Смешивание выходов двух программ и микрофона и запись в третьей. Посоветуйте решение.

> Основная сложность с jack - выбрать конкретную звуковуху. Как?
man jackd

ALSA BACKEND OPTIONS
-d, --device name
The ALSA pcm device name to use. If none is specified, JACK will use «hw:0», the first hardware card defined in /etc/modules.conf.

Это будет глобальная звуковуха. А мне записывать надо через hw:2,0, а воспроизводить через hw:0,0.

http://jackaudio.org/multiple_devices

1. Use the alsa_in and alsa_out clients (Linux & ALSA only)

If you are using JACK on Linux and want to use additional devices that have ALSA driver support (i.e. most PCI, USB and Bluetooth devices), then this is the best option.

alsa_in and alsa_out are two clients written by Torben Hohn that make a single specified ALSA device appear as a set of JACK ports. They both use Erik de Castro Lopo's libsamplerate library to do any resampling required to keep the audio in sync as the clocks of each device drift over time.

2. Use the JACK2 audio adapter(s) (Jack2 only)

3. Using OS facilities to merge devices into a single pseudo-device

Linux

You will need to use a text editor to create or add to your ~/.asoundrc file. This file is read by any ALSA application (including JACK, if its using the ALSA backend) and can be used to define pseudo-devices of many different kinds. The key idea here is that you're going to define a new pseudo-device composed of 2 or more other devices.

4. Using the -P and -C arguments to a JACK backend

Several JACK backends, including the ALSA, FFADO and CoreAudio versions, support the -P and -C arguments that can be used to specify two different devices, one for playback and one for capture/recording. You cannot use this to merge multiple devices for playback or capture. This approach will not do any clock drift correction, so as the two devices drift over time, you may get glitches in the audio stream. Nevertheless, it can be an easy if unreliable way to set up JACK so that, for example, it records from a USB microphone and plays back via a builtin audio device.