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Sustainer Ideas


psw

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Have you got access to a stompbox compressor? Adding that and an EQ pedal to your original one-string would probably make a great testbed setup for testing coil designs. Of course, a frequency counter and an O-scope would make this a lot easier, but nobody I know has one, so I tend to use the "listen and guesstimate" method for circuit tuning. My gut tells me that gain control is the key here, but I certainly can't justify that, mathematically or logically, so it might just be my personal blind spot. Keep me informed... :D

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Well if we had an o-scope and knew how to use it we could mabe debunk the phase difference I guess...anyone want to try out there!!!!!

Meanwhile...yep, stomp boxes galore. I tried to use a flanger as a means to alter the phases on my original experiment years ago. What I got was a real interesting sound as it would catch a frequency (harmonic) then drop it as another would predominate and the rate would change as the harmonics got closer at either end of the sweeps...interesting.

I'll try a fuzz as well to get a square wave.

I've got a tone generator on the PC so I thought there maybe a way of optimizing coils by testing with pure tones and measure it's response somehow...any ideas there?

Meanwhile, I'm gearing up to make a hex piezo undersaddle PU for the test strat as a source for each driver...be great to get acoustic sounds and infinite sustain and the posibility of hex effects. Perhaps a simple midi out breakout box to drive software sequences and notation software...

Well, maybe...

baby steps

psw

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You can go to Steve Ekblad's Audio page and get a freeware program called FREQ. It's a spectrum analysis program for your soundcard - I've had fairly good results, but I don't have a really good mike, so I use it mostly for direct inputs, like my digital recorder. At least that way you could get a handle on the frequency response of your driver. I've used the signal generator in WinISD (a speaker cab design tool, also available on Steve's page) to drive the analyzer with some success, but you already have a tone generator, so you should be good to go. There are also a couple of o-scope programs on that page, but I haven't used 'em. Too much thinking - going to bed now...

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Andreas

I know you're out there! With your physics background...what is the effect of vibrating a string from it's end (say bridge) on the propagation as the waves travel down the string...will it amplify, as in small waves become bigger? Obviously vibration is transmitted through the bridge to the instrument, what is the effect of the reverse? This may relate to the model C which vibrates from the nut end.

First of all...the waves formed in the guitar strings are stationary waves. The stationary waves are loops which contain their energy within the loop. If you manage to input some of that energy as it fades out you normaly will get an infinite sustain.

For stationary waves to be formed a wave must come in contact with an opposite moving wave of same frequency and similar amplitude. In short..it needs a collition of two identical waves. (LK- The amplitude could be the answer to the gain control...if the two amplitudes mismach the larger wave will overrun the other.Of course this could be insignificant since that wave will be reflected in its turn and pass over it self so prety much nothing is noticed except an increase in volume)

In the guitar these are formed when the string is plugged. How is this im not prety sure but I can think of 2 possble scenarios why:

1) the wave starts where it is plugged and moves out hitting on the bridge and on the nut (or fret) and is reflected back. As the two waves come on each other they form the stationary wave.

2) The string when plugged tranfers the vibrations to the wood where it "stores" the energy and vibrates. The nut and the bridge are conected on the wood and thus start to vibrate the string at each end. This generates pulses of disturbance (wave pattern) that flows down and up the string thus resulting in an overlap of identical waves thus stationary wave.

I believe tho that it is a combination of the two since as you plug the string you see a large vibration that seems to move....the reflected waves in scenario one that overlap in stages and so they form the loop in stages....and then latter the vibration seem to subside and form more constant pattern..the second scenario explains that.

Also the sustainer C that is clamped on the headstock gives back the reserve of energy to the wood and thus maintains the string vibrations.

I believe that an electromagnetic drive should be focused on the wood vibrations rather than the string vibrations....use piezo to feed the driver and not the signal from the pickups...this might remove any feedback problems since no feedback loops will be formed between the pickups and the driver.

This might even retain the natural tone and not make it thin since we are adding the wood filtration of the tone....energy flow : Strings > wood > piezo > amplification > driver > Strings....and so on.

The thinnes of the sound in other sustainer models I believe it is caused by leaving out the factor of the wood vibrations...altho it most definatelly affects the strings the pulses that drive them is the initial wave formation (scenario 1)that is also moving...and could be causing phase problems..where as the wood vibrations are more stable and define the tone better.

Now for all those who read up to this far let me tell that this was one of my longest posts and sorry for the wasted time :D

I hope this is food for thought since mostly it underlines some theory issues and not practical aspects of the sustainer.

Post your remarks questions Ill be happy to try and answer them....afterall I have my GSCE A level physics examination next thursday B)

Cheers,

Andreas.

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Andreas

I really appreciate you taking time out to contribute and I doubt anyone really minds the length of posts too much if you've got someting to say. Anyway, they don't have to read it but I noticed that this thread just past 1000 views and look at the length of my posts :D

What your saying about the way in which the string vibrates is very relevant. This is an important area that I guess we haven't dealt with too much. It would be interesting to see what effect different drive signals have on the vibrations, and what are the limits to the type of sounds a string (and the wood, etc) can produce.

The adverse effects on tone however is, I believe, created by the effects of powerful magnets on the string and the changing of the shape of the field around the pickups. This is present whether the device is on or off. Say your pickup has a south polarity and further down the string is a driver with a powerful south polarity. The fields repel eachother and so the PUp is sensing a smaller area of the string. Conversely, if the driver has a north polarity, the PUps field is attracted and so the field is distorted such that less is travelling through the core of the PUp to be picked up...if you see what I mean... B)

I should have drawn a pic before I started the post, ay. I must do this stuff offline. :D

There could be something here to explore in adjusting the tone of pickups by the addition of static magnets near pickups to reshape the field...I can imagine a humbucking mounting ring with tiny mags to concentate the field on a smaller area of sting to get a more P-90 tone perhaps...hmmmm

The CP5x, the cage device and other ideas I've tried, are designed to produce a polarity neutral zone for the string. As it vibrates, the string alternates between more north or south. It senses (or drives) the strings in a side to side motion predominantly, very different from conventional coils, and...according to my theories...is very efficient in both containing magnetic radiation and in operation as it utilizes all of the field in its own localised area.

Anyway, stick to your studies and good luck with the exams, your input is truely appreciated. Remember, we all have theories here but don't reference them as we really are feeling in the dark, and the patents could well be BS too...don't let us confuse you

wishing you well from downunder...

psw

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The adverse effects on tone however is, I believe, created by the effects of powerful magnets on the string and the changing of the shape of the field around the pickups. This is present whether the device is on or off. Say your pickup has a south polarity and further down the string is a driver with a powerful south polarity. The fields repel eachother and so the PUp is sensing a smaller area of the string. Conversely, if the driver has a north polarity, the PUps field is attracted and so the field is distorted such that less is travelling through the core of the PUp to be picked up...if you see what I mean... :D

Yeah that is what troubles me the most. It will dampen the vibration of the strings...distort the signal of the magnet of the pickups. The best thing I can get my mind to think is a pure electromagnet with a simple iron core that wont store a magnetic field it self....(altho it will produse one when the strings are moving and when the pickups get too close).

An unatural solution I can think of is using the frets as magnetic material to vibrate the strings but it is highly imposible B)

I wish a large enought piezo speaker could be made to be added on the body of the guitar and vibrate it :D

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Hey There A.

got to KISS :D

Believe it or not, I actually tried the piezo idea and had a leaver idea to improve the throw so that the piezo would move a mag. I'm having trouble getting piezos and the buzzers are a pain to cut as you lose some crystals...

What this did achieve is an interesting piezo/magnetic hybrid pickup that may have some potential (I think I can hear Larry DiMarzio running to the patent office now...). Basically, if you glue a magnet to a piezo, as the string vibrates it causes the magnet to move generating a signal in the piezo. It's a kind of coiless magnetic PUp! It also senses the string in a totally different way that I intend to follow up on! If you used my polarity balancing trick you might even get a better response and lower adverse effects on the other PUps. You would do this by placing opposing mags on the piezo, either side of the string. The magnetism is contained by travelling through the string, from side to side, rather than along - in other words is very localised - so my theory goes! B)

Lovekraft

What do you reckon...tone generator to coil then back to analyser, commons connected, no mic...analyse resonant frequency...add components to suit response desired...

Sleep tight...its 7am here!

psw

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...I think I can hear Larry DiMarzio running to the patent office now...

Keep your voice down, he'll hear you! :D

What do you reckon...tone generator to coil then back to analyser, commons connected, no mic...analyse resonant frequency...add components to suit response desired...

I think running the coil in series should give you it's response - a sweep generator changing at a fixed rate should give you a fairly clear response curve. So:

tone generator=>coil=>sound card input.

You should get a low-pass curve, with a resonant peak at the "knee".

I've been trying to follow the stuff you and Andreas posted on the physics, and just thought I'd mention a couple of things -

  • First, I think that the actual vibration pattern of a guitar string is at least partially rotational rather than in a single plane, so I don't think that orienting the coil to move the string from side to side will make much difference, but it will take a lot more power since the distance to the string will increase, and I see no way of implementing it without two coils and a push-pull current amplifier.
  • Second, unless you find a way to "bias" the string itself with a magnetic polarity, you can only attract the string and relax that attraction, so an iron core (not magnetized) sounds like the best idea - just make sure there's no standing DC current on the coil when there's no input (a coupling cap would do it).
  • And finally, and Andreas would need to verify this because I only have anecdotal evidence to go on, the physical system that is the string, bridge, guitar body and fret will have its own frequency response with a resonant low-pass curve, so you may have to compensate for that as well.

Andreas, I like the idea of using piezo sensors to drive the system - it would probably help eliminate any "tone-sucking" by eliminating another inductive load from the system, and avoid any magnetic crosstalk between sensor and driver. I sure wish I had paid a little more attention to those physics classes I slept through. B)

Keep thinking, at this rate, you'll have a working prototype before the summer's over (well, i guess it's winter where you are, psw, but you know what I mean). :D You are archiving this for your patent app, right? :D

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sustainfeedbackdevice.jpg

finally got around to posting this at the forum new electronic sustainor with a synth like feedback. still awip. but very closely coming out of prototype stages.

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Hey There A.

got to KISS 

KISS = Keep It Simple Stupid ???

That was the first thing my physics teacher told me :D

Basically, if you glue a magnet to a piezo, as the string vibrates it causes the magnet to move generating a signal in the piezo.

Very interesting and original idea!! I think if you break up rare eath magnets (but carefully so they dont demagnitize) and ground them up to dust and then glue it on you will get a more responsive system and it could be thin enought to be placed anywhere. Also the breaking up of the magnet will make it to loose polarity so the string will be evel less affected by dampening. The small individual magnets will still be affected by the string.

And finally, and Andreas would need to verify this because I only have anecdotal evidence to go on, the physical system that is the string, bridge, guitar body and fret will have its own frequency response with a resonant low-pass curve, so you may have to compensate for that as well.

Sure it has these overtones as they are called. A single frequency note would be really anoying...in fact it will sound like a simple piezo speaker...simple and constant which it would form a simple sine wave on an osciloscope.

The overtones are the ones that make the sound of the guitar interesting and unique and differend than the same note on a piano or on a saxophone. They have the same frequency curve but with alot more overtones coloring the sound.

That is the reason differend wood make different sounds and why differend hardware and construction quality affect the sound. Afterall if it didnt affect anything why the same pickups with the same strings sound differend on different guitars.

The overtones will be sellected in the amplification system that you will setup driving the string since they cant be avoided anyway. They introduce distortion in the curves which are the overtones and this distortion will be amplified as well. (distortion not in a heavy metal headbanging way...distortion of overtones that colors the sound of the guitar and makes it unique)

Sorry for the repetition of the words overtones:P im down with a fever right now and Im a little bit shakey.

Cheers,

Andreas.

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EUREKA!

I have just started teste on a fadical new design with very exciting results:

CP6x

unfortunately the graphic wouldn't upload

The CP6x prototype is a very different driving design utilizing the polarity balancing principles found in the CP5x but in a different way

I'm very excited about it because it has some fantastic features:

The field is neutral in the area of the string and an important part of it's internal design

- this means little to no drag on the string

- no interferance with PUps when off

- no wolftones

- can be set close to the string

- more powerful magnets can be used in the design

The field is very directional and moves in a circular manner across the string

- very little energy is wasted in all directions

- a more natural vibration pattern is achieved

- both polarities, push pull effect, is used

Two principles are at force to create the circular field

- twice the energy at work means a more efficient driver

- all of the energy produced is concentrated on driving the string

- very little energy has a chance to leak out

It's tiny and cheap

- Each CP6x element measures 5x5x10mm

- the first one took me 10mins to make (I could do it in 3)

- it involves no coil winding

- the materials are not common but are easy to source

- cost A$3.00 to make each element

It works!

- preliminary tests show that even with the no frills 386 amp and a 9 volt battery, it was able to drive the string.

- I was able to mount it with ds tape between the middle and bridge pickups of a strat

- a 6R5 resistor was required to bring up the impedance and so most of the power went up in heat, yet it still was able to drive the string!

This could be a breakthrough...stay tuned

psw

P.S. Shhhhhhhhhhhhhhhhhhhhhhhhhhh...seriously I think I need some advice on this...i've got little money and I'm on the otherside of the world....

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Dude, I was only kidding about the patent app, but if you think you've got something truly innovative, seek competent legal advice and for jeebus sake, don't post it here!! I'd hate to see your hard work lining some corporation's pockets. I know for a fact that certain manufacturers monitor forums (don't know for sure about this one), and there's no sense in giving them a head start. I'd love to see what you've magicked up, but you might want to play this really close to the vest, especially if you've got a potentially commercial product. Prototype it, photograph everything, and document everything before you publish anything - and find out about Aussie and UK/International patents. So far as I know, the US recognizes international patents so long as there is no conflict with a US patent, but don't take my word for it, get some informed advice. Good luck with it! :D

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I agree. Of course, I'll happily sign a confidentiality agreement and be a field-tester for you. :D

And IF you discover that you don't have enough original intellectual material to apply for a patent, for the love of God let us in on the secret. B)

Greg

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:DB)WARNING :D :D

DO NOT TRY TO BREAK A RARE EARTH MAGNET

THE FORCES WITHIN, EVEN THE TINY ONES, MAY CAUSE THEM TO EXPLODE AND CAUSE SIGNIFICANT INJURY

ah ok. Thanks for the warning.

Congradulations on the discovery. After you patent it if it is that low cost in production then start selling them in this forum :D

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:DHold on Guys, clearly I'm excited...but B)

theres a way to go yet :D

Actually, I wouldn't mind if someone bought up my idea and made a lot of money (did you get that Larry...) as long as I got a slice. Realistically, I'm not sure that that is going to happen...

Meanwhile...Let's all marvel at the CP6x drive element (no it's not a coil Larry...) as a possible building block of the sustainer idea (further testing withstanding) and assume for now that I really have something here. We still have to design an effective means of driving it...

But first, I would like to thank you all for your contributions and support.

Thanks guys, I appreciate the help and ideas :D

Yes, I do think this is something new and simple. While it is designed primarily as an efficient driver it would also make an interesting pickup.

A special thanks to LK for turning my attention to a better driver as a solution and getting me off some of the obscure stuff in the patents. Your comment about concentrating on the driver helped motivate me to change my approach <ahttp://www.projectguitar.com/uploads/emoticons/default_biggrin.png' alt=':D'> cheers mate!

A mistake I was making, I think, was to follow in the footsteps of previous designs which is to make, effectively, a reverse pickup.

I have never seen anything quite like this design anywhere and I was quite amazed to see that it worked.

I'd love to get a patent and sell it to some corporation (if your listening...larry), especially as I'm lifting boxes for a living and have hurt my back (don't worry not too serious, just a pain in the arse {ass})

I'll make up a hex version soon and then concentrate on drive circuits.

If people feel that they could contribute more fully to the project by testing the drive element, and it lives up to it's promise, I would be prepared to make it available, hidden within epoxy, with some specs for this purpose...

There is a real possibility that I could produce these drive elements and/or a completed model. I don't know much about securing my designs or making a profit from them but perhaps, by having a working model produced and in use, this would help my claim...so...who knows...

All advice taken on board, keep it coming

I didn't expect to make this much progress so fast so I wont be suprised if it slows down...

cheers

psw

By the way, I have some graphics showing how it acts upon the string differently from a conventional coil design, but unfortunately I can't seem to upload the jpegs into photobucket as I did the last one...any ideas for posting images?

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By the way, I have some graphics showing how it acts upon the string differently from a conventional coil design, but unfortunately I can't seem to upload the jpegs into photobucket as I did the last one...any ideas for posting images?

I can host 'em on my Erflunk account if you can't get Photobucket to work - just email me, and we'll get 'em loaded.

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OK, seem to have graphics capabilities again!!! (ignore that message LK)

CONCOIL1.jpg

CP6X2.jpg

These two graphics show the differences between the controlled cycling field of the cp6x driving element and that of a conventional coil - eg cp1

enjoy :D

psw

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