F holes
 

Emerald's Kestrel raises an ongoing question regarding the best way to transmit acoustic sound in a musical instrument. Violins evolved to the F hole for its more pronounced projection. I don't know if the evolution applies to guitars. But there is a really interesting on-line article explaining "Why Violin Makers adopted the F-shaped hole."

Has anyone here experienced the acoustic sound of a Kestrel?

I haven't experienced the acoustic sound of a Kestral. I have a Godin semi hollow with f holes (Montreal Premiere) which is not that loud acoustically as its meant to be plugged in. I do love it plugged in compared to other electrics like my Les Paul for instance as it adds a nice airiness to the tone.

There's a bit of back and forth on f holes vs round but the general consensus seems to be that f holes will be louder, more focused, but lack sustain compared to a round hole. I'm a big fan of the f holes though I think they look "cool".

I sure am waiting for the first Kestrel reports to come in. If they sound as good as they look, I might be broke for a while. I wonder if the Nuttyprof had a chance to play one while at the factory??

Interestingly, biscuit-bridge resonators (which send their sound first into the body) tend to have F-holes while dobro (spider-bridge) style resonators usually have 2 round soundholes. I think that would support the consensus above.

I did briefly play one although i didn't properly tune it. I didn't really think the sound was for me, but that goes for all archtops. I've not had enough experience with them to really appreciate it I think.

RIVB:

You say your resonator has non-metal strings--I'm not sure what that means.

I couldn't really stop playing the two available Kestrels while I was visiting the factory last fall before they had a name. I had planned to pick up a guitar while I was visiting, but there were just too many choices I wanted. I kept coming back to the Synergy X20, the Kestrel and a fan fret X20-7. I wanted all three but came away with none. I also have a soft spot for the Synergy Uke. I did manage to put an order in for something, so maybe I'll tell you about it sometime.

The Kestrel was quieter than my X20 and the X20s I played there, but it may have just been me because I didn't really have much time to focus on it. The Synergy X20 was probably as loud and probably as deep as the X30 I tried with its 7 inch depth. The acoustic tone of the Kestrel was pretty awesome in my opinion for melodies. I never played it plugged in, but I didn't see the need or think to ask over the short time I was there.

That it has nylgut (Rubino) trebles and wound composite bass strings (Aranjuez A500G).

Or that indeed it projects better and thus seems less loud to the player?

Interview with authors and summary of the research paper:
news.mit.edu/2015/violin-acoustic-power-0210


The research paper:
royalsocietypublishing.org/doi/full/10.1098/rspa.2014.0905


The Royal Society prefers papers that are interesting to many of its members over those written for hyper specialists.


The paper talks about violins as small systems that need to be very efficient.

It talks a bit about violin design and performance, and notes that the largest contribution is from the front and back plates (implying that the area given to the sound hole should be carefully managed).

It describes how the Helmholtz physics model previously used to analyse guitars with round sound holes was adapted to analyse violins with f-holes.

The paper reports that the best performing part of a violin sound hole is the edge where sound pressure is highest.

And that an f-hole maximizes the amount of high performance edge, and minimizes the low performance centre area.

The research traced the evolution and refinement of f-hole performance over time by measuring 470 instruments from different periods.

The authors credit the good hearing of craftsmen for recognizing which deviations improved the sound and should be repeated on subsequent violins.



Cheers.

In the early 1900s there were three parallel approaches to louder guitars:
1. Bigger guitars such as dreadnaughts and jumbos
2. Bigger guitars with violin/viola features such as arch top guitars with f-holes
3. Electric amplifiers

Electric amplifiers won by a wide margin over pure acoustic guitars.

Dreads became mainstream for acoustic performance and jamming. Amplified arch tops have a small market in jazz performance.

Today f-hole arch top guitars are mostly for tone and/or style, and that's OK. There isn't much incentive for much f-hole evolution.

My guitar tech and guitar teacher warned me that those cool looking arch top guitars are fussy to maintain because the wood panels and necks shift out of alignment with the floating parts as the weather changes. Is carbon fibre a solution?

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Nice summaries of F holes with violins and then guitars.

I don't know for sure, but my money is on carbon fiber being a robust solution to this issue. CF has already proven itself in other guitar constructs such as multiple necks, multiple strings or any other situation where a wood version would be fragile or clunky if the design is even feasible.

You missed one:
3. Resonator guitars

T,FTFY ;)

Yup. I love when dobros come to jams. :) :) :)

Casual;

Very nice reportage!

I'm thinking of the F holes for a thin-bodied, nylon string electric guitar. Have you run across any reference to nylon string instruments with F holes?

I once had a beautiful Yamaha, thin-bodied, nylon string guitar and while its acoustic presence was OK, it wasn't anything to write home about.

As usual, the introduction of carbon fiber opens up a lot of questions.

Didn't you read my answer to your question above? :)

Why would soundhole shape change anything on an electric instrument? I'm tempted to refer to the weird ones Ovation put in some of their instruments...

Remember that bowed instruments make almost the opposite trade-off in terms of sustain vs. projection, and can do so because sustain is handled by the player. There's also the question to what extent the arched design of top and bottom (and the coupling via a soundpost) interact with soundhole shape.

If you're thinking of this kind of instrument I see no reason why it wouldn't work equally well with nylon strings, provided you adapt plate thickness and/or bracing to the lower tension ... and use appropriate pickup(s)

https://lordofthestrings.com/picture...ll1x-i2534.jpg