via Kyle Weiss in the comments of
this post.
"
This link has a noise-reducing modification that I'm going to give a try..."
The link also mentions an old DOS based editor called the K5MP. The link appears to be from Sound Doctorin, who I'm guessing is this
sounddoctorin.
"K5MP FEATURES:
* Runs on any IBM compatible with DOS 3.2 or higher, floppy DD
and an MPU-401 compatible (UART) midi card.
* Eases the process of becoming K5MP proficient, by providing
COMPLETE MENUS, which prompt for all options available.
* Allows you to create custom MACRO LIBRARY files, which help
you generate complex sounds in minutes! A library file for
each "page" of data on the K5 can be accessed. Just imagine
selecting your favorite piano timbre without searching your
patch libraries for the sound that contained that timbre, and
then extracting it into your working patch. Setting up these
libraries as you please will allow you to remove the obstacle
which has kept your imagination from running wild on the K5!
* Takes out the guess work when editing delays and envelopes
by letting the user enter real times. (eg. trend of 4.2 sec.)
* Provides logical and imaginative tools for creating timbres, a
very efficient discrete harmonic entry utility, and a waveform
plot utility.
* Patch can be sent to or received from the K5 with one keystroke."