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Meeblip as an independent instrument

ArvidArvid Posts: 25
edited August 2012 in MeeBlip

Hey guys,
As an intern at Meeblip/CDM I'm working on quite a special design project: To demonstrate the power and flexibility of the Meeblip, I'm designing a self contained electronic instrument with the Micro board as the centerpiece. There's a lot going on, and in this post I'm trying to make clear what the design considerations are and where I'm at. Any questions? Fire away.

This new instrument I'm designing, should be a instrument which works in acoustic setting, say, together with an acoustic guitar and a singer. While there have been electronic instruments that work in this setting, like a portable piano or the Omnichord, they are either trying to emulate acoustic instruments or are considered as toys. I think synthesizers shouldn't be exclusive to amplified settings, so my quest is to create a independent serious electronic instrument.

The most immediate problem here is sound; 1.the instrument should be loud enough 2.the instrument should sound 'full' and 'pleasing'. The first one is easily solved as both speakers and amps have been getting smaller and smaller with increasing power. But the second problem is harder to deal with. I feel this is where many others have gone wrong, usually just slam a loudspeaker into a plastic casing and call it a day. Well, sound is produced in a system, and when you neglect something like the acoustic properties of the casing, it will sound like crap. This is exactly the difference between a €2 recorder and something like a clarinet. (I wonder whether or not the big companies who make the self amplified keyboard consider the acoustic properties of the encasing?) As I barely know anything on this topic, would anyone have some pointers on how to do this right?

The cheapass 5V speaker/amp I'm using for prototyping

The usual way to 'thicken' the sound in electronic music is to add effects. A simple waveform might be made more interesting by doubling it with a delay or deforming it with some distortion. I think a simple delay would work it's magic into this device, so I've already made something based of the PT2399 chip. Quite lofi, but a nice touch it is.

The monstrous breadboard with strange caps

Next to sound, the other factor what makes an instrument is its interface. This will have a huge impact in what kind of music will come out of the device, like how an Eigenharp sound differently than a midi keyboard, even while its controlling the same synth. The easy way here would be to just slam a keyboard on the Meeblip. But when going for a electronic instrument, you might want to have some of the advantages of electronics into the input method as well. I'm thinking of a sequencer/arpeggiator here. But now we've created another issue; you'd want to have an expressive musical instrument and a sequencer is far from that. To make the sequencer expressive, I'm thinking of controlling it by velocity sensitive pads. So you set the pattern in advance, and by drumming the pad, you will go to the next step. This allows you to have both human timing and expression, while having electronic pitch control. (I imagine this as being like a hang drum.)

I've been debating on the shape of the sequencer and hanging between the analog linear or circular layouts. I think I'll prototype both and see which feels most natural.

The instrument should be able to make music without any wires connected, so it doesn't just need the input device, and the speaker/amp, but it also needs a power source included. I'm not yet sure how much energy my device will pull, but I guess a li-ion battery's are the way to go.

The last, but certainly not least part of this project would be it's design. To be a serious musical instrument, it certainly needs to look like one. I feel like the way to go here is not to go for something entirely new, but to ride the wave of retro synth aesthetics. This will make clear what category the instrument is to both synth users and people looking for something new.

Please feel free to contribute or comment on any of my thoughts. Updates will appear here when they occur!

The workspace with various experiments


  • Arvid -

    Way to see a need and work towards filling it! I'm excited to see what develops.

    I think people sleep on wood. For a speaker cab it's relatively ideal - it's not brittle, it's got some ability to change with the environment (humidity!), and it can act as a "cushion" for the nasty high frequencies that make plastic sound terrible. My current favorite speaker is a Dayton Audio 4" driver inside of a small cab made from birch boards.

    A big problem with small drivers is the fact that the cone can't travel all that far - this goes away around 4" or so, but you need to make sure you leave enough room for low-frequency driver travel. If this is confusing go see if you can find a video of a subwoofer in an acrylic casing (like this one )

    Was that helpful?

  • ArvidArvid Posts: 25

    yes, interesting.

    For the casing I was thinking of either laser cut wood or a 3d printed hard plastic, where the first one would have an advantage in material, where as the second could have an advantage in geometry.
    Talking about the nasty high frequencies of plastics, the un-uniformity of 3d printed materials might just be helping in this case. Including some 'high' traps might be a cool experiment as well.

    I'm not really sure though how low I should go in resonant frequencies. I'm not making a bass instrument, but rather a melody or chord-playing device. So a lower limit of 150Hz should be enough. Though a lack of low frequencies will always make something sound thin...

  • FyrdInstrumentsFyrdInstruments Posts: 1
    edited August 2012

    Hey Arvid,

    Nice project ! I have two remarks:

    • sequencers/arpeggiators can have a kind of "human" feel, just need a proper programming :) It's not the easy way but it can save a lot of money when producing the device (save the velocity sensitive pads) ! By the way, I'm interested on how you think to design velocity sensitive drum pads ? I mean, do you plan to make some kind of custom silicone drum pads ? I'm interested by this technique and don't know anything on it (cost, soft for designing the parts, etc).

    • for the casing, you can mix two materials (like wood and alu). It's nice and not so expensive as you save the cost of bending the metal sheet. That's what I choose when I designed the MCP. If you have some questions about how I made the enclosure box, feel free to ask !

    Keep up the good work !

    Julien Fayard

  • ArvidArvid Posts: 25

    Some good idea Julien. The pad thing is something I breaking my neck on right now. I have been experimenting with some piezo's, but it doesn't seem to be producing the desired results... Pressure sensitive pads don't seem to produce the desired response as well. Might be trying something mechanical next, where I'm measuring time difference between touching the button and having it completely pressed...

    For the casing I'm taking a look around for facilities here in Berlin. I would really love to use either 3d printing, laser cutting or CNC milling on this project :) (and next to being cool, those techniques should produce high quality parts.

    This is what I was working on now, using two coupled multiplexers for the sequencer. (using just four steps now due to a lack of jumper wires, could easily be up-scaled to 8 steps)

  • meeblipmeeblip Posts: 558 admin

    Looks nice, Arvid.

  • ArvidArvid Posts: 25
    edited August 2012

    First experiment: powering the Meeblip and amp from arduino 5V thru usb (which will later be replaced by a battery)

    Meanwhile I've been building a plywood case and connecting the electronic parts. The plywood was just too thick for the potmeters so I had to do some extra work on the front panel which sadly didn't turn out to pretty.
    I've finally got everything together, but in hindsight not in the most optimal way; way too many poorly soldered wires...

    After correcting some faulty pins at the multiplexers, it functioned like this:

    It's obvious that some wires are loose, but the huge mess of wires I have to check right now, are making me considering doing this whole thing another way. Does anyone have suggestions?
    My thoughts were to either get this thing on a big pcb, or use some ribbon cables to neaten it up.

    The next issue is that I'm still looking for the right drum pads to use. My experiments with piezo's weren't fruitful, so I'm looking into velocity sensitive things now, either to modify a normal button or making my own out of silicon... Suggestions are welcome!

    An interesting thing is that at one point, I was powering the Meeblip through the MIDI port. The power cables slipped out of their sockets, but somehow the meeblip was still running.

  • ArvidArvid Posts: 25

    and now, with knobs!

  • ArvidArvid Posts: 25

    A long pauze... and then:

  • ArvidArvid Posts: 25

    a demo of the thing 90% finished

  • ArvidArvid Posts: 25

    yay, a bit more progress!

  • ArvidArvid Posts: 25

    Version 0 of the instructions!

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