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Sustainer Ideas


psw

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Current sustainers on the market or been developed, of the type I'm working on, are about the same size of a single coil. Examples are the sustainiac, fernandes, micheal brook infinite guitar, floyd rose had one, as did hamer.

Typically they replace the neck pickup but may also be used as a pickup when the sustainer is not in use or teamed with another single coil in a humbucker sized format.

It's interesting that you mention putting it under the pickup as I had thought of doing that with my super slim device, driving it through the pickup itself.

Regular contributor, Ansil, has a sustainer mod featured in the tutorial section. This is simply a speaker under the pickup with a tiny amplifier to create feedback. As I understand it though it does not drive the string but creates a feedback loop through the pickup itself. Unfortunately I, like others haven't had much luck with this though Ansil swears it works (and if someone would just get a sound clip on the site they would be real popular I'm sure!) :D

My goal is to produce a device that will make a note that will sustain for as long as you want, have touch control of the note's attack (swells, etc), it's tone and it's harmonic content. I can see the device even going alot further to radically change the way the string vibrates by having it driven by a synthesised signal, but thats a long way off yet.

The first step is to create an affordable and acceptable device that doesn't radically alter the existing instrument but enhances it.

I am approaching it from a slightly different angle from previous designs. I am using tiny Rare Earth Magnets, very thin coils, and magnetic focusing strategies to minimize interferance and maximize power and control. I am seeking to address a number of problems that other designers have sought to solve through electronics with specific coil design solutions.

So to answer your question, a sustainer often replaces, and can even substitute for a pickup in the neck position. It's purpose is to actually drive the string, vibrating it by electromagnetic means. It can be thought of as a pickup in reverse!

thanks for your interest

cheers

psw

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:D

By the way, I've built Coil Prototype 3 - CP3

CP1 was a simple circular 12mm coil with a ferrite core.

CP2 was fairly rough but proved and developed a number of theories.

mainly - that super slim coils were practical and workable.

- that a simple bobbin design was easy to create.

- that it was possible to produce side to side movement

- that powerfull magnets could be used without excessive attraction to the string (causing intonation problems, etc) if it was controlled

- that my "cage" magnetic focussing device could be utilized to enable the above two points as well as reduce radiation.

CP3 was finished today.

CP3 is as slim as CP2 (2mm) but uses finer wire and is only 10mm wide. The "cage" adds another 2mm so 12mm in total. It is designed to operate across all strings and is slightly flexable as it happens, so may be shaped to the string radius. In addition, I created an identical air core version to try to cancel the radiation. The whole is now 5mm thick, a little much to fit on my strat but kind of works on my test guitar. Let's just say it's promising!

Still alot of testing still to go and I have plans to bi-amp the design but I already have the next one in mind.

CP4 will develop this further with a novel concentric coil approach to keep the thickness down (about 3mm) but go back to the thicker wire so as to handle more current. CP3 used a powdered pure iron core. CP4 will utilize a secret alternative material to increase responsiveness and further focus the field. It's only theoretical at the moment so I'd like to see how it goes.

got any suggestions or comments to keep me enthused, feel free

psw

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:D

LK

Damn you're quick. You guested the secret core material!

Can't get tubeolator in Oz yet so I made my own by drying the cat's furballs in hot air then mix with super glue and glow in the dark nail varnish.

Evens out the odd harmonics and can even accentuate the odd!

WARNING : Do not take orally, the product has been pre-digested. Seek professional advice should tubeolator persist

psw

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Glad to see you're in a constant state of development. That means you can finish a working prototype in only a few months, give the blueprints to the ProjectGuitar members, and then move on to selling it for hundreds in the world market. :D

;-)

Seriously, though, I'm impressed with the speed of development and look forward to hearing about each new discovery, even when I only understand about 25% of what you're all saying.

Greg

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psw, well done experimenting here, really, id like to be working on a sustainer, but i never got round to it, i have however glued a piezo speaker to my pickup and am gonna build the amp for it to see if it works!

i think it would be cool to have some photos and or sound samples!!

good luck with CP4!! really hope this works well, and so on, cos i think that if you can build one instead of paying £250 for a fernandes etc... you have accomplished something very cool... keep me informed :D

Mike

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:D

Thank's guys I really appreaciate the support for the project. I'm really quite tenacious yet nothing should be considered too silly to try. I have a feeling that the final solution will be not too complex but a combination of ideas, observations and coincidences that will fall into place.

For instance, I was playing around with CP1 to assure myself of the goal and that the thing works at least in one form, when a stray piece of 2mm piano wire attached itself to the rare earth mag. I duely pointed it at the string right next to the bridge close to the active pickup and it drove the string in a fashion, perhaps as well as CP2 & CP3 which are far more complex.

Such a pointed magnetic field is extremely focused but as it is located at the bridge end of the string it is immune from the problems of string bending. It also holds the potential for the actual coil, which creates alot of the magnetic interfence, to be located deep within the guitar or behind the bridge well away from the pickups.

I'd tried this type of thing before as it would leave the guitar fully functional and modification could be restricted say to the bridge but wouldn't have thought that such a simple idea would have worked.

People reading of my experiments should bear in mind that I conduct them on what I've now dubbed my WCS Guitar (Worst Case Scenario). It is a 3/4" piece of pine with a crap neck, a piece of aluminium for a bridge, one string and a super cheap single coil with a giant ceramic magnet below it. All of the wiring is unshielded and I'm using (crocodile clips which should act as an antenna) to connect the test cores. I figure that if I can get it to work acceptably on this it will work on anything!!!!

keep up the feedback...

psw

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I have a question for you psw. I was thinking about what you are doing and cant understand how you could make it aply on only one string. Lets say you play a single note on a single string and the sustainer is activated. If it covers all the six strings wont it force them to vibrate as well?

All I can thing of is making a dual sustainer like a humbucker. The one coil will act as a single coil and recieve the signal and the other coil will be the actual sustainer and send it to the coresponding part (6 parts in total) to the other coil to vibrate the string. When passive it can act as a single coil but when activated I dont think it can be used. The feedback from the sustaining electromagnet will drive it wild.

Just my thoughts for now. As I understant more of it I can be of greater help.

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Andreas :D

All ideas are appreciated. I know I'm wordy but I'm no expert. Basically I'm just like you with some experience mucking around with magnets and wires in search of a dream!

The humbucking description is how existing sustainers are configured generally.

One string at a time....well you have to be good at string damping, just like with a super loud guitar, and you can control the sensitivity (power). All six strings typically do vibrate if not dampend but the driver is only feeding back the signal that it recieves. The strings respond to the driving signal, very much more so, if they have the same resonant frequency. The pickup maybe trying to drive all of the strings but only the string that is played will have exactly the resonant frequency of the signal as it created it, if you get what I mean.

It would be possible to enhance the effect if desired by having a kind of noise gate circuit so that notes will not be driven unless they are loud enough to cross a given threshold.

Hex PUPs and Hex drivers:

Each string could be activated individually though if you were to make 6 PUs and 6 drivers - A Hex Pickup Driver.

The current working prototype - CP1 - is a single string driver. Basically a 10mm circular coil. It is small enough that 6 could be placed alongside eachother in a single coil package. You could have six switches, say behind the bridge, that activates each of the coils.

You could perhaps use a Hex driver with the guitars normal PUs switching drivers to activate in a similar way, or visa-versa, a hex pickup with string selection switching (say a bridge piezo system) and a common driver.

There is an effect that I have noticed that will dampen all sound output from the PUs by sending a driver signal opposite to the input and putting them over one another. The effect could perhaps be used to automatically deactivate unplayed strings from the driver.

My Designs :D

I have been working on very small drivers for a number of reasons. One theory that I have is that the smaller the coil the less radiation and the more focused the magnetic power the less interfence with the other PUs. Magnetic deflection and cancellation coils as well as coil orientation in relation to the other PUs are other avenues I'm exploring.

I'm trying to keep the electronics very simple and address string response issues with the coil designs.

If an effective design can be accomplished it would add a whole new dimension to guitar playing. Playing a standard guitars may seem like playing a violin without a bow - limiting!

The next step...

But wait theres more.....

The sound of the guitar is a product of the way in which the strings vibrate. So consider this. If the drive signal is modified (remember you don't hear the drive signal, it serves only to activate the strings) they whole character of the sound can be controlled. You don't just have unlimited sustain but a kind of natural syntheser that effects the sound not by modifing the signal like an effects box, but by actually changing the way the string fundumentally vibrates! Now that would be cool. B)

But for now it's back to the drivers

cheers

psw

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One string at a time....well you have to be good at string damping, just like with a super loud guitar, and you can control the sensitivity (power). All six strings typically do vibrate if not dampend but the driver is only feeding back the signal that it recieves. The strings respond to the driving signal, very much more so, if they have the same resonant frequency. The pickup maybe trying to drive all of the strings but only the string that is played will have exactly the resonant frequency of the signal as it created it, if you get what I mean.

Yeah the signal given out will make forced vibrations on the other strings except the one with the same frequency which will be at the fundamental and will resonate. But I said that because I noticed that even the smallest string vibration will be picked up by the pickups and this will be continious small vibrations. Also the fractions of the fundamental will vibrate at resonance as well thus creating octave and harmonic problems. For example lets say you play an E note then all E (regardless of their octave) notes present in the fretboard (that are freted or open chords) will resonate since they are fractions of the fundamental. Again tho this will be minimal if dampened by hand which is the same case as you mentioned "playing loud guitar", but at low volumes i think it can create muddyness in the sound and loss of clarity especialy if you play something complicated that you dont have any spare fingers to dampen the strings. Of course we are talking about very very rare situations where they can be considered as negligible.

There is an effect that I have noticed that will dampen all sound output from the PUs by sending a driver signal opposite to the input and putting them over one another. The effect could perhaps be used to automatically deactivate unplayed strings from the driver.

That I believe is the best solution if you can manage to confie it to the strings not being played since it can stop all the sound .Also the idea of using opposite signal to cancel the unwanted signal can cancel the effect the driver`s magnetic field has on the pickups and not just the strings.(actually is the principal of the humbucker to stop hum if im not mistaken). This solution will also alow you to use a single driver and not as a humbucker design..less space used up.

The noise gate can hassle you if you want to play something gentle if it is required at the song. I once had some problems with that and ever since I hate noice gates.Maybe I did something wrong I dont know but the sound was continually interapted as it faded out and sounded like a cell phone was close which wasnt the case.

The individual string drivers I think is too much trouble and takes too much space in the long run with all the individual parts and if you make a mistake and hit string by mistake and do not damp it will resonate it again and the piezo for each string i thing is useless since even one string is hit all piezo will vibrate.

But wait theres more.....

The sound of the guitar is a product of the way in which the strings vibrate. So consider this. If the drive signal is modified (remember you don't hear the drive signal, it serves only to activate the strings) they whole character of the sound can be controlled. You don't just have unlimited sustain but a kind of natural syntheser that effects the sound not by modifing the signal like an effects box, but by actually changing the way the string fundumentally vibrates! Now that would be cool.

That is not actually 100% true I believe. Actually the sound of the guitar is disturbances in the magnetic field around the pickups. One of the thing causing them can be the way the strings vibrate. To see ...err..hear what I mean take a classical song that you may have around. Put it in a cd player or anything that has a headphones socket. Play it through the headphones (preferably small headphones that fit into the ear) and move one headphone close to the pickup of the guitar. The guitar now will sound like a full orchestra B)

The coil the headphones have inside creates the magnetic field that is picked up by the pickups. That coil could be the guitar strings so if a proper signal (the output of the headphone socket) is fed to the sustainer/driver normaly would make the guitar sound like that.

Nevertheless it easier and more logical to just take that signal and instead of passing it to the strings to be picked up into another less clear signal (efficiency losses) to send it directly to the jack of the guitar to be sended to the amp, which I dont see why it isn`t better to keep the signal out of the guitar and treat it alone which brings us back to the begining.

After saying all that I think that it is useless to spend so much time in trying to figure out a way to stop unwanted string vibrations for the folowing reasons.

1) The sustainer will be activated in a very small proportion of the playing time so the examples I said above become even more negligible.

2)In practice the sustainer will be turned on when infinite sustain is wanted. In such cases logicaly you will have all the time in the world to dampen the strings. When the infinite sustain is not needed the guitars own sustain will normally work just fine for every need you have.

hmm..that was a long post. Sorry for the wasted time :D

Ah..and remember I dont know most of these things as a fact, they are logical assumptions. (like almost everything that is known in physics)

cheers,

Andreas

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hey psw i had a thought on our previous synth feedback sustainor idea.

what if we take a detector circuit that drives an led with a varible threshold point on it off say our positive rail. and also at the same time we use a small opamp or an invertr to square up the signal a little bit dump it into a 555 set to free running osicilation but going into the fourth pin. so we are clocking the oscilator at the guitars freq. essentially its a more synthy out but now heres the fun part. we put an ldr on the output before the volume pot. and we have blend from the original guitar signal and the output of the synth output. now we have a nice little circuit to start with.

if we take the signal from the ldr and send it back into the fourth pin.. then we have this.

******------------------preamp------oscilator---ldr--volumepot

guitar--------detector----led **------------------**

since it is a free running oscilator once we clock the input signal it will continue to sustain the note till the input dies out killing the detector circuit. now if we set the sensitivity of it so that the slightest noise from the guitar will keep the note running or ie the ldr on.. then we can trigger it once and let it sustain the synth type note forever virtually.

also we could do away with say the triggering system and just have a break switch on the output of it to break the loop. as long as the input note is higher threshold than the sustained note ie the loop then we have a variable sustain unit done electronically without driving the strings.

now what does this mean in the real world. well i threw it on the breadboard and since it was late and i was at a friends i only used a signal generator to trigger it and had to pad that down. what i found that my theory was right so far now i need to try it with a guitar and see how it works.

i will try to post the schematic so if anyone wants to tryit they can

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"One more point though. Why are ldr's always used in this sort of thing? I understand an ldr to be a light dependant resistor, where does the light dependant stuff come into this circuit? "

well its quite easy to take say a single transistor and figure it as a gain amplifier and use the guitar signal to trigger the led. which you can also use a pot above the cathode to control voltage so that it has a sensitivity function.

and well the ldr in this instance keeps the oscilator from running a muck when its not triggered. now since its set to oscilate from the reset pin ie pin four it shouldn't be too noisy but in the past i have had issues with it "speaking to me" while i was not playing. and i dont' want it to speak unless i tell it too..

basically we could do the same thing with a capacitor and a diode. ala the tracking trick from joe davisson in the little harmonizer thing he did. but i just figured also since i got a sack of leds and quite a few ldr's {amps use them to keep from killing you wiht high voltage so the switch doesn't short out after repeated use, and 400+ volts jumps through the switch and kills you dead. i am sure there are other good reasons they use them in amp switching systems but that seems to be the best.} also leds have a faster response time than say regular bulbs and ldr's have a really fast changeover time so its like the movie said.. I.O.L. instant on lighting.. :D

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ok updated i got ahold of my buddy in knoxville and he was off so he decided to give me some time to expirament on my new circuit posted here.

he said it works and we can probally forgo the whole led ldr thing. for the faint of heart.

as long as i use the right blend of signal via putting a pot in series with the output of the 555 an take the 2nd lug to the fourth pin. the oscilator is pretty quiet. until you start playing then it does its thing.. and by using the pot this way it lets you set the trigger threshold alot better, so now even when the guitar signal dies out completely or you can just roll off the volume pot a little. the last note played will continue to ring out. although its still a synth version of the note however it is still the same note. and reasonably good. it still needs work.. also everynow and then when you hit another note it rings for like a few miliseconds enough to harmonize with it. so if you set the blend correctly and set the threshold to be pretty high then you could actually drone over the sustaining note.

basically its like this with the 555timer

8]--------V+

7]10k----V+

4]------*-------INPUT

3]-----POT--------OUTPUT

6]--*

2]--*-.1UF*

1]---------*----GND

STILL WORKING ON IT THOUGH.. and of course you need something to drive the front end of it.

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:D

Ansil - Great stuff. I take it is monophonic, yes? Would there also be a tracking issue like with my octaver? Not to worry, the world needs new effects. Keep it up.

I've been busy...you can't type with a soldering iron in hand! :D

Andreas - you got me thinking and I came up with some new ideas and another approach to the coil design. I built a single string prototype which seemed to work well. So well as far as containing EMI that I had it running within 1cm of the bridge pickup that was driving it. I was so encouraged I dropped CP4 for a bit even though it was all set to wind and went ahead and built a hex version CP5x. 12 miniture 4x4mm hand wound coils, 6 identical revese wound pairs. The principle used was to have the string in balance between the poles of a powerful magnet and then use these tiny coils to upset this balance...so cool, and yet.... :D

I think the design holds promise both for a driver or a pickup, but I may have made some errors in the internal connections between the coils and I had to set the thing in glue as the tiny components are so delicate, and...ah...I'll just put this aside for a bit I think... B)

Still, lessons learnt. Although it did'nt drive the string as I intended, the wiring fault caused it to fight an internal battle trying to maintain the balance rather than upset it. I guess, due to inconsistancies between the coil pairs, it struggled. Anyway, I mention this to illustrate the following...

Modifying the driving signal is not simply a matter of adding an effect. My problem is that in my designs, I'm trying to avoid the pickups picking up the signal. It's not like playing an orchestra into a pickup. In this scheme you are using the speaker and pickup coils as a kind of transformer or microphone. What I'm trying to do is send a signal to change the way the string itself fundumentally vibrates! So a noise gate doesn't sound like a gate, rather it is used to set threasholds for the drive signal so that only intentionally played notes will sound (theoretically). I think I mentioned this before, but years ago when I first tried to experiment with this, I ran the signal through a flanger which produced amazing bird chirpy swoops as the phase passed through various component harmonics...It sounded nothing like a flanger, per se!

The internal battle within my aborted CP5x produces this wonderful detail behind the note. Related harmonics are brought out and disappear like a kind of tinsel, especially as the note dies away and the driver wins and loses the battle to drive the various harmonics, beautiful.

Now thats what I'm talking about! These and many other effects are just waiting to be discovered I'm sure. But it is not simply an effect, it is an extention of the natural qualities of the instrument - individual and highly responsive to the players touch. It amplifies, if you like the qualities that we all love in the guitar, the way it responds to the player.

So my quest, eventually will lead not only to infinite sustain, but to use that ability to drive the string, to drive them in new and interesting ways..I have a dream...

So, back to my failings. I've switched my test bed from the one string WCS guitar to a strat. I've put the basic amplifier and battery into a small box taped to the guitar and am taking the guitar signal from a double adaptor drirectly from the jack socket. The experiments are gradually getting into the real world.

Anyway, got to run for now. Fantastic to see the interest and inspiration

later

psw

P.S. Got some promising new ideas for constructing these miniture coils that will make the whole process easier and faster and save whats left of my hair!

P.P.S. Could someone tell me how to post .bmps to save on text.

PPPS Ansil, got any ideas to stop the signal being loaded by the circuit, some kind of low power buffer, I think it's effecting the performance...cheers

PPPPS Have I mentioned that these driver ideas will work in reverse as an active hex pickup, perhaps just the thing to drive the front end of your mono effects, Ansil...

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psw

actually it tracks pretty well considering that its only really designed for single notes at a time.. so yes its mono.. but i haven't tried chords could work i guess.. maybe a blending effect of all the freq.. or the strongest one winss..

i wil see what i can thin up for the buffer. :D nice work btw.

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No way could you have read all that so fast!!!!! Ansil. B)

Seriously, thanks :D

Oh' in case someone suggests it, I've tried copy and paste between paint and explorer but its not happening. Things would be alot clearer with a picture I'm sure and...well... it would save a thousand words...several thousand in my case! :D

psw

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Cheers LK - I'll get onto it

Greg P's avatar has given me the finger in the right direction B)

By the way, I'm getting a handle on the phase problems we spoke about way back when. They do matter for efficiency as they alter the resonance of the coil, although, you're also right that the string can be forced to resonate in phase with the coil (about 90 degrees out of phase) but with significantly more powerand altered response.

It seems, that now I'm working on a real world guitar, CP1 was (coincidentally)ideally matched to the g string WCS test guitar. It worked well all along this string. Current designs take the signal from the guitars pickup (it's hard enough to make the driver, let alone a dedicated PUP!), into a hex driver. I'm expecting to takle this problem by wiring the coils with a passive crossover type circuit. Capacitors in series and in parallel have opposite lead and lag times when wired with inductors it appears. I hope to use this to roughly tune each driver coil to it's string.

The coils that I'm using at the moment are truely tiny and of extremely low impedance. I'm using resistors to bring this up. I learn't today how a current divider works and hope to use six parallel resistors of various sizes to divy up the power. This is important because the thinner strings, of less mass, are harder to drive. In fact, CP1 can not drive the high e at all on the real guitar. I feel that this is related mostly to the resonate frequency of the coil.

Here's another interesting phenomenon. CP1 was extremely efficient when attached to the test guitars truss rod adjustment nut (at the body end) by it's magnet. I originally thought that this was because it was being held stable (not trying to vibrate itself). Rather it is that huge rod of metal that was acting as a type of ballast to the opposite of the driving pole. This was shown by sticking the magnet to the end of a 5mm drill bit, producing a similar result.

This discovery has rekindled my idea of building the driver into the bridge as this too provides a conveniant hunk of metal to work with...

Anyway...off to bed, then up at 4am and back to the warehouse job for a while

good morning from Australia...and good night

psw :D

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This discovery has rekindled my idea of building the driver into the bridge as this too provides a conveniant hunk of metal to work with...

If you build it on the bridge will it have the power to drive the strings? I mean if you consider momentwise it is much much easier to drive the string as close as its midpoint is. (not the 12th fret since when you fret the half distance changes)

Think of it like trying to open a door by pussing it at the hinge and not at the knob.

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If you build it on the bridge will it have the power to drive the strings?

Well yes...and yet. This is the principle that current sustainers use. I have been able to drive a string from the bridge and I'm not sure exactly how it's working. The principle is to send the magnetic pulses along the string itself. Perhaps it is being moved around by the magnetic field of the first pickup the pulses meet.

It is perhaps more likely that, unlike conventional pickups that sense (or in this case drive) a small portion of the string, this is driving at, of all places a guaranteed node where all vibrations meet. Therefore just ahead of this node is the place where you can be guarenteed that all vibrations occur.

Harder to drive physically, but, more chances to hit resonant frequencies. The resonance is what multiplies the power.

Various configurations were being tried just prior to joining this forum. At that point I was searching for people who had done a DIY ebow. Ansil's Sustainer Mod came up. The result was that I was returning to conventional coils just to get something working.

By the way, I have done quite a bit of playing with the program FEMM which is freeware. It is a magnetic field simulation program. It's been great in showing me the effects of various materials and magnet types and sizes have. It is not the real world so have moved on but it's great for working out ideas.

Another thing that I made recently was a Magnetic field detector. This has been really usefull to check what is going on with the invisible magnetic field circuits.

off to work...

psw :D

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It is perhaps more likely that, unlike conventional pickups that sense (or in this case drive) a small portion of the string, this is driving at, of all places a guaranteed node where all vibrations meet.

Hmm so it forms some kind of electromagnetic stationary wave in the string, which (due to the pickup magnetism) translates into mechanical stationary wave which in fact is a vibrating string.

Interesting....if that is true then all you need is a signal generator on the bridge...altho it sounds too simplistic to be fuctional.

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