Things that other Wind controllers do

Feel free to post any broad WARBL questions or comments here.
Post Reply
gonzoB
Posts: 27
Joined: Thu Jan 28, 2021 9:45 pm

Things that other Wind controllers do

Post by gonzoB »

I've discovered that my WARBL
a) doesn't reduce CC2 to zero when I stop playing. I've set my "output" slider to minimum, but I get 1 not zero. This is not a great problem providing I don't get any hung notes, and the minimum value is not audible. The only reason I discovered this is because my Xpresso synth shows the current value of CC2.
b) doesn't have a key delay setting. Would that interfere with half-covering holes?

Comments?

Gonzo
---------------------------
Gonzo Projects Page: https://gonzos.net/projects
User avatar
admin
Site Admin
Posts: 379
Joined: Tue Mar 26, 2019 5:17 pm
Contact:

Re: Things that other Wind controllers do

Post by admin »

Good point about the minimum CC value-- in the next firmware I'll make sure that drops to zero if the pressure is at the calibrated minimum level. Right now it uses the raw sensor output, and because every sensor is slightly different, they don't always drop exactly to zero. I just re-wrote all those pressure calculations to make them several times faster as well-- they weren't noticeably slow, but that opens the possibility of having separate mapping for velocity, CC, channel pressure, and key pressure.

I hadn't entertained adding a key delay setting because with MIDI there's always latency so I was trying to make everything as fast as possible. I can think about it, though. Is the primary purpose to filter out brief unwanted notes?
Andrew Mowry
info@warbl.xyz
gonzoB
Posts: 27
Joined: Thu Jan 28, 2021 9:45 pm

Re: Things that other Wind controllers do

Post by gonzoB »

On the CC value, with the instruments I've built, I set the minimum air pressure to something above ambient. Then the CCs don't start (with the minimum value of CC) until it reaches a small pressure above that. The CCs drop to zero when the minimum pressure is reached. All the controllers I have used (and built) send a CC2=0 when blowing stops. On one controller I have the pressure sensor in the mouthpiece, and I needed to apply a correction for ambient pressure as the mouthpiece heats up with use. The WARBL sensor shouldn't have that problem, as it is well clear of the mouthpiece. Nevertheless, a regular check on ambient pressure might be useful.

The key delay is there to filter out intermediate notes when playing legato. For example when you go from recorder C to recorder B no matter how fast your fingering is it can't happen immediately - it will always be either C-C#-B or C-A-B. The (adjustable) key delay filters out the intermediate note. Typical values go from 20 to 50 msec.

Gonzo
---------------------------
Gonzo Projects Page: https://gonzos.net/projects
User avatar
admin
Site Admin
Posts: 379
Joined: Tue Mar 26, 2019 5:17 pm
Contact:

Re: Things that other Wind controllers do

Post by admin »

Okay, thanks— I checked the code and it is using the calibrated (ambient) pressure plus a small amount of hysteresis, but the previous mapping algorithm I was using had an truncation error that was mapping 0 to 1. It’s fixed in the new firmware.

I’ll consider adding the key delay. I don’t think most WARBL owners would use it because even 20 mS would be a huge amount of added latency for fast tunes, but I can see how for slower stuff it could be useful. This is related to “crossing noise” which bagpipers spend a lot of practice learning to avoid through fingering techniques, but it’s not as much of an issue for most other acoustic wind instruments with a slower attack.
Andrew Mowry
info@warbl.xyz
gonzoB
Posts: 27
Joined: Thu Jan 28, 2021 9:45 pm

Re: Things that other Wind controllers do

Post by gonzoB »

Re the key delay, a while back I did some testing with my acoustic clarinet and recorders, and found that the legato latency was around 40msec. It took that long for the pipe to start resonating at the new frequency. I may have not been too accurate, but I doubt it was half that value. 40msec would allow you 25 notes per second. I can't play that fast! I think you'll find that a 20msec delay will be unnoticeable and a 50msec one will be annoying. The attack phase of the synth preset will also have an effect. Good players (not me) set the delay to 20 or less, but even at that it cleans up the playing.

Gonzo
---------------------------
Gonzo Projects Page: https://gonzos.net/projects
User avatar
admin
Site Admin
Posts: 379
Joined: Tue Mar 26, 2019 5:17 pm
Contact:

Re: Things that other Wind controllers do

Post by admin »

Yes, instruments like clarinet have a very slow attack so you wouldn’t notice latency much. I agree the key delay could be useful for that. In studies of bagpipers, it’s been found that grace notes are often in the scale of 20-30 mS, and good pipers can sense latency of 10 mS, so I don’t think they’d be able to use it (some pipers have said they can’t use MIDI at all because of the normal latency). Even with tin whistle sound, I find the delay of 20 mS for the velocity calculation to be pretty noticeable, so I keep it turned off for that reason. I’ll definitely play around with adding the key delay, though. I’ll have to figure out how to do it with the pitch bend, but I guess I’d just have to put it all in a buffer and send it after a given time if a new note hasn’t been triggered.
Andrew Mowry
info@warbl.xyz
Post Reply