trying to design a tapping instrument

[RevJack]

First, allow me to introduce myself.
I am an artist, painter, sculptor, and all around crafts person.
I AM NOT, HOWEVER, A MUSICIAN. I can't play a lick.

I was discussing possible instruments with my wife, and said that I would like to find something I thought I could learn to play by ear. (BUT I'M WEIRD)
I don't want the usual guitar, or keyboard, or what have you. I want something interesting.

With this said, I fell in love with the HARPEJJI.
www.marcodi.com
Just not the $4000 price tag.
So I started doing some research and found things like the KELSTONE, the TAPLADDER, the CHAPMAN STICK, the ZENTAPPER, and other such tapping instruments.

By combining different design elements from the different instruments, I came up with a concept that I would like to build.

A 24 string tapping instrument using the strings from a harpejji, the frame idea from the tapladder, the fretboard idea from the kelstone, all wired up like the harpejji.

what I have so far is.

the sting list from Marcodi. I used that to determine that the scale length should be 31 inches.
the frame concept from the tapladder could be adapted by using bedrail angle iron and a welder.
I would build a wooden fretboard, and use guitar electronics.

My first problem is that the string spacing is 9/16in or 14.29mm.

the harpejji uses saddlemount pickups but those things are $200 for 6. not an option. I need cheap parts. EBAY FROM CHINA cheap.

What would be the best way to adapt regular pickups to this string spacing.
how do I tell the difference between pickups with pole magnets and bar magnets. Can they be placed at an angle so the pole magnets read the strings better. should I just build pickups with the right spacing.

I will have many more questions, but let's do this one at a time.

And thanks in advance for any help.

---

quick drawing.JPG
Description:	A quick drawing
Filesize:	80.91 KB
Viewed:	291 Time(s)
This image has been reduced to fit the page. Click on it to enlarge.

---

[robsol]

Hi RevJack and welcome to the forum!

I love the sound of tapped instruments as well. I made a quick prototype to see how hard it was and found it not too difficult. Being precise is obviously paramount, esp when it comes to fret placements. I'd suggest you may have to build one or two instruments first before you get it completely right, but you can reuse the parts from old designs. When it comes to pickup placements, as a very general idea, the closer you place them to the end of the string, or bridge, the thinner the strings will sound. Messing about with different placements before committing is the best solution.

Pickup type... for tapped istruments, it is possible to place the pickups closer to the strings since they move a lot less than when you pluck them. The obvious choice for me is to use active pickups, since they have weaker magnets and therefore won't pull on the strings so much. You therefore find that you get a much longer sustain from less dampened strings. Pickups all sound very different and is a personal choice though.

For me, making the frets is the most difficult part - you may want to buy fret wire, apart from the machine heads and pickups. You can roll your own on these too but it will make things much more involved.

For the easy maths involved in fret placement and much else you'll find a lot of info on this site: http://www.liutaiomottola.com/

[robsol]

Here is the thread covering my work on the tap style guitar thing...

http://electro-music.com/forum/topic-47743.html

I made that without proper tools and skills so it is not a great instrument but it is still playable.

Best of luck to you! Let me know how things progress.

[DES]

Being a Stick player I'm always interested in new tapping instrument endeavors! WRT pickups, do you have to have saddle pickups or can regular guitar style pickups work? Saddle pickups can give you separation between strings which is good if you want to drive a Midi convertor or process the strings individually. But as you've seen they can be pricey. The Roland GK pickups are 6 individual magnetic pickups that can be removed from the housing and spaced as needed though you will not be able to get closer then ~.3" center to center. The pickups can be had relatively inexpensively on the used market, though it still will be more then regular guitar pickups.

You could try to roll your own...either magnetic or piezo/contact style. Years ago I wanted to mic the flute and process it thru delays and such but wasn't happy using a mic and flute pickups were expensive. I ended up taking an old transistor radio earphone and threading it onto the flute head stop to the point where it just made contact with the earphone diaphragm....worked great! Now with todays technology reducing the size of things, you might be able to get ear-buds to work. Either as a contact pickup or maybe as a magnetic device though it probably won't be strong enough...

[RevJack]

Muied Lumens ,I really like that adjustable bridge. I'm actually thinking of going this route with adjustable pieces made from brass L brackets.

https://www.youtube.com/watch?v=OXRJCtkJskQ
https://www.youtube.com/watch?v=LzEeEMyzkjo

As for the pickups. I'm actually trying to avoid saddle pickups due to the cost.
I'm building this thing so that it is actually pretty modular. For eample, the fret board is a 14 x 21 piece of wood with the frets that just drops into the metal frame. That way, If I mess up, I just redo THAT piece. The same goes for the pickup area. I NEED to go as cheap as possible now, but I can easily upgrade later. I just wanna know if I can make it play right.
I'm guessing I will have to go with 4 or 6 BLADE pickups if I can find them cheap enough. I am even considering making my own, but I need to see which is more cost effective.

If I do make them, I might experiment with making a Gittler style tube pickup. Making one for each string.

making them might be better anyway, cause I might also have to custom build sustain drivers at the same time.

Anyway, here are some links you might find interesting.

Another fret calcular
http://www.tundraman.com/Guitars/FretCalc/

Virtual Harpejji
http://web.ticino.com/demarta/chris/harpejji_virtuale-playable.swf

Harpejji features
http://www.marcodi.com/product/features/

[RevJack]

Ok, the harpejji is described as having an INTELLIGENT MUTING CURCUIT which filters out any string not touching the fret.


What is it?

Is it something I can buy, or get in an external control box(stompbox)?

is it somehow wired to the strings and frets to complete a circuit?



It also has a VARIABLE AUTO-SWELL but I think that is a modulator.

[robsol]

I don't know for sure, but I suspect that the muting has to do with the way tapped instruments are played. After you let go of a string, leaving it 'open' it can still vibrate, unless you play in such a way that you carefully let go of the string, dampening each string in the process. You can also solve this by having foam or cloth to dampen the strings on the nut end, between the first and zeroeth fret basically. I suspect that on the Harpejji this is either mechanical or electronic, where open strings are muted because there is a circuit involving the frets and strings.

I'm not a particurarly virtuoso player but I don't find it hard to dampen strings as part of my playing style. You can try for yourself on a normal guitar, even an acoustic one.

As for the auto swell, perhaps it is just simple compression or it could be a sustaining circuit, similar to the ebow. Making a sustainer is possible DIY, but it will take a bit of trial and error, and is harder on the higher strings for some reason. By the sound of it, and I have not listened to any demos yet, it could also be an envelope circuit that fades in each note. This would also be triggered by the string/fret circuit I suspect.

Just guessing here, of course, but these are highly involved circuits and not something I would try on my first instrument. You will have to do a fair bit of research if you are not already experienced in building your own circuits - especially as these circuits involve physical strings which complicate things a bit.

[robsol]

[RevJack]

did more research and found out that it is a system similar to the one used in the MOOG E1 guitar.

individual pickups wire thru the frets and wires to a synth board.

WAY OUT OF MY REACH.

but I might be able to adapt some of the ideas used to a polyphonic pickup system.