I don't have a keyboard that uses YEM for expansion voices, but I do have a Tyros4 and a Regi-Stick RS4. You can examine and edit expansion voices on a T4 using it's Custom Voice Assembly function.
None of the 'custom' voices on the RS4 that I have use external samples, they are all just based on existing samples from the keyboard's wave ROM.
I have checked the Pedal 8' long UVN with the T4 Custom Voice Assembly function and it only uses a single voice element.
As John has already suggested, you can produce a change in the release time of the voice by changing the 'Release' setting on the 'Sound' page of the 'Voice Set', and this may be sufficient for your requirements.
On a T4 you can either do this in the actual UVN, or you can simply edit the Voice Set of the installed voice and save it as a user voice. I don't know if you can do the latter on a T5 or Genos.
I modified the UVN on the T4, comparing the sound with the original Pedal 8' long and Pedal 8'med, I reduced the 'Release' setting in the 'Sound' group to -3 to produce a voice which sounds somewhere between the two originals on my T4.
I have loaded the modified voice into YEM v 2.4.1, and it allows me to further edit the Voice Set parameters (or rather the 'Common' parameters as they are called in YEM), although I can't play the voice to hear the changes from within YEM.
I have attached the modified UVN if you want to import it into a YEM pack and try on your T5.
If it works, and is better but still not quite what you want, I can modify it further if you are not sure how to do it yourself, but it is really very simple to do, and I suggest that it is probably better that you try and adjust your own version of the original voice, since you will then know how to make similar changes to other voices if necessary.
Regards
Ian
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