The Korg SV-1 is very cool, and also quite frustrating: there is no proper way to organize sounds in layers, even while there are some layered sounds available. Unfortunately some obvious combos are missing, for example, although ‘Piano+Strings’ is offered, there is no ‘Rhodes+Strings’. Darn.
There is a partial solution: select a layered patch such as ‘Piano+Strings’, then use your computer to send a Midi sysex message to change the sound assigned to layer 1 (piano here).
F0 42 30 60 00 00 01 00 01 vv 00 F7
where vv is the base sound number. Use 00 for a Rhodes. Enjoy playing the ‘Rhodes+Strings’ you always wanted. 🙂 Other values work too for other sounds besides Rhodes. The same trick works with split patches.
(Still searching sysex for layer 2 sound… I’ll update this article if I find it.)
Important: as with control-change values tweakable with the SV-1 Fun app, the SV-1 can’t save the changed layer. The change is completely ignored if you try to write it in a favorite patch. More, there is a risk to corrupt the SV-1 memory if you write improper data. Using the sysex message is completely safe as long as you don’t try saving the result. You have been warned. 🙂
Note that I did try, and I’m still alive to tell about it. Backup your SV-1 memory using the Korg editor before attempting to send undocumented sysex messages. In case of problem, do a hard reset by powering-on maintaining ‘function’ pressed until it blinks, then pressing it again to reload the factory settings. Then launch the Korg editor and reload your own patches from your backup.