Sustainer Ideas

[Tony Enamel]

Update:

Installed my sustainer in my Fender Prodigy last night. It's working (which makes me feel great) HOWEVER... My harmonic mode doesn't seem to work very well. I only get harmonic sustain on like, 4 notes on the entire fretboard! I was just listening to "Beckistan" and I can't get those sounds. Any suggestions? My driver core is a bit wider that Pete's (about 4.8mm or so). Perhaps that's part of the problem.

I was also wondering what parts of the Fetzer-Ruby circuit affect frequency response (ie. EQ)? I was playing around with my knob (tone, you dirty bastards!) and found that when I rolled off the the top end my sustainer hardly worked. So, I wonder if I can adjust the ruby to allow more highs through (maybe a different value cap or resistor somewhere )

Can it be done and do you think it would work?

[psw]

found that when I rolled off the the top end my sustainer hardly worked

The signal to the sustainer should come directly from the pickup...not via the volume or tone. The tone control therefore should only effect the output tone of the guitar, not that going into the amp. Similarly the guitar should sustain the same if the volume is on 10 or Off plugged in or not!

The tone control does effect the harmonic mode though in that it will roll off all the high end and those really high harmonic frequencies will be filtered out...the guitar is sustaining them acoustically, but the amp is not reproducing them. Similarly a really dark tone on the amp will do the same...a wha or treble control could be used to bring those sounds out more and on the really high frets is probably useful but not essential.

I was just listening to "Beckistan" and I can't get those sounds.

I am planning on re-recording that, it's a neat tune and remarkable for a straight out improv and first go with the sustainer. A lot of those really high harmonic notes (in the middle section) are actually on the g string from the 4th, 5th, 6th and 7th frets. I use the tremolo arm (a standard cheap non-locking thing) a quite a bit to bend strings...and I recomend a tremolo with the sustainer to manipulate these long notes.

For instance, I use the sustainer to hold a note slowly bend it up then as I release it I slide the finger back four frets...the result is that the bend sounds as if it goes up 2 steps and comes down 6. The next prase ends the opposite in that I use the bar to bend up and as I do I slide the finger up two frets so it sounds like a bend of 5 steps and back 3. The notes continue to sustain even though the frets are changed without re-picking them...the sound of the slide is enough to trigger them.

These types of techniques and sounds are unique to the sustainer guitar and cant be done quite like that without it. I'd love to hear more ideas for techniques and music once people get their sustainer guitars together. One tip though is that string damping is esential...those high notes wont sound if any lower string is allowed to sustain or feedback at the same time.

I did notice in playing it again right now that the very high notes in harmonic mode don't work too well on my guitar at the moment (19th fret on the high e string) and this is because my strat's action is a little too low and badly needs adjustment again...the strings vibrate against the frets above that dampens the sound. They work perfectly in non-harmonic mode. The other factor is that these notes are incredibly high on those frets (at least an octave above) and are really hard to hear, let alone for an average amp to reproduce...you are looking at sounds vibrating on the equivielent of an imaginary 38th fret or higher. If you took a slide and played notes close to the bridge pickup...that is the kind of range there so they will be hard to hear...unless you have some canine blood in you!!!

If people would like me to do some work on that track and describe it more or other techniques, let me know...the point of this project really is to make a device that can do totally new things and so it can be hard to realise it's true potential.

hope that helps... pete

[Primal]

I'm looking forward to getting a trem guitar sometime in the future. Right now I just use my sustainer for controlled feedback and some nifty solos (think Jambi and Rosetta Stoned off Tool's new album). Even though I'm not using any specialized techniques, I can still get some pretty cool sounds.

[psw]

It may be worth linking the sustainer sounds thread as it is burried pretty deep now if people want to hear and see my guitar...Sustainer Sounds Thread

Here is the link and description for the track beckistan described above...

Beckistan MP3

Here's a little tribute to my favorite guitarist, Jeff Beck. Watch out if you're listening with headphones 'cause there's some very high notes, and I don't want any one hurt. I did better versions, but this is the improv that got recorded.

This is a kind of ethereal sound with a fair bit of delay and a British kind of crunch to the sound. All the harmonics are produced by the sustainer and should show that, made right this thing has no trouble sustaining those high strings…even in harmonic territory.

This track illustrates quite a few things.

First the neck pickup. The first phrase is the neck pickup (no sustainer)…this was recorded within 2 feet of a 17in CRT monitor BTW…pretty quiet for a single coil!!! The second phrase is the bridge pickup…you can use this to compare the difference to it's sound with the sustainer on, and how it effects the guitar's normal tone. On the last note of the phrase, as it dies away, I turn the sustainer on…notice no "pop" tuning the thing on…and the note builds up again.

This first part is the fundamental mode…you can hear me switch to harmonic mode when those high notes, go really high. Then I go and play a couple of power chords to demonstrate how the harmonics come out down there.

Then, I play a typically beck-like melody with harmonics provided by the sustainer…all this these high notes are on the g string below the 12th fret…you can see how the harmonic mode can be used to extend the guitar's range without having to reach for the cramped end of the fretboard.

By the way, that faint thumping sound in the background is my loose trem arm, there's a bit of spring noise too… There is also an effect in the delay's that you really don’t hear too often. As these pure high tones are bent (by the trem) they interact in a kind of psychoacoustic effect creating some really bizarre, but musical, interactions in with the echoes as they cascade over each other. Very Beck-esque!

pete

[Tony Enamel]

Hey all,

I recorded a small sample of my sustainer guitar for you guys to hear. It's two tracks (one clean the other with high gain) both in fundamental mode. My harmonic mode is not really working. I got a little debugging ahead of me. But, the clip shows that the sustainer works!! Check it out...

http://www.asanteguitars.com/Hosted/Sustainer.mp3

...And here are some pics:

http://www.asanteguitars.com/Hosted/pics/top.jpg

http://www.asanteguitars.com/Hosted/pics/driver.jpg

http://www.asanteguitars.com/Hosted/pics/driver_side.jpg

http://www.asanteguitars.com/Hosted/pics/guts.jpg

http://www.asanteguitars.com/Hosted/pics/off.jpg

http://www.asanteguitars.com/Hosted/pics/on.jpg

.

Edited July 26, 2006 by Tony Enamel

[psw]

Hey Dezz...sounding good, really does work...

Those switches are really tight in there by the volume control...you cant be using a 4PDT cause it wouldn't fit I'm sure. Did you need to route out the guitar some? Where does the circuit and battery fit in?

BTW, do you get an octave lower sounds on the lower strings in normal mode, or is it always a continuation of the original pitch?

Really need to get some of those harmonics going...

OK...so your blade is wider than mine but it looks really good, good work on that. Now, the thin blade idea has not been proven (it's more of a hunch on my part) so before running out to make another, lets look at a few other things.

I am not sure what the output capacitor on the ruby is (ahh...it is specified as a 220uF)...now, on mine I have changed that to a 100uF and that's on a bright sounding single coil guitar. So, this output capacitor if made lower will give a brighter circuit (less bass) and may compensate for the darker sounding humbucking pickup you are using and bring out those harmonics.

You may also get that "mix" effect I get on the lower notes where the morph into notes an octave above as they sustain. This will give more character to those long held notes and a singing quality to the lower strings which is kind of neat. Sounds more like singing feedback than like a continuously held organ note if you get my meaning...more guitar like!

I am not sure how you have wired it, but I did need to use a switch to lift the ground from other pickups. I gather at this stage the neck pickup is disconnected (is it disconnected completely or just one end or shorted?) so that shouldn't cause a problem...if it is a single pickup guitar and you aren't using bypass, it should work out ok just to turn the circuit on of course...maybe a few more details

Otherwise, the harmonic mode works in reverse, it actually tries to stop the note ringing and as a result, leaves and sustains a harmonic above it. What is happening when you reverse the wires? Do you get sustain?

Anyway, nice clip, I couldn't get the previously posted wav file to work, but this came through fine and not too big, great! I like the way the clean track sustains along under the picked notes...kind of like a guitar and organ combo...very floyd!

Here's a trick for you, if you play a harmonic with the pick or finger, the note will return back to the normal note as it sustains in normal mode.

Nice contribution and I hope it inspires and you are enjoying mucking about with the thing... pete

[Tony Enamel]

Hey Pete,

Thanks for your suggestions. I'll try the lower value cap tonight.

I am not sure how you have wired it, but I did need to use a switch to lift the ground from other pickups.

I have completly removed all other pickups. Just the bridge remains. The circuit fits under the pickgaurd where the middle pup used to be.

What is happening when you reverse the wires? Do you get sustain?

I get harmonic sustain on maybe 3 notes low on the 6th string and nothing at all anywhere else. It almost seems like the driver is stopping the vibration altogether. So, not only do I get no harmonic I don't even get the guitars' natural sustain!!

I instaled the LED last night and today my sustainer doesn't seem to work as good. Do you suppose I need a higher value resistor to the LED? My uneducated theory is that the LED is "stealing" too much juice from the circuit. Does this make sence? The LED is pretty bright.

Also......

The drain bias; does that just trim the amount of current the circuit recieves? What I mean is, If my battery is going dead and I open the trim a little, will that effectively bring the bias back to 4.5V?

[psw]

It does sound like you have a problem with the circuit there....is the battery still getting hot?

This device will take up a bit of juice...hence the need to replace the battery often. You could add more resistance to the LED to bring down the brightness but compared to the circuit itself, it shouldn't be that much...mine is very bright too BTW.

Don't alter the drain...the idea is to create a balance for the transitaor for the voltage supplied to make it work properly. (you may wish to check that you have it right, check the voltage of the battery first). The voltage needs to be divided evenly and each transistor has manufacturing inconsistancies that need to be adjusted for...henc e the trim pot. So, if the circuit is getting 6 volts, it would trim to 3 if you see what I mean. (this trimming thing is what turns me off the fetzer preamp and I would still like to see an alternaltive circuit, maybe with an opamp, instead...my preamp uses two transistors and no trimmers and a bit of filtering with a lot more gain...the down size is that it is a little bigger, the up side is that I converted it from a kit so I get a printed circuit board...same with the LM386 )

There should be no drain on the battery when the sustainer is switched off though, I wonder if it isn't slowly draining the battery some how by some kind of short...hence the heat...bit odd that one.

It almost seems like the driver is stopping the vibration altogether.

Aah, well see that is how it is supposed to work, it does stop the guitars natural sustain...leaving the harmonic...just like a finger over the twelth fret will stop the natural vibration yet leave a harmonic.

Now, this also feeds my thin core drive theory in a couple of ways...the wave length of a low pitch is longer and slower and the low strings have more mass and are easier to drive... That said, the sustainiac has a fairly wide core, so I could be wrong, and your's is not that wide!

here is the fetzer/ruby circuit...maybe someone else can see a problem with it...

A capacitor wont allow a direct current to throw through it so I can't quite see how the power could be flowing from the +ve to -ve...but it might be and that would cause the battery to slowly drain.

Maybe the first thing you should do is put a fresh battery in the thing and see how you go. If you have been testing and using the same battery through all this, it is probably time for a change

Good luck, and at least you have got it going thus far, that's pretty cool! pete

[Tony Enamel]

My battery is not getting hot anymore. I had the on/off switch wired wrong because I didn't understand how switches were wired inside(I told you, I'm new to this electronics stuff!) but I did a little research and got it right.

If the drain is supposed to be 1/2 of the voltage supply, would it not make sense that if my battery was worn down to, say, 7V then the drain should be adjusted to 3.5V?

Pete: Any chance of you givin' up a schematic of your circuit? I'd love to compare it to the fetzer-ruby using the same driver. Or maybe you can build a fetzer-ruby and try it with your driver so we can isolate which symptoms come from the driver and which come from the circuit.

[Primal]

Its not that the drain is supposed to be half of the voltage supply, it just happens to be so in this case. That just happens to be the optimal voltage for that transistor. For instance, I am using 12v supply, but I still biased my drain to 4.5v.

Now I'm not 100% sure about this, as this is just a google research, but according to Ohm's Law: Voltage = Current x Resistance. Now, assuming that current draw is constant throughout the batteries life (which seems logical to me), we can see that so long as the current draw is constant, then everything "behind" the trim pot that controls the drain bias should remain constant as well. You see, the above equation has no place for an input voltage. Thus, the voltage behind (as in, going from v+ to the transistor) the trim pot is dependant on the current draw of the circuit and the resistance of the trim pot. Technically, I suppose, as long as you have enough current, you could have 1v input.

I have absolutely NO idea if thats correct or not. In all likelihood its not. I'll let a "professional" correct me.

Either way, if you really had to adjust biases, etc, as your batteries go down, NOTHING in this world would work correctly after the first few seconds of operation.

[psw]

Pete: Any chance of you givin' up a schematic of your circuit? I'd love to compare it to the fetzer-ruby using the same driver. Or maybe you can build a fetzer-ruby and try it with your driver so we can isolate which symptoms come from the driver and which come from the circuit.

Weeelllll...the quick answer at this stage is...NO!

The longer answer is that I have had a catastropic life collapse, lost everything and am going through the courts at the moment to regain my property and my children after a marriage collapse a year ago. So, for the last year I have been living out of a suitcase and have my guitar and this computer now...and that's about it! Now...I hope to be back on track in the next few months but am possibly going to have two children to care for and even when I get my stuff back, it will likely be stored somewhere and I may lack the time and energy. It's all very sad, especially when I was making such progress on all manner of things, including this project.

So, I don't actually have the circuit diagram (it is in the other computer I think) but I could reproduce it at some stage. It isn't really suitable for DIY without the circuit board but this may become available. I did find someone who may have been interested in helping me develop a standard circuit, but that seems to have gone by the wayside. I do have another person in mind, and that could be good as he already sells boutique stompboxes online so I could perhaps supply something that way.

That said, I have had people look at it and consider that it should be loading the pickups, but it doesn't seem to...so...eh! Basically it uses two traditional transistors and a bunch of capacitors to filter everything bar the audio frequencies out of it. It requires no trimmers. I modified the kit to have a lot more gain in the preamp section. The LM386 part is from another kit which has the modification of the 100uF output cap (I have had 220uf or even 440uF in other ones). This also has a few extra capacitors to help with stability, especially a 10uF between pins 1 & 8 of the LM386. The circuitboard for the preamp is 44mmx35mm and the poweramp 45mmx2.5mm. I could do something to supply this kit with modifications at some point (it would be easy to post), maybe even the wire...but I still have that pop and a few other concerns.

The fetzer/ruby could be made smaller than mine, but it takes a bit of work to do without a circuit board. Getting one made could be a little expensive really unless you were going to make a lot of them and I suspect my kits complete with components would be cheaper than making your own board!

The history behind the fetzer/ruby is that it is a combination of things from the runoffgroove site proposed by galagamike in his tutorial. It is great to see that we have positive results from it now, as there were some concerns with Mike's project. He didn't quite follow the formula though in the driver design. He used a wide coil of dubious magnetic quality (claimed it was stainless steel which would be non-magnetic, but possibly not, who knows) and had a lot of trouble getting the harmonics to work.

I am loath to attribute too much to any circuitry hocus pocus...however...I am told that to get the kind of gain I get out of my preamp, you'd need 3 or 4 fetzers chained together! Effectively, my preamp works as an overdrive (I have very wimpy single coils though) and if you wanted to experiment you could put an overdrive pedal or make some kind of fuzz as the preamp, or even into the fetzer/ruby and see if that helps. Such gain will cause both clipping and natural compression and may help to bring out the harmonics a little more. I would try that output cap mod though first as that is just as likely to yield good results. As for the battery consumption, well I am not playing a lot, but with intermitent playing (1/2 hour at a time) the battery lasts for a few weeks.

If the fetzer or some variant could be developed it could be made really small. I would have added a few more components in there, particularly a 10uF cap between 1 & 8 to help with any oscilllation, but then perhaps my thing has a bit of overkill in it.

I did try quite a few attempts at building alternate preamps. I was particularly taken with the idea of an op-amp circuit but had very little success (I was self taught electronics for this project) and did build a compressor limiter with on board LM386 circuit for testing the Hex designs at oune point that worked well (if a little big to be practical).

These experiments though were aiming for the moon, true hexaphonic sustain and use of all pickups with the sustainer...I even hoped to have the thing mounted right up against the bridge (using the bridge as a magnetic sink to cut back EMI) and have the whole device including batteries mounted in a box on the front of the guitar like a tailpiece.

The Hex driver technology is still the only really secret thing here, though it would be very difficult for anyone to DIY it and has it's own problems and has been abandoned. I think the main contribution that the year doing that stuff was that I miniturized the device to such an extent that I found that their size overcame a lot of problems with speed and hence the thin driver was derived from that. The thin driver works just as well as any of my Hex designs as far as they were developed and the combination pickup/driver is a far superior concept in my view anyway.

Perhaps one day, maybe next year, depending how my life turns and who I may meet along the way, I might make something more of this project, but for now all I can do is encourage others and learn from their mistakes, lord knows I've made enough of my own...be of good cheer... pete

PS...Oh, and I should add that seeing these projects come to life makes me tremendously proud and that is it's own reward in troubled times...also...that helping you guys gives me a pleasant distraction from all the crap I am having to deal with at the moment. Thanks P

[psw]

Sustainerites may wish to note a sustainiac equiped LP in this months GOTM GOTM August 2006 from JFC.

I'm not sure where the controls are, perhaps they are rotary or push pull or something, but it is a good pickture of the top of the sustainiac pickup. Unlike Fernandes who now seem to disguise their device as a normal pickup...this is obviously a sustainer. It does not really look like their patent diagrams though. The core is really wide, or so it seems. You can see it is split at an angle between the high and low strings. This is a so called bilateral driver (the next logical step for our thin driver perhaps) having two coils of opposite winding and magnetism so that (like the humbucking principle) there is some cancellation of the EMI (electro-magnetic interferance) by putting out equal amounts of opposite polarity. Fernandes used a similar principle on a driver that was like a stacked single coil on it's side with fins coming up on the sides and the centre from a pair of coils...a little odd, and no longer in production, but interesting all the same.

To make a bi-lateral driver based on our model here, I would be proposing two coils sitting on top of a humbucker with one over one coil for the low strings and another on the other coil for the high strings (about 4 ohms each)

If one were to do enough R&D on this, you could even tweak the coils so the high string driver coil had a little more omph and treble response perhaps. This is what I was working towards in the hex driver where each string would have a driver tuned to it's particular characteristics (mass, speed of vibration, etc) and hopefully give a better polyphonic response from a single amp (that's how I was proposing to do it without a hex pickup and six amps, anyway)

One way of driving a bi-lateral driver may be two use a stereo poweramp with trimmers and response characteristics tweakable by trimmers. However, when ever you get into this kind of thing you are running into further problems with power consumption and the size of the circuit. There are plenty of stereo poweramp chips out there or even two LM386's but power is going to be at a premium...I guess it depends on what kind of commitment you are going to make to the sustainer...

Had to go to town to get my car serviced today and was checking out some guitars...saw a neat new cort with onboard overdrive fitted...very tempting as there's room enough in there for a sustainer and a ready made battery compartment...the overdrive would probably make an ideal preamp for the sustainer somehow anyway (meaning you'd only need the tiny LM386 part) and, a single coil neck pickup just begging for a driver conversion...A$350 and not a bad looking axe...grrrrr... must save, must not spend money on guitars...

Actually, there are so many things I'd like...thinking of a getting a proper sound card for this computer....if I got MIDI I could plug in a controller I got at home somewhere and muck about on that too...not to mention get a bit of recording happening...so many temptations...

pete

[Tony Enamel]

Hey Pete,

I am not sure what the output capacitor on the ruby is (ahh...it is specified as a 220uF)...now, on mine I have changed that to a 100uF and that's on a bright sounding single coil guitar. So, this output capacitor if made lower will give a brighter circuit (less bass) and may compensate for the darker sounding humbucking pickup you are using and bring out those harmonics.

Thanks for the suggestion about the output cap. I changed it this afternoon from 220u to 100u and I'm getting lovely sustain on every string.

You may also get that "mix" effect I get on the lower notes where the morph into notes an octave above as they sustain. This will give more character to those long held notes and a singing quality to the lower strings which is kind of neat. Sounds more like singing feedback than like a continuously held organ note if you get my meaning...more guitar like!

Now, in normal mode I do get that octave morph you described! HOWEVER, I still don't get much in the harmonic mode. I'm getting more than I did yesterday though, so we're moving in the right direction!

Any other suggestions on bringing out those harmonics? What percentage of your entire fretboard give nice harmonic sustain?

BTW, I'm using 11 gauge strings. Do you think I should try 10's or lower?

Also, I designed my driver with a removable core. I cut a new piece of metal and ground it down to about 3.5mm and my sustain still works about the same (although I only got to play with the thin core for a few seconds). I'll try a little more playing tonight and give you a 100% confirmation on your thin core theory. My original core was just under 5mm so there's not a huge difference. But If I find that one works better than the other I'll let you know.

Originally, my driver just used the alinco pole piece slugs from the pickup. It worked but as I bent away from the pole the sustain faded. So I cut a 5mm steel core from a strip of welders steel and just set it on top of the poles and pushed them down into the flatwork of the pickup. Bends worked much better. So, that confirms that theory. Now, as I mentioned, I'm trying the thinner core theory.

I'll keep you posted.

Dezz

Edited July 28, 2006 by Tony Enamel

[psw]

Now, in normal mode I do get that octave morph you described! HOWEVER, I still don't get much in the harmonic mode. I'm getting more than I did yesterday though, so we're moving in the right direction!

Makes you wonder what would happen if you used a 10uF cap...or even a switch to switch between different output caps....hmmm

BTW, I'm using 11 gauge strings. Do you think I should try 10's or lower?

No, the thicker the better, Id say, stick with the 11's...I don't think a thicker string would make a difference to the harmonic mode function.

Also, I designed my driver with a removable core.

Ingenious...but not really a true test...now the coil is not right up against the core so I think you will lose efficiency.

I wonder, did you get harmonic sustain when testing over the neck?

Keep tinkering...if it is a problem with preamp power, you could try patching an overdrive between the pickup feed into the F'n'Ruby.

Keep up the good work, this is giving us more confirmation of the way to proceed which will make attempting this easier...less theories more perscriptive... pete

[MiS]

Hi all,

i was just skimming through the pages (too many of them). I am not really interested in a sustainer, but the basic idea is the same. I want to drive strings with a coil but feed coil with an audio signal (in my case, from a computer) and make strings vibrate at the frequencies I choose.

My theory is that I should be able to make the string move at different harmonic nodes, depending on the audio frequency I feed the coil. I built a simple amp (http://tangentsoft.net/audio/cmoy-tutorial/) but it is not enough (not even with my cheapo 25W guitar amp in series) to drive the strings. The signal leaks to pickups like hell (unless I place the coil far from PUs) but I can't get the strings to vibrate.

I would appreciate any ideas, you seem to have been through all this. I am beginning to think that I probably need some kind of feedback mechanism but my goal is to control the frequencies (overtones) from the computer.

Thanks.

[spazzyone]

in got it and i got it good

i used a cheap blade pick up from ebay as the driver

i used a digitech rp 6 with the grunge cranked into

a little 20 watt radio shack pa using the 70 volt output

to drive it. worked awsome although i dont remeber the phase of the pickup

so i dont know what mode it was but........

when i kicked in the wah pedal it went nuts

i was able to take it from sustain to mad harmonics with a rock of the foot

i did not have time to try other effects but will

and when i get a chance ill post a sound clip and a pic of the mess

that is my system. while it is out board i can live with it

[psw]

in got it and i got it good

Very strange spazzy...doesn't sound too stage friendly...hahaha

Seriously though...are you using the blade pickup as is, or did you wind it as a driver? Also, that's a lot of watts...it's not simply feeding back through the pickup itself...that can sound like feedback sustain...but not actually drive the strings any longer...the electromagnetic coupling through the pickup produces an enormous output...be careful you don't damage anything, you impedances may be all over the place...

As for the Wha...primal was talking about puting one in the signal chain...I certainly find it usefull to bring out the harmonics with some sounds (on the guitar, not the sustainer direct). Many, many years ago (in the 80's) when I did my first experiments with this, I used an old hifi amp (see the first post) and also experimented with effects in the signal chain...which brings me to the previous post...

Welcome MiS...interesting, but...

My theory is that I should be able to make the string move at different harmonic nodes, depending on the audio frequency I feed the coil.

Well...yes, if the frequencies directly relate to the natural harmonic serious of a given pitch.

A lot of this is to do with resonance. A given length, gauge and tension of string will vibrate at a given pitch (it's fundumental naming note/frequency) plus higher harmonics related to it (the natural harmonic series). You can play the natural harmonic series by fretting over the 12th fret, the 7th, 5th and working towards the nut (or the bridge...ie the ends of the strings), ever higher harmonics not related to the frets (which are placed for the western equal tempered tuning we use in the west).

Now, as a side line, the "tone" of a guitar (what it is made of and how it is played, etc) relates to the mix of these subtle harmonics underneath the fundumental note. The differences in pickups too relate to this, a pickup placed near the end of the string length (the bridge) will pickup up vibrations rich in harmonic overtones (brighter frequencies) than those at the neck (more rounded fundumental frequencies). The vibrations are also stronger near the centre of a string (there is more movement, or "throw") than at the ends where eventually it reaches a fixed point (the bridge)...hence the need for a stronger output pickup at the bridge to compensate for volume.

Anyway...The string can only vibrate in relation to it's string length. You can not take an open E string for instance and vibrate it as an F note frequency. You could make it vibrate an octave, a fifth or a natural 3rd above it's pitch, as these are part of the harmonic series and could sound as harmonics (ie the fundumental tone is suppressed. This is how the Sustainer makes the harmonics...by suppressing the fundumental (running in reverse) and driving the harmonic frequencies. Just like stopping the main vibration at the twelth fret and leaving the next order harmonic (the octave) to sound.

So, our sustainer exploits the resonant frequencies of the string in real time by amplifing the string with it's own signal...creating a feedback loop. It is one of the reasons that it doesn't need massive amounts of power to physically shift the strings (as you have with a pick for instance). Also, with the smaller output cap mod that I suggested to Dezz, and I have on my guitar, the sustainer amp is biased for the higher frequencies (a wha would have a similar effect) and so the low notes are gradually driven to it's octave which are more amplified and reinforced by, the fundumental...hence that octave harmonic jump.

Perhaps using a wha circuit, as Primal suggested and I went on about early in this thread (using effects for a natual synthisis) to some derision as I recall, does have some legs. Perhaps the whole reversing of the driver to produce harmonics could be achieved by a wha like circuit to bring out natural harmonics stronger (like the output cap mod) and thus be more selective as to what harmonics are brought out...hmmm

Now, let's relate an experiment from way back...I have experimented with putting effects into the signal chain. One very interesting one was the use of a flanger that could sweep through the frequency spectrum (think slow jet flanger sound)...this produced wierd harmonic chirps from the string as it hit frequencies that existed within the harmonic spectrum of the strings vibration. What it didn't do was to drive the string at any of the non-related frequencies.

So, the proposal to drive the strings by artificially creating tones from a computer is possible but only in that they relate to the vibrations of the string itself. I did do experiments at one point using a tone generator to drive a string, where the string and the tone were tuned to one another fairly precisely. I was doing this to test different wave forms (sine, square, triangle, etc) to see if there was any prefered signal for sustain.

I stopped that nonsense mainly because it was not practical and that I could drive the string with any of these wave forms, but with my crude experiments, could not detirmine any advantages. It did not really produce different tones though. The string will vibrate as it will (a combination of various sine waves), it is possible that a sustainer could eventually be produced to change the "tone" a little (bring out different harmonics in a note) but this would be fairly subtle I would think. What the string wont do is actually vibrate in a square wave for instance. This sound can be produced by clipping of the waves electronically (with a fuzz) on the signal...but not with the string itself.

Feel free to experiment by all means, but be aware of the limitations of the physics involved. Even if you could control the frequency spectrum of pitches...ie the "tone" of the guitar...the computer would need to be able to track each note you play and bring forth an interpretation of it in exactly the right phase to be effective...any delay will result in trying to push the string instead of pulling...resulting in damping of vibration rather than driving it.

This could be what you are trying to do (suppress some modes of vibration to accentuate others) as we do with the harmonic mode of the current devices, but it is unlikely that the computer could keep up enough in real time to take all the information into account (pickup, driver placement in relation to the changing length of a string as it is fretted).

In the end, you need to examine the practical application and if there aren't other ways to pursue what you are after. For instance, by simply varying the output capacitor on our simple circuit, it gives it a much higher frequency bias and as a result drives the lower notes an octave above as it sustains through and the sustainer takes over the drive of the string. Would a 10uF cap as I suggested above do the same for even higher frequencies, and what of the low strings...will they now be driven at an octave and a fifth (the next higher parts of the natural harmonic series)...are these the type of sounds people want to creat, and for what purpose.

Certainly these ideas are interesting and could reflect upon the type of music possible with the instrument. It brings the guitar much closer to the natural harmonic series, the in-tune-ness, available to wind and the fretless families of instruments. Is this what people are really after, or do people ultimately want to rock out and spice their playing up with a little feedback action or infinite sustain.

Feels free to experiment and do share your experiences, it will certainly be a learning experience into the fundumental physics of things. I cant help thinking (having been through a lot of this stuff already) that more rewards would be gained from building this as is, then work on it further. But, each of us have to find our own way and this thread is an example of how things can be found by following a path less travelled...

Good luck, and thanks for the interest...sorry for all the theory for those not interested... pete

[MiS]

Well...yes, if the frequencies directly relate to the natural harmonic serious of a given pitch.

Absolutely. This is my intention.

I am sorry for not having been more verbose from the start, I would have saved you a bit of typing as you explained some things of which I was aware already. But I thank you for your your input, your posts are very informative.

So, a little background.

I have been playing the guitar for almost 25 years. Classical (mostly 20th century music) and electric (a little jazz, a lot of blues, some rock/prog-rock type of thing). For the past 7 years I've played mainly free experimental improv using the guitar and the computer (as an fx rig, resynthesis tool, guitar induced synthesis, algorythmic improv tool etc). Lately I started exerimenting with live coding.

In the past couple of years I also started foling around with alternative tuning systems based on natural harmonic series. I have started writing some pieces using only open strings and harmonics.

So, today, the idea is to put together all these things. live coding and outputing specific frequencies to run the strings at the specific harmonics (and, optionally, perhaps running the guitar signal back into the computer for further processing but for now I would like to go back to basics).

Some of my recent work is here

...hence the need for a stronger output pickup at the bridge to compensate for volume.

So you mean, I have to modifiy the guitar as well?

Anyway...The string can only vibrate in relation to it's string length. You can not take an open E string for instance and vibrate it as an F note frequency. You could make it vibrate an octave, a fifth or a natural 3rd above it's pitch,

I would like to go even higher up the harminic series. Say, up to the 8th harmonic.

So, our sustainer exploits the resonant frequencies of the string in real time by amplifing the string with it's own signal...creating a feedback loop.

Ok, so, I do need a feedback loop...

...this produced wierd harmonic chirps from the string as it hit frequencies that existed within the harmonic spectrum of the strings vibration. What it didn't do was to drive the string at any of the non-related frequencies.

I know that you have to hit the exact frequency. But in my set-up I mentioned in my first post I cannot get the string vibrate at all. I can feel the core in the coil vibrate but the strings remain silent (or, at least there's not enough movement to be audible). I used various oscillators sweep various ranges of frequencies to no avail.

I did do experiments at one point using a tone generator to drive a string, where the string and the tone were tuned to one another fairly precisely. I was doing this to test different wave forms (sine, square, triangle, etc) to see if there was any prefered signal for sustain.

I think this is the element that would interest me the most, ATM.

I stopped that nonsense mainly because it was not practical

This is the kind of impractical nonsense that interests me ATM

and that I could drive the string with any of these wave forms, but with my crude experiments, could not detirmine any advantages. It did not really produce different tones though.

I am not interested in producing different tones. For that I use prepared guitar techniques and the computer. I want the pure string harmonics and vary the tuning of the guitar (well, not necessary on-the-fly) and thus be able to create all kinds of pure intervals in all kinds of configurations.

Feel free to experiment by all means, but be aware of the limitations of the physics involved. Even if you could control the frequency spectrum of pitches...ie the "tone" of the guitar...the computer would need to be able to track each note you play and bring forth an interpretation of it in exactly the right phase to be effective...any delay will result in trying to push the string instead of pulling...resulting in damping of vibration rather than driving it.

hmm... this is interesting. So I need a feedback loop for this thing to be effective and track the frequency in order to properly drive the tone generator at the correct frequency. Right? BTW, I reiterate that I am not interested in controlling the spectrum through this technique.

This could be what you are trying to do (suppress some modes of vibration to accentuate others) as we do with the harmonic mode of the current devices, but it is unlikely that the computer could keep up enough in real time to take all the information into account (pickup, driver placement in relation to the changing length of a string as it is fretted).

I dunno... I think the computer can keep track of a lot of informatino if provided with proper data... oh, BTW, I do not intend to use any fretted notes.

Certainly these ideas are interesting and could reflect upon the type of music possible with the instrument. It brings the guitar much closer to the natural harmonic series, the in-tune-ness, available to wind and the fretless families of instruments. Is this what people are really after, or do people ultimately want to rock out and spice their playing up with a little feedback action or infinite sustain.

For me, playing infinite drones = rocking out

Feels free to experiment and do share your experiences, it will certainly be a learning experience into the fundumental physics of things. I cant help thinking (having been through a lot of this stuff already) that more rewards would be gained from building this as is, then work on it further. But, each of us have to find our own way and this thread is an example of how things can be found by following a path less travelled...

thanks. I did start experimenting but I came here because I am failing on some fundamental level. I may have >20 yrs experience in music but I'm a noob in electronics.

thanks for the pointers, though. You have been very helpful. I will reevaluate my experiments and try to pick up on some of the ideas in this mega-thread. I will certainly report back and share what I have found/learned. I certainly welcome more ideas WRT to what I have expleained above.

./MiS

Edited July 29, 2006 by MiS

[Tony Enamel]

OK...

In the beginning, there was no harmonic goodness. Then Pete said "Let there be a 100uf cap on output!" and a few rays of light could then be seen. Being blessed with free will and an inquisitive mind, Dezz set out to let his light shine. In doing so, he changes to a 47uf cap... and the clouds began to part. The warm harmonic glow began to shine a little brighter (but just on the 6th string and 1 or 2 notes on the 5th)!

I'm going to try your 10uf suggestion later today. I'll keep you all posted.

Question: What would happen if there were no cap at all?

[Ben]

Question: What would happen if there were no cap at all?

Only one way to find out!

[Tony Enamel]

...Indeed.

[psw]

In the beginning

...ah yes, to where it all began, I'll get back to some of this shortly...but first...

The warm harmonic glow began to shine a little brighter (but just on the 6th string and 1 or 2 notes on the 5th)!

Hmmm...well it wont hurt to change the output cap or even delete it though removing it all together may cause some problems...but I'm with Ben here indeed, indeed!

Ultimately though, the harmonic function isn't working for you as it should (as mine does) and we need to look at how we can address this I feel. About lowering the output cap or wha's on the input, I was thinking of inducing harmonics in normal mode (not in harmonic mode). The harmonic mode is simply trying to stop the fundumental, reducing the fundumental frequencies by reducing the lower tones may not improve this function.

MiS - Don't you hate it when the PG forum rejects the quotes...it's something to do with too many"" it seems...oh well...

OK, well I know where you are coming from, a little advertised fact is my background in music at University and apreciation of experimentation and "20th century" experimental forms...

This is the kind of impractical nonsense that interests me ATM

Further...there is a reason this thread is so long...verbosity is my specialty ...anyway, the thread is about Sustainer Ideas, whatever they may be. We had a post a while back proposing using this technology to drive a piano harp with an audio signal...

A lot of what I write in those long threads are for the general audience as this is interesting stuff for a lot of people and relates to how a guitar, it's pickups and it's "tone" is produced which relates to the site as a whole. Generally, for instance, the bridge pickup is hotter to compensate for the less movement of the string near it's end, this is not a mod so much as typical of most guitars...so this isn't a mod.

Ok, so, I do need a feedback loop...

Yep, that's what these things do...just like a really loud amp, but instead of vibrations in the air moving a string, it is vibrations in an electromagnetic field that produces the effect. So it is just the same as acoustic feedback but with a tremendous amount of control.

I know that you have to hit the exact frequency. But in my set-up I mentioned in my first post I cannot get the string vibrate at all. I can feel the core in the coil vibrate but the strings remain silent (or, at least there's not enough movement to be audible). I used various oscillators sweep various ranges of frequencies to no avail.

Ok...well, there is likely that there is a problem with your driver...it should not vibrate at all. Nor should it take so much power, I was able to run the tone generator directly from the headphone output of the computer's cheap low powered speakers...true.

Also, perhaps as a starter try to get the thing to work from the guitar itself...at least you will know that whatever the tuning, at least it is driving at the precise frequency of the vibration of the string (by definition).

Another approach is what I used very early on (about the 2nd page). I wound a coil around a 4mm ferite inductor core with a magnet stuck below it. It was half an inch round, had papper bobbin and wound in glue. As I recall this was able to be driven directly from the computer headphone socket.

"I was doing this to test different wave forms (sine, square, triangle, etc) to see if there was any prefered signal for sustain."..."I think this is the element that would interest me the most, ATM."

Well, the results were fairly the same...it did not result in a different tone from the instrument as a result...just different (if any) drive efficiencies.

I am not interested in producing different tones. For that I use prepared guitar techniques and the computer. I want the pure string harmonics and vary the tuning of the guitar (well, not necessary on-the-fly) and thus be able to create all kinds of pure intervals in all kinds of configurations.

Well, there is scope for this, but harmonics that high will be virtually imposible to hear in the guitars tuning as these harmonics will be so high. Are we still talking guitar here, of some kind of electromagnetic aeolian harp?

For me, playing infinite drones = rocking out

Ok, I see where you are coming from and this thing certainly does drones to infinity...hahaha

Yes, well only too pleased to share my experiences with these ideas. Much of what I tried to do were not fully explored as they produced little results of interest. I was never aiming to produce experimental sounds from this device but to extend the potential of the guitar as an instrument. The sustainer really does hold the promise of adding a whole new vocabulary to the guitar in terms of technique and musicality...how it is applied and the success of it's application depends on a critical mass...the more people involved, the more results will become apparent and new applications become visible...if nothing else, it is an excellent interlectual exercise and a creative challenge...

have fun thinking and putting ideas in practice... pete

[spazzyone]

hey Pete

no i did not rewind the pickup and only used one coil

yes it had a lot of feedback but it was sustaining very well

notice i said was..... i dont think the coil liked 70 volts

as it no longer works......ha ha

but im gonna try again on the second coil as it was a twin rail

humbucker that was only 15 bucks

my question and i know it's probably been posted more than once

how can i isolate it from feedback

im not sure of the impedance of the amp at its 70 volts as i originaly stated it was a small

20 watt radio shack pa amp that has 4/8/16 ohms and a 70 volt output

and i only tried the 70 volts cause i read the original infinate guitar

ran at 100 volts. the guitar i have it in is completly copper sheilded

with no ground to the bridge so i was not was not worried abut getting shocked

ill make sure im set to record it when i rewire it with the other coil so

you can hear it when i kick the wah forward and make it screem

[spazzyone]

well i found my problem and its not the pickup

the amp no longer has any sound

ill figure it out and get back to ya's on this setup

but here is a pic of the pickup. i belive i bought it from

guitarheads.net on ebay. sounds great by the way

http://i32.photobucket.com/albums/d38/femf...tar/rich002.jpg

[psw]

Oh no...didn't read the often repeated phrase...A PICKUP IS NOT A DRIVER!!!!

I'm not surprised you burnt out the pickup, and probably the amp too. A pickup is wound with very fine wire (fragile) to 1,000's of ohms while your amp wants a load of 16 at most. Do yourself a favour and get hold of some 0.2mm winding wire and block up the bottom of your burnt out pickup bobbin leaving about 3mm at the top and wind a couple of hundred turns (by hand) with glue (PVA) to an impedance of 8 ohms.

You can still use an amp if you must to experiment with it but you should only need about 1/4 of a watt to get sustain, any more is going to put out so much magnetic energy it will make your other pickup squeal like a pig.

A driver is more akin to a speaker coil, it uses the same principle but instead of moving the papercone to move the air, it is moving the metal string. The wire is much thicker to allow a strong current to pass through it. The squeal is the same as if you put a microphone (the guitars pickup in this case) up against a PA speaker (the driver)...to get as close as we do (neck to bridge locations) low power is necessary.

More power is not the key, driver efficiency is where it is at...hence the magic thin coil design...simple, but very effective.

Be careful with your experiments, beware of mains voltages, high currents and especially (as it is a temptation) do not attempt to break or cut Neodyminium/rare earth Magnets. In fact any magnets should be treated with caution, when they break they turn into separate magnets and tiny sharp pieces will be shot out at high velocity by magnetic repulsion (think uncontroled rail gun), so DO NOT DO IT. Other magnets are a risk, but in the very least, if you dont destroy them by breaking them, you will demagnetise them anyway. You have been warned and I am not kidding...there is no need, suitable magnets may well be stuck to your fridge right now!

Good luck, but I would advise all to get with the program and start winding drivers suitable for experimenting with similar to that described...you are sure to get some result and something to build on... pete