[jacktrip-users] How to use jack_metro

[Daisuke Yoshida]

Hi,

I have been using jacktrip and it is pretty awesome ! Looking at the binary beside jackd I see there is jack_metro and I would like to utilize it. When jackd and jacktrip are both running I called the following command:

jack_metro -b 120 -d 0.2 -f 400

I didn't hear a ticking sound. From this manual I see that I may need to configure the port - does anyone here know how to set it up ? 

For example I would like to have a tick 120 bpm at the frequency of 440hz for 0.2 ms. If you could guide me how to do it that would be very helpful. 

Thank you!

[IOhannes m zmoelnig]

On 3/7/21 4:03 PM, Daisuke Yoshida wrote:
> I didn't hear a ticking sound. From this manual

> <https://manpages.debian.org/testing/jackd2/jack_metro.1.en.html>I see that

> I may need to configure the port - does anyone here know how to set it up ?

`jack_metro` doesn't automatically connect itself to any anything, so it
plays it's beeps to nobody.

you must manually connect it to your system output (or jacktrip, or,...)
using something like `qjackctl` (or `jack_connect`, if you prefer the
cmdline)

gfmasdr
IOhannes

[Dave Adams]

If you don't want to use qjackctl to manage your connection to this metronome you are in for an adventure.

As noted above, you will likely use "jack_connect".  To use this you will also probably need "jack_disconnect" and "jack_lsp"

That's just the start.  The jack_metro command runs until you stop it.  If you try to write a script that starts jack_metro THEN tries jack_connect it will wait until you QUIT jack_metro to make the connection.  Probably not what you have in mind.

If, as your link somewhat suggests, you  are on Linux, you can use "process ID" (PID) info in a bash (or other) script to "detach" the metronome, catch the PID, set up the connection, wait for some sort of "stop me now" signal, use jack_disconnect, run jack_disconnect, and be done.  If things go well, jack_metro will finish starting before you try to connect to  it.  If not you  get to learn about adding delays into your script.

To keep a burgeoning script simpler you can run jack_lsp once you have an instance of the metronome running and see what connections you can make.  The names are unlikely to change between uses.  But the metronome name WILL go away as soon as the metronome does (makes sense.)

There are long bash and other script tutorials out there to help you along, all by people better at it than I.