The VP-330 project

VS-305 Vintage Voice and String synthesizer


I’m SansNom, an Audulus user since version 1. You probably don’t know me but I used to be pretty active in the old forum. This thread is the continuation of this thread.

Today I’m posting a special “module”, a project I’ve been working on for many years, literally thousands of hours of work.

This is an instrument based on the Roland VP-330 and RS-505 string machines. Since I don’t own the original instruments (never ever seen one for real either!), I built this emulation using:

  • the extremely detailed service manuals for the original machines published by Roland
  • analog circuit simulation techniques (using the now defunct SPICE MultiSim touch app for iPad)
  • samples and videos found around the web

Disclaimer: This module has been developed and tested in Audulus v 3.5.3. I have not installed the latest version of the app since one critical node has been modified, in fear that it would completely break the instrument. It is also quite demanding in cpu, tested and working fine on an iPad pro 12.9 1st gen. That’s probably the minimum requirement. Hoping that it works on the last version of Audulus (3.6). Edit: it works!

VS-305 specifications:

  • phase-locked oscillators mimicking the divide-down circuitry of the original instruments
  • emulation of the original waveforms using analog modeling techniques
  • strings section with feet mixing knobs (taken from the RS-505)
  • human voice section
  • bass section (taken from the RS-505)
  • VP-330 ensemble effect
  • modeling of the pitch shifting modes of the VP-330 and the RS-505 (Manual and Auto modes)
  • vibrato sections for the human voice or all voices (taken from the RS-505), with correct timings
  • the instrument voicing can be paraphonic (original) or fully polyphonic
  • includes a BBD harmonic distortion model
  • includes a compander model
  • mono/stereo control

Note that the instrument will only play with keys depressed from C1 to C5. Any notes played non legato outside this range will only reset the envelope (paraphonic mode).

The instrument:

The synth is divided in 2 parts: lower (below C3) and upper


[Knobs, Buttons] Function Notes
Human voice section Choose the appropriate voices for each part
env Envelope Controls the attack of the human voice and/or the strings. The release is shared
Strings section Tone control and mix between 8’ and 4’. To get the VP-330 sound keep these knobs to 4’. Buttons activate each part.
Bass section Bass section of the RS-505, contrabass, tuba and cello. This section is monophonic (even in polyphony mode) and the lowest note has priority.
HV_vibrato HV vibrato Vibrato control of the human voice
main_vibrato Main vibrato Controls the vibrato that will affect all sections
pitch_set Pitch set Controls the maximum range covered by the ptich shift knob (Manual mode) or the lower starting point of the pitch shift (Auto mode). The mark represents the “realistic” setting for the human voice
pitch_time Time Time for the pitch shift (Auto mode). The mark represents the “realistic” setting for the human voice
pitch_shift Pitch shift Controls the pitch shift in manual mode, the range being defined by the pitch set knob
pitch_control Pitch control Set the pitch control to manual or auto
tune Tune Global tuning
balance Balance Controls the volume balance of each section
para_poly Para/Polyphonic voicing The original instruments were paraphonic (Envelope shared) but you can switch to full polyphony (except bass, remains monophonic)
mono_stereo Mono/Stereo Progressive control over the stereo field. The instrument is designed to be used in stereo, but you can merge the outputs with this knob to produce phasing that is characteristic of some recordings.

Due to the nature of this project and the considerable amount of time devoted to its development please do not distribute your own versions of the instrument, and post instead your comments and suggestions in this thread. Thank you!

That’s all! I hope you’ll enjoy it and make music with it! I’ll share later some details on some specific parts of the instrument.

Version History

Revision File Date Notes
[1.02] VS-305 1.02.audulus (1.9 MB) 02/08/2021 First release
[1.03] VS-305 1.03.audulus (1.9 MB) 02/11/2021 G#3/4 human voice bug fixed

Demo track


Reserved for additional modules/comments


Welcome back! It’s been quite a while. This looks awesome, can’t wait to try it out. BTW there’s currently an open beta for the iPadOS version of Audulus 4. You can find out more here:


I will never forget you, you made some of my favorite filters!


I’m seconding that
I wasn’t even on the old forum but still know your name for that reason :smiley:

Now to the VP-330:
This sounds amazing!!!
I just wanted to check if it works in version 3.6 and immediately got sucked in for an hour or so.
From what I can tell, everything seams to work as intended in 3.6. At least everything sounds like it is supposed to sound the way it does.
Bear in mind I don’t know the original, so I might me missing something but it certainly doesn’t sound broken.

I have to make one little bug report though:
It seams like the note input for G#3 is also wired to G#4 for the upper voices (Male 4’ and Female 4’).
(G#3 sounds like it has two octaves layered and G#4 doesn’t produce any sound)


@stschoen @robertsyrett Hey good to see you again!


@J031 Wow good to know that it seems to work on the last version. I might be able to upgrade my iPad also after all :sweat_smile:

Thanks for the positive feedback and for reporting the bug, already corrected for the next version.


OK, no more bug reports so I just posted the fixed version (1.03).

1 Like

I downloaded the file from the URL above, and copied it to the « Audulus » folder (on my iPad), but I can’t find a way to have Audulus 3.6 actually open that file — can you help?

Hi RockBottom. Just did that on my iPad: downloaded with Firefox, then in Audulus went to ‘my iPad’, Firefox, Downloads - was there.

I’m also happy to confirm that the instrument works fine in Audulus 3.6!

From my understanding Audulus 4 is retrocompatble with 3.6 patches? Has anyone tried to open this instrument in Audulus 4?

yep, it is there for me too, albeit ghosted, i.e. greyed out, and totally unusable — what gives?

You have to rename it. The file uploaded has a *.txt extension, you have to remove that extension. It must have the .audulus extension.

Hi and welcome to all the new peope :slight_smile: nice to have you on board.

This works theoretically. However, there is no native way to change the file extensions on iOS (as far as I know). You can do it using the shortcuts app, but we usually use another workaround (also using shortcuts)
See here:


With the app ‘Documents’ from Readdle you can change a file extension without any problem.

Yes, thank you: I realized this doesn’t show unless you display the ‘info’ tab from the ‘files’ contextual menu… the problem is the ‘.txt’ suffix is appended over the ‘.audulus’ suffix and, as far as I know, there’s no way a ‘rename’ operation can remove the extra appendage!

In both Audioshare and Documents by Readdle, you can change the type suffix.

Aha, OK, thank you