Some Questions about F-hole Design

[Steve Lavelle]

I've been wondering about why F-holes don't get thinner at the edges near the "scrolls". The ones I see on mandolins and guitars all seem a little chunky to my eye. Is it because the tool size prevents the gap from becoming to small? Is there some acoustic reason that dictates the total area of the hole to get a specific Helmholtz frequency?

I can understand how there might be tooling limitations to holes with binding that would dictate a minimum gap, but the majority of holes aren't bound, so why aren't the designs more "delicate"?

Enclosing two pictures. The first is the F-hole on the only instrument I ever made (4 str. dulcimer, 43 yrs. ago, summer before last yr. of H.S.), cut by hand with a coping saw and filed and sanded to get the shape. The second is the hole from my '93 Flatiron. See what I mean?

I've shown you mine, now you show me yours.

[Steve Lavelle]

Steve Sorensen is doing some thin gaps on his FX mandolins, so I guess it's more about the maker than the acoustical physics.

[George R. Lane]

I was once told that smaller f hole give more bass tone and wider ones lean more to the treble side.

[Steve Sorensen]

The area of the F-hole opening does impact the balance of response -- particularly if too small. If too small, you can actually hear the note where treble response is muted as you go up the neck.

While I do appreciate delicate and artful sound apertures, I also make sure that the area is appropriate for the entire tonal range of the instrument. With every new design, I test and adjust the sound holes as needed.

In fact, I was pleased to find that the "scooped" outer edges of the new Stealth design added effective opening area thus allowing for a narrower profile from the front-on view of the top.



From a straight-on view, these "slash-holes" are less that 1/4" at the widest point.

Steve

[sunburst]

Area of aperture needs to be in the optimal range for the size of the instrument if there is to be good coupling between the top, back and air mass in the instrument. Two apertures to each side, like f-holes, make the air withing the instrument behave differently from the air within a similar instrument with a centrally located single aperture, like an oval hole, thus there is a sound difference. The shape of the apertures is not so important.
We have tools all the way down to razor blades, so tooling has very little to with how thin we can cut a slot in the top. If an builder uses a specific design or shape of f-hole (or any other hole shape) it is a design decision, not a limitation of tooling.

[fscotte]

Cause that's how Loar did it. And it has been proven time and time again, there is literally nothing that can be aesthetically improved upon in the Loar designed F style mandolin. It is as perfect as perfect can be. Change anything even slightly, and you disrupt the balance of the universe.

[Marty Jacobson]

All my f-holes have 1/8" or even 1/16" gaps. In typography the idea of adding drama to a design by varying line width is called "stress", and that's the idea I take advantage of. It's calligraphy, basically.
I've done some very elaborate soundholes using laser cutting. You can do whatever you want these days, within reason.
The classic design is gorgeous, but I'm kind of ADD, so I get bored if I don't get to play around and try new stuff out.

[hank]

Steve do your apertures fan out the sound in any noticeable way(to the player or out front). They look like they could be engine compartment louvers on your inspiration roadster. Keep the cool California Hot Rod designs coming.

[billhay4]

And it has been proven time and time again, there is literally nothing that can be aesthetically improved upon in the Loar designed F style mandolin.

Bull.
Bill

[fscotte]

I dunno about that Bill. It may be a matter of opinion, but years of cloned F5 design says alot. If there were some aesthetic design choices that could have enhanced the F5 design so that it would appeal to the masses, then maybe it would be bull. And wouldn't that have already been established? I don't mean a few mm's deeper rim ala Gilchrist, but true aesthetic redesign choices. So far however, the original F5 design continues to be the king.

[Marty Jacobson]

I dunno about that Bill. It may be a matter of opinion, but years of cloned F5 design says alot. If there were some aesthetic design choices that could have enhanced the F5 design so that it would appeal to the masses, then maybe it would be bull. And wouldn't that have already been established? I don't mean a few mm's deeper rim ala Gilchrist, but true aesthetic redesign choices. So far however, the original F5 design continues to be the king.

Wes, I thought your original comment was sarcastic. :-)
There is no such thing as a perfect design. The F-5 design is very good, exceptional even, but there is a lot to be said for familiarity. We tend to gravitate toward what we're used to. People from other cultures won't see the Renaissance influences in the F-5 design as being particularly appealing (and might even consider it a bit gauche).
Like everything else, it comes down whether the design works for the intended user. A lot of folks on here see a scroll as being superfluous, and it absolutely is, in the functional sense. For some, a scalloped-stave Italian bowlback is the epitome of good design.

A lot of designers see many current model cars as being quite ugly, but that doesn't keep them from appealing to the masses. I'm not saying the F-5 is ugly, just that market success can't be used to validate the content of a design.

[fscotte]

Yes I intended a bit of sarcasm, especially the perfect part - I even thought about commenting how angels came down and delivered the F5 plans to Loar... But then I realized that history itself is the final judge. Until more history is revealed, the F5 design remains the king due to its influence and continued demand.

[Marty Jacobson]

Yes I intended a bit of sarcasm, especially the perfect part - I even thought about commenting how angels came down and delivered the F5 plans to Loar... But then I realized that history itself is the final judge. Until more history is revealed, the F5 design remains the king due to its influence and continued demand.

It really is king. My point is just that it's kind of like how the original Ford Mustang just "works" and is timeless. Not sure how much of that is the inherent design, or the combination of the design, + culture at the time, + the accumulation of that car in movies, cool uncle's cars in the driveway when you were 6, etc.

[pops1]

I don't know, a 1950 MGTD is much more appealing to me than a Mustang, and I am old enough to remember when they came out. Most 30's cars are more appealing to me. But then I play A style bodies.

[Dale Ludewig]

Just to be obstinate, maybe the Loar design's continued popularity says a lot about the human psyche. Perhaps the desire to belong.

[Graham McDonald]

I would suggest that it is more the carving graduations and bracing which is the difference rather than the number, shape or position of the soundholes. The critical thing is the area of the port - aka the soundholes(s), which is a controlling factor in the instrument's air resonance.

cheers

Area of aperture needs to be in the optimal range for the size of the instrument if there is to be good coupling between the top, back and air mass in the instrument. Two apertures to each side, like f-holes, make the air withing the instrument behave differently from the air within a similar instrument with a centrally located single aperture, like an oval hole, thus there is a sound difference. The shape of the apertures is not so important.

[Steve Lavelle]

I should say that my questions about F-hole design and the desire to see a little more stress than is normal came from my own aesthetic sense. I was at Gryphon playing a Northfield and I noticed that the gap on the head stock scroll of the F style seemed disturbingly big to me. I realized that I looked for small gaps in the body scroll of Fs as well. That led me to muse about the F-hole's big gaps wherever I saw it on production instruments. Except violins. So I wondered why the f-hole on mandolins tend to look more open even though both instruments have the same tuning and carved fronts and backs.

If I ever get the money to commission a mandolin, I now know there are physical constraints, but most of my aesthetic desires can probably be met if I can find a luthier who is agreeable.

I'm sure I drew my inspiration for the holes in that dulcimer from a violin, and that thing has been hanging on my wall for 43 years because it looks better than it works. If anyone can post a picture of a mandolin with a more stressed traditional shaped f-hole like a violin's, I'd like to see it.

Loars are great, but so are Stadivarious violins, and I prefer the Strad f-hole. Even Campanella mandolins styled like violins have the more open hole. The luthiers have made it clear it's more about design choice than any one design being better acoustically as long as the open area requirement is satisfied.

I can't afford a new mandolin, but that doesn't mean I don't get MAS!

[Steve Lavelle]

Based on what the folks in this thread are saying , If I wanted an f hole like the one on the left in my original post, I would have to scale it up relative to the one on the right to achieve the same area of opening and that might lead to some asethetic imbalance on a standard F body design. Maybe the Sorensen holes look right because he changed the body?

[sunburst]

I would suggest that it is more the carving graduations and bracing which is the difference rather than the number, shape or position of the soundholes...

The difference between oval hole and f-hole port positions is in the air modes. With two holes, one to each side, the air mode that Dave Cohen often refers to as the "side to side sloshing mode" causes air to pump in and out of the f-holes, though the air movement is out of phase at the two apertures. Alternatively, with the oval hole, that doesn't happen. Instead, the longitudinal sloshing air mode causes air motion at the port. Whether that simply changes the frequencies of those air modes, I'm not sure, but even if that is all it does, that could be enough difference to hear. If I try to take this any farther I will quickly get in over my head.

[Graham McDonald]

The difference between oval hole and f-hole port positions is in the air modes. With two holes, one to each side, the air mode that Dave Cohen often refers to as the "side to side sloshing mode" causes air to pump in and out of the f-holes, though the air movement is out of phase at the two apertures. Alternatively, with the oval hole, that doesn't happen. Instead, the longitudinal sloshing air mode causes air motion at the port. Whether that simply changes the frequencies of those air modes, I'm not sure, but even if that is all it does, that could be enough difference to hear. If I try to take this any farther I will quickly get in over my head.

I will of course defer to Dave's much greater understanding of such things, though my understanding was it was the different in area that caused the difference, the oval hole being about 25% smaller that the combined f-holes. I do miss Dave's enlightening contributions. A shame he was driven out by the flat-earthers.

cheers

[Marty Jacobson]

A shame he was driven out by the flat-earthers.

Like all stories, there are two sides to that one.

[Graham McDonald]

Like all stories, there are two sides to that one.

Of course 8-)

[hank]

Steve Gilchrist’s thoughts on this bring the bracing and the effect it and the oval hole have on plate movement. Horizontal shaped for oval X(cross)bracing and lateral bracing and vertical for f holes and tone bars or cross braced for more bass end of the his tone formula. He describes how he chooses only hard woods for his oval hole designs because of this horizontal bass heaviness. He does a great job of describing his perception of tonal generation and his methods of manipulation.

[Steve Sorensen]

Going back to the original question and observation -- it is absolutely true that many of the Loar era F5s had F-holes that were clunky and kind of chubby looking. Definitely not the refined control one sees in the best violins.

In general, to my eye, the F5 is far too Victorian and would have benefited greatly with a touch of 1920s Art Deco/Art Nouveau streamlining and refinement. Even by the time these instruments were being produced, the design aesthetic was rather antiquated and clunky.

It is important to remember that the Loar-era F5 was essentially a failed effort to re-boot the dying mandolin market after World War I. The design was not a success at the time that they were being built.

However, the tone, balance, and power of the best Loar-Era instruments is undeniable . . . so variations on the form must account for the mechanisms of that success!

What a fascinating twist that 20 years later, those same instruments were the best mandolins available for the new bluegrass music (and remain the ideal for most American classical and jazz players too).

As I think Marty also indicated, my belief is that the openings should be artfully and aesthetically integrated into the design of the instrument as a whole. I tend to always touch back to the core form of the body, bracing, and layout (as I understand it), in an effort to not lose the seed of voicing genius in the Gibson/Loar F5 form.



Ironically, on an absolutely pragmatic level, the wider F-Holes do allow for much easier work inside the body of a finished instrument if you are tweaking tonebars or graduations . . .

Learned that the hard way.

Steve

[oldwave maker]

Built a dozen fiddles decades ago, always thought the gibson f holes were either an attempt to be different, or the result of their pin router capabilities. The midwest in 1922 was probably well stocked with WW1 european violinmaking refugees adept at cutting f holes quick and clean. My early speriments altering f hole size to change resonant frequency were bizarre- here was a half step above gibby D, couldn't bring myself to burn the entire mando! Stole from Epiphone and others who looked right.......