Interesting Pickup Design from Fishman

[charrich56]

Rick,

You just hit several nails on the head. With your indulgence I would like to respond with a couple of comments.

1. CD 44.1KHz sound circa 1980 just wasn't consistently good by anybody's definition today. The mastering engineers were just getting into the digital realm and really good A/D front ends were few and far between, as well as just knowledge of what a good A/D front end and digital mastering process should be doing. Lots of early sucky CD's were made. (e.g. first release Santana "Abraxas".) All of that is so much better understood and distributed in the industry now.

2. Appreciate your comments on the "over 20KHz" area. Since we are focused in the guitar area, I can't help thinking that this issue has been dealt with pretty empirically by the recording engineer community as they have to routinely record cymbals and hi-hats which I'm pretty sure, and something you were alluding to, have significant frequency content over 20 KHz. There might be some experience there and/or tribal knowledge worth getting.

And so, too, this pin-point focus on coil resonance. It's just one part of the picture, albeit one that anyone can easily measure now. But are we interested in what is basically an EQ curve superimposed upon a simplified model or do we want to know what the string is doing with and to a dynamic 3D magnetic field? I'd say we want to know both in order to be able to tweak the results. But you have to at least intellectually separate the effects that are going on. And, yes, it's complex...but you're never going to get "there" winding and listening only to high Z pickups.

I think that if you can understand what you hear with LowZ pickups, you'll be much better at then EQ'ing/filtering them in the High-Z realm. In other words, if you can't hear the 3D magnetic dynamics as a separate issue from what I now see as the dumb-ass simple LCR coil resonance factors that anyone can measure, then you can't take magnetic pickup design into the next level. Or...for that matter...even completely understand the past 80 years of mag pickup design.

Still, if you're limiting your understanding of the sound of magnetic pickups to the resonant filter of the coil, you're doing yourself a serious dis-favor. It may be the easiest factor to understand, but it's not the only "game in town".

Yes, absolutely, positively. Couldn't say it any better than you just said it. I do want to add though that not all people understand that the exact LCR resonance and damping effects that work with hi-Z pickups also work just as well for low-Z pickups, if you want to reproduce the sound of some given hi-Z pickup or go in that voicing direction. It's just a lot easier with a low-Z pickup where the basic resonance of the pickup is out in "bat" range, as you said. You can bring the resonance down to anywhere you want in the audio band with just a capacitor, and damp the peak just with a load resistor.

I would go beyond what you said here about using low-Z as a research tool, go way out on a limb, and say that once someone understands how to "voice" a low-Z pickup correctly, there might not be any need any more to apply or translate that knowledge back to hi-Z pickup design -- because you can probably get everything you want and need voicing and sound-wise without having to go back to hi-Z. You just need more clean gain somewhere to make up for the difference in output. That isn't hard to come by these days compared to 60 years ago. And the higher E-field electrical noise immunity of low-Z is just icing on the cake.

Ok, having just probably put my foot in it, here's a real nitty-gritty test/example/experiment for some of the folks on this forum to think about. Build two Gibson vintage PAF-style humbucker replicas with exactly the same good quality and reasonably authentic-spec parts. One is wound with AWG 42 hi-Z coils to whatever is their idea of a good-sounding PAF clone these days. The other is exactly the same but coils wound with #32 or #34 and ending up at about 50 ohms DCR and 30 millihenries inductance for both coils series. Can you add just a resistive/capacitive network directly to the low-Z pickup leads and get it to sound as good as, or better than, the hi-Z pickup, with the only major difference being output?

I say, (eek, this is scary because I am not there 100% research-wise) yes, you can duplicate the basic voicing of the PAF model pickup and the low-Z can be made to sound as good as, or better than, the clone, with about 50 cents worth of resistors and capacitors providing the resonance and damping. Will it have the same "vibe", "mojo", player responsiveness to pick attack of a good example of a genuine PAF?

Maybe or maybe not, but with the low-Z version you can easily modify the voicing externally with cheap parts to get more of whatever quality you are looking for out of your signal chain within the constraints of the basic hardware and magnetic design, without having to rewind the darn thing every time you experiment. You can just take it back to flat response to check out some other design elements, or to do more things downstream with EQ and DSP. Or, you can just quickly tweak it to match it better with the player's style, guitar construction and amp, again without rewinding it.

With the hi-Z version you are constrained by the shackles of hi-Z; you can play around with minutiae of hardware, wire, windings, magnets, metallurgy, construction for decades , wind and rewind thousands of times, and not get any closer, or only a tiny bit closer, to the things you are looking to bring out more of in the sound.

I guess that started out to be a sidebar point but really circles back to and reinforces your point quoted above.

-Charlie