An example/test of what Xpressive can do, along with an example of the syntax - there is very limited documentation available.
A 1.6-second speech sample was converted to 4 harmonics over 35 frames using FFT in MATLAB, and then translated into a series of sine and cosine expressions.
It might just be my computer, but with 8 harmonics, I couldn't play this in real time (although the rendered version sounded as good as an Amiga module).
The original spoken sample is 39 years old, from a Detroit Techno record (Model 500 - Testing 1-2). This rendering is very low quality, so I don't think there will be any issues with using it.
Additionally, this is in mono, playing this in stereo doubled the number of expressions, making this impossible to play in real time using my computer. You can adjust PN2 to centre to play through both channels.
Why did I try this? I wished to see if I could store a sample within the LMMS file (well not actually a sample in this case). In reality, this method is too slow if we wish for any representation to actually sound good.
I have since tried this again with sinew() which allows input of phase, which is showing a lot less CPU usage on the graph.