Onde Magnetique Will Wow And Flutter Your Ears

[Scott Campbell] built a cassette-based synthesizer that sounds exactly like everything you’ve heard before. The sound generation comes straight off cassettes, but the brainbox of this synth varies the volume and pitch. It’s called the Onde Magnetique, and it is what you would get if you combined a Mellotron and Ondes Martenot.

The key component for the Onde Magnetique is a Sony cassette recorder that conveniently and inexplicably comes with a ‘tape speed input’ mini jack. By varying the voltage sent to this input jack, the speed of the tape, and thus the pitch of the sound being played, is changed. Build a box with a touch-sensitive button for volume, and a few tact switches for different speeds, and you have an electromechanical bastard child of a Mellotron and an Ondes Martenot.

By itself, the Onde Magnetique produces no sound – it only controls the pitch and volume of whatever is on the cassette. [Scott] produced a few single-note cassettes for his instrument, with ‘voice patches’ including a flute, choir, and a synth. With the CV and Gate input, these sounds can be sequenced with outboard gear, producing the wonderful sounds heard in the video after the break.

29 thoughts on “Onde Magnetique Will Wow And Flutter Your Ears

  1. Well, it’s a hack, all right. Unfortunately it doesn’t have either of the distinctive features of the Mellotron OR the Ondes Martenot. The Mellotron is fully polyphonic, this can only play one note at a time. The Ondes Martenot has a continuous glide control, which I don’t see anywhere here. Looks like a lot of work for a toy.

    1. Wow. What a miserable first post. Everyone always warned me about HaD’s horrible comments section but this just takes the cake. Never coming back to this website again!

        1. Actually just a little thought on tape player speed… If you put the tape on fast-forward and held in the play button, you could often hear the tape sped up. So it must be possible to play a tape with the speed governor disengaged. So there’s a possibility. Just need a bit of mechanical dicking about with.

      1. He did say “it’s a hack alright”, just that it doesn’t fully resemble it’s namesakes.

        Still, there are plenty of monophonic synths about. Having to use a continuous tape, with no auto-rewind like a Mellotron does, will I suppose limit it to certain types of sound. Very lucky finding a tape player with a speed input though. Maybe it’s meant for dictation, perhaps some of the micro-cassette dictation machines have that feature, if they did it would be a good way of expanding it’s polyphony. And micro-cassettes would be easier to keep as a sound library. The cheezy sound quality might end up being a feature.

        You’d probably need a microcontroller to do that, have it read a keyboard (or CV input, or MIDI, or whatever) then prioritise for as many notes as you have tape recorders. Did any early non-computerised synths offer polyphony, other than using the method of one oscillator per keyboard key? How did they arrange routing keypresses through oscillators to output? I’m imagining some horrible thing with telephone relays.

        I wonder what the market’s like for second-hand dictaphones? I can see them being obsolete now mobile phones do the same job much better, and for no extra cost. But do they wear out and break quickly? I wonder, too, how an average cheap walkman would take to having it’s motor PWMd. I think the speed governor in those is partly mechanical, so maybe it’d be difficult.

        This is certainly cheaper than a Mellotron, and much more easily available, if you can get the tape players. I can see it finding a nice little niche somewhere in some esoteric musician’s instrument collection. Maybe Quintron would like one.

        1. You know “Mark” we are starting to suspect that you have a diagnosable mental illness, you certainly are pathetic. BBJ has more in common with you than anyone else on HAD.

          1. Paging Benchoff for an IP check….

            You know you can’t say “we” when you’re just one guy and his sock puppets.

            Ah now I’m involved in this stupid thing, the gang’s all here. I’m going now bye!

      1. Both, actually, but that’s beside the point. If the comments are to be limited to “great job, cool project”, then I’m out of here. If you’re going to name your project after something cool, you’re setting the bar yourself.

      2. Oh, and yes, I DID make something better, about twenty years ago as an assignment for a musical acoustics class. But considering how personal people get in their attacks here, if you think I’m going to post anything about it here, either you’re delusional or you think I am.

    2. Oh yes… continuous glide control… It has a force-sensitive resistor, the bigger button to the left. So that’s pretty much the same thing. Or failing that you could hold down a key and twiddle one of the potentiometers. So it has continuous tone, and I suppose could be tuned to any old scale you liked.

      It sounds very good for what it is, works well, the tape player is obviously well made, something Sony used to be good at. Would’ve been nice to hear an actual flute instead of a synthed one, perhaps that wouldn’t have sounded too well. This machine has quite a few features you wouldn’t expect, he’s really put the work in for what’s a simple idea.

      1. The force-sensitive resistor is for volume, not pitch. Pitch is controlled by the rotary controls adjacent to each button. So yes, you could hold down one button and twiddle its pitch, but the knobs are small and this would be a very coarse control.

        I agree that [Scott Campbell] has put a lot of work into getting the most he possibly could out of a variable-pitch tape recorder. I just question whether it was worth the effort. On his web page, [Scott] is attempting to sell this as a product. I don’t know where he plans to source the recorders from, since I seriously doubt that Sony still makes them, for one thing.

    3. Try watching the video since you have no imagination or reading comprehension. You may want to have your unfulfilled, alienated girlfriend to leave you a letter to tell you that it does have a glide control, dipshit. Polyphony is only limited to the number of cassette players since it can be split to a snake of 1/8″ adapters. At least that is what I was able to suss out from the demo video alone.

      1. Thanks, Abby, for extrapolating something I said into proof of my sexual inadequacy. I could have paid a professional psychologist lots of money for that, but you provided it for free!

      2. Oh, and in response, I think I comprehend both the text and the videos just fine. And no, you can’t just plug in a whole bunch of cassette players and get polyphony, because they would all be playing at the same speed. Yes, you could record a different pitch on each one, and thus be able to make all major chords or all minor chords, but this does not polyphony make. Furthermore, I don’t think that the speed control on Sony dictation recorders is calibrated, so the likelihood that multiple recorders would track each other well is low.

    1. I’ve got a friend who collects the Korg Volca range. IIRC it’s an old range of analogue-ish synths (I think the sound generators are analogue, with envelopes, filters and all), that Korg re-launched recently. They’re about 70 quid each (IIRC). Nice start to a collection and a cheap entry into real synths.

      They have a jack plug input for the little inbuilt sequencer, one click of 15ms to advance it one place. My friend composed mostly, before that, on his Sony PSP. But how to connect them?

      In the end, I wired up a simple stereo jack to two mono sockets. Put a click track (he managed to find some 20ms or so clicks on an Internet sample bank, so no need to even make them) on the left audio channel, and the music on the right. Feed the clicks into the Volca, Bob’s yer uncle! Quite proud that it actually worked, without needing any amplification, the PSP’s headphone output happens to be good enough. I suppose it was only expecting a volt or so.

      Anyway my reply to you, check out the Korg Volcas. There’s 4 (last time I looked), one for bass, one for normal, and 2 I’ve forgotten. There’s also mailing lists dedicated to them. A lot of synth fans are excited, buying them just for toys.

      There’s an endless amount of tweaking you can do with the filters etc. Real twisty knobs, but routed to the sound circuits digitally, so each knob can have several functions, depending on the mode. Still, far as I know the sound is generated by real
      analogue oscillators and filters etc, just controlled digitally. Subtractive synthesis, I’m told.

    2. I build noise devices so let me suggest a few resources.
      Fun with Sea Moss is a cool tutorial on using CMOS chips to create sounds- it’s a good starting point-

      After that, check out Ray Wilson’s Music From Outer Space for some more advanced projects, especially the Weird Sound Generator-

      For something a bit more esoteric and customized, check out the lunetta forums at electro-music.com. Lunettas are DIY open patch synths that use basic digital logic gates to create complex sounds, rhythms, melodies and sonic textures.

      My lunetta is my favorite project ever! I have less than $100 total in parts and materials, and it makes sounds like this-

      Finally, Elliot William’s logic noise series here on HAD is very well presented and offer plenty of background and applications.
      Have fun and get noisy!

  2. This is interesting, I was reading about wire and tape recorders only yesterday, two of the old books from that site I posted the link for this week. If you could make a nice clean loop of wire and have one for each key they could move at different speeds to get the notes, this would let you have any scale you like. You can start with the plastic tape and use that to load the wires so that your instrument is more robust. Nice sound.

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