Here's a fairly simple hack to use the full 64-bit precision in Ruby for processing in ASM.

It appears to be working nicely! I have been down this rabbit hole before too. I have tries several methods of curve fitting IIR filters with mixed success.

Least squares:
+ Tends to have lower average error
+ Can yield a smoother response than other methods

- Rounding error can go * really ...

Here's an endless / Shepard tone phaser I made with the hilbert transform. I added an "insanity" mode which self oscillates with tanh saturation in the feedback and a "spaceship" mode that adds a delay to the feedback.

I fixed up the harmonic generator a bit and I realized something. A complex square root is a subharmonic! You have to tell it to flip polarity every 180 degrees because the low harmonic is full wave rectified. I also made a 1.5 harmonic from it too! This complex waveform harmonic generation is ...

Martin - Yes, that's what I meant when I said the impulse response looked very good! Pretty cool, huh?! It still looks pretty good with Olli's coefficients, but it has much better symmetry with yours.

I'm not sure of a good way to make complex poles out of this structure. I've been trying to figure ...

I'm having issues with modules and primitives disappearing in the search. If I type in say, "multiply", I get a few weird random modules, but no multiply primitive. It's very crippling for me to get anything done when almost no modules and primitives show up. I've tried re-installing several times ...

I made a new one with your 16th order coefficients and I optimized the filter with asm. The impulse response looks very "correct" with your coefficients and the CPU hit is nearly 1/4th of what it was! I modified the code from one of the optimized delay code generators.

I'm glad you like the ...

Here are some more examples of stuff with that filter structure. I've got lots of different versions of it (some of them rather old) and I didn't test them before uploading but I think they should work fine. I made a simplified example so that it would be easier to follow what I'm doing.

One ...

Thanks. I'm not sure where I went wrong. I've noticed you get significantly better performance on Olli's version if you square the coefficients before converting to 32 bit. I have a version of his that is close to linear phase (as in all frequencies -90 degrees) using a backwards IIR with one half ...

Are you using the same filter structure that Olli Niemitalo used? I tried plugging the coefficients into an existing allpasses and it didn't work. I'm having trouble deciphering the code.

The performance is very impressive.