Tech: Self-tuning guitar - is it possible?

Subject: Tech: Self-tuning guitar - is it possible?
From: Scrump
Date: 01 Mar 07 - 10:53 AM

Talking about tuning guitars in another thread reminded me of something I was thinking about a while ago.

Would it be possible to make a self-tuning acoustic guitar?

I'm not talking about one of those electronic gizmos that pretends a guitar is in tune when it isn't.

What I had in mind was some sort of electronically controlled stepper motors attached to the machine heads, which would move the tuning slightly up or down as required, to keep the guitar in tune as you play. The frequency of each string would be constantly monitored and if it was detected to be out of tune, the motors would adjust the strings accordingly. Of course you could programme it to allow for different tunings.

I can't be the first person to think of this, but I haven't seen any such guitar. So why wouldn't this be possible?

"If we can put a man on the moon, etc., etc...." :-)

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: dick greenhaus
Date: 01 Mar 07 - 11:08 AM

Some old pre-jukebox coin-operated music machines had fiddles that were self-tuning: the instrument was mounted parallel to the floor. Instead of a nut, each string ran over a small roller, and there was a weight attached the end of of the string to tension the string.

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: The Fooles Troupe
Date: 01 Mar 07 - 11:10 AM

I've heard of the idea before...


'but it was in tune when I bought it'...

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: GUEST
Date: 01 Mar 07 - 11:19 AM

you wouldn't be able to do vibrato or bends though!

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: Bill D
Date: 01 Mar 07 - 11:23 AM

It's probably 'possible', but these little servo-motors....you're going to put them where? Adding HOW much weight to the neck? And the keyboard/control panel for changing the settings for different tunings?

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: The Fooles Troupe
Date: 01 Mar 07 - 11:24 AM

"you wouldn't be able to do vibrato or bends though!"

Well.... small mercies....

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: Bill D
Date: 01 Mar 07 - 11:24 AM

indeed...'bends'! An override button? Sounds like Windows for guitar...*grin*

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: kendall
Date: 01 Mar 07 - 11:32 AM

This should come with every Martin. LOL

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: Scrump
Date: 01 Mar 07 - 11:40 AM

You're right Bill D - the weight is an issue. I guess the tuners could be inside the guitar at the body end, as opposed to the neck - there are some electric guitars that have this type of configuration (i.e. tuning at body end rather than head end).

Anyway, I'm glad the discussion is taking place. Maybe between us we could invent that Holy Grail, the Guitar That Never Goes Out Of Tune!

As for bending notes, etc., I'm sure there must be a way round that - need to think...

Remember this was primarily aimed at an acoustic rather than a gadget-laden electric - although the same benefits could apply to that.

I guess the monitoring interval could be programmed in, so you could make it check every minute instead of continuously. Then in between, you would be able to play normally.

Not sure how the monitoring would work yet though - that's a mjor challenge. It would need to measure the frequency of the open string when played. How would it 'know' you were doing this - any ideas from techie types out there?

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: George Papavgeris
Date: 01 Mar 07 - 11:45 AM

They make small, light, powerful motors for model planes; it should be doable, and the weight would not be prohibitive (an extra 4-500 gr perhaps).

They would be situated under the bridge, inside the body, and that is where the tuning would be done, like in some electric guitars without a headstock. Easy. Though there may have to be some sort of construction to minimise the dampening effect that the motors would have on the sound, being attached to the body.

Small keyboard on the top side, where the pre-amps usually are.

All that is easy. The killer is the power. These motors would consume power like nobody's business. Tw AAs or even a 9V battery wouldn't cut it; and that is where the weight might come into play. Unless...

...you could run the motors off Phantom power (and you plug the guitar into the amp with an XLR) - but that means the system would only work plugged in, which is only half the job done. Anyway, I think Phantom power would be insufficient in all likelihood, so back to the batteries. Unless...

...you plug it into the mains power. But the safety issues then take over, with 6 wires ready to fry you should something go wrong with the insulation.

You could of course install a tiny wind generator in front of your mouth to power it as you sing...

I'll get me coat.

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: George Papavgeris
Date: 01 Mar 07 - 11:46 AM

Scrump, to answer your last question: Sensor pads on the frets...

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: Bert
Date: 01 Mar 07 - 11:59 AM

I did see such a thing for sale one time. I think at Lark in the Morning. It attached to the head of the guitar.

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: The Fooles Troupe
Date: 01 Mar 07 - 12:35 PM

George

Run it on methane and eat lots of baked beans...

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: Mooh
Date: 01 Mar 07 - 01:21 PM

It's been done but it was unwieldy, expensive, and without much market. Memory might be doing a disservice now, but wasn't Jimmy Page an early endorser?

Peace, Mooh.

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: Grab
Date: 01 Mar 07 - 01:21 PM

I don't know about anyone else, but the very last thing I want one minute into a song is for my tuning to suddenly be tweaked! More realistically, it would be something you'd run at the start of the gig and then occasionally during, when you thought it needed it.

You can't rely on just sensing finger position - pitch depends too much on finger pressure, and there may be intonation-related issues as well if you're switching between playing up the neck and down in first position. So checking the pitch of fretted notes is out. It's also likely to need repeated plucks to get the pitch, and having the player do it might not be ideal (consider the effect of striking the string hard so that it bounces off the frets), so it'll need some way of making the open string resonate. Probably an eBow per string would work.

Also, as George points out, motors and other gubbins in the bridge will severely impair the sound. That's "severely impair" in the sense that loss of all your limbs would "severely impair" your playing... :-/ It'd be acceptable on an electric because an electric doesn't require the bridge and top to resonate strongly, but it ain't never going to work on an acoustic.

The real solution - get yourself an Intelli IMT500 and tune it yourself.

Graham.

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: Bernard
Date: 01 Mar 07 - 01:47 PM

The real real solution - learn to do it accurately by ear! I've never needed any tuner gizmos, and can tune a damn sight faster than people fiddling with electronic thingies!!

;o)

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: GUEST
Date: 01 Mar 07 - 01:52 PM

I think they should tune them at the factory before they ship them out. It would save everybody a lot of trouble.

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: Lucius
Date: 01 Mar 07 - 01:54 PM

Mean tone, just or equal temperament?

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: GUEST,Dan
Date: 01 Mar 07 - 02:13 PM

Theres been a few different designs over the last ten years. Jimmy Page endorsed the transperformance system which was large and expensive.

This seems to be the latest, and is small and unobtrusive. Strictly for electric guitars though - http://www.tronical.com/index_normal.htm

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: GUEST
Date: 01 Mar 07 - 02:15 PM

Tuning by ear is peasy when you play on you own. But if you're playing with someone else a tuner lets you each tune quietly while the other does an intro - then be in pitch when you strike up. Bands like flook who wander about all the time peeping into eachother's ears, or others who constantly parp melodeons at eachother are much more annoying than those who quietly employ an electronic helper.

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: Songster Bob
Date: 01 Mar 07 - 05:12 PM

They sell a gizmo that combines a small motor and an electronic tuner, which you place on each tuning peg in turn, and it fiddles with the tension till it's satisfied that you're in tune. You could hook six of them up and it would work, but I'd probably only use it between numbers. While you're nattering on about the ancient agrarian field hand you learned the next number from, it could be tweaking you into DADGAD or some such tuning (like Baghdad tuning -- DADGAB*).

But the weight of the mechanism and the need for power (a wall wart at the very least) would doom it to failure for sure.

Bob

* Arabic is written right-to-left

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: Dave the Gnome
Date: 01 Mar 07 - 05:19 PM

...should come with every Martin.

Particulary Martin Carthy?

I'll get me coat as well...

:D

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: JohnInKansas
Date: 02 Mar 07 - 12:04 AM

a weight attached the end of of the string to tension the string ???

That keeps the string at constant tension, but if the temperature changes, or if a change in humidity changes the length of the guitar, you'd have to have something to tune the weights (????)

My suggestion would be to dispense with the mechanics and just run an electric current lengthwise down each string. The current can be controlled to warm the string just to the extent needed to drop the pitch to the correct point, assuming that each string is tuned just a little sharp before turning on the juice.

And I can get you a great deal on asbestos gloves, if quantities ordered are sufficient.

John

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: Gurney
Date: 02 Mar 07 - 03:21 AM

Rod Felton of Coventry used to swear he'd tune his box perfectly one day, and then GET IT WELDED.

If I was capable of making a rig for self-tuning, I'd fit it to a tailpiece.

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: bubblyrat
Date: 02 Mar 07 - 04:32 AM

One could take the concept a whole lot further---for example,harpists could have little motors in place of those little levers that they have to reach up and tweak. They could be initiated by the use of foot-pedals,like those of an electric guitarist, or why not have a metal helmet on the harpist's head, with electrodes implanted in the brain ?? And five-string banjo players? WELL !!-----They could have servo-operated 'Scruggs Pegs' for those complicated breakdowns ! Hydraulics would be a better option than electrics,actually----a lot safer, for a start !! The string tension could be altered by miniaturised hydraulic swash-plate motors , although the noise of the diesel hydraulic rig might impinge somewhat on the performance. On second thoughts, I think I"ll stick to Mr. Grover, and his chums----It"s a bit tedious sometimes, but much more natural,somehow !!

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: Grab
Date: 02 Mar 07 - 07:29 AM

On the retuning theme, has anyone tried a Variax?

It claims (and the website shows a demo) that it can electronically change your EADGBE tuning to behave like DADGAD or any other tuning you want. Of course, acoustically it'll still sound like EADGBE, but what comes out of the jack plug is in the altered tuning of your choice. It doesn't mention auto-tuning though, so I would guess it just pitch-shifts each string up or down as needed.

This beastie is *so* on my wish list - just need to save up a bit first!

And maybe that'd actually result in a Martin Carthy performance being 80% music and 20% chat, instead of the other way round.

Graham.

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: Mooh
Date: 02 Mar 07 - 08:24 AM

Yes, www.transperformance.com is the place to look.

Peace, Mooh.

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: Greg B
Date: 02 Mar 07 - 08:12 PM

Can you just imagine when it all goes terribly wrong, and
determines that all the strings are too low and begins to
tighten them all simultaneously?

Oh, the humanity.

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: The Fooles Troupe
Date: 02 Mar 07 - 08:40 PM

"determines that all the strings are too low and begins to tighten them all simultaneously?"


hmmm.... should be made compulsory on all banjos... now we just need to define "it all goes terribly wrong" as far as banjos are concerned....

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: Bee-dubya-ell
Date: 02 Mar 07 - 09:57 PM

A couple of bandmates and I were talking about the self-tuning guitar idea many years ago. One fellow, an engineer by trade, had an idea for a device using piezoelectronics instead of little motors.

Piezoelectric crystals, when subjected to an externally applied voltage, change shape. If an onboard electronic tuner were to detect an out of tune string, it would send current to a crystal incorporated into a fine tuning device attached to that string. That crystal would deform, placing (or releasing) pressure upon the string until it was in tune, at which point the current would cease. Of course, the amount of deformation piezo crystals undergo when subjected to voltage is very small, so the idea would probably only be feasible for fine tuning. The instrument would have to be reasonably close to in tune to start with.

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: The Fooles Troupe
Date: 02 Mar 07 - 10:08 PM

Well, that rules out most of us then...

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: JohnInKansas
Date: 02 Mar 07 - 10:23 PM

In addition to the difficulty of producing only very small motions, piezo devices - for useful mechanical output - also require rather high voltages. A tap on a small one, from a lightly spring-loaded "hammer" is sufficient to produce sufficient spark to light the burner on your camp stove, and to produce a motion of .008 inch per inch of crystal thickness (about as much as one can get without cracking the crystal?) may require on the order of 1500 V or more.

I can add a stock of dielectric insulating gloves (and maybe vests) to my store of asbestos ones - if order quantities are sufficient.

Alternatively, or perhaps additionally, small neon bulbs can be attached with the second lead simply hung out as an "antenna" so that the light flashes from the parasitic discharge when the device operates, much as some CB radio operators (a.k.a. "truckers") used to do so that their antennae would blink when they keyed to talk.

John

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: Seaking
Date: 03 Mar 07 - 03:43 AM

I must have one of these, I never tune my guitar and it always sounds fine to me....

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: The Fooles Troupe
Date: 03 Mar 07 - 08:32 AM

... lucky it was in tune when you bought it...

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: Seaking
Date: 03 Mar 07 - 12:56 PM

apparently it wasn't.. :- )

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: GUEST
Date: 03 Mar 07 - 01:08 PM

It may be better, as others have said, for the Mark 1 version of the STG to limit itself to making small adjustments, rather than expecting it to change from say EADGBE to DADGAD or whatever. This would reduce the amount of power needed.

The firmware could be programmed to intelligently work out what the tuning should be, from the frequency of each string, and be preloaded with the most popular ones (EADGBE, DADGAD, DADGBE, etc.) or custom tunings that can be programmed in and downloaded via a USB PC connection. Then if it detects any difference in the actual frequency and what it should be, it could make the small adjustmants necessary.

This could be done on demand by the player, by pressing a button. Normally this could be done between tunes/songs, to avoid the player having to mess around on stage and annoying those members of the audience who hate paying to watch people tuning up.

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: Scrump
Date: 03 Mar 07 - 01:11 PM

Sorry, that last GUEST was me. Just logged back in.

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: Bill D
Date: 03 Mar 07 - 01:37 PM

and when you all get done modifying that guitar, this is what you'll have

(YouTube video... broadband only)

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: Forsh
Date: 03 Mar 07 - 01:49 PM

I dunno about a SELF-tuning guitar, no one has yet invented one that I can tune anyhoo... :)

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: Mr Happy
Date: 03 Mar 07 - 09:51 PM

why don't the shops sell ready tuned strings??

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: The Fooles Troupe
Date: 04 Mar 07 - 05:57 AM

Well, actually, Mr Happy, speaking from a technical viewpoint, they do, sorta, which is why they sell so many diferent types.... ;-P

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: EBarnacle
Date: 04 Mar 07 - 08:34 AM

There once was a luthier named Oppornockity who sold his instruments pretuned by his own hand and they came out perfectly. A performer had been playing for a while and had a major gig coming up, so he changed his guitar to a fresh set of strings and could not get any of the strings to come into the correct pitch. When he took the instrument back to Oppornockity, he was told that













"Sorry, Oppornockity only tunes once."

Where's my hat?

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: Bee
Date: 04 Mar 07 - 09:15 AM

Groannnn!

I have a hard enough time keeping one external electronic tuner working, let alone dealing with persnickety onboard doohickeys.

I'd love to learn to tune by ear. I can tell when my guit is out of tune, even a little, but no amount of tweaking can convince me that I've got it right without referring to the little green light on the tuner.

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: EBarnacle
Date: 04 Mar 07 - 10:53 PM

Thank, Bee

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: Scrump
Date: 05 Mar 07 - 07:22 AM

and when you all get done modifying that guitar, this is what you'll have [link to Youtube video above]

That's pretty amazing - any idea what it's from?

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: GUEST
Date: 05 Mar 07 - 08:17 AM

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: C-flat
Date: 05 Mar 07 - 08:43 AM

I know someone who tuned his guitar then super-glued the machine-heads to save himself from having to do it again.

Doh!!!!

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: Bernard
Date: 05 Mar 07 - 11:41 AM

Ummm... C-flat... what's your point?!! I welded mine...

;o)

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: Scrump
Date: 05 Mar 07 - 11:44 AM

I simply returned my guitar to the shop and swapped it for another one, as it was still under warranty :-)

Now then, it's second-hand guitars that are the real problem...

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: GUEST,Sailorboy
Date: 05 Mar 07 - 11:49 AM

Jimmy page had a mechanically self tuning Les Paul many moons ago. I don't know if its a one off or what but I read an article about it. Can't remember which mag and it was a long time ago.

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: GUEST
Date: 06 Mar 07 - 09:52 AM

I read some years ago about a self tuning piano. Each string had a miniature heater attached and and the temerature was adjusted to expand or contract the string to maintain perfect pitch. I can't visualise devising a similar "gizmo" small enough for a guitar.

Subject: RE: Tech: Self-tuning guitar - is it possible?
From: GUEST
Date: 06 Mar 07 - 09:56 AM

Here it is
Hot-wired piano tunes itself
19:00 04 December 2002
Exclusive from New Scientist Print Edition. Subscribe and get 4 free issues.
Mick Hamer

Tools






Why call out the piano tuner when you can flick a switch? (Image: C. SARRAMON/CORBIS)Related Articles
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A piano that tunes itself is due to go on sale at the end of 2003. All the pianist has to do is hit a switch and wait for 40 seconds while hidden electronics tune the strings.

With more than 200 strings inside them, pianos are the one musical instrument that musicians cannot normally tune themselves. And even after tuning by a professional, strings quickly go out of tune because of slight changes in temperature, humidity and the permanent stretching of the piano wire under tension.

The idea of a self-tuning piano is not new but, until now, most inventors have tried to develop devices that mechanically alter the string tension in the same way that a human piano tuner would do.

In a piano, one end of each string is wrapped around a metal pin. The human tuner adjusts the tension by turning the pins, increasing the tension to raise a flat note, and reducing it if the string's note is too sharp.

No moving parts
Don Gilmore, an inventor based in Kansas City, Missouri, has come up with an electronic self-tuning piano with no inherently unreliable moving parts. Gilmore had good reason to find a better way to keep pianos in tune. He trained as a classical pianist in the 1970s before he became a mechanical engineer and inventor. "My piano at home is audibly out of tune a fortnight after being tuned," he says.

During a three-month break between jobs, Gilmore firmed up his idea for a self-tuning piano. He realised that carefully controlled electric currents could be used to tune the strings - based on the principle that warming a string with an electric current causes it to expand, reducing its tension.

Before it leaves the factory, Gilmore's invention requires a piano's strings to be manually tuned nearly a third of a semitone sharp. The system then tunes the piano using a warming current to ease the tension of the strings. Underneath each of the strings are two magnetic coils, like those used in electric guitar pickups.

In a guitar, a vibrating metal string induces alternating current in the coil, producing the note. Gilmore uses the reverse effect: he applies a current to one coil, inducing a magnetic force that vibrates the string. This induces a small electrical current in the second coil, which is amplified and fed into a frequency analyser.

"Absolutely appalling"
A microcomputer compares this frequency with the correct frequency for each string and then instructs a power transistor to deliver pulses of a correcting current through the string. The pulses warm the string, lowering the pitch to the correct frequency. The sound from each string during the tuning process is scarcely audible, says Gilmore.

The electronically controlled strings have an operating temperature of around 35°C. "The strings feel as though somebody has just put their hand on them," says Gilmore. The piano draws about 500 to 600 watts.

Gilmore's system will go on sale in some grand pianos made by American piano maker Story and Clark at the end of 2003. But the firm says it is too early to say exactly how much extra a self-tuning piano will cost.

As might be expected, piano tuners are unimpressed. "From a pragmatic point of view I think it's an absolutely appalling idea. It would put me out of a job," says Martin Surrey, who tunes pianos for the English National Opera company. He points out that one problem with the idea is that concert pianos have to be tuned to suit the acoustics of the room: "They can't be tuned to a fixed formula."