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 RapidComposer by MusicDevelopments is a Virtual Instrument Audio Plugin and an Audio Plugin Host. It functions as a VST Plugin. It can host VST Plugins.
RapidComposer RapidComposer RapidComposer
Product RapidComposer
Developer MusicDevelopments
Price (MSRP) $199
Type / Tags
Plug-in, App & Soundware Format(s)
Can Host
Operating System Availability
Download Released
 3.4  Downloads Released
System Requirements
•Supported operating systems: Windows Vista/7/8/10 (32-bit or 64-bit)
•Intel/AMD processor 1.4 GHz minimum
•512 MB RAM
 3.4  Downloads Released
System Requirements
•Mac OS X 10.7-10.13 (latest update)
•Intel Core Duo minimum
Supported Sample Formats (loads or saves) include
AIFF, SF2 (SoundFont), WAV
Miscellaneous Information
Copy ProtectionSerial Number

RapidComposer is a rapid music prototyping software designed for composers, song-writers and musicians of all musical styles.


  • Unique non-destructive, phrase-based music composition.
  • Advanced tools for phrase editing, phrase morphing, phrase generation, phrase grouping, motif development, chord progression editing.
  • Chord suggestions, chord progression generation, chord progression rules editing.
  • Melody generation, melody harmonization.
  • Timeline with chords (absolute or chord functions) which all phrases automatically conform to.
  • Piano roll with scale notes, visually editable chord notes, and smart arranging of overlapped notes in two styles.
  • In-place non-destructive phrase-level and note-level editing.
  • Sophisticated MIDI CC editing and recording.
  • Articulations can be assigned to phrases or even individual notes.
  • Extensive scale, chord, guitar chord, chord progression databases.
  • Movable, resizable and transposable smart phrases that always conform to the current chord.
  • Phrase and rhythm generators help you to create thousands of musically useful (not random) phrases.
  • Taggable instrument database of all MIDI, VSTi and SF2 presets in one place.
  • Variations can be applied to phrases, or whole tracks.
  • IdeaTool that can generate a multitrack composition based on the provided parameters and rules.
  • Intuitive drag and drop environment (you can drop chords, progressions, phrases, instruments to the composition).
  • Fully customizable user interface with preset themes.
  • Unlimited undo and the ability to make several versions of the same composition.
  • MIDI drag-and-drop tracks or composition to DAWs.
  • Virtual instruments (VSTi v2.4 plug-ins) support.
  • SoundFont (.SF2) support.
  • Standalone and VST version (32-bit and 64-bit).
  • Available for Windows and Mac OS X.
User Rated

Review RapidComposer Now!

Discussion: Disabled


6 June 2013 at 12:18amAtonal

Where are the (three) YouTube videos Chris was planning to produce ??

- atonal.

7 June 2013 at 7:13amftnwo2012

It sounds cool. Same thing on Windows ?

12 June 2013 at 2:45pmBiancaNeve

Well all I can say about it was that (on my venerable iMac running snow leopard) the demo version kept crashing before I could see what it was about .....

1 July 2013 at 6:32pmVariKusBrainZ

Pretty damn crashy on my Win8 laptop.

Luckily it autosaves before it crashes.

3 August 2013 at 11:36pmChandran

Hi tommyzai, I agree with you concerning the concept of this software, but sadly rapid composer is unusable for me, buggy as hell, unstable...c'ant use it more than 5 min without problems! I have seen you are on Mac like me, please can you tell me what OS you use? I' m on mountain lion my computer is a Mac book pro quad core I7 end 2011. My vote is 10 for the concept and 2 for the reliability...

Best Regards.

1 April 2016 at 4:42amtommyzai

Hi Chandran, I am so sorry I never replied to you. I had notifications turned off by mistake. I just happened to peek at my user review and found your inquiry. I hope the latest update of RC is running smoother for you. I have not had many freezes or crashes, and I've used it from Snow through El Capitan. I also have a i7 2011, but a MacBook Pro. It could be a conflict with other things, or I've just been lucky. Others have mentioned instability with early versions of RC. Hopefully, whatever it is. .. it's now fixed. It's a cool app and very useful. Tommy.

12 December 2013 at 7:27pmangelonyc

Yes, it does seem a bit unstable. I sent an email with bugs I found, and Attila seems very keen on perfecting his software.. Just keep saving... Logic went thru quite a 'buggy' stage at one point (years ago). I'm using a MacPro 2008 (intel) OS X 10.7.5.

6 May 2014 at 12:57amJcpstrat

The manual on page 6 says: "CUSTOM MIDI FILES, SAMPLE COMPOSITIONS, and AUDIO SAMPLES are available for download for Demo & Registered versions.

Where exactly are these?

7 May 2014 at 8:57ammusicdevelopments

This is not too exact in the manual. The sample compositions can be found in the program as templates (click on the 'Using' menu next to 'New Composition').

Registered users get about 250 very usable phrases, and you can find hundreds of additional phrases on the support forum here at KVRAudio that can be used in the demo version as well. These are mainly strings staccato and piano phrases.

If you want to listen to songs created with RapidComposer, you will find them in this topic:


7 May 2014 at 12:43pmJcpstrat

Thanks for the quick response. After finding this forum and seeing it so un-used I was about to write RapidComposer off. I did find the link you provided (before you sent it), and after listening to songs I realized I really want to check RapidComposer out.

Just a suggestion ... in the kva forum there was no indication that I was actually in a forum about RapidComposer until I got into some posts. I would suggest that somewhere in the forum headers you make if obvious which areas are about RapidComposer. Once you know it if's find but for newbee's ... they might miss out on checking RapidComposer out.

7 May 2014 at 3:32pmBlackWinny

Yes, purposed to the visitors and the newbyes, simply change the header of the forum.

from "musicdeveloments"

to "MusicDevelopments RapidComposer"

would be an excellent idea to better identify the forum.

(who composes now exclusively on RapidComposer since last december)

7 May 2014 at 4:27pmmusicdevelopments

You are both right, but I cannot change the forum title because that should be the company name...

7 May 2014 at 3:56pmmusicdevelopments

Yes, this discussion is not really used. The open support forum has lots of interesting topics:


In addition some comments here are outdated, e.g. the OS X version is very solid now. The work on RapidComposer is continuous, bugs are fixed in very short time, and the forum is full of creative people. Registered users can try the latest beta version and use features weeks before the release.


5 May 2016 at 9:51pmtommyzai

I just wrote a new user review based on the beta of v3. I hope users and potential users find my words useful.

5 May 2016 at 11:17pmBlackWinny

Very good review, Tommy! I would have added just another point at the end: Attila, the developer, is one of the kindest and of the most communicative guys in the world, and present IN PERMANENCE within his beta testers to have the most reactive returns and the best way to make the tool enhance permanently. Remarks, alerts, suggestions, engine, harmony rules, GUI... everything is discussed all together (and always in the best ambiance) to help Attila in his wonderful but very hard work. A bug found during the beta tests and confirmed by another tester or by Attila is generally fixed within the next days when not in the next hours! And we are a very active and a very enthusiast team around him. In my opinion, RapidComposer is now for the piano-roll what Sibelius or Finale are for the classical score writing, and nobody has gone as far as Attila in the quality concerning piano-roll writing and in the incredible sum of features to compose for the modern music as well as for the classical music, jazz music, rock music, ambient and chillout music, ethnic music (even for Asian, Indian, African, Arabic scales), songs, etc. Not only composing with RapidComposer is a true pleasure but contributing to his team of testers is one of the most pleasant times I have known in my life, now close to 60 years.

BlackWinny, who composes EXCLUSIVELY with RapidComposer since December 2013, the tool being used simply as a VST in my DAW to drive at its outputs all my instruments, each one on its MIDI channel.

5 May 2016 at 11:38pmtommyzai

I'm honored to join such an amazing team of dedicated users.

6 May 2016 at 1:52amtonedef71

Another decently-written review. It looks like we use some of the same music programming tools, despite being users of different platforms: you on OS X, and I on Windows.

6 May 2016 at 2:26amtommyzai

tonedef71, thanks for appreciating my efforts. We're in it together. .. using tools to compose. .. looking for a better way.

6 May 2016 at 3:29amtonedef71

Indeed. I couldn't have said it better myself. :)

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Average user rating of 10.00 from 1 review

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