Welcome to GuitarExtended!

This blog is about the possible future of the electric guitar as a computer-augmented  instrument through DSP (digital signal processing) Using the open-soucre audio programming language Pure Data (Pd) and a DIY footcontroller  based on a Arduino board (open-source hardware as well), I have developped a mobile setup that considerably extends my guitar’s sound. It basically works as a super multi-effects.

I have been working on this setup for about 3 years, and I have used it during many practice and recording sessions, as well as during gigs.  You can hear the recordings on the  Bancamp webpage of my band.

I have used Pd and a DIY pedal on all songs, but the result can be most clearly heard on songs like We own the sky, Canopée, Nyctalope and Not too sad.

The goal of this blog is to show that recent developments in computer hardware and the availability of powerful open-source DSP software make it possible to create a reliable, mobile and fully expandable guitar effects setup.  For the cost of a few analog stompboxes, it is now possible for a guitarist (or any musician, actually) with some knowledge of computers to develop effects for her instrument with virtually no limit but her own imagination.

In this blog you’ll find posts about :

38 Responses to Welcome.

  1. massat says:

    Hello Pierre!
    It’s nice to find you here on the web showing up different ways in making music.
    I’ll try to read it through, in order to improve my technical english.
    I hope you’ll enjoy sharing it all with blogers, as music actually does, “connecting people”.
    Have some fun and carry on son!
    Philippe M.

  2. Hey Pierre,
    Some great ideas! I have a break from university this summer, so I have time to try them out 🙂 I’ll probably keep referring back to this website. Thanks for all the information.
    Keep it up!
    Hugh R.

    • Hi Hugh, thanks for your comment. One thing this blog lacks is feedback and constructive comments. Please feel free to get back to me when you have tried my patches. Have fun!

      • I had been working on a similar, but much smaller project myself about 3 months ago. Then University work got the better of me! I had made a fuzz, and a basic compressor type thing (I’m not sure if it works similar to how a normal compressor would). I had plans for some other things, you can see the code on my site http://www.codeoclock.co.cc. Now that I’ve found this blog I’ll be referring back to the resources here a lot more!

  3. Richa says:



  4. mhampton says:

    Just discovered Pd and Arduino recently and I started thinking about combining them so I really appreciate your posts here.

  5. TomasMiguel says:

    hello Pierre, Im starting with Pd and arduino, I’m using some of your effects with amazings sound results. I’m really gratfull. –
    i listened your music and i find very cool.

    The record name Error de paisaje was made testing your Bold As Love and Polysinth.

    Thanks for all, and go on-

    from Buenos Aires, Argentina.

  6. Butcher says:

    Hi, great job. I’m interested to do something similar. But first I’m looking for a quite good (not so expensive) soundcard full compatible with linux. Could you tell me which one do you have and how is it (latency, support, price)? Or if you know some other good ones?

    Thank you

    • Hi, I’m using an external E-MU 0404 (USB). It is pretty cheap compared to the rest.
      Whatever you buy, make sure you do a little research on the web first to see if there’s any feedback on potential problems in Linux.

  7. coloscope says:

    Hi Pierre,
    first of all thank you for your blog, I’ve learned a lot from it to design my own multi-effect guitar patch : http://coloscope.wordpress.com/2012/11/22/racko-sifredi-rack-deffets-pour-guitare-sous-pure-data-beta/
    I hope you’ll keep on adding new stuff, I’m sure a lot of people are interested.
    Cheers from Strasbourg !

  8. tkessler says:

    Nice, are you using ffado to recognize your interface? I am having trouble using mine in Tango Studio…how do you make it work with an alsa driver?

  9. I am *loving* all the work you’ve done and written up here. Please keep it up. I’m hoping to get a second Pi and try it for some live mangling – the first problem, aside from getting past the newbie stage with Pd, is the reamping thing. Are you really still pretty happy with that Shure transformer? I’m surprised it works well enough for this.

  10. bufalo1973 says:

    I was thinking about using a Behringer Guitar to USB adapter to do the same thing. Maybe it would be a simpler design.

  11. Hello j’ai suivi ton travail et me suis lancé moi aussi. J’ai faits un patch PD en utilisant une autre solution pour mettre les effets en série dynamiquement. Tu peux récupérer ça à http://leyoy.free.fr/Guitareffect.zip et me dire ce que tu en penses …

    • Salut, j’ai pas le temps de regarder en détail pour le moment, mais ça a l’air intéressant ! Pour ton info je vais bientôt mettre en ligne un post sur distortion bien meilleures que la fuzz avec un clip.

  12. Bruce Boyes says:

    Wow, just discovered your blog. Looks really interesting!

  13. I enjoy what you guys are usually up too. This kind of clever work and coverage!
    Keep up the very good works guys I’ve incorporated you guys to my blogroll.

  14. moverdrive says:

    This is great stuff. I’m still pouring over it. Thanks for sharing this! Hope to put it all to good use in live applications and recording.

  15. André Bispo says:

    Hi Pierre!
    Great job and website you got here. I’m just starting out with Pd, and I’ve been loving all the effects you made – my personal favourite is the phase vocoder polysynth. So sweet!

    I was primarily interested by Max/MSP and Pd due to Jonny Greenwood from Radiohead. There’s a particular patch that he uses (for a stutter effect) that would be nice to replicate in Pd. There have been some versions of it on Max/MSP, but not yet on Pd.

    The main problem, I think is the non-existence of a equivalent object in Pd for tapin~ and tapout~
    There exists delread and delwrite, but where as in the tape out you can specify which chunk of audio you wanna listen to, from the delay line, I don’t think you can do that with delread. What do you reckon?

    Thanks a bunch for the website, once again!


    • Hi André,

      I’m not really convinced that what he does in the video is similar to what Greenwood uses. To me it looks and sounds like a regular delay with feedback (and this can definietely be achieved with delread and delwrite in Pd).
      Greenwood’s effect plays bits of sounds at different points in time, repeats them for a random number of times, and even plays some of them backwards if i’m not mistaken.
      The proper way to replicate this in Pd would be (I think) to use one or two tables as buffers instead of delay lines and write into them continuously. you could then read anything from anywhere in the tables.
      I’ll give it a try when I have time…


      • André Bispo says:

        Yeah, when I actually saw how it sounded after posting the video I got that impression too. I’d seen some good versions of it, I thought this was one – apparently not.
        Cool, will look forward to it.

  16. Joseph says:

    Hi Pierre,

    That’s very interesting project and inspiring one.

    Have you played optimizing the raspberry linux to
    improve the sound latecy – real time kernel and bit
    of configuration tuning?
    I can help eventually, if you’re interested.
    I’m thinking of building one of these setups
    for myself (beginner guitar player myself).

    Keep up the good work.

  17. Fede says:

    Nice setup!

    Do you mind telling us how you achieved the effect you show as at 00:50 on the video? It sounds like an organ.

    Congrats and keep it on!

  18. Fernando Quiros says:

    Nice guitar effects! I’m checking your other posts too. Thanks for sharing 🙂

  19. Autumn says:

    I must thank you for the efforts you’ve put in writing this blog.

    I’m hoping to check out the same high-grade blog posts from you later on as well.
    In fact, your creative writing abilities has motivated me to get my own site now 😉

  20. Hello, thank you for the post! I’m trying to do some similar work with the Raspberry Pi B+ but I have some problems with the USB audio interface, the mic input signal have a tone and I don’t know how can I solve that. I’m using this interface: http://kb9mwr.blogspot.co.uk/2013/01/raspberry-pi-and-sound-input.html

    Thank you very much.

    • Hi, I have tried a similar interface and the sound was really bad. I’m not sure what you mean by “have a tone”.

      • When I put in PD a simple ADC to DAC it sounds the mic input + a tone of 500Hz more or less. But doing the same in my computer it works ok. So I don’t know why this sinusoid sounds, I think it could be because of something wrong in the configuration. I have tried everything and don’t know what more can I do.

        Thank you very much!

      • What do you plug into your ADC ? A guitar or a mic ? The tone could be feedback.
        Make sure your soundcard works ok by trying a simple [phasor~ 440]–[* 0.2]–[dac~].
        Make sure you’re running Pd at the correct sample rate for your soundcard, and try high values for the audio buffer first.

      • The problem is that the tone is present even without anything connected. When I plug in the guitar or some line input, then come out the signal plus the tone. The phasor works ok, the problem is the input. Can be something about the configuration?

      • With the alsamixer the input works ok, it’s a problem of pure data. I try to change block size, delay and sample rate but it have still the tone. Any suggestion? Thank you.

      • No, sorry, it’s hard to tell what is going wrong.

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