thanks guys,Now I can apply 'recipe' to a whole .sou (see linked file)The function search the parameter, as named in the manual, and set it to a new hex value, then save as a new file.It can't select a specific sound, as I don't build an object for each sound and its set of parameter (as a sample in a drumkit)The code is just a find and replace. It let me to fix ChickSys Translator translations mistakes, or to apply a list of setting in 1 second.I noticed the 50h byte have no effect.ASR-x user samples ignore those settings.I though it may be used for the Rom sound only.I took a look to the OS binary file, and notice all settings of Rom factory sound are written the same way. It could be possible to extract all settings from a program, and apply them to a user sample, as you can't edit them directly on the asr. Or output a readable CSV file, with all the settings.I noticed on a homemade wavetable (128 single cycle waveform, morphing from sine to square), the setting I was looking for was 04h, 'loopstartX'.Assigned to modulation wheel, it works. (but this sound was boring).The settings to write a such transwave is on the linked image.@44100, I found a note frequency that match perfectly the loop lenght to prevent any clicking (may be 'G')05h 'Transwave' have to reach the end of the sound to loop. Didn't understood how it was intend to work.I also tried 06h, but found nothing, it was just as 00h. cixelsyd , Thanks for your offer, But I can't do anything in Java.Only Python at the moment. I read many article about GUI in python, but first I have to finish this script. Generate the sysex is doable, but it's a lot of work, and probably a better approach than writing the file as I do.Actually I'm trying to figure why the ASR don't let you edit all the parameters in an imported .sou. It just let you tweak track parameters, not all the settings, even if it convert the .sou to a RAM-Kit. It don't write the 'DRM1' chunk in the file, so I have to generate it, then test.Thanks for your interest !