Author Topic: Frequency Modulation Pickups  (Read 1402 times)

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Frequency Modulation Pickups
« on: January 01, 2011, 12:19:31 am »
Yeah, that's right.  I dreamed up more smoke and mirrors for ya to think about.  First we have the Own Your Tone pickup system that we've discussed here on the forum, and now we have the FM pickup. 

Thing is, this one is highly unspecified.  The OYT thing works and is sitting right next to me waiting to be shipped to it's next owner.  Cool.  This FM thing is totally conceptual and requires someone with more radio frequency experience than I have to complete the project.  So I'm looking for partners in crime here.  How does it work?  Listen up: 

A guitar string is coincidentally just about the same length as an FM radio antenna.  That means it's got enough inductance and capacitance to act as an electric circuit element of it's own right without any conventional pickup or even OYT magnet configuration.  The guitar is a resonant element, just like Aretha Franklin breaking the wine glass with her voice, we can make that thing sing. 

How?  we add the voice.  Specifically an oscillator which is so designed that it interacts with the antenna during its oscillation.  Why do that?  Well, a little observation really which is the following: 

The guitar string is a certain length, fretted or not, it is X meters long.  When it vibrates it gets a little longer.  Say what?  yes, take a string and pull on it and think about the triangle that's formed.... it's longer than  when at rest.  This additional length changes the whole physics/electronics reality and makes the string resonate at a lower electric frequency. 

So in summary, what happens is that vibrations in the string change the inherent electrical resonant structure of the string, which the proper circuitry can detect. 

Make sense?  Of course not, not to most, a little to some an crystal clear as daylight to just a few readers.  Regardless of your particular skills and knowledge in this area, I welcome your response. 


Offline TB-AV

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Re: Frequency Modulation Pickups
« Reply #1 on: January 03, 2011, 07:59:39 pm »
You know... Yamaha invented one of these a long time ago. Problem is, some joker came by and stole the strings off the guitar. It was crunch time and the Big Boss was coming to town. So they stuck it all in a piano at the last minute. Needless to say the Big Boss approved and gave everyone a raise.

The rest is history. True story. No...I'm serious I didn't make that up.



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Re: Frequency Modulation Pickups
« Reply #2 on: January 03, 2011, 11:01:25 pm »
Hehe, well, I dunno about that TB-AV!  But I did talk to my friend Dan the other night about it.  We both did the same experiment, which was to attach a guitar string to the antenna of a cheap FM radio and see if we could detune the station by motion or vibration.  His worked, mine didn't, presumably because he used a cheaper radio with less isolation between the antenna and the input circuitry  (tuner). 

Holding the antenna so that it touched the bridge of a taut string worked good for Dan also, but had a very minor change in the sound.  Whatever this approach does, I expect a lot of string-to-string interaction and tuning problems, so it is more for experimental music than traditional guitar I suppose.  However, maybe some specific form of the concept will work well on "real" guitars.  Time will tell. 



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