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  • tomas's Avatar
    03-12-2021, 11:39 PM
    Just wanted to say Thank You, Paul Stoffregen, for doing all the work you do. I can imagine how stressful keeping up with all things is, as I am running the some other tech forum. Thank you for sharing the info about...
    470 replies | 49731 view(s)
  • tomas's Avatar
    02-17-2021, 08:27 AM
    CMSIS provides ready-to-use implementation. For interpolation you need call arm_fir_interpolate_init_f32 (once) and arm_fir_interpolate_f32 ( in the loop) For decimation you need call arm_fir_decimate_init_f32 (once)...
    207 replies | 8156 view(s)
  • tomas's Avatar
    02-16-2021, 11:08 PM
    If you did oversampling "by the book" you would need polyphase FIR interpolator at the input and polyphase FIR decimator filter at the output. These are costly. Not doing things by the book results in aliasing. FWIW...
    207 replies | 8156 view(s)
  • tomas's Avatar
    02-14-2021, 06:32 PM
    With max resonance you can clearly hear that analog filter has some "gritty" quality to it (2:52 of your video), while digital is sterile and lacks this effect completely.
    207 replies | 8156 view(s)
  • tomas's Avatar
    02-14-2021, 12:00 PM
    I noticed that you are using copy of the same input sample when oversampling and averaging output. You may consider using linear interpolation on input and dropping on output.
    207 replies | 8156 view(s)
  • tomas's Avatar
    02-14-2021, 11:41 AM
    Sorry, I did not want to sound harsh, I realised that I was too quick to post feedback, so I deleted it as it requires more time. I will run newest code and do more tests. UPDATE: Now I am running your newest code...
    207 replies | 8156 view(s)
  • tomas's Avatar
    02-13-2021, 03:08 PM
    For obvious (performance) reasons nobody uses math library tanhf for audio. It is way too slow. And if you read previous posts, you would see that I earlier wrote to use float everywhere, not double as it was used in...
    207 replies | 8156 view(s)
  • tomas's Avatar
    02-13-2021, 01:43 PM
    For what it is worth soft saturation (distortion) is absolutely essential to Moog sound. https://www.youtube.com/watch?v=5sAq0FjRUI4 And using tanh() in simultation is not random choice. Moog ladder filter consist of...
    207 replies | 8156 view(s)
  • tomas's Avatar
    02-12-2021, 03:39 PM
    Was busy with other stuff, but over the weekend I intend to pull that code and check against analog 4pole "moog" filter simulation in hardware Virus TI synthesiser. Guys from Kemper Music are famous from good sounding...
    207 replies | 8156 view(s)
  • tomas's Avatar
    02-12-2021, 01:53 PM
    Here you can find the document that describes from where the delays come from: https://www.ti.com/lit/wp/slyy095a/slyy095a.pdf?ts=1613141458124
    24 replies | 911 view(s)
  • tomas's Avatar
    02-12-2021, 01:29 PM
    For what it is worth it is not possible to exactly simulate non-linear analog filter with feedback in digital domain because of the delay introduced by digitization. So called "zero delay" filters were developed to...
    207 replies | 8156 view(s)
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