Ebow? What's it and how does it work?

[Baran Ismen]

This one is something that I've been permanently avoiding to get one. Now that I've got simple circuitry-building experience, I think I can build one for myself. But first;

1- How does it work? I think it's sort of the magnetism that vibrates the strings permanently, right?
2- Would it be worth the hassle to make one?
3- How does it sound focused on a single string as the Ebow's I've seen are big enough to cover multiple strings but somehow only the played string sounds.

[FiveseveN]

Are you familiar with Sustainiac / Fernandes Sustainer systems? It's basically the same. There's a hundred-page thread somewhere that goes into the details.

[Mark Hammer]

E-bows preceded sustainers, historically.  For me, their chief virtues are that they don't occupy a space on the guitar that could be taken up by an actual pickup, and can be gradually introduced or faded out by approaching and withdrawing from the strings.  Sustainer systems generally require fixed placement near the end of the fingerboard, though if the guitar is routed to have space for a double-coil humbucker pickup, one coil slot can be the sustainer coil and the other an actual pickup.  Their disadvantage is that they take your picking hand out of commission, in order to hold the E-bow.

From a DIY perspective, sustainers are easier and more feasible, since the electronics can be installed into the control cavity and don't have to be miniaturized to fit in your hand.  Some folks like to provide power to on-board electronics via cables or even rechargeable batteries.  Anything you hold in your hand would require an enclosed power source, because trying to use one that is connected to an external power source (as opposed to a bunch of internal AAA batteries or rechargeable Li-ion) would seriously interfere with playing.

The two approaches each have their advantages and disadvantages, as commercial products.  But from a DIY perspective, stick with a sustainer.

[amptramp]

There is nothing new under the sun:



If you look at the violin, there is a thin brass rod that comes from the chromed motor drive on the right to a white felt ball just over the violin where the bow would normally be.  The upper casting of the player piano section says 1912 on it, the year the casting mold was made.  This is the mechanical precursor to the e-bow.  Player pianos were common, but this was a player piano/violin that was rented out to taverns with the owner of the instrument and the tavern owner sharing in the proceeds.  At the right of the mechanism is a coin slot.  This predated the juke box but served the same purpose.

In this case, the felt sphere is rotated by the motor and brought into contact with the correct string by the aiming mechanism behind it.  The piano section is behind all of this.  The player piano rolls are stored in the bottom and the roll reader is shown with the rolls strung between the drive and dummy spindle.

There were other devices of this type that has pianos, violins, drums, and any other instruments that can be automated.

Here is another one with drum, triangle and xylophone with the instruments in the top cabinet and the player roll reader in the bottom:

[Baran Ismen]

Are you familiar with Sustainiac / Fernandes Sustainer systems? It's basically the same. There's a hundred-page thread somewhere that goes into the details.

No, sir. But I've googled it now and both seem to be separate pickup sets with their own circuit board. I think Ebow is the mobile version of it, with the same principle tho.

[R.G.]

How electromagnetic sustainers work:
A guitar string is a mechanical resonant circuit. Put energy into it by disturbing it in some way, and it rings/oscillates mechanically. As it rings/vibrates, the energy leaks out as sound, air friction, friction of moving the bridge and/or fret, things like that. Eventually, all the energy leaks out and it stops moving.
You can feed energy back into the string and keep it moving. Using a pickup and amplifier/speaker and holding the sting up to the speaker puts energy back in by the air vibrations from the speaker moving the string. The speaker can put enough energy back into the string to keep it going as long as you want. Note that microphone feedback is much the same thing, just not using a string and magnets.
You can also constantly put energy into the string mechanically. A violin bow does this, for instance.
You can do the same pickup+amplifier and arrange an electromagnet to put energy back into the string. This is the ebow or sustainers. They arrange a magnet and coil near the string so that when you drive the coil with the output of an amplifier, the sustainer's magnet and coil pull/release on the string magnetically.  Beyond that, everything about ebow and sustainers is the mechanical arrangement of getting the magnet/coil near enough to the string to work and driving the coil with enough of the fed-back and amplified signal.
So you need a pickup, like already on the guitar, an amplifier, and a drive coil.

[amptramp]

There is another way to make a sustain.  Go to page 52 of the May 1968 Radio-Electronics:

https://www.worldradiohistory.com/Archive-Radio-Electronics/60s/1968/Radio-Electronics-1968-05.pdf

and you will see an article on vibrating wire filters and oscillators.  This differs from the usual sustain in that it drives a current down the guitar string and relies on a fixed permanent magnet that is not electrically driven at all.  BTW the next pages have a great tutorial on op amp circuitry.

[digi2t]

Even cruder version...





The small transducer (read "vibrator") unit clamps onto the headstock, and the larger floor unit controls the oscillation. In a nutshell, the vibrator can be set with the controller to vibrate (excite?) the strings at particular sympathetic or harmonic frequency. That leaves both hands free to move about picking, fretting, damping, and retightening hardware on your guitar. Tuners take an especially hard shit kicking during the exercise. I know. I have one. Used it once. Now collecting dust.

On the upside, my guitar sounded 20 years older after a 30 minute session. It's a great auditory relic'ing tool. My neighbour's wife gives it rave reviews, though, I've never seen her play guitar.

[garcho]

I like playing guitar with an ebow and slide. It's like a weird theremin but since I already know the fretboard, much easier to play (and cooler sounding).

[Rob Strand]

It was all discussed in these threads:

Ebow Exposé - Part III
Dec 2022
https://www.diystompboxes.com/smfforum/index.php?topic=129920.0

Ebow Exposé Part IV - RESURRECTED!
Dec 2022
https://www.diystompboxes.com/smfforum/index.php?topic=129995.0