Transduced guitar = endless sustain

Started by kvb, March 30, 2010, 09:39:43 PM

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joegagan

looking forward to hearing the results doug.
my life is a tribute to the the great men and women who held this country together when the world was in trouble. my debt cannot be repaid, but i will do my best.

psw

I did a lot of work with these kinds of things in the sustainer project. Generally, I've seen pages on making the transducer from a small speaker, cutting out the cone and adding a small weight (like a washer or coin) to the voice coil part.

I got some interesting results...not that impressive compared to conventional electromagnetic sustainer devices though.

If people like simply playing with thee things, an LM386 circuit can run an electric motor from the output on bass strings...well it will try to move it back and forth in time with the strings, but it can't cope with higher frequencies as momentum in one direction overcomes the force in the other...solenoids and other such devices were also tried.

Sticking them on the trem was the obvious idea...but there are two problems #1 the effect of momentum creates an out of phase lag (as with the motor above), these things can't move as fast as most guitar frequencies, they may even dampen vibration if reversed...and #2 these things put out a fair bit of electromagnetic signal or EMI that will get into the pickups if placed directly below them say in a strats spring cavity.

I did get some good results on a very resonant hollowed out strat I used to use for sustainer experiments (become the first DIY sustainer strat I made) with a transducer around the output jack.

This brings up another element of the project, you are needing to shake the guitar, doing so from the headstock like the 'model C' keeps the transducer well away from the pickups which is good and gives you a fair leverage as well and connects where the strings are connected, but the guitar itself has all kinds of resonant frequencies and momentum and lags and such and these things can amplify the effects of these a lot more...with a big transducer and enough power you may well over come thaese limitations...even the 'model C' puts out a pretty hefty punch.

Conversely, with a purely magnetic sustainer...you are working directly on the strings themselves that are tuned to the resonances of the signal in it. I look at these 'drivers' like a speaker coil and the strings as the cone of the speaker...far easier to drive a tuned string alone than a guitar with a complex of additional resonant frequencies and structurally stiff.

I had looked into some kind of bridge that would work just on the bridge saddle, but there are enormous pressures there.

I suspect these things would work a lot better on a bass, the vibrations are a lot slower and less effected by the phase and lag things...they do not have to respond as fast as a guitars high strings, and there is a lot of neck there to shake.

I also found my transducers made an incredible racket...kind of buzzing sound even with the cones removed and all...of course this is acoustic so doesn't come out in the signal of the electric guitar and would be masked by a loud amp...but it also shows the kind of sound you are shaking the guitar with...not the most analogue of the actual vibrations of the strings, and so again, not the most efficient way of driving the things.

But, the so called 'acoustic sustainers' like this do have their charm and can sound different again from other proposals. The vibrations can certainly help initiate normal amp feedback effects sooner and with more certainty...having a big fuzzed out compressed sound can also help.

There is a good forum dedicated to the fretless guitar that I had some connection with through the sustainer thread. A good sustainer can do wonders for the fretless...not just to create endless sustain, but to create any kind of sustain! Generally, they prefer rock hard, often glass or steel boards, perfectly flat, a higher action (so there is more of a lift off the board to avoid undue buzzing, like on a violin) and very heavy strings. A guitar with a sustainer can keep strings vibrating even with a wooden board, but without frets, wear can be significant...many coat (like I believe jaco did) with epoxy.

I have liked the sound of the fretless  guitar since I heard a larry coryell and  ??? catherine record years ago, beautiful sound. Vai sctick with his triple neck with fretless and fernandes sustainer may give an impression of what these things can sound like
http://www.youtube.com/watch?v=A9qyeUOoAZU&feature=PlayList&p=D95844BFDC62D7BF&playnext_from=PL&playnext=1&index=54 go to about 2:20

But it's good that there are some transducers about to experiemnt with, cutting cones and weighting speakers is not a whole lot of fun. In the end, I abandoned working with them as a conventional magnetic sustainer working on the strings for an electric guitar is so much cheaper and easier and practical...uses less power and works on all the frequencies...so a far better return.

I have always had a fretless on the to do list with one of my sustainers, but it certainly isn't a priority and I tend to ahve too many guitars cluttering up the place as it is...and too many projects...moving house again only reinforces this perception!

Other cool things people might consider with a good sustainer...mute a "stick" like tapping instrument by tying a sock around the nut so that every note tapped is sustained for as long as you hold it down...make a half fretless guitar by removing only the higher frets so that you can still play chords in tune on the lower frets...brain storm ideas with your friends and internet buddies...the scope is endless once you get into the more esoteric applications....

Oh here's one that works kind of well...connect a little LM386 like circuit to a small speaker as you might find in a computer, use the back of the speaker like a slide...or build something more elaborate like a transducer connected to a slide...you get a powered slide that works directly on the strings a is pretty effective...just don't let it get near the pickups to avoid squeal or get tangled in the lead!

There is a relatively new one I saw, a magnetic device much like an ebow, but connected to a mic stand, aim the thing at a string...instant ebow without having to hold the thing...there's a good vid somewhere on the thing...

Good work though...have fun, continue to experiment!

Paul Marossy

Ooo... I just had a thought. A Vigier fretless electric with a sustainer in it. Now that would be pretty cool. You could probably make it sound like you were playing it with a bow.

DougH

Just for the record, I'm not dedicating my life to building the ultimate perfect guitar sustainer here. I'm just playing with this transducer and having some fun- seeing what it can do, that's all. With the clips that Kevin did, it sounds pretty useful to me.
"I can explain it to you, but I can't understand it for you."

Quackzed

 ::)
QuoteJust for the record, I'm not dedicating my life to building the ultimate perfect guitar sustainer here. I'm just playing with this transducer and having some fun- seeing what it can do, that's all. With the clips that Kevin did, it sounds pretty useful to me.

well, your definately not going to build the ultimate perfect guitar sustainer with that attitude!  :icon_wink:
nothing says forever like a solid block of liquid nails!!!

punkin

I wonder how it would sound if one were to stick the transducer inside the spring pocket just under the pickups?
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DougH

Quote from: Quackzed on April 15, 2010, 12:19:09 PM
::)
QuoteJust for the record, I'm not dedicating my life to building the ultimate perfect guitar sustainer here. I'm just playing with this transducer and having some fun- seeing what it can do, that's all. With the clips that Kevin did, it sounds pretty useful to me.

well, your definately not going to build the ultimate perfect guitar sustainer with that attitude!  :icon_wink:

LOL!  :icon_mrgreen:
"I can explain it to you, but I can't understand it for you."

psw

Quote from: punkin on April 15, 2010, 06:11:45 PM
I wonder how it would sound if one were to stick the transducer inside the spring pocket just under the pickups?

My experience is that electromagnetic transducers in the spring cavity result in a lot of squeal problems as the EMI leaks into the Pickup above it.

...

There is no "ultimate Sustainer" just devices that have the effect you are after...having fun with it is at least as high a reward too!

...

If you search around, you will find a lot of fretless players use a sustainer device for this very reason, very much like a bow. Also, it can be even easier with heavier strings to get a good result. In fact, with a sustainer as the main form of articulating, you can get away without the exotic steel or glass boards to an extent and get decent results. The main reason for these boards is to be like a continuous fret or slide under your fingers and allow some kind of sustain (your finger pads though still often create a fair dampening effect though), a sustainer can compensate for this by continuously exciting the string for as long as you want.

...

I'm surprised to lear that a little lm386 circuit is enough to shake the thing...this is good news...Perhaps it could be mounted in the neck pocket of a bolt on some how, I know piezos can work really well there for 'acoustic like' output...just a thought...may still be a little close to the pickups, but who knows till someone has a go...

DougH

#48
I got started experimenting with this idea last night.

I used one of these:



This is the "parts-express blowout" transducer. I epoxied the "ears" of it to a thin piece of pressure treated fencing lath. I C-clamped this to the headstock of my Squire Strat. I put a Y-connector in the guitar jack and ran one output to the breadboard with a Little Gem Mk I (w/input buffer), the other side to my 2W amp dialed up clean. The output of the Little Gem was connected to the transducer.

I was really surprised how well it worked. I jumpered pins 1&8 on the 386 for maximum gain. IIRC, I was having some sort of oscillation problem with Little Gem (maybe it's a breadboard thing), so I increased the .01u input cap to .1u to solve it. So the transducer works better with the wound strings at lower frequencies. It seemed to really resonate with the open A string, and if I let it ring while playing on the upper strings it sounded like a hurdy-gurdy or something. It *really* droned. I don't remember how I had the guitar controls but at one point it sounded like a ring modulator with the droning A string being the carrier. I think with some tuning I could even out the frequency response a little. I also drove it with my unidrive booster between the guitar and Little Gem and it went crazy. That helped *all* the strings react real well, but it still favored the lower strings which were almost out of control. Again, some freq tuning should fix all this so I'm not worried about that right now.

Things to do:

1. Try the Little Gem Mk2 with the bridged output for more power. I want to see if I can get away without boosting the input to get all the strings to react better.

2. The transducer buzzes really bad when driven. This doesn't pick up in the guitar amp at all, in fact I was getting really beautiful clean sustaining sounds. But it is pretty distracting when you are playing. I have another transducer I cut the "ears" off of. So I'm going to mount it to another piece of wood and see how it works. I know this will restrict the transducer movement, but that might be okay, esp if it stops the buzzing. (I noticed on the one I tried last night, when I pushed it down to "seal" it with the wood surface the buzzing stopped but it still seemed to work.)

This thing has a lot of potential and is a lot of fun. Once I get some of the fundamentals nailed down I'm going to experiment with mounting it on different areas of the guitar.

EDIT: BTW, if you use one of these transducers, make sure you remove the cap and jumper the wire terminal directly to the transducer terminal. They have some kind of cheesy crossover arrangement with these- apparently one of the pair is supposed to be the "woofer" while the other is the "tweeter".
"I can explain it to you, but I can't understand it for you."