To start, thank you to all who chimed in on my first post, I have learned so much about guitar building in the last few weeks and much was due to the direction I received here. To summarize: This is my first build, started 17 years ago during a brief apprenticeship with a violin maker, so it really started out as a hybrid. Now as an experienced custom woodworker (mostly custom doors and windows), I have the time and woodworking skills to get this structurally finished. Since this is clearly a hack job, and will never really be a fine finished guitar, I have decided to experiment with it to see what I can learn. The guitar: Carved arched back, curly maple. Flat top, floating bridge. 22" long, sides 2.75 at the neck, 3.5 at the heel. 13.5" Upper bout, 10 middle, 15.5 lower. Neck is 3 piece laminated maple, joining at the 12th fret, no truss rod. The neck is set pretty high, so I have to add some riser feet under the bridge to get the height needed. Messing with variations of the feet has been informative as well. The other thing that has been interesting is changing string length. I know that I am ignoring the intonation, but I do like the softer feel of longer strings.
Experiment 1: This was what the first post was about. It involved a heavy set of trusses running from neck to heel, these trusses live 1/2" under the top and supported the neck and also the top with a small stick between the top and the trusses. The top had no bracing and was sitka .125 thick Conclusions: The guitar has a crisp woody tone, sounded a bit banjo-esque, decent sustain, good volume, very little bass. Sounded pretty good with a slide. Not a sound that I would trade my standard dreds for. It was a great experiment though. The ability to move the underbridge (as I called it) was very interesting. By moving it forward and back, both in front of and behind the bridge, I was able to observe how the loading of the top affected sound, with the underbridge just in front of the bridge so that the top started to deform, I go the best sound, from there I could push it forward and hear how the sound became murky and weak. I think this somewhat resembled the Sel/Mac pliage.
Experiment 2: I took this top off and added a simple x brace, 1/2" thick so it would rest on the trusses. The only change to the sound was a bit of added warmth to tone, but still very stiff with no bass. Since this top was soon to be removed, I drilled a bunch of 1" holes in it to observe how that would change the tone. The added holes opened the tone up a bit.
Experiment 3: I ordered 5 engleman spruce tops from ebay, $10each, most have some discoloration, student tops. For the first (thickness .110) I tried to imitate standard bracing from pictures on line and Cumpanio's book. I wanted to try laminated x braced since the top is going to deform inward from the strings. These braces are 1/2" wide by 3/4 tall to start. I should have made them a bit thinner, but I just misread the book a bit. I did scallop them by the bridge a bit, just imitating a picture on line. I tapped away on the top as I did this, but it was meaningless as I have no idea what I was listening for. I concluded that braceless tops are boring because of all the fun I had shaving away at the braces. I hacked the trusses down to allow for the bracing to be untouched. The guitar strung up deflected about an 1/8" at the bridge. The sound was much nicer, like a real guitar. The volume is good, it has some nice crispness or attack, and the tone is nice. Changing the feet on the bridge heavier= more sustain less volume, lighter, less sustain but good volume. I have also moved the feet in and out to rest more or less on the x brace. On the brace more diminishes tone and volume. I tried a 5 contact point bridge feet, so I can be on either side of the x and in the middle (see picture) This did not help much, I think I picked up something in tone, but clearly lost volume, picked up sustain. Basically it is just heavier.
During this I started thinning the back. Picking up a better bass as I removed material and defined the recurve at the edge.
Personal conclusions up to this point: First, this is so difficult living in Mount Shasta, a small town, we have Medford OR. an hour to the north, and Redding to the south. The point is that there are not any great guitar shops to browse, certainly nothing with contemporary hand built guitars. So I spent some time playing all the Taylors and Martins I could to get an idea of what kind of sound you get for the money. The Taylors honestly were a joke, the sound was very stiff and lacked bass. Clearly these guitars needed to open up a bit, but still, $2500-4500? Nothing impressed there. The other shop had Martins and some Breedloves. For $1200 a basic Martin had a Martin sound, full, medium loud even. The only guitar that to me had some wow factor was a small Breedlove at $2400. It was the only guitar that I played that I would trade my 10 year old $350 blueridge dred for. Unfortunately there were no archtops to play.
This experience of comparing guitars was very helpful in calibrating my ears to have clue what is going on with the guitar that I am messing with. It also helped me get a tone in mind that I would like to strive for.
I like the hybrid idea, it seems the carved back gives the guitar volume and punch. I love the volume, and diminished sustain works stylistically with much of my repetoir. I play fingerstyle and like the more percussive bass that I am getting.
Questions: I have 4 more tops to play with on this. I would like to try a more closed x, bringing the ends in towards the neck and heel. It seems that I will need to move the intersection of the x towards the neck to get the needed spacing between the braces, or minimize the bridge feet.
I would like to try something asymmetric, but I have not seen a picture of anything to go off of. I would like to try something in the Kasha vein, but I think this should be a bit later.
Is it really a problem that the top sinks in an 1/8"? It looks odd but holds tune, it seems that I would have a more flexible top then a dome or pliage. Is there a reason why a top deforming upward is more stable then downward? Seems 6 of one and half dozen of the other.
Alan mentioned in a post that some students have done this and that it is possible to get a flat top sound with an arch back and floating bridge, I would love to hear more about this. (Thank you Alan for all the great posts, very helpful.)
I have the Benedetto book on its way, suggestions on one of the tap tuning videos?
So I am open to suggestions, for those who like to experiment, I would like to be able to contribute to something that you may be wondering about but don't want to dedicate an instrument to.
Sorry this is so wordy but I am trying to get the details in. Thank you all, Rob
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