0" of "gx_head_fx"; and "playback_1" and "playback_2" of "system". In Audacity, select "gx_head_fx" in the pull-down menu next to "JACK Audio Connection Kit" on the upper left corner. The "gx_head_fx" is the loop return to connect with other virtual effectors and enables "Master Volume" of Guitarix GUI.
Enjoy playing and recording!
Guitar Riff Using This Environment
It's D major so you can do solo by B flat minor pentatonic (half tone up of A flat scale).