Speculation on Raspberry Pi computer

Discussion in 'Digital & Modeling Gear' started by Shane Sanders, Mar 1, 2012.

  1. Shane Sanders

    Shane Sanders Supporting Member

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    Anyone else really curious about what kind of DSP "pedals" might spring up around the Raspberry Pi computer that costs around $35? I can see this finding its way into some unique home-made type enclosures with hand-rolled DSP on it. I can also imagine some awesome C-Sound stuff happening on it. Your thoughts?

    Quick video overview on YouTube:
    http://youtu.be/6BbufUp_HNs

    http://www.raspberrypi.org


    https://plus.google.com/u/0/107182636490355951240/posts#107182636490355951240/posts

    http://www.element14.com/community/groups/raspberry-pi
     
  2. burningyen

    burningyen Vendor

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    Looks like a fun little card! Wish I knew how to code in Linux. I agree that this would be a great platform for an open source DIY MFX community project.
     
  3. Pietro

    Pietro 2-Voice Guitar Junkie and All-Around Awesome Guy

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    At the very least, it might power some sequencers/MIDI controllers, etc., if it's not up to the task of digital audio. Who knows?!?!

    It looks like something very very cool and interesting...
     
  4. Shane Sanders

    Shane Sanders Supporting Member

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    I looked around a bit today, and there is a Debian flavor of CSound. I know CSound will do real-time stuff on older computers, so there is hope that something might emerge right away. Fingers crossed!
     
  5. mpr

    mpr Member

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    Too weak for serious things, I think. More interesting would be an open dedicated audio platform, something DSP based.
     
  6. shasha

    shasha Member

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    This is what I'd be thinking too. Really interested in the I/O section of this. I'd imagine that MIDI would be pretty simple for it to handle.
     
  7. Shane Sanders

    Shane Sanders Supporting Member

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    This is not my area of expertise at all, but I was able to get hopeful about its realtime DSP processing power from learning that it has an ARM1176JZF-S 700 MHz processor. Take a gander at some of the devices which use ARM chips at the bottom of that Wiki entry, and it seems likely that this device would easily be able to support a few effects in realtime. I'd be thrilled to just see a lot more reverb or delay units coming out that had GUIs we could manipulate with a mouse. Plus, Linux would be 64 bit, which can't hurt its chances of being awesome.

    Again, I don't know much about hardware at this level, but if an iPod can do it, the Raspberry Pi probably can, too. I'm stoked to think about what might come about.
     
  8. Bakachan

    Bakachan Member

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    For this you can use an Arduino board, it's even simpler to use/program/run, there's already a good midi library that i'm using for creating a small router/looper.
     
  9. MKB

    MKB Silver Supporting Member

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    Thanks for the post, I hadn't heard of this gadget, but I want one bad. It would be great for test fixturing around our lab at work.
     
  10. mwc2112

    mwc2112 Supporting Member

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    It uses a fairly popular processor (ARM) that is employed commonly for DSP processing, especially in mobile devices. While it may not power a state-of-the-art mult-effects unit, I think it could handle discrete effects (or maybe even 2 or 3 simultaneous effects).
     
  11. shasha

    shasha Member

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    Interesting. Thanks for the link.
     
  12. mpr

    mpr Member

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    You can do anything on any CPU, but general purpose ones such as this will be more limited, especially with low clock speeds. DSPs with their signal-processing-oriented instruction sets can do more in a given clock speed. Cellphones have job-specific processors (or sub-components) for the heavy lifting; stuff like 3D graphics, video decoding/encoding, etc.

    If a 2nd gen iPod Touch could do something equivalent to the HD500 then it'd start getting interesting, but I don't think that's the case.
     
  13. shasha

    shasha Member

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    I'd imagine that latency and bandwidth would be the biggest limitations for processing realtime audio since this isn't an audio optimized DSP.
     
  14. Scrutinizer

    Scrutinizer Member

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    Just placed my order for a Raspberry Pi Model B. Received a confirmation email with the expected ship date: 8/14/12.

    Hopefully they can ramp up production soon to reduce the wait time.
     
  15. Shane Sanders

    Shane Sanders Supporting Member

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    06/12/2012 for me, but I ordered earlier. There are some fun threads on the Raspberry Pi forum related to cases and such. Fun stuff.

    -S
     
  16. Shane Sanders

    Shane Sanders Supporting Member

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    Mine is finally here. Can't wait to get home and begin loading Debian on it.
     
  17. Scrutinizer

    Scrutinizer Member

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    Got mine a while ago, have it up and running with Raspbian Wheezy. I am impressed with the number of packages that are available for Raspbian. I was able to successfully install and run:
    Jack (provides low latency audio and midi connections)
    QJackCtl (utility to control Jack)
    KMidiMon (midi monitor)
    Pure Data (graphical programming environment for audio/midi processing)

    Getting MIDI in and out of the RPi was very easy. I had to install a driver for the MidiSport 2x2, but it was simple plug and play after that.

    The RPi is not very fast compared to a modern desktop PC. But it does have a lot of features for a $35 board: HDMI output w/ support up to 1920x1200, composite video out, analog audio out, Ethernet, two USB ports, and GPIO pins.
     
  18. prinspatrick

    prinspatrick Member

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    +1!
     
  19. Scrutinizer

    Scrutinizer Member

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    I agree, the Arduino boards are perfect for hardware MIDI projects. Keep in mind that long sysex messages are problem if you use the Arduino MIDI library. The library uses a fixed-size buffer to capture the incoming sysex message, so messages larger than the buffer size will be corrupted. Rarely a problem, but could be if the device is routing messages between an AxeFX<>AxeEdit or AxeFX<>Mfc101.

    One thing the Aduino can't do easily is act as a USB host. I bought a Mega ADK board, which has the USB host connector and support libraries, but getting the Mega ADK to recognize & communicate with USB MIDI devices is not easy. Getting it to work with a USB hub would be very difficult. I've abandoned my plan to try this, it just does not make sense now that the RPi is available.

    Yesterday I was able to compile and install Pd-Extended on my RPi, following these instructions. I could have downloaded the package he had built, but I wanted to see if my RPi could compile the huge software suite.

    Pd-Extended adds a pile of functionality to PureData. It's like Max/MSP/Jitter with a huge library of externals. And it's free software running on a $35 board. Amazing!
     
  20. Lightcraft

    Lightcraft Member

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    Interesting thread...is anyone still playing with the Pi for audio work?
     

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