“Release Time” is the Envelope parameter that describes what happens to a Note-On event once the Key-Off message is received. This includes lifting the hand from the Key or lifting your foot off the Sustain Pedal (If the Key is not physically being held).

The parameters setting range from 0 (immediate) to 127 (a very long time; could be in excess of 90 seconds). This is not a linear range. The actual Time involved is concentrated to optimize the use for musical instrument Envelopes... that is, more resolution in the lower range. The time difference between 16 and 17 would be measured in milliseconds while the difference between 126-127 would be measured in seconds.

No acoustic instrument has an immediate release. But very rapid release times can be generated... Piano has fairly quick Release Time but by no means immediate. If you study any piano sound you’ll see the Release Time is a rather significant number. But as you raise it the time expands exponentially.

String sounds would typically have an envelope where “Decay 2 Level” is not 0.
This means as long as you hold the note (or use the Sustain pedal to hold the note) the instrument will sound.

Percussion instruments, like drums, piano, plucked strings, (hammered, struck or plucked) will have “Decay 2 Level” = 0.
This means that no matter what, the sound will reach 0 (no sound) whether or not you hold a key or the pedal... you can only delay the time it takes to disappear. It will, however, disappear. Unlike bowed strings and brass (bowed and blown instruments) which continue endlessly when held.

Release Time is the parameter that takes over as soon as you let go. If you have a slow attack, a slow decay, it does not matter, the envelope will jump immediately to Release Time as soon as the Key-Off message is initiated. Whatever Level has been reached... the envelope goes immediately to Release.

If you change the Release Time (via cc72) you are offsetting the amount of time the signal takes to disappear completely. A high number will be a very long time and very slow return to 0 (Release Level = 0 always).

Question is was the file prepared for the Amplitude Envelope Generator found in the MODX, or some other product?

For example, create a midifile on a PSR or TYROS or GENOS
There is some CC72 midi events in the midifile to tune the release time of the instrument
Then play the same track on the MODX, the sound never stop

Usually in the XG or GM / GM2 synth, the value 64 mean No changes , No offset…

But on some MODX sounds, when we put for example 70, a bit more than 64.... the sound never stops, while on the Genos, it is just a bit longer after you release the key

As you may know, the MODX is not a GM, GM2 nor an XG product. Undoubtedly, there are going to be differences in the speed of the Envelopes (and/or there are other factors in play in this issue). You may expect to have to edit things like Filter settings and Envelopes when transferring such files to non-XG/GM products. The MODX features 18 different Filter Types, and fully programmable envelopes.

But on some MODX sounds, when we put for example 70, a bit more than 64.... the sound never stops, while on the Genos, it is just a bit longer after you release the key

With cc72, a value of 64 would be the normal pre-programmed Release Time. Neither lengthening nor shortening the original Release Time... A value of 70 would be applied as an Offset to the the preprogrammed Release Time of the selected Part... lengthening the Release Time.

If there are Sustain messages additionally on the Strings Track this can interfere with how sounds behave. I cannot do anything but guess at why you get this behavior. Without see/hearing it... Is it consistent (does it happen at the same places each time?) A Sustain message that occurs during the Release will latch the level at that setting.

A hung note is one that never ends, however, a note being held by Release Time will eventually fade to 0 In absence of a key being held, on a normal (non-Drum) program.
They behave similarly in the beginning but eventually the difference becomes clear.
Are you sure which you are dealing with?

I tried this here and even though MODX is not GM/GM2/XG certified (it doesn't claim or want to be any of those) - at least the part of GM2 spec that says 0x40 (64 dec) is a 0 offset appears to be true. When I set "CFX + FM EP" (all PARTs' MIDI channels) to CC72=70 dec - the release increased by a few seconds but not forever. I know you said "some" sounds - so we'd need to get more specific to align. But, in general, it looks like CC72 is being parsed as we would generally want it to - at least that a decimal value of 64 = 0 offset.

How it may scale vs. PSR/Tyros/Genos is not necessarily guaranteed.

One thing I'm wondering is if you are using a value of 70 decimal or 70 hex? As 0x70 would be 112 decimal - nearly the high end of the scale for release (127 decimal).

I have tried a MIDI CC72 value = 96 in my PSR, the sound last 2 more seconds after the NOTE OFF message
(the same for some other gm2 keyboards)
I have tried a MIDI CC72 value = 96 in my MODX, the sound last 100 more seconds after the NOTE OFF message

why so much difference?

it's so bad, because all my songs are using some well tuned CC72 values

No need of an answer like MODX is not a PSR.... I already know such answer.
i am creating a very nice software for MODX, I am sure many of you will love it 🙂

The lack of CC84, the CC72 that last too long and the program changes that is slow are the 3 missing things to make the things perfect

Keep looking... you will find many, many more differences between an XG/GM engine and most any other synthesizer that does not adhere to those protocols. They are way, way
different. Pro synths, in general, do not necessary have any uniformity of Release Times (like in GM). They don’t necessarily have similar envelopes, filters, effects, etc., etc.

It's true that MODX is not expected to be the same as GM keyboards. Lack of GM spec adherence is advertised - so there's not a need for these to align. However, if you're trying to document something - even if barking up the "wrong" tree - why not detail which Performance(s), by specific preset name, you're having issue with?

Without such documentation, one -could- assume the complaint is about "DJ Montage" - something which would need no fix since it's "exclusive" to MODX/Montage. Something like "Goblins" from the GM set - if that's documented to be wildly different - may be worth underlining. Still, there's no policy to make sure these will all match from a GM keyboard and non-GM keyboard.

After more tests, it seems all the sounds on the modx have a very long release time with a cc72 value of 96
I have seen on the documentation some SYSEX talking about release time. Something like AEG Release Time. If some pro users are here….
Maybe there are some messages to tune the overall release time sensitivity that I can send at init time?

When I see the MODX tables, I can see that the Yamaha engineers are smart, and even if the synth does not comply with the GM or XG standard, they tend to follow it the maximum they can. for example they have a GM sound set, many GM drum kits, most GM like compatible messages
Only if they want to overcome GM/XG limits, they will change from protocol

We can see 2 children of the same father

Still no mention of problematic Performances. I tested ""CFX + FM EP" which seemed fine for a value of release time you stated having problems with using your initial "too long" setting of 70. I'm not really wanting to fish around Performances as I don't use this feature. When you omit details - it slows the process.

If you want to learn about how to access release time through MIDI - download the Data List for MODX (it's a PDF) and view it - press Ctrl-F (or your computer's search key combination) then search for "release time".

... but if you were going to go through that trouble - I'm not sure why you wouldn't just scale CC #72 instead of introducing another Sysex on top.

Sorry, the value is 96 and not 70

There is a lot of release time in the modx data list 🙂 not sure if one can limit the CC72

I prefer to send a sysex at init time if possible, rather than have to scale all my midi messages later

When I was imagining how to apply the SysEx - my thinking was to chase the CC72 with a Sysex that changed the release time to what you would have intended.

I imagine CC72 is not setting to an absolute release time, but an offset from the programmed release time. So changing the programmed release time to something smaller may limit the range of release times by the most negative (0) and most positive (127) swings of CC72. I'd have to test on a Performance you think is misbehaving to see if I can bring it in line.

I'm noticing you still haven't communicated a specific Performance you're dealing with. That would help so I'm not throwing arrows in the dark.

Maybe you're dealing with lots of them - just pick one that is your "go to" - "it fails horribly" Performance.

I send a GM RESET sysex message
Then you can send any single performance bank/program change on a midi channel

There are no PCs (program changes) that are worse than others?

I'm assuming MSB=0, LSB=0,, PC is something from 0-127

... to cover the GM voice set.

There's not something called "GM Reset" in Montage docs - although there's something called "GM MODE ON" - which matches what is elsewhere documented as "GM Reset". Adding this just for the sake of documentation.

Yes, I send the GM MODE SYSEX Message, so I can use 16 different instruments in the 16 midi channels
F0 7E 7F 09 01 F7

I think you don't even need to send a program change
As any instruments seems affected by the very long CC72 at value = 96

100 seconds vs 2 seconds on any other keyboards