Pickup Engineering

[frederic]

After 10 days of searching the web on and off in my free time, i have no found an answer to my question(s), so I'm hoping you guys could maybe point me in the right direction?

I have a very strange application, where I need a pickup design that has the usual six poles, but each pole has its own coil - therefore the vibrations of each string is pretty much isolated from each other, electronically.

Does anyone make such a thing?

If not, where does one buy the alinco magnets and poles to build their own? Or should I just make the entire thing from scratch?

Thank you VERY much in advance.

Direct replies more than welcomed at midiguy732@hotmail.com

[Scooter B]

The only way I have seen this done is with piezo pickups.

Some stereo guitar and basses have been made with each individual string being panable in the stereo field. Brian Bromberg a jazz bass player who also plays lead parts on a picolo stereo bass uses this on all his CD's

Some of the guitar synth/pickup systems also have each string output seperated (or isolated) so each string could be (if desired) asigned a completely different instrument sound via MIDI.

Stewart-MacDonald Guitar Supply may have some individual pick up parts like you are looking for but winding each pole piece seperately sounds pretty tricky.

What exactly are you wanting to do by isolating each polepiece electronically ?

[frederic]

What exactly are you wanting to do by isolating each polepiece electronically ? [/B]

You hit the nail on the head with your reply, actually - midi controller. I made a controller that actually knows what notes/chords you are going to play before you actually strum, depending on your playing technique. The problem is, since guitar pickups sum all the strings vibration(s) together, I can't electronically determine if a particular string is vibrating as an open note, or if its not vibrating at all. On our "test guitar" I took off 5 of the 6 strings, and it tracked extremely well, even with slides, pitch bends, hammers, picks, fingers, plucking, you name it. Even capturing per-note volume for even more detailed capturing of the player's abilities. My problem is isolating the six strings from each other, hence my weird pickup need

Whats that technique called where you guitarists move the string side to side to increase the pitch add vibrato? Well, I can capture that too, even though I haven't a clue what that technique is called.

Anyway, I'll keep hunting, I'm sure I can wind my own if I have to, I just have to figure out where to source magnets and which way N and S go (up or down), if that even matters.

Thanks!

[Middleman]

Did you try the Stewart Duncan site?

http://www.seymourduncan.com/

Send them an email and see if they can build or sell you something similar. If not, maybe one of their techs can provide some info.

[pchorman]

I would bet that individual pole windings still wouldn't electronically isolate adjacent string vibration. These have a broad magnetic field.

[frederic]

Originally posted by pchorman
I would bet that individual pole windings still wouldn't electronically isolate adjacent string vibration. These have a broad magnetic field.

I would agree... I'm just hoping to isolate them enough that I can have a little logic to remove the bulk of it, thats all. I can do it with one pickup, however that will require high-speed a/d, a little dsp processing, and possibly some filtering, which increases cost, programming time, and more importantly, it delays the time from when the guitarist does something to when Midi codes fly down the cable, which is what I'm trying to eliminate.

I could isolate them a little bit mechanically - by putting a thin steel plate between them, or something like that, but I'm trying simple first. the KISS theory has worked on this project so far

[Scooter B]

Frederick,

You may see if you can find one of the older Roland Guitar Synth pickups used and modify it to you needs. I don't know that much about how the Synth/MIDI pickups work but there has been a lot of upgrades since the first models which means there should be some used ones you could pick up cheap.

I played with a guy that had one of the adhesive mount Roland MIDI pickups and he did some pretty cool things with it. We even did a Tejano number that he got a convincing accordian sound out of.

Let us know how it works out.

I admire the inventors and innovators...if had more money I would do more myself.

[frederic]

Money? Whats that? I spent all mine

Anyway, I'm now the proud owner of a 6-coil pickup, thats approximately telecaster pickup sized.

If anyone is interested, this is how I made it:

I bought six fender pole magnets.
I bought a large spool of 43 gauge insulated magnet wire.

I took a circuit board blank (full copper on the bottom) and used a small hole saw in my drill press to drill out small circles. The bit in the center of the hole saw was slightly smaller than the magnet diameter, so the magnets would fit snug. I drilled out 12 such circuit board circles.

I'll just describe one coil, since they are all the same give or take a few turns.

I notched the center hole of the bottom circuit board disk, scraped off some insulation of the end of the magnet wire, soldered it to the copper on the circuit board, inserted the magnet, then forced on the top circuit board circle. Both disks have the copper facing out. Put the end of the magnet which was sticking out slightly into the chuck of my drill press, then plugged the drill press into a light dimmer through some wire nuts and wire.

Took me many tries to get the first coil/bobbin correct, but after about 8 tries I got it down okay. Being that its round, rather than a normal pickup which is oblong, it was much easier I think. Anyway, once the spool was full, I ended the winding at the top circuit board disk, notched the outer edge with a file, ran the wire through the notch, then soldered it to the copper on top.

Then I attached two wires to the circuit boards away from where I soldered the magnet wire, and viola, instant pickup coil. I have to pot them today, and I think just for convienence, I'm going to soak them in polyurethane rather than wax, then scrape off the poly off the top exposed part of the magnet.

Since I'm not interested in the frequency response of tonality of the pickup, only the volume, I'm not overly worried about having too few or too many turns. Just need to know which string is vibrating when.

Its ugly, but it should work

[Scooter B]

Sounds interesting,

Keep me posted and post a pic if you are able.

I am not too good at visualizing it so far, but I hope it works for ya.