How to record a nice sounding podcast over Skype, using Linux

howto-record-nice-sounding-podcast-skype-linux.md

How to record a nice sounding podcast over Skype, using Pulse and Ardour

The situation: we record a podcast over Skype. We both have USB audio interfaces (Behringer U-Phoria UMC202 and 404, respectively). We each record our respective audio inputs and mix those later, manually adjusting the delay. Skype is only used for communication and is not involved in the recording.

There might be a way to do this without ardour, pulse-only. But since we have ardour in our workflow already, we prefer this way, even if it seems needlessly complicated.

Tested on Arch Linux; all referenced programs refer to Arch packages.

Requirements

• Two Skype accounts (duh)
• A browser that can handle web.skype.com (native and other skype apps are bad)
• pulseaudio
• jack
• pulseaudio-jack
• ardour

Recommended

• pavucontrol
• cadence + catia

How To

The gist: skype/the browser will use the external sound card through pulse; ardour will simultaneously record the microphone's audio input through a jack-pulse bridge.

1. Set up the hardware. If you're using an external sound card, plug it in, connect headphones and a microphone.
2. Launch pulseaudio, if not already running
   e.g. pulseaudio --start, or via systemd.
3. Launch jack via cadence
   • Click the Configure button
     • Select the sound card as both Input and Output Device
       it might look something like hw:U192k,0 [USB Audio]
     • Set the Sample Rate. Both parties should set the same sample rate, e.g. 48000.
   • Click the Start button
   • Check JACK Bridges / PulseAudio: it should say
     PulseAudio ist started and bridged to JACK
4. Make the browser is using pulseaudio & JACK is bridged
   • Re-launch the browser if needed
   • Launch pavucontrol, keep it open & visible
   • In pavucontrol, under Input Devices, you should see the sound card and also "Jack source (PulseAudio JACK Source)". Make sure that the meter under it moves when you speak. Unmute if needed.
     Under Output Devices you should see a "Jack sink (PulseAudio JACK Sink)"
   • Point the browser to web.skype.com, log in.
   • Make a Skype Test Call
   • In pavucontrol, check the Playback and Recording tabs while making the call.
     • Under Playback, you should see
       Browser: Playback on … select Jack sink from the dropdown here.
     • Under Recording, you should see
       Browser: Record-Stream from … select Jack source here.
     • Both meters should be moving.
   • You shold have heard yourself on the Skype Test Call.
5. Launch ardour and connect to jack
   • Create a New Session
   • Ardour should connect to jack automatically, if not, click to do so when asked.
   • Track > Add Track/Bus/VCA
     • Add: 1
     • Configuration: Mono
     • Add and Close
   • The new track might already be connected to the external sound card's mic - talk to it & check the track's meter.
   • If not, connect the mic to the track
     • either via ardour's Audio Connection Manager (Window > Audio Connections, Alt+P)
       • On the left, vertical side, select the Hardware tab
       • On the bottom, horizontal side, select Ardour Tracks
       • Click the square box/cell at the intersection of the system capture_N row (N being the input you plugged your mic in) and the Audio in column (there should be just one, since the track is mono).
         A green dot should appear.
     • or via catia
       • "Drag a cable" from the system box's capture_n output
         to the ardour box's Audio 1 input.
   • Disconnect the Master Bus from any playback_ns to avoid echos.
   • In ardour: Toggle Record. Click the red round button in the main transport toolbar (Shift+R). It should start blinking.
   • Arm the ardour track by clicking the track's red round record button.
   • Hit play in the main transport toolbar to start recording. A region with a waveform should start appearing.
     After stopping the the recording you have to re-toggle record mode.
6. Record!
   • Call the other party via Skype (who are set up just like you are now)
   • Start the recording in ardour
   • Gab
7. Mix the podcast
   • Get the audio file from the ardour session folder: …/interchange/…/audiofiles/Audio-1…wav
   • Add it to the other party's ardour session
   • Adjust the delay manually
8. ???
9. Profit