Different soundholes

[Darryl Hattenhauer]

How do size, shape, and placement of soundholes affect sound?

In other words, what is gained and lost by using an oblong soundhole on a songbird?

What is gained and lost when people expand the size of a round soundhole on a flat top?

 

[danerectal]

I would guess that a change in the soundhole would affect the resonant properties of the top. It makes me wonder how the first soundholes were designed and positioned... :?

 

[West R Lee]

Only the short, fat sound waves can get out of an oval soundhole Darryl (you'd think they'd have more bass), where as a round soundhole is an equal opportunity soundwave getter outer. Any more questions?

West

 

[Darryl Hattenhauer]

Dane,

You might be on to something. The size of a sound hole would affect how much top wood there is to vibrate. So if you made it oval, you made affect top movement above the upper bout, and above the lower bout.

James,

Then maybe Guild put an oval sound hole on the studio 24 to get back the bass lost by making it a thinline.

 

[Guildmark]

So can someone explain the McPherson off-center soundhole in the upper bout?

Or the tiny oval soundholes in some Selmer-Maccaferri jazz boxes?

Or the latest thing from Kevin Ryan - the "flutes" along the edge of the bass side of the lower bout?

Another maker, whose name escapes me (help), puts a second sound hole in the side of the guitar that faces up toward the player's head. This one is intended to give the player the same tone a listener in front hears (according to the ad I read).
I'm sure it has more to do with acoustics than I'll ever be able to grasp. And some of it, I'm just as sure, is simply style or even just a gimmick.

 

[Darryl Hattenhauer]

Marco,

I hope we get some answers. My first guess is that the hole on the base side of the top picks up bass string sounds better than treble string sounds. It must also affect which sounds come back out, but I can't imagine how.

hf

 

[danerectal]

How about the Tacoma tiny sound notch, or the Ovation multiple top hole scatter? Too much to wonder about...

 

[Darryl Hattenhauer]

Dane,

Ovation does the same with its mandolins. It's beyond me.

 

[danerectal]

I've played the mando, and a Celebrity with scatter-holes and a centered hole. The scatter-hole sounded pretty scatter-toned. The Mandolin had a little more output than the F-holes I've played, but I've never AB'd them, nor have I tried a round/center hole Mando. I was at a Taylor roadshow where they said that the cutaway doesn't affect the resonance of the top because of its location. I seem to remember them saying the resonant pattern was like a teardrop, or an A-style mandolin.

 

[Darryl Hattenhauer]

Dane,

From my limited experience, an oval hole mando doesn't sound as full-bodied and substantial as one with f-holes.

Which also makes me wonder why they put f-holes only on archtops but virtually never on flat tops, whether mando or guitar.

 

[jp]

For guitars or any of the string family insturments, I do know that the f-holes have a couple of functions. I read about this once, but it was a while ago. They're supposed to allow the belly plate--the area of the top--between the f-holes to vibrate more freely than the rest of the top and project sound. The f-holes also allow the air from the inside of the instrument to meet the air from the outside and different resonances of sound meet. There are two different resonance theories and patterns for f-hole guitars vs. center hole guitars, and the construction of each type are based upon these theories.

If I recall for center hole guitars, a well-crafted and dimensioned instrument balances the lower frequency of air on the inside (like blowing air over a jug) with the lowest frequency of the guitar top. The f-hole theory was pretty complicated and has been refined over the years. Serious violin, viola, cello, and double bass luthiers have collections of f-hole patterns and templates from all the great instruments, which they trade and swap and share.

I think the center hole construction is based on something called Hemholtz resonance and f-hole on Chaldini resonance. That's all I can remember. Sorry, Darryl. Wish I could explain it better. That's all my addled mine can draw up to the surface this morning.

 

[Darryl Hattenhauer]

Serious violin, viola, cello, and double bass luthiers have collections of f-hole patterns and templates from all the great instruments, which they trade and swap and share.

Sheesh! Sounds more complicated than computers.

 

[jp]

Well, you are messing around in the Tech Shop!

 

[Darryl Hattenhauer]

JP,

I should have realized that the physics and engineering of guitar technology is going to be just as compicated as anything else. I can barely change an amp tube.

http://www.gmi.edu/~drussell/guitars/hummingbird.html

hf

 

[capnjuan]

Wow JP; F-Hole break-dancing .... the part about the F-holes allowing the deck between the holes to move back and forth more easily makes sense since the top would get less flexible as it approaches the junction of the top and sides ... interesting stuff! cj

 

[jp]

Wow! Gives new meaning to the phrase "guitar porn."

the part about the F-holes allowing the deck between the holes to move back and forth more easily makes sense since the top would get less flexible as it approaches the junction of the top and sides ... interesting stuff!

Yeah it is. I wonder where the notion of the actual f-hole shape came into being. A lot of German archtop makers messed with shape quite a bit. When thinking how it might have a profound effect upon the vibration of the soundboard, it seems a lot more significant.