Hi,
I am using Ardour 5.5.0 on Debian 9. I am new to Ardour.
I spent hours trying to get a midi track with percussions sounds with no result. I created a midi track, tried different instruments (a-fluid synth, Calf fluidsynth and so on) but only a-Reasonable Synth makes sounds.
So I keep a-Reasonable and tried to change the default piano sound to percussion sound. I saw in the manual the “Patch selector”. But when I edit the plugin there is no such thing (only latency, pinout, controls and so on). I also tried to insert patch change to a selected region but whatever I tried (change patch, canal, program or bank), it is always the piano that sounds.
I would really appreciate some help or advice.
Thanks
Reasonable Synth only ever produces a piano-sound – everything else would be unreasonable 
a-fluidsynth (like calf’s) does need a soundfont (.sf2) file. There are various sites that do offer soundfonts. One example is http://www.schristiancollins.com/generaluser.php for drums you may prefer a dedicated drums e.g. http://www.bandshed.net/avldrumkits/
The patch-selector is new in Ardour, 5.12. Also the binary fro ardour.org does include a general-midi-synth.
You may actually prefer a drum plugin: https://x42-plugins.com/x42/x42-avldrums or https://drumgizmo.org/
Thanks for the answer and the links ! I did create a-fluidsynth and import some AVL sf2 files and that works !
I also understood why I didn’t have any sound from other instruments (like Calf fluidsynth) : it is because all the notes of the scroomer are not active, one have to test all the areas of the keyboard.