Pickups And Materials

[Myrk-]

Ok I can't really say what its for, its a very, very cunning idea of mine. So I'll skip to the electronical side for a question or 2.

If I was to construct a fabric of mesh, would the mesh need to be nickel for it to cause the pickup to make a sound, or could it be any metal... or any material full stop?

Secondly, on a humbucker or pickup, there are usually 6 dots that emerge under the strings. One for each string. Is this because each dot picks up just the string above, or is it merely there to amplify the strings vibration without trying to pick up the vibrations of nearbye strings. I suppose another question of the same format would be- whats the point in those metal extruding dots on a humbucker?

I'll show you all what I'm up to when its done!

[aidlook]

Ok I can't really say what its for, its a very, very cunning idea of mine. So I'll skip to the electronical side for a question or 2.

If I was to construct a fabric of mesh, would the mesh need to be nickel for it to cause the pickup to make a sound, or could it be any metal... or any material full stop?

Secondly, on a humbucker or pickup, there are usually 6 dots that emerge under the strings. One for each string. Is this because each dot picks up just the string above, or is it merely there to amplify the strings vibration without trying to pick up the vibrations of nearbye strings. I suppose another question of the same format would be- whats the point in those metal extruding dots on a humbucker?

I'll show you all what I'm up to when its done!

Do you know how a pickup works?...maybe you should read up on it before trying to construct one..

Anyway, the 6 "dots" are magnets, they're constructed a bit differently depending on the pickup. They are all of the same polarity and are inside a coil. When the string vibrates in the magnetic field an alternate current is induced in the coil around the magnets.

Edited July 20, 2006 by aidlook

[Ben]

If I was to construct a fabric of mesh, would the mesh need to be nickel for it to cause the pickup to make a sound, or could it be any metal... or any material full stop?

I'm not sure I'm interpreting this mesh thing correctly... but I think you are suggesting substituting the pole pieces for some sort of 'mesh'.. right?

If so; anything magnetic is ok ( e.g. Nickel Iron, steel)

[Pr3Va1L]

That guy's idea sounds a lot like a good old diaphragm microphone, I guess...

Anyways, before trying to reinvent the wheel... understand how said wheel works

[Drak]

Yeah, I thought the same thing, for having such a cunning idea, then to call magnets 'dots', and not have a clue how they work, how cunning could the idea possibly be?

Inquiring minds need to know.

[spazzyone]

try tinfoil

[psw]

Hmmm...secret questions will receive secret answers....maybe a little less secrecy is required!?

Anyway...the idea of an electromagnetic pickup is that a magnetic field goes through the "dots" and surround the metal strings. The strings vibrate which causes the magnetic field to vibrate with it and within the coil. The coil produces a tiny current analogeous to the strings vibration resulting in a signal, which when heavily amplified, produces a sound.

So, the magnets, poles within the coil, whatever, are just there to allow the metal in the strings to become a part of the system via magnetic coupling.

Now, if you wish to replace the poles with some kind of mesh...it will need to be magnetic, or be able to be magnetised...and will have to go through the coil. You may be thinking of putting a mesh on top (for instance), but this is only likely to have an adverse effect on performance by diffusing the magnetic field, as opposed to focusing it through the coil.

Using metals (even non-magnetic but conductive materials like aluminium) for bobbins around the coils also have an adverse effect (hence they are generally plastic) as they can cause interferance in the coils efficiency and frequency response.

As a cosmetic thing, like a pickup cover made of mesh...generally metal covers are made of non-magnetic material like brass plated with nickel and are not a part of the pickup itself nor disrupt the magnetic field adversely.

So...if you could give a little more, perhaps you will get more in return that may help... pete

oH...You may wish to look into a freeware progarm called FEMM that will allow you to model various magnetic effects and materials on the computer...it helped me to come to grips with some of this stuff a little more and experiment outside the box, so to speak!

[Myrk-]

Fine. Its in the creation of a new electronic drum (don't hiss and spit, I learnt drums because there aren't enough drummers around UK)...

Basically I'm replacing the strings with a mesh, which becomes the drum head. The pickup goes below the mesh, and acts as a piezo, like roland V drums. Another way would be to thread pieces of metal through a normal drum mesh head, so as not to diffuse the magnetic field as psw implied. I find the best way of testing is good old practical testing.

My idea is to eliminate the need for midi- I have a few old pickups lying around and plenty of spare parts to create such a device, except the mesh, which I would need to manufacture into a skin with hoop.

I'll then plug the drum into my Line6 spider amp, and tweak it till it sounds somewhat right. If it works it could be the era of a new electronic drum, if not, meh, I'll keep it as a memento.

Thats the idea anyway! If I see it pop up soon I'll know you stole it, but I'm sure it won't be that great anyway, but I'm curious.

Edited July 20, 2006 by Myrk-

[Pr3Va1L]

Well, As I said, It's pretty much the same principle as a diafragm mic, but I like the idea of implempting it to drums!

It sounds like a good idea, but I can see 2 problems: 1.How good will it actually sound? 2. Will you be able to make a 'mesh' of magnetic material strong enough to withstand the abuse of a drummer bashing it (and god knows some drummers hit hard on their drums)?

Anyways, I wish you good luck with your project!

[Ben]

I really like the idea!

I'd expect it to feedback pretty horrifically at high volumes if you put it too close to the amp though!

[fryovanni]

Sounds like you would have a lot of issues to overcome before you produced a usable signal, and I am thinking it will not sound quite like you may be imaging it will sound. A dynamic mic although not directly coupled to the head allows you to capture more of the energy created by the shell, res. head and batter head. It is a cool thought, but I would do a little more research on how the magnetic coupleing works to generate current flow. I would use that understanding to think about how the batter head would vibrate. If you are still thinking it has merit. Then start looking at the signal headroom and dynamic range potential. Then start looking making a mesh that will be durable enough to last for a reasonable period of time and still be able to vibrate as a drum head should ( That should be a task in and of itself). Then you could give it a shot and see if it can generate a signal that is appealing.

Good Luck!

Rich

[Ben]

What about a regular drum head with a mesh attatched to the bottom?

[Myrk-]

Then its noisy, and as such, useless!

I think I could possibly do it with a current Roland mesh head with metal woven between and fixed. Either that or use fibreglass sheeting without the resin- plenty of V-drummers have actually made heads this way and they seem to last fine. I'd need to use a material that wouldn't degrade like guitar strings too- something that sweat doesn't destroy.

As for drum heads, mesh drum heads last longer than normal heads (probably because the strike surface is a mesh and as such only 50% of a normal surface), its wierd to explain- go to your local guitar/drum shop and try out a V-drum kit with mesh heads, very nice- I have a TD-10 kit personally. Its my baby along with my Roland G-707 guitar.

Edited July 20, 2006 by Myrk-

[Ben]

Then its noisy, and as such, useless!

uh... yeah I kinda forgot about that

[Mike Sulzer]

"whats the point in those metal extruding dots on a humbucker?"

They are the "polepieces". In a humbucker they are usually some kind of soft steel of the type that can be magnetized, but do not hold much magnetism permanently. They have two purposes:

1. They become magnetized by the magnet on the bottom of the pickup, and then they magnetize the strings; the one below a string contributes by far the most to magnetizing that string.

2. When the string vibrates, a time-varying magnetic field is produced at the pole pieces; the pole piece amplifies this field because its magnetic domains (little groups of atomic current sources) line up with the applied field. This amplified field then induces a voltage in the coil.

Most folks do not really understand much about pickups, so let's not be too rude.

To make a drum as you describe you could use a steel material similar to guitar strings. If it is attracted to a magnet it will work. Your project sounds like a lot of fun!