A new and improved magnetic cello

Over the past few months, [Magnetovore] has been working on his magnetic cell project. It’s a very interesting instrument that seems right out of the electronic music explosion of the 1970s. Now, he’s ready to share his invention with the world, and we wouldn’t be surprised if we see this instrument being picked up by a few avant-garde musicians in the next few years.

Last September, we were introduced to [Magnetovore]’s magnetic cello. The original version used four ribbon sensors for each of the strings and had completely analog electronics, leaving us wondering why this cello wasn’t invented in the 70s. The new version of the cello keeps the analog electronics that sound remarkably like a real acoustic cello, but does away with three of the ribbon sensors. Now the cello has a single ribbon sensor being used as all four strings – to change which string is played, the musician just has to press a button on the ‘bow’.

There is a drawback to using only one ribbon sensor; it’s now impossible to play two strings simultaneously as on an acoustic cello. The electronics in [Magnetovore]’s original magnetic cello were monophonic anyway, so we’ll chalk this design change-up to reducing component cost.

After the break, you can check out a trio of very talented cellists playing [Magnetovore]’s magnetic cello. There’s the classic Pokemon Center theme, the Mario Bros. theme, as well a Bach minuet and a crazy improvisation showing off what the magnetic cello can do.

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Slide rule for musical scales

For all those engineers who dabble in music [Magnetovore] has your back. Musicians simply must know their scales and he came up with a papercraft slide rule for major and minor scales.

The system is very easy to use. He’s uploaded PDF files that let you print out the mask for the top layer and bar chart and directions for the bottom layer. The top layer is laid out like a piano keyboard, with windows for each key and a couple of windows to identify the major and minor scales being displayed. Just slide the mask until each key is a solid color. The color codes show the tonic, third, and dominant for each key so you know where to start. In the video after the break you can see how it works by playing all of the non-black keys in order. But wait, if you order now you’ll get the slide rule for Cello scales at the same low-cost; free!

This is a fun quick-reference, but you really should know your Circle of Fifths. Continue reading “Slide rule for musical scales”

Why wasn’t this magnetic cello made in the 70’s?

[magnetovore] made himself an electronic cello. Instead of pulling a few cello samples off of an SD card, he did it the old school analog way. The finished build is really impressive and leaves us wondering why we haven’t seen anything like this before.

[magnetovore] uses a permanent magnet to play each ‘string’. A lot of details are in this post and [magnetovore]’s provisional patent (PDF warning). From what we can gather, each string is a resistive ribbon sensor connected to a voltage controlled oscillator. The output of the VCO is sent to a variable gain amplifier that is controlled by a coil of wire and the magnetic ‘bow’.

From the video (after the break), [magnetovore] already has an amazing reproduction of the cello sound. It’s a bit electronic on the lowest parts of the C string, but with a little bit of processing it could definitely pass for an acoustic instrument. We’re left wondering why we haven’t seen anything like this cello before. VCOs and VGAs were the bread and butter of the old Moogs and even the ancient ondes martenot. Ribbon controllers were being attached to electronic instruments back in the 50’s, so we’re really at a loss on why a magnetic cello is new to us. If any Hack A Day readers have seen anything like this before, leave a message in the comments.

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