On Windows 10:
Windows+R (run command): Control (enter) to open Classic Control Panel.
Choose the 2nd tab, Recording Devices
Enable the Stereo Mix or Sum
not found? right-click in the list, mark “Show Disabled Devices” and “Show Hidden Devices”
still not found? download the latest Realtek codec at
or download a High Definition Audio Codec for your soundcard. See the bottom of this post on how to find the vendor and the subsys to find the correct drivers.
Finder, choose Go > Utilities. Open the Audio MIDI Setup.
Control-click the device (Built-In Output),
or select the device to be used, (Built-In Output)
and click the Action menu gear icon at the bottom of the sidebar.
Choose “use this device for sound input”.
If you want to connect multiple sound cards to one input, read https://support.apple.com/en-us/HT202000
On Linux via PulseAudio:
add PulseAudio Volume Control (pavucontrol) to your system. This is usually available in the distribution’s repository.
Ensure that PulseAudio is running.
Open PulseAudio Volume Control and choose the “Recording” tab.
In the "Capture from " dropdown, select the “Monitor” option of the playback device to record.
Then you can select the ALSA / pulse recording input in Renoise.
On Linux via JACK:
Jack may be started using QjackCtl or from the command-line.
Any Jack-compatible applications that are running will have their ports available in Device Toolbar (or rescan the devices).
Applications that do not directly support Jack may also be used with Jack on a system that uses PulseAudio (such as Ubuntu and Debian based distributions) by installing “pulseaudio-module-jack”. This provides the modules “Jack Source” and “Jack Sink” that allow PulseAudio to use Jack.
On Linux via ALSA:
Use alsamixer, type alsamixer in a terminal window. If a Mix device is shown as a capture device, set this as the active device to enable recording sounds that are playing on the computer.
on Windows, how to find the sound card Vendor and Subsys:
use Windows+R (run command): Control (enter) to open Classic Control Panel.
open Device Manager.
open the branch of Sound, Video and Game controllers.
right-click your sound device (could be High Definition Audio Device) and click Properties.
go to the Details tab.
find the value of “Hardware ID”
search google for the VEN_??? and SUBSYS_??? listed, ? are numbers, to find out.