Offset soundholes

[Sage97]

I know they are not for everyone but just out of curiosity, which ones do you prefer/like and why?

[Tim McKnight]

We have only built one ... so far ... but I like the end result. I purposely did not add a side sound port thinking since the sound emanates from closer proximity to the player, it may not be needed. My hunch was right. We have since added a few more orders on the books based on that experimental guitar.

[Wade Hampton]

Well, one of my best friends was part of the Tacoma Guitar Company's R&D team that designed the offset soundholes on the Tacoma Papoose and Chief:



Tacoma Papoose



Tacoma Chief


The Papoose was actually the first instrument that was designed and put into production, after noted vintage instrument dealer George Gruhn suggested to the company's management that they design, make and market a steel string version of the Mexican requinto, with its A to A tuning, to sell as a travel guitar.

If you talk to George Gruhn or any of his employees, they'll tell you that Gruhn "designed" the Papoose and Chief.

Ummm....not quite. I've seen the original sketch he made (on a cocktail napkin,) and it's got a crude drawing of a small guitar with the notation "A to A tuning" beside it and a soundhole in the normal spot.

It was the Tacoma R&D luthiers who had to make the thing work and sound good, and when they built the first prototypes what they found with the normal soundhole location was that the little guitars simply didn't have as much tone as they wanted. So they shifted the soundhole to the upper bout, and designed the bracing in order to let that additional expanse of top vibrate to its fullest.

Everyone was pleased with the results, so they designed the Chief to have the same offset soundhole, and made it a trademark of that particular product line.

But it wasn't as though the Papoose and then the Chief were the first guitars ever to have offset soundholes. I'm not sure who invented the idea, but a Hawaii-based luthier named Stephen Grimes was making offset soundhole guitars before the Tacoma Guitar Company was even in existence:






Grimes guitars

Other builders of fine guitars have also used offset soundholes, like this one by Howard Klepper:



And of course McPherson guitars are now being built in a small shop operation, and the folks who play those instruments tend to be very enthused about them:




As for myself, I still own the very early production model Tacoma Papoose that I got when they first came on the market. It's a handy little guitar, especially when you are squeezed for space. I also employ it as a rhythm and accent instrument when playing in a large group: it really cuts through the mix in a way that the Chief does not. I've capoed a Chief guitar at the fifth fret and then alternated between it and my Papoose, and the Paoose simply cuts better, even though with the Chief at Capo 5 both instruments are at the same pitch.

So it has its advantages.

I haven't had much of a chance to play many handbuilt guitars with offset soundholes, and while I have played half a dozen or so McPhersons, those guitars don't do a lot for me.

So, for me, anyway, the jury is still out on offset soundholes. I actually like the look of offset soundholes a LOT, but have never played a Chief that I would want to own (the one I tested the Papoose against belonged to a friend.)

The unusual appearance of offset soundholes is something that players either tend to like, as I do, or else just despise in a visceral sort of way, if the intemperate remarks about them that I've read online are anything to go by.

Which I think they are.

So, short version: the look's not for everyone, as we already know, and while the design definitely works in the case of the Papoose, I'm not so certain that it's completely successful in musical terms when it comes to full-sized production guitars. I'm sure the Grimes guitars would blow my socks off, but I have yet to play a full size factory-made offset soundhole guitar that I would want to own.

So for me, the jury's still out. I'd love to be won over, but haven't been yet.

Hope that makes sense.


Wade Hampton Miller

[gitnoob]

Why not combine the offset sound hole with a sound port?

[Acousticado]

The offset soundhole on CA guitars (the GXi and Cargo) work great. I own both and really like those guitars with this soundhole design.

[Sage97]

Wow!

Tim,
When I first saw that guitar, I remember being very impressed with the concept and the aesthetics. It still generates the same response as the first time I saw it.

Wade,
I really like that Tacoma style. Never played a Grimes before but I'm sure they rock. The McPherson for me almost looks like the "norm" for offset soundholes because its the one that I immediately think of. I've only played 3 -4 McPs and I remember liking them quite a bit.

Howard's take is very interesting. It looks like a face. One of these days, I will try a Klepper guitar and I expect it to be superlative.

[Sage97]

Gitnoob,

What are your thoughts on the sound/tone of that particular guitar?

[Alan Carruth]

Offsetting the soundhole has some interesting acoustic outcomes. One thing is that, for a given size of hole, the closer it is to the end of the box the lower the 'Helmholtz' resonance. This usually translates into a lower 'main air' pitch, and, on a small box, could very well enhance the low-end sound.

There are other internal air resonances that don't normally put out sound through a central soundhole, and those might become more pronounced in the output as you move the hole up. One would be the 'A-1' air mode; a sort of lengthwise sloshing of the air in the box. It's usually somewhere near the pitch of the open E string, but would be higher if you had a soundhole that could actually 'hear' it directly.

That 'A-1' mode actually does contribute to the sound of most guitars, but it does it by a circuitous route. What happens is that the 'long dipole' resonant mode of the top, where the bridge is rocking toward and away from the neck, tends to drive that air-sloshing mode. The top mode also often occurs at nearly the same frequency as the air mode, so that the two can work together particularly effectively.

If you've got them working together, AND the guitar has a reasonably pronounced waist, AND the soundhole is near the waist, the air mode actually appears at two different pitches, one of which can move air through the soundhole, and one that can't, owing to a different position of the 'null' ('node') of the air mode. All of these conditions seem to necessary for this to happen: Dreads, with no real waist to speak of, often don't show this, and moving the hole up into the upper bout also kills it. It doesn't work on a rigid tube, either, even with a waist and a soundhole in the 'right' place.

The variation of the A-1 mode that radiates often is up in the range of A on the high E string for a 'normal' guitar, and helps to fill in a hole in the spectrum where there is not another resonance that can put out sound effectively. Since this shows up on all sorts of guitars (except Dreads) with round holes, I tend to think it's something that's part of the design, even though nobody tried to make it happen explicitly. It's one of those things that 'fell out' once, and people liked it, so they kept the design elements that made it happen.

I did build one guitar with a pair of holes in the upper bout. We called it 'Caspar the Friendly Ghost', since, with the form my belly bridge takes, it did look like a happy face with round eyes. One thing that was notable on that guitar was that the 'crosswise sloshing' air resonance in the upper bout, which happened around 700 Hz on that one, tended to radiate a lot of sound toward the player, due to the interference of the sound from the two holes. Any note that had an overtone in that range came across to the player as loud, and you tended to back off on those. This was _not_ what the audience was hearing, though; to them those notes you backed off on sounded 'weak', because, of course, they were.

Acoustics sure can be funny sometimes...

[gitnoob]

Originally Posted by Sage97

Gitnoob,

What are your thoughts on the sound/tone of that particular guitar?

That's a new creation from Emerald. It's a bass, and you can hear it here:
http://macnichol.com/taxonomy/term/94/all

I just thought it was clever to build it with a semi-circular sound hole combined with a semi-circular sound port in the shoulder. That could weaken a wooden guitar structurally, but it appears to work fine with carbon fiber.

My personal experience with the offset sound hole is with my CA Cargo, which has the greatest bass response of any small guitar I've played. Some might even say it's too bass-dominated.

[Wade Hampton]

Originally Posted by Sage97

Wade,
I really like that Tacoma style. Never played a Grimes before but I'm sure they rock. The McPherson for me almost looks like the "norm" for offset soundholes because its the one that I immediately think of. I've only played 3 -4 McPs and I remember liking them quite a bit.

I've always liked the Tacoma guitars in terms of their visual aesthetics. It's amazing how much vitriol those offbeat looks can generate in an online guitar forum discussion, however. Yo! It's as though the concept of "agreeing to disagree" on such matters is beyond some folks...

Originally Posted by Sage97

Howard's take is very interesting. It looks like a face.

Look at it a little more closely, Sage - see if it reminds you of anything else...

Originally Posted by Sage97

One of these days, I will try a Klepper guitar and I expect it to be superlative.

Well, mosey up here to Alaska any time after this April and I should have a very nice walnut guitar that Howard has built for me. So long as you promise to wash your hands first and keep from scratching up the back of the instrument with some big honkin' rodeo champion belt buckle, you can play mine.

Hope this helps.


Wade Hampton Miller

PS If Howard's work interests you, check out this thread:

http://www.acousticguitarforum.com/f...d.php?t=203278

Cheers!


Wade Hampton Miller

[Sage97]

Wade,

D'oh! I see it now. Howard Klepper is artist but then again I've always thought that looking at his build threads.

I just reconnected with a HS buddy who now lives in Fairbanks. I do plan on "dropping by" one of these days. I really enjoyed my last visit to Anchorage years ago. Don't worry, I may live in Texas but I'm not quite the cowboy. I bought a pair of cowboy boots once but had to return it same day as I couldn't stop laughing at myself in the mirror. There's a reason why you don't see very many Asians like me wearing cowboy gear.

Thanks Wade.

PS
I wish I knew how to do the quote thingy like you did with mine.

[Wade Hampton]

Originally Posted by Sage97

I wish I knew how to do the quote thingy like you did with mine.

Wel,. it's pretty easy. What I do when I want to respond to various parts of somebody else's post is hit the "quote" button at the bottom of the post. Then what I typically do is copy the "end quote" bit of code shown at the bottom of the quote.

It looks like this: [/QUOTE]

I then go drop that in at the end of each sentence I want to respond to, and hit the return key after each time I've inserted the [/QUOTE] code. That gives me space to write what I want to say in return.

Then I go back and copy the beginning bit of code, which in your case is [QUOTE=Sage97;2552331] I go and put that at the start of each sentence or paragraph of yours I want to respond to. That way each distinct point or thought is visually compartmentalized.

Naturally, using the quote codes like this means that if was unscrupulous, I could have you saying all sorts of things you never actually said, like:

Originally Posted by Sage97

Camptown ladies sing this song

What song is that, Sage?

Originally Posted by Sage97

Doo dah, doo dah!

And just how long IS that racetrack, Sage?

Originally Posted by Sage97

Camptown racetrack five miles long

And is that your last word on the matter?

Originally Posted by Sage97

Oh, dee doo dah, day!

See what I mean? It's pretty easy once you get the hang of it.

Originally Posted by Sage97

Gonna run all NIGHT!

Okay, that's enough.

Originally Posted by Sage97

Gonna run all DAY!

Hey, let's get serious now...

Originally Posted by Sage97

Bet my money on the bobtail nag...

Okay, now I'm sorry I brought this up...

Originally Posted by Sage97

Somebody bet on the bay!!

Alright, let's have a big flourish of banjos at the end..

Originally Posted by Sage97

No, I HATE banjos! It's gotta be tubas!!

Tubas it is, then.


See what I mean?

Hope that makes sense (the technical part, not the Camptown Races discussion...)


Wade Hampton Miller

[Sage97]

Originally Posted by Wade Hampton

Wel,. it's pretty easy. What I do when I want to respond to various parts of somebody else's post is hit the "quote" button at the bottom of the post.

Got it!

Originally Posted by Wade Hampton

Sage plays guitar like Tommy Emmanuel and Rambo put together.

Thanks for the instructional and the nice laugh

[Ehvamone]

I love offset soundholes- or none at all. I just am not sure what effect they have on tone, and don't have much access to a well built custom to judge what they might be like. I have played Tacomas and own a DM9 ( no offset) and they sound good... but I have heard clips from some other makers and find the sound to be "boxy" or "nasal", but again, Its a very small sample etc.
Can one get a traditional sound from an offset soundhole? I would love to have one without a soundhole or offset.
BTW, those guitar pics above are awesome

[HD28andthensome]

Recently, a number of newly designed guitars with extremely off-set sound holes have made their way onto the market. That generally indicates the idea works and with good reason. While I understand a great deal about sound, this makes zero sense to me.

As someone who has taught grad school, I tell my students that no question is too dumb to ask. Interestingly-it's always the smart kids who wont "fake it" when trying to understand something new. They will ask any Q.

In that spirit, could someone explain- from an acoustics point of view why this has become an interest among luthiers today? What is its value in creating sound-how does the offset change the way sound is generated?
I know that this is one part physics-another part acoustics and a third part ? Part 2 and 3 are my question.
Thanks
Like to know your thoughts

Thanks