Rocking a New Sound for Guitar

We’ve seen inventive sound hacking from [Jeremy Bell] before on Hackaday. You may remember reading a few months ago about how he invented a new way to produce that familiar effect DJs create when scratching records. By clipping samples from cassette tapes and stretching them across a set of short rails, he was able to refashion the audio pickup to glide over the tape at his fingertips. With a clothes pin wrapped in strips of foil teetering over a contact, he had a responsive tactile switch to aid in producing the cutting needed to carve out a beat.

Since then, [Jeremy] has been evolving this same switch concept and testing out new applications for it. The most recent of which he appropriately referrers to as the “Rocker”. With an electric guitar as a starting point, [Jeremy] uses a similar switching technique to bounce back and forth between two audio signals. The first of which being the sound produced in real-time by hammering on the frets of the guitar, and the second channel having a slight delay. By leveraging the glitchy effect created when switching between the two channels he is able to produce a sound all its own.

The prototype seen in his video is table-bound like the early versions of his Scrubboard, yet he’s able to play one-handed with the guitar and demo his device like a cake walk. It’d be fantastic to see this quirkiness and ingenuity taken to the level of his previous hack, leading to a stand-alone add-on for the guitar. Either way, this is yet another great example of sound play:

26 thoughts on “Rocking a New Sound for Guitar

  1. The most dexterous use of duck tape ever. That and the delay can be built into the axe. It’s high time the guitar become truly electric, not just passive pickup. My sustaining slide is completely self contained.

  2. Playing one handed is not hard. That said, the guy has rhythm and has obviously practiced with this technique, now just stick it on the guitar so he can go between.

    Cool Hack. Good Sounds. No ukuleles, I am impressed!

  3. he could also just use a mixer and play with the fader like a dj…but i guess that’s cool too
    i’ve always thought if you could set up mixer channels so that it would switch with a drumstick hit you could make the switching much faster
    imagine instead of his fingers it was drumsticks…of course you’d need someone else to play guitar but if you were just switching between two tracks you wouldn’t

    1. That’s a pretty good idea — you could make a fairly simple device that does much more complex switching using a little finger-drum-pad, a keypad, or even a small conventional keyboard as the “glitcher” controller and a microcontroller for everything else.

      A TIVA-C launchpad board has a two 12-bit ADCs that sample at 1 mega-samples each (and can be multiplexed over a bunch of input pins), a ton of memory and plenty of GPIO – so sampling, delay, key sensing, control logic etc. could all be easily packed into one little board that costs $13 and fits easily on the guitar itself.

    1. 1:20 in video “four beat delay” time depends on tempo. This is an impressive creative use of a simple switch to achieve superlative music, by the way, this guy is a very good guitar player/musician. If you like this you might check out Robert Fripp and his use of two tape machines (Fripperetronics) in the late 60’s/early 70’s for a less frenetic version of live/delayed – present/past music.

  4. SO it’s essentially a wet mix between the delay feedback and the audio sample. I’ve been doing something very similar but off a foot switch and pedal, the switch flips the effect on-off to reset the buffer. Mind you I’m just using an off the shelf Digitech GNX 3 and abusing logic of the effects to generate interesting sounds so I’m much more limited.

    However I do believe a foot pedal is a better fit for an effect like this. Then you can play with 2 hands.

    1. Actually it’s an A/B switch between the live audio and the same audio delayed by 4 beats, no feedback involved from what I understand from the video. By the way, Les Paul was doing this a long time ago (1940’s) using a disc cutting lathe with a delayed pickup tone arm behind the cutting head live in performance. He called it the “Paulverizer”. Les was an original God of the Hackers, he made his first electric guitar using a phonograph needle on the top of his acoustic guitar. He also invented multitrack tape recording for audio and the original video tape recorder, an inspiration to us all, may he rest in peace in hacker heaven!

  5. Thanks for your feedback everyone, and thanks to Sarah for this great writeup. I wanted to mention that I’ve been experimenting with these concepts for years, and I’ve found that the rocker design really takes advantage of your fingers’ dexterity to create precise rhythms that just can’t be matched by foot pedals or even pushbuttons. And yes, I’m definitely looking into mounting the rocker onto the body of the guitar. Also, one thing that I should have made clearer in the video is that the rocker has three positions: Live, mute, and delay. It springs back to that mute position when you’re not applying pressure to it, and that really helps to articulate rhythms that ordinarily would be handled by the pick. So in a sense, it’s not only creating that live/delay effect, it’s also picking up the slack that’s left by the strum-arm’s absence.

  6. No, it seems more like stomping the 4 beat delay (try getting the tech and drummer to agree how long that actually is for each song) while also hitting the mute pedal every time you switch. The very short mute while the rocker travels from side to side, I think, might be what delivers the very unconventional sound. I honestly can’t imagine tapping my delay box that accurately, even if it were just a temporary on switch and had the mute built in.

    All that said, my thoughts go towards MIDI triggers off of a drum machine output. If you have a live drummer, triggering from their snare or bass mic (filtered for the drum, trigger to a rolling timer to get X triggers per beat) could also be worked out.

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