Wood Choice By Tapping

[theodoropoulos]

This is a major issue for wood choosing among many pieces...but could anyone help me in what to look for when i tap on a wood???

the sustain?the colour of the sound?? what??

and the most importan WHEN MUST I NOT USE A PIECE OF WOOD....

[westhemann]

All you can really get is a sense of the "liveliness" of the wood at first...if it is a dead sounding chunk you will hear a dull thunk,but a live piece is more of a sharper rap sound with a slight ringing and vibration which you feel through your fingers more than hear.

With experience you can get an idea of what it might sound like as a guitar,but it is only an idea.I keep all of my guitars on hangers on the wall,and if you put a hand lightly on the back and rap the front with your knuckles,you will hear a different sound on each guitar.If you do this with many different guitars(I have a few and have had many more) you will build a "library" of sorts in your mind of different tap tones.

But really,I don't bother with it much.Only time I do that is if as piece is highly figured,because those can be dead...and if they are you only want to use them as a thin top for looks.

[verhoevenc]

At this point you should be holding the piece of wood at a node (unless it's a giant board, then just sit one end on the ground... really only option lol) and hitting it. When you do this enough you'll find a sustain length figure for different woods. You'll eventually go "OK, well that doesn't sustain as long as some other honduran mahogany I have" or vice versa. Another thing you're looking for is the 'timber' (aural timber, not like wood) of the wood. A good example here is some rosewoods will have a high pitched "ping" sound, other will have more of a rumble. Example, I find mad rose to have a nice ping to it, EIRW much less so. And this will come out in the final product as well. I'd expect a much more mid-rich and 'excited' neck out of mad rose (talking full neck here, not fretboards now, just to give a more pronounced picture) and a more warm, but slightly muddy, sound from new growth EIRW. Take this with a grain of salt as this is observations I've made from PLAYING guitars with these necks, and then tapping blanks of that wood IIIII own. I have yet to build with mad rose for a neck. This also comes a bit from talking to other luthiers I trust.

THAT SAID, I don't believe, especially at the point you're at, that you're not going to tap woods and go "yes, these two things go together!" What is more likely is you tap all your woods, find stuff that sustains well and doesn't ALL have too high a ping, or too much of a rumble, and you'll end up with a NICE instrument.

Also, keep in mind, THICKNESS of the wood you're tapping makes a BIG difference. So if you're tapping two fretboards, one 1/4" and one 3/8" rough blank... they will sound different. This is a BIG thing with acoustic tops.

I've found that one of the most interesting tap tests that will give you a good idea of what you're listening for it the 'maple test.' Take two maple drop top pieces. One plain (or mild flame, fine... I know no one but me really keeps PLAIN maple around hahaha), and one that's HEAVY quilt. Dimension them the same and then tap them both out, holding them at the node. The plain maple will ring nicely. The quilted maple will go "chunk!" and not sustain worth a dang hahahaha.

Chris

[theodoropoulos]

At this point you should be holding the piece of wood at a node (unless it's a giant board, then just sit one end on the ground... really only option lol) and hitting it. When you do this enough you'll find a sustain length figure for different woods. You'll eventually go "OK, well that doesn't sustain as long as some other honduran mahogany I have" or vice versa. Another thing you're looking for is the 'timber' (aural timber, not like wood) of the wood. A good example here is some rosewoods will have a high pitched "ping" sound, other will have more of a rumble. Example, I find mad rose to have a nice ping to it, EIRW much less so. And this will come out in the final product as well. I'd expect a much more mid-rich and 'excited' neck out of mad rose (talking full neck here, not fretboards now, just to give a more pronounced picture) and a more warm, but slightly muddy, sound from new growth EIRW. Take this with a grain of salt as this is observations I've made from PLAYING guitars with these necks, and then tapping blanks of that wood IIIII own. I have yet to build with mad rose for a neck. This also comes a bit from talking to other luthiers I trust.

THAT SAID, I don't believe, especially at the point you're at, that you're not going to tap woods and go "yes, these two things go together!" What is more likely is you tap all your woods, find stuff that sustains well and doesn't ALL have too high a ping, or too much of a rumble, and you'll end up with a NICE instrument.

Also, keep in mind, THICKNESS of the wood you're tapping makes a BIG difference. So if you're tapping two fretboards, one 1/4" and one 3/8" rough blank... they will sound different. This is a BIG thing with acoustic tops.

I've found that one of the most interesting tap tests that will give you a good idea of what you're listening for it the 'maple test.' Take two maple drop top pieces. One plain (or mild flame, fine... I know no one but me really keeps PLAIN maple around hahaha), and one that's HEAVY quilt. Dimension them the same and then tap them both out, holding them at the node. The plain maple will ring nicely. The quilted maple will go "chunk!" and not sustain worth a dang hahahaha.

Chris

Thanx for the response !!

my questions is about the matching.....if 2 woods ring well separetly will they be combined well????

and a second question is about the grains...when sound travels along the grains sounds different than when not...

so,should i use only quartersawn wood for better accoustcis??

thanx again!!

Edited October 26, 2010 by theodoropoulos

[Helldunkel]

Check out these 2 video in which Ervin Somogyi talks about tap tone and wood Q, its very interesting, enjoy

Not sure this will help you (its mostly for acoustic guitar) or maybe it will, in both cases its very interesting and worth mentioning...

Also:

PRINCIPLES OF GUITAR DYNAMICS AND DESIGN

[RestorationAD]

Last point on tapping wood. You can usually hear hidden cracks and voids in wood as well by the tone of the tap.

A cracked piece of wood will have a distinct crack sound when you rap it. Also a void might manifest itself as a thud as you move across the piece while tapping and listening.

[theodoropoulos]

Last point on tapping wood. You can usually hear hidden cracks and voids in wood as well by the tone of the tap.

A cracked piece of wood will have a distinct crack sound when you rap it. Also a void might manifest itself as a thud as you move across the piece while tapping and listening.

well i see that experience is the key here,something i dont have and obvisously is difficult to be tought.But i wiil study the documents...

So it's a bit difficult to distinguish a "correct tapping tone" from a "bad"....

But i that it depends from where you hold the wood...If you hold it from wrong place it may be muted and not bell loud although the wood is good...

How should i hold correctly a simple piece of wood?

[verhoevenc]

my questions is about the matching.....if 2 woods ring well separetly will they be combined well????

and a second question is about the grains...when sound travels along the grains sounds different than when not...

so,should i use only quartersawn wood for better accoustcis??

If two woods tap well separately, no, that does not mean they will combine well. Look at it this way. You could tap some hard maple that sounds good, then tap some ebony for a fretboard, and then some birdeyes maple for the neck. They may all tap great. But you're gunna end up with one BRIGHT guitar. Tapping is not a tell-all. It's a point in the right direction that that piece of wood is nice.

As for your sound transfer question. Yes, sound travels more effectively ALONG grain. This is why Uli Teuffel is convinced you need at least one section of nice, long, straight, uninterrupted grain in your designs. You can see this obviously in the birdfish, but it also shows itself in his other designs, especially the Tesla IMO. That said, this has little to do with quartersawn vs. flatsawn. In both cases you can have long, continuous grain. What I talked about with tapping quilted maple and plain maple illustrates this better. The quilt maple is just RIDDLED with runout (ie: lots of short, interrupted grain) while the plain is not. That is a better way to think of it.

THAT SAID, there are OTHER reasons to use quartered wood for acoustics. It's usually more dimensionally stable (and predictable when it does change with humidity), is less prone to warp with water (important for bending), etc. So yes, quartered wood I would say is better for acoustics, but it's not a question of sound transfer, more of structure.

Chris

Edit: The correct place to hold it is at it's vibrational nodes. These are places that remain relatively neutral when vibrating and therefore your fingers being there does little to inhibit vibration. You'll know when you're holding it in the right place However, a good place to start is at 1/3rd the length down, 1/3rd the width in.

[theodoropoulos]

my questions is about the matching.....if 2 woods ring well separetly will they be combined well????

and a second question is about the grains...when sound travels along the grains sounds different than when not...

so,should i use only quartersawn wood for better accoustcis??

If two woods tap well separately, no, that does not mean they will combine well. Look at it this way. You could tap some hard maple that sounds good, then tap some ebony for a fretboard, and then some birdeyes maple for the neck. They may all tap great. But you're gunna end up with one BRIGHT guitar. Tapping is not a tell-all. It's a point in the right direction that that piece of wood is nice.

As for your sound transfer question. Yes, sound travels more effectively ALONG grain. This is why Uli Teuffel is convinced you need at least one section of nice, long, straight, uninterrupted grain in your designs. You can see this obviously in the birdfish, but it also shows itself in his other designs, especially the Tesla IMO. That said, this has little to do with quartersawn vs. flatsawn. In both cases you can have long, continuous grain. What I talked about with tapping quilted maple and plain maple illustrates this better. The quilt maple is just RIDDLED with runout (ie: lots of short, interrupted grain) while the plain is not. That is a better way to think of it.

THAT SAID, there are OTHER reasons to use quartered wood for acoustics. It's usually more dimensionally stable (and predictable when it does change with humidity), is less prone to warp with water (important for bending), etc. So yes, quartered wood I would say is better for acoustics, but it's not a question of sound transfer, more of structure.

Chris

Edit: The correct place to hold it is at it's vibrational nodes. These are places that remain relatively neutral when vibrating and therefore your fingers being there does little to inhibit vibration. You'll know when you're holding it in the right place However, a good place to start is at 1/3rd the length down, 1/3rd the width in.

a big thanx !!

all those are worthy info!!

[theodoropoulos]

after some experiments i noticed that hardwoods like rosewood had this bell like ring in contrast with softer woods...I tried to hear this tone

by tapping mahogany and cherry...the sustain was almost zero....do dimensions of the wood play rolle in tapping??