reverse connected guitar pickups make strings resonate - how to make it stronger?

hey all , 
im having a problem , 
i connected some guitar pickups to send frequencys instead of receiving , when close to a certain section of a piano , it makes the strings resonate , and i can play music thru the strings (i even get voice timbres)

now , my problem is like that -
the vibrations are extremely soft ,and i need to somehow make them stronger , 
i think one of the ways would be to magnetify the strings , but i would really like to know if there is a way to strengthen the pickup signal without blowing anything up , anyone has an idea?

i think it has to do with electro-magnet power , so amplifing it should work , but adding a 5 watt small amp didn't make any diference...

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dogme (author) 5 years ago
hey all , thanks for your comments , i didnt know i dont receive an email to notify me that someone replied

just updating ,

tried it with a big transformator coil , it makes the strings move but the coil itself also makes sound (working with a frequency generator and square waves to get more atack to the vibrations)

as well i added a pickup to receive on the other end of the string (of a piano) and i get the analog signal to the speakers

going to keep on updating about it - for now its less important though .

fyi - i am not trying to use this technique on a guitar but on a harp of a piano which is outside of its case - so a lot of resonance because none of the strings are muted - which is a good thing
caitlinsdad5 years ago
Look through those topics or search on guitar string sustainer. Devices like the ebow or configuring guitar pickups(forgot the name of what is on the market) to do that is discussed there. Good luck.
Fernandez, for one.

But those devices (including the ebow) are designed to resonate @ the fundamental frequency--I.E., whatever note is currently being fretted.

They just take the sound of the string as plucked and feed it back to the string (which is a pretty accurate description of  "positive feedback"-- a bad thing, if not controlled properly).
I'm not sure what the user is doing, but maybe just use audio output or the magnet from the speaker to drive the strings. "Talkbox for your strings".
I think the OP is trying drive (open?) guitar strings with an external audio signal, kinda like a speaker... I don't think anyone will be playing the guitar at the time, although it would be possible to fret the appropriate notes while the source is playing, in a performance setting.

It will work, but with dissonance, because the strings will resonate only slightly at the higher harmonic frequencies, and instead want to resonate a LOT nearer the fundamental--which is getting dangerously close to a definition of resonance itself...

As opposed to the guitar body itself, which (like a speaker) resonates over a wide range (has a low Q).
gmoon5 years ago
Interesting idea. It has some possibilities, but some inherent limitations.

-- Standard guitar pickups are medium-to-high impedance input devices, usually in the 5K to 10K (5000-10000 ohm) range. If you hook one up as an output device, to an amplifier expecting a load of ~8 ohms, very little current will pass through, so very little "amplification" can happen.

A hand-wound coil with heavier gauge magnet wire will do much better. Or even use the driver coil / magnet from a small speaker.

-- Guitar strings are resonant, but they have a very specific resonant frequency. The fundamental resonant frequency of a string is the note the string itself is tuned to. Beyond that, strings vibrate in sections--the harmonic frequencies of the fundamental; 2nd harmonic, 3rd, 4th, etc.

But each harmonic is progressively quieter compared to the fundamental note, so they are progressively harder to hear.

The strings in a piano tend to resonate more than a guitar, because they are so many strings--there's always another string with a fundamental frequency that corresponds as an octave (same as the relatively strong 2nd harmonic frequency.)

One interesting note from the wiki on Sympathetic String:

The guitar is normally unable to produce effective sympathetic string resonance for tones other than E (resonance from the 6th and 5th strings, tuned to E and A, respectively), B (from the 6th string), D (from the 4th string), and A (from the 5th and 4th strings). (The treble strings are negligible in practice, as they are almost constantly being fingered.) However, the ten-string guitar invented in 1963 by Narciso Yepes, adds four strings tuned to C, A♯, G♯, F♯, which resolves the imbalance of resonance on the guitar. By adding the above mentioned resonances and, of course, their fifths (the fifth being a strong resonant frequency)—that is to say, G, F, D♯, C♯—the guitar's strings now resonate more equally with all 12 notes of the chromatic scale, bringing the guitar's sound closer to the consistency and sustainability of the harpsichord and piano

-- Of course, you'll also need to use magnetic pickups on the guitar to hear any of the resonance. Obviously, any sounds produced by an electric guitar are soft without amplification. Especially harmonics.

-- You could try using an Autoharp instead of a guitar. It has many strings, so many more fundamental tones to resonate.
Kiteman5 years ago
There are two options:

1. More power into the pickup.

2. Make the strings more responsive to the pickups.

You're trying "1", but to try "2", you could wrap a length of iron or steel around the string near the pick-up. Maybe a thin paperclip, or one of those ties that are used to fasten sandwich bags.