I'd like to use an iPad with software which provides an isomorphic keyboard (the app called Musix) to make some music, but the built-in MIDI instruments don't sound very good. The software can send OSC and MIDI outputs over wifi, I have managed to make them appear on my computer using rtpMIDI.

Is there a simple, preferably free, piece of software that can turn these inputs into sounds? e.g. for concreteness, the sounds of a piano.

I've read around online and I understand that there are large software suites that will do this--DAWs like Reason, and Ableton, etc.... But I find them very difficult to use and I don't need all of their features.

I am somewhat comfortable programming in Python (perhaps other languages if required) so I can do simple transformations of the input data if it required. But I'm really looking for something as user-friendly as Synthesia. If only I was able to use the OSC inputs as input for that--and if it had a "free play" mode--that would be perfect.

2 Answers 2


Yes there is!

There are many freeware synthesizers whose express purpose is turning instructions like MIDI into sound. Currently it's far more common to support MIDI than OSC (I couldn't name one that supports OSC off the top of my head), but there's no reason why one couldn't exist.

Most of these "softsynths" tend to be released in Steinberg's VST format, in which they act as a "plug-in" to other hosting software, usually a Digital Audio Workstation environment like Ableton Live, REAPER, Pro Tools or similar programs. The host handles routing the MIDI data to the plugin and managing the audio output. There are other plugin formats too, like Apple's Audio Units, but VST is pretty pervasive and most hosts have some support for it. Likewise, there are also standalone versions of some synths that don't require a host, but I don't know of any free ones offhand.

Most DAW packages cost money, but there do exist some free ones such as Ardour. You can also, if you just want to play with your VST synthesizer but don't need the other features, find a standalone host that just loads the VST, nothing more.

Try these for free

If you're on OSX, you can actually just use GarageBand, which should be preinstalled. It handles MIDI inputs and loading virtual instruments. If you don't like the included instruments, you can use Alphakanal Automat, a free AU synth plugin that GarageBand can host.

On Windows, I'm fond of Ichiro Toda's Synth1 VST plugin. It is also free, and you can host it in any VST host. The free evaluation version of REAPER will host it nicely and has the nice property of not being a time-limited despite basically being a demo.

Going further

There's more to MIDI than notes. Once you're all set up and happily playing your softsynths from your iPad keyboard, you might also want to be able to control the synth parameters from your iPad as well. See if your software supports sending MIDI continuous controller messages, which are analagous to knob/slider movements. Most synth plugins will respond to these, but there is some setup to map your CCs to the desired parameters. Check your particular host's documentation to find out how this is done in your host.


If you already have MIDI messages being transmitted into you workstation, then you have a plethora of options. The choice is vast, it mostly depends on what your requirements are (usage pattern, sound quality, solely playing or processing and of course price).

For starters you could try getting Kontakt Player a free version of the flagship Native Instrument's sampler. It's very easy to start with and can work in standalone mode if what you need is "just playing". The full version is one of the most renowned samplers in the industry, so you can't go wrong this way.

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