Simi Hollow Archtop

[Dave Weir]

Hopefully I'm in the right section here. Anyway, I think of an Archtop as having a suspended tail piece and pressure down on the bridge and top. But a lot of Simi Hollow Body "Archtops" have T.O.M. bridges or even wrap around bridges. So the pressure is really pulling up on the top. Is this acting like an archtop at all, or is it really just a pretty top shape, and really adding nothing sonicly over a flat top?

[Michael Lewis]

What you are seeing is that the "semi hollow" guitars are not dependent on making acoustic sound or tone. The bridges are anchored into a beam much like a neck through design. They are made to withstand high volume situations without having too many feed back problems.

[Barry Daniels]

A semi-hollow archtop definitely adds a bit of acoustic flavor to the mix, compared to a solid body guitar. In my opinion, a semi-hollow is the halfway point between a solid body and a full on acoustic archtop.

[Dave Weir]

What I'm really wondering is the difference between a simi hollow arch top and a simi hollow flat top. It seems like since the top isn't really powered, it wouldn't be much different.
It seems like what would make a bigger difference is the construction of the back and sides, if it is bent and glued or a hollowed out slap.
Any options or experiences?

[Dave Locher]

I believe you are correct that the shape of the top doesn't make much difference on a semi-hollowbody guitar. The composition of the top and what is under it, however, could make quite a difference. If nothing else, a typical arch-top semi-hollow has more material under it than a flat-top semi-hollow would. My ES-335 was a few inches thick in the middle because the back and front were both arched. That allowed for spruce blocks between the laminated top and back and the solid maple block in the middle. The guitar I recently built, however, has the maple top glued directly to the mahogany block because it's flat with no arch. The total thickness in the middle is 2 inches, whereas the 335 was more like 4 inches thick at the bridge. I would imagine that alone makes a difference in tone.
(There are too many other differences between my two guitars to give any definite answers about the effect of the top shape, though.)

[Randolph Rhett]

I know what you are asking, but I think you mean to ask what is the difference in tone between a semi-hollow body and a chambered solid body. "Flat top" usually means an acoustic guitar like a Martin Dread.

This speaks to the endless, "does tone wood matter to an electric guitar?" I can say that I have seen jazz played on a Telecaster slab of wood and it sounded fine. Beautiful, actually. Regardless, as a player with 30 years of guitar fetish, I've played a number of different guitars. Completely non-scientific personal experience has given me the following beliefs: It seems to me that a solid spruce carved full hollow body archtop somehow sounds richer even through its floating pickup than a plywood full hollow body. A plywood hollow body sounds generally "sweeter" to my ears than a plywood semi-hollow. Solid bodied chambered guitars sound like their pickups to me with little color from the guitar, but are lighter than their non-chambered cousins.

However, I'm sure that if you ask a dozen luthiers you will get a dozen different answers. Someone will no doubt opine that my experience is absolutely backwards to theirs and either will claim NO difference, or that chambered solid body electrics are the most musical instruments that exist. So, take what I said with a big grain of salt.

[Barry Daniels]

I might provide the answer you are looking for by stating this conjecture: The extra work of building a semi-hollow body versus a chambered solid body would not add sufficient acoustic tone improvement justifying the extra work which might be as much as two times as difficult and time consuming to build. The solid body has the potential to be just as nice sounding as the archtop, or even better. But the archtop does look nice.

[Dave Weir]

Just so we are on the same page, a semi-hollow body has bent sides glued to the top and back, and a chambered solid body has a carved out body with the top glued on. Right?
So I think what I am designing is a heavily chambered solid body. The top would actually be attached all around the sides and around the upper bout and neck and hollowed out in a sort of circle defined by the lower bout. I'm wondering if this small top plate would benefit from a block under the bridge or if it would be more the semi hollow sound if the top was left to vibrate.
The other thing I'm wondering is if a pickup like a Fishman Rare Earth and Bronze strings would move it toward an acoustic sound.

Thanks everyone for you input.

[Randolph Rhett]

Just so we are on the same page, a semi-hollow body has bent sides glued to the top and back, and a chambered solid body has a carved out body with the top glued on. Right?

Yes, I think that would be consensus on nomenclature.

So I think what I am designing is a heavily chambered solid body. The top would actually be attached all around the sides and around the upper bout and neck and hollowed out in a sort of circle defined by the lower bout. I'm wondering if this small top plate would benefit from a block under the bridge or if it would be more the semi hollow sound if the top was left to vibrate.

My gut is that you would have to make it very thin and have a relatively large free area to make a difference. But I'd love to see the results of your experiments.

[John Mueller]

Barry Daniels wrote:
The extra work of building a semi-hollow body versus a chambered solid body would not add sufficient acoustic tone improvement justifying the extra work which might be as much as two times as difficult and time consuming to build. The solid body has the potential to be just as nice sounding as the archtop, or even better. But the archtop does look nice.

I do not agree with this statement. I have owned chambered electric guitars and I own several 335 type guitars. There is a resonance from the larger chambers in the 335 semi hollow body that is not there in the chambered guitar. Here is a video on the building of a reproduction of a 335. https://www.youtube.com/watch?v=7CfQGXuPlMg At 31:30 the body is being glued up and you can see how large the open spaces in the body are. The body itself is larger than most chambered guitars and the top and sides are much thinner than the chambered guitar. They both can sound "nice" but they sound very different.

[Barry Daniels]

I didn't say a semi doesn't sound better or that they sound similar.

[Jason Rodgers]

Just so we are on the same page, a semi-hollow body has bent sides glued to the top and back, and a chambered solid body has a carved out body with the top glued on. Right?
So I think what I am designing is a heavily chambered solid body. The top would actually be attached all around the sides and around the upper bout and neck and hollowed out in a sort of circle defined by the lower bout. I'm wondering if this small top plate would benefit from a block under the bridge or if it would be more the semi hollow sound if the top was left to vibrate.
The other thing I'm wondering is if a pickup like a Fishman Rare Earth and Bronze strings would move it toward an acoustic sound.

Thanks everyone for you input.

Dave, I've been looking at your guitars a bit lately on The Gear Page "What's on your bench?" thread. If I understand what you're asking here, you want to take your standard shape, make top and back halves - each chambered similarly, in what folks often call "clam shell" - and glue them together. With your bridge and string-attachment method in mind, I'd suggest chambering as you describe, but leaving a segment (a "jetty," if you will) about the width of your tailpiece extending from the tail to just under the bridge, or from the neck to just under the tailpiece. That would leave material under these high-tension/pressure areas and allow you to chamber the top and back as thin as you'd like (within reason) and not worry about the bridge area caving in or the tailpiece tearing out.

Acoustic benefits of this design, I think, would be limited to a different resonance and resulting tone due to reduced weight, but maybe not enough to get an "acoustic" sound from acoustic pickups. You could experiment with different amounts of material under the bridge, maybe tapering that "jetty" to a point under the bridge, so the wings are over open areas, or stopping it just shy of the bridge, so the tailpiece is still supported but the bridge is floating over open space.

By the way, I really like the simplicity of your design (and the price you're able to offer). It makes me think about some of my design and process decisions.

[Dave Weir]

I really do try to keep it simple, and am trying to do something a little different but not redesign the whole thing.
I wasn't really thinking clamshell, more just the back is carved out and the top is set on or maybe an inch or so smaller and inlaid.
I have some rather plain and heavy Meranti that I think would be a good back and was thinking of a spruce top or something.
The peninsula seems like a good option or maybe a little island for the tailpiece to screw into. It's like I want it supported for strength, and floating for sound.

Maybe the first one could just have the top screwed on so I could keep working away under the hood.

Another thread here got me looking at a Ken Parker I think site and he was talking about the fishman pickup and bronze strings and I thought that might be interesting. I have this on a Martin DX1 and it makes a very nice recording set up, not really a miked acoustic, but very good.
Anyway, I'm wondering where this tone comes from. Is it the strings and pickup like on an electric or is it depending a lot on the vibration of the top that is the moving the pickup around. Or is it the way the string vibrations decay because of the the top is absorbing energy. It's probably all three, but it seemed like if I had the right strings and pickup and could figure out the decay, I might be half way there.

[Jason Rodgers]

Another thread here got me looking at a Ken Parker I think site and he was talking about the fishman pickup and bronze strings and I thought that might be interesting. I have this on a Martin DX1 and it makes a very nice recording set up, not really a miked acoustic, but very good.
Anyway, I'm wondering where this tone comes from. Is it the strings and pickup like on an electric or is it depending a lot on the vibration of the top that is the moving the pickup around. Or is it the way the string vibrations decay because of the the top is absorbing energy. It's probably all three, but it seemed like if I had the right strings and pickup and could figure out the decay, I might be half way there.

I don't know these products, but it looks like there are three versions: single coil, humbucking, and blend, which has a microphone. Which are you using on that Martin? In the case of magnetic pickups on a flat top guitar, while the pickup attachment and body style contributes to the tone, I think it's mostly the string-to-coil action that produces the resulting tone. Of course, these Fishman pickups are active, so they're probably low impedance for a wider frequency response, with a preamp and built in EQ to more closely emulate an acoustic tone. If you already have one of these pickups, you could you mount it on one of your solidbody guitars, string it up with the bronzes, and see what happens. The pickup might get you most of the way toward the tone you seek, with some experimenting with chambering to get you the rest of the way.

[Dave Locher]

The one and only guitar I've built from scratch is vaguely similar to what you describe: 1/4" maple flat top glued to a solid mahogany body hollowed out everywhere except from the bridge to the endpin. So the tom bridge and stop tailpiece are supported by the mahogany but the two hum bucking pickups are mounted to the maple top with nothing but air under them & all around them. I basically made a mahogany bowl and glued a maple plate to the top.
Mine is small compared to most arch tops, about 13.5" wide and 2" thick.
It does sound louder than a solidbody unplugged, but nothing like a true hollow body guitar. When played through an amp I can hear the "hollow" tone I was looking for.
This was my attempt to combine aspects of several different guitars I've loved. It is a compromise, and it suits my playing style well. It feels about like an SG but with a tone that falls midway between an SG and an ES-335. I think that is partly the wood (mostly mahogany) and size, and possibly the light weight.
I am happy with it but it does not sound like an arch top hollowbody.