Created by Olli Niemitalo on 2009-08-28, last modified 2014-08-28

Olli's portrait, 2013


My name is Olli Niemitalo. I live in Oulu, Finland.

You can reach me at o@iki.fi and Facebook.

I write here of technical and creative things that I am doing.


  1. Great blog :D

    Comment by joxer — 2010-01-26 @ 22:40

  2. Hi Olli,
    I have just started on the maddening journey into audio/dsp programming and came across this link from Tobybear.
    He notes it as a must read for this kinda journeys start, but alas I don't find the destination...
    Any help would be most welcome

    Comment by colin — 2010-09-27 @ 07:02

  3. Colin,

    Thanks for pointing this out! The article had disappeared from the right hand menu due to a bug. Now it's back in there. A direct link: http://yehar.com/blog/?p=121

    Comment by Olli Niemitalo — 2010-09-27 @ 09:24

  4. Hi Olli
    Last night I asked for info on where to find "www.student.oulu.fi/~oniemita
    /DSP/DSPSTUFF.TXT"...I was directed to you from Tobybear.
    Well I also downloaded his flex filter explorer, and within was said document...
    So I have it and have just started to read...A very good place to start so it appears
    AND a very big thanx for putting it together,

    Comment by colin — 2010-09-27 @ 15:54

  5. I was so keen to get into it , I made this comment b4 reading the comments.
    So big thanx 4 getting back so quick...am well impressed.
    Cheers, now to twist my poor ragged brain cell some more..ha!

    Comment by Olli — 2010-09-27 @ 15:58

  6. Hey Olli! Just wanted to thank you for your easily readable work. Better than uni courses. ;) I'm enjoying reading your interpolation paper over and over at the moment.
    I've just started started coding DSP - and it's so much fun i forget to make music. :)

    Comment by Dennis Tapper — 2010-12-09 @ 15:43

  7. Thanks Dennis! By the way, I have enjoyed listening to your music in a few occasions over the years as well. :-)

    Comment by Olli Niemitalo — 2010-12-10 @ 14:59

  8. The resampling paper on this site is incredibly useful. Thanks for making it available!

    Comment by Evan Balster — 2011-08-19 @ 08:17

  9. I found your re-sampling paper very interesting, and I wanted to know if your algorithms have ever been adopted in any products that I might have heard of?...

    Comment by Richard Murison — 2011-11-17 @ 21:54

  10. Richard: An early version of Fruity Loops used a resonant lowpass filter from me. Of others I don't know.

    Comment by Olli Niemitalo — 2011-11-18 @ 00:25

  11. How would the SRC algorithm in your paper rate against popular algorithms like those found in iZotope and SoX?

    Comment by Tim — 2012-01-13 @ 02:54

  12. Tim, I'm guessing your question is about the maximum achievable quality. I don't give a single algorithm or complete sample rate converter implementations, but properly implemented in a sample rate converter some of the algorithms in the paper would give better than "good enough" results. Also iZotope and SoX are better than "good enough". To go further in the comparison of maximum quality achievable would not make practical sense.

    Comment by Olli Niemitalo — 2012-01-13 @ 03:57

  13. Have you ever looked at the challenge of DSD-to-PCM conversion? Do you have any special insights into that problem?

    Comment by Richard — 2012-02-20 @ 21:55

  14. Richard: No, I haven't done anything related to DSD

    Comment by Olli Niemitalo — 2012-02-20 @ 23:02

  15. hey Olli. just discovered your site (you were the yehar guy?) didn't you used to have a SHARCPAGE or something?

    good to see you at the dsp.stackexchange .


    r b-j

    Comment by robert bristow-johnson — 2015-04-14 @ 20:21

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