I still suspect it's more to do with your mac, as I'm hammering out "jeep" and "jjjjjjjjjj" at break-neck speed without issue... And I'm a drummer.
As part of detecting the press and release of the "J" key in a standalone macro.
The trouble is, KM "eats" the keypress , so if you want to use J as a hotkey and type J at the same time, you have to simulate pressing "J" as part of the macro.
KM would already have to be aware of the keypress, so J has to be the hotkey. See what I mean?
If you can think of a better solution, I'm all ears.
Mh … What I do not understand. When I press the letter "a" normally while writing, the system makes an "a". Of course, what else? The "a" is typed when the key is down, not up (released).
If I press "a" and hold it, this menu appears
Isn't this exactly the same short/long press action? Why does this work here without interference?
Hi @ccstone, thanks a lot, I disabled this a long time ago because I don't need it (and it is annoying). But that does not help here.
Single key short/long press actually doesn't work at all - unfortunately. Not for people who can write fast. The reason is clear: if one letter is typed on release and the next on pressed, it can't work.
The question is: Why does macos manage it with its "bubbles"? "a" is written on down (short press). If the key is held longer (long press), the "bubble" appears. This is perfect short/long press behavior, which apparently no other software manages
Ok, I didn't know that, thanks for pointing that out! After a quick look, I have no idea how to use that. Before I get into it. I'm looking for something that doesn't cause delays in writing with a single key trigger. Eg, short press "a" = "a", long press "a" = something else. Do you think this works?
This method isn't perfect, because Keyboard Maestro is listening to the system and emulating key-presses and is not a driver-level utility. Even so – chances are pretty fair that it'll be good enough for your purposes.
If you need something more sophisticated the only thing I know of is Karabiner-Elements – it does run at the driver level.
Unfortunately this is not true, dear Chris, the macro you suggested suffers from the same disease as all of its kind. The letters are typed when released, not when pressed.
This leads to the problem I explained in the post above. Example with "j". The macro does not type "jeep", but "ejep". The reason is obvious.
Karabiner Elements does exactly the same (mess). The only way would be to output the letters in the same order as they were typed. Like in a queue, who comes later, stands behind.
I know only one software, which "manages" both actions, short and long, when pressed, so that normal writing is possible. But this is a bug in the software, which I discovered by chance! Setting up these actions is very laborious and it is a maintenance nightmare. That's why I'm still looking for other solutions.
I nevertheless thank you very much for your help. If you think of anything else, I am a grateful listener.
If you think of anything else, I am a grateful listener. 
