Here's a continuum patch that I created that gets a reasonable voice from the AES theremin input very much like the Talking Machine using BiqMouth formant generation modules - but with a more usable higher end I feel. This one assumes a stereo input but if you are using only mono in, remove the 1s in the BiqMouth1 and Biqmouth2 columns for the input you are not using. Reverb is on so you can adjust that as well at the bottom right and using reverb/recirc gain on upper left.
The .mid file for this should be downloadable here that can be loaded in as a preset (I'm not 100% sure it will function as expected if you are using an older version of firmware - I'm running 7.42).
https://www.dropbox.com/sh/hts6phhbcvv4xcr/AAD1vOxHWPfu9tRq4oYuB-AXa?dl=0
This uses a barrel (the parameter control to the right of the Recirc Mix dial here) I called FormBand - alters formant bandwidth on the second BiqMouth formant generator. You can play with (drag) this a bit to slightly alter the vocal sound - and you can greatly alter the sound by fiddling with the Direct constants at the bottom that control the two formant generators. BiqMouth 1 is set to emphasize a female voice. BiqMouth 2 is the male vocal setting. Together they seem to just give a bright male voice with a higher end that moves a little to the counter tenor sound high up. Removing the 1s in the analog inputs (filled triangle column) of either BiqMouth module will turn it off and you can then just hear the male or female setting by itself - which can be used as well.
Note that you can easily input this into the editor and experiment. If you are not used to barrles - just type a 1 where there is a A in the BiqMouth2 sB column.