QJackCTL, what are readable and writeable clients?

[arpegadream]

I see tutorials and threads about connecting up with QJackCTL, but nowhere do I see it addressed in a way I understand, just what a readable or a writeable client is, I don't understand what in and out are, I can't decipher.

[j_e_f_f_g]

A "client" is jargon for "a software program that supports JACK". It's just some executable you run. Some software programs generate sound, like a virtual synth, or a sample player like LinuxSampler, or a speech synthesizer. Other programs don't generate sound themselves, but instead modify sound that is feed into them, such as a reverb unit, or a flanger, or an equalizer. Some programs do both (for example most virtual synths have built-in effects. They produce musical pitches that can be internally routed to built-in effects).

The programs that generate sound are "readable clients" because they create audio (or midi) that can be "read by" (output to) other programs that will modify that audio/midi. And the programs that can input/modify that audio/midi are "writeable clients" because other programs can "write" (input) their audio/midi to these programs. And a program that can do both is a readable, as well as writeable, client.

In other words, a readable client outputs audio or midi. A writeable client inputs audio or midi.

You connect a readable client's "output jack" to a writeable client's "input jack", just like you may connect a cable from your guitar's audio out jack to your amp's audio input. But of course, software programs don't have actual physical jacks that you connect with a cable. These are software "jacks" (referred to as "ports"). You need a software program to make these connections. And qjackctl is an example of such a "connection manager".

[arpegadream]

Oh man, thank you thank you. You all here are the best. I need to thank the rest of you in my other threads. I'll get a handle on this yet.

[b.horn99]

I hear you there, Jack is a beast...
Thanks j_e_f_f_g for your explanation