Thicker Plates - Deeper Carve

[Groyniad]

hi all

a new guitar has led me to wonder about this:

is it the case that the famous archtops of the forties and fifties from D'angelico, Gibson, Epiphone would have had thicker top and back plates and a deeper more pronounced carve than more modern instruments?

I haven't seen such a pronounced arch - top and sides - or such relatively thick and stiff tops/backs before - and it seems to me that the guitar has a really excellent voice.

I know for example that Andersen's archtops have very thin tops/backs with a very shallow arch - and that my Eastmans seem to follow the same pattern....

I have never seen - e.g. - a fifties L5 or D'angelico.

cheers everyone

[RJVB]

There are enough copies of the original L5 around that would presumably reproduce the top and back arches, though not necessarily the (top) plate thickness.

A builder once told me that Ken Parker is an advocate for building less pronounced arches.

I would assume that there has to be a relationship between the arch, the load it has to carry and how thin it can be but really wouldn't know in which direction that would go.

What I do know is that there is a probably coincidental analogy in the evolution of the violin, where evolving taste and requirements led the instrument to move from pronounced to much flatter arches (and change shape slightly). That changed the sound from warmer/rounder (could also be heard as more hollow) to a brighter, opener, more powerful and projecting sound. Neither of those changes seem a particularly driving factor on instruments that are mostly played for their acoustic qualities. Maybe their builders still think they might of course, but it could also simply be that a flatter instrument is easier to play?

[Jimmy blue note]

The history of arch top guitars is barely over a century old and as a musical instrument it is unique in how closely its design, concept and execution have followed, paralleled and changed the sound of the musical culture. The arch top's evolution is literally the evolution of the music of huge dynamic change.
When the instrument began, it was very much an experimental idea when some kind of instrument was a given for a family's entertainment. Everyone who could, had a piano, or a mandolin, or a uke, or a guitar and before electronic reproduction, you made your own, and the guitar was the family's HiFi (or iphone). As public music and dance halls also became a cultural matrix in society, the high volume instrumental band also created a demand for instruments.
The guitar had a role in both these branches of musical society.
Yes Groynaid, the early history of archtop design was very experimental. Although the concept was taken from violin family design, the guitar, not being a bowed instrument, needed more mass so the thin conduit of a violin top wouldn't dissipate the energy too quickly. A thicker top was essential. Bracing was essential. A more massive bridge was essential. A higher arching pattern became the foundation of the archtop trademark.

Arching patterns are the patent and trademark of the builder. Strad, Amati and Guirneri were prototypical luthiers who created seminal arching patterns that marked personality in violins. Gibson, Loyd Loar, Stromberg, D'Angelico, Epaminondas Stathopoulos of Epiphone all helped pioneer the acoustical parameters of the archtop's sound, projection and tonal personalities of their instruments based on the arching patterns and thicknesses they produced and evolved. Ex: Stromberg used a relatively straight peaked arch that gave his later guitars a huge sound. D'Angelico's evolved from and grew out of Loyd Loar's Gibson L-5 archings (which were different from earlier L archings), etc.
One way to control top flexibility was the graduations of the patterns; the tapering of thicknesses from the rim to the peak. The graduations and the tuned braces are one (of many) reasons a luthier tuned guitar can get the evenness and sound quality of harmonics that mass produced, pressed and laminates will never have.
A scoop in the graduation along the outer perimeter is also a way to control, or free up sound. That's the aspect of the graduation that I personally tend to use a lot in re-graduations. Every luthier has their own preferences of how they tailor their sound and feel of their guitars.

In modern instruments (I see Jimmy D'Aquisto as being the most experimental and influential- and to my ear, the most successful), some luthiers strove to get a more nuanced sound from using thinner tops that allow more overtones to be sustained in the envelope of the note. This "open" sound does distinguish the Gibson/Heritage sound from the later D'Aquisto and Eastman sound. It's a matter of what the luthier's concept is and how successful they are in juggling the many elements and trade-offs needed to realize the guitar they imagine.

Modern players also have the opportunity to choose what traditions and innovations they want in their own music so again, there is no right or wrong, but there are those players who, through experience and personal tastes, need guitars that meet THEIR needs, and there are some builders who are good enough that a complementary relationship forms and creates instruments that didn't exist before.
It does take an imaginative player to demand something a masterful luthier can build. When things are right, there's music that was never heard.

[supersoul]

I only have first hand experience with three carved archtops: 2 old German ones from the 50s and a modern Thorell.
Both of the German ones have recurves around the edge of the top and bottom plates, whereas the Thorell doesn't. The shape of the arch on the German ones is much more complex; it goes down into the recurve, then up steep to an almost flat plateau, then down steeply into the recurve on the other side. On the Thorell, the arch just curves at about the same rate from side to side.
The German plates are much thicker than the Thorell. The German ones are parallel while the Thorell is X-braced.
Personally, I much prefer the sound and feel of the German archtops, even though the Thorell is a top-notch and beautiful instrument. Their sound is punchy and woody.

[Groyniad]

I've used a number of boutique American - Benedetto inspired - archtops, and more recently a number of Eastman archtops (also Benedetto variants), and the European boutique instrument which I recently acquired (built 2023), is the first archtop that has been satisfying to play acoustically. I didn't think archtops could be satisfying acoustically - I've had to put up with so many that weren't. It amplifies its acoustic sound very nicely - so it has a warm amplified sound too.

I have no idea how it is achieving this striking effect - but the top and back feel stiffer and thicker than the guitars I'm used to.

fascinating that violin building has gone through a change from more to less pronounced arching. and that more pronounced arches are associated with a less shimmering and more earthy sound.

[supersoul]

Do Benedetto inspired archtops have a recurve?
Aside from the vibrational properties, I think recurves just look cool.

[Jimmy blue note]

European boutique instrument which I recently acquired (built 2023), is the first archtop that has been satisfying to play acoustically. didn't think archtops could be satisfying acoustically -


fascinating that violin building has gone through a change from more to less pronounced arching. and that more pronounced arches are associated with a less shimmering and more earthy sound.

Have you ever played a Jimmy D'Aquisto? I would not have believed an instrument could have such clarity, control and rich fundamental and harmonic sustain. It's got a scoop and a tubular arch and is quite thin relatively speaking.

Also an instrument like an archtop matures with playing...a LOT of playing. It opens up over the first year especially. I've experienced many a carved spruce top that was damaged (choked) from growing into what it could be because the collectors who owned them didn't give them the due respect of playing them constantly. It really matters, in the range of acoustic sound and the response to touch.


It's not really fair to compare archtop guitars with violins. The violin is a constant source energy system and it is integral with the bow. A guitar has much more interaction with its braces and the energy of the acoustic envelope must be self sustaining, and along with that is the decay envelope.
Really, no fair comparison, IMHO.

[Jimmy blue note]

Do Benedetto inspired archtops have a recurve?
Aside from the vibrational properties, I think recurves just look cool.

Not really. Not the way I would have done it but to each his own. Maybe one of these days I'll summon the required insanity to actually re-graduate a 16-B. That will be interesting.

[RJVB]

Really, no fair comparison, IMHO.

Since I introduced them: not as a comparison but rather as a parallel. Too many differences indeed, but I do find it hard to believe that the physics of how the resulting plate vibration is converted into sound and how that sound radiates as a function of plate curvature isn't shared at least to some point.

Maybe I should have compared to the arpeggione but I really know to little about those critters

I'm almost regretting now that I never learned and got equipped to do some luthery myself. I'm getting very curious how an x-braced violin would sound now

[Jimmy blue note]

Since I introduced them: not as a comparison but rather as a parallel. Too many differences indeed, but I do find it hard to believe that the physics of how the resulting plate vibration is converted into sound and how that sound radiates as a function of plate curvature isn't shared at least to some point.

Maybe I should have compared to the arpeggione but I really know to little about those critters

I'm almost regretting now that I never learned and got equipped to do some luthery myself. I'm getting very curious how an x-braced violin would sound now

There are parallels, and it's absolutely fascinating. One thing about a violin, it receives energy from a bowed input and that moves not just the top but also the back as the bridge serves as a tuned element rocking back and forth between exciting the top and the back at thousands of times a second. So an X brace which tunes the top is alternately paralleled by a bass bar and a sound post.
You should check out some articles on the physics of the violin (a well thought out entry level article might be Carleen Hutchens' Scientific American article)
The Physics of Violins | Scientific American
But yes, even as an armchair luthier, it's absolutely fascinating reading that something that small can fill an entire hall full of people clad in acoustically absorbent material, yet with the clarity that nuance and dynamics of a vibrato can be clearly heard...and felt. No amps!

[powerwagonjohn]

My 1950 Epiphone Triumph has a much more pronounced arch to the top compared to my 1952 Gibson L-4. Also quite a different tone. I find this stuff very interesting.
Thanks john

[deacon Mark]

Bill Hollenbeck made his guitars with a high arch much more than his teacher Bill Barker. The neck angle is around 3.7 degrees and the carved his tops to be most responsive directly over the bridge. His guitars do not sound like Barkers and nothing really like a Gibson. His guitars do have some of the characteristics of the 1930s D'angelico's but hard to explain.

I have also played guitars that have very shallow neck angles and Barker guitars can have shallow neck angles at 3 degrees. Some of these are the smoothest most lyrica sounding guitars I have played. I am not sure the whole process since bracing and carving must be taken into consideration. But sometimes I find I real hard to make and hard and fast generalizations. Play some real old and large 19 inch Stromberg's and hear the differences it is wild.