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My holy grail is to make a parlor or OM shaped guitar with the bass and mid response of a dread or jumbo, and before I waste six months build time I'd like the advice of those here.

My current thought is to have a very thin to say 0.085" jointed to the wide grain is in the centre using a heavy bridge maybe with brass bridge pins. Having the x brace say 1/4"x 3/8" at the x increasing to 9/16" where the bridge patch starts the tapering to the rim and notching the ends in like you suggest having 1 tone bar tight to the bridge patch in an effort to grab and propagate the energy around the bracing like a conduit really and either have a bar at around 90 degrees off it either side to have an even support also using only 1 finger brace each side, finally after assembly thinning lower bout only in an attempt to create more monopole, with greater arching say 13'-18' to help the mids and trebles

Then on completion use say 13-56's in bronze to aid the treble response, and I was hoping before I spend the next 6 months building it some of you'd agree that this approach would give a bass heavy response or would suggest that I'd be better following a different bracing scheme.

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Formerly JJH

I learn more from my mistakes than my successes

1) Ain't ever going to happen. You can get good/great bass response from smaller bodies (OM's, definitely, Parlors is tougher), but all else being equal, the dred and/or jumbo sound like they sound in no small part because of their shapes and volume (size).

2) So you want to make a thin top (hello banjos), and then add a ton of weight by using a heavy bridge and brass pins? To what end? I'll let others with more experience chime in, but what you're describing sounds like a decent way to build a guitar that's stiff in all the wrong places and weak in all the others, so welcome high-end, bye bye bass response. My thinking: tighter arch = more tension = higher tap tone (think archtop, Selmer; not so much sustain, usually). Low X-brace intersection (= the area that takes most of the downward pressure), peaks in the X-braces where scalloped braces are normally at their lowest, and locking in the area behind the bridge with tall bracing/locked in bracing. None of this would seem to help in your goal to achieve more bass in a smaller body; for that, methinks you want to loosen the lower bout up as far as is feasible, and use something that'll tame the upper end (= relatively more bass).

A heavy bridge and brass pins will only drop the 'main top' resonant pitch, lower the power, and increase the sustain, all else equal. The deep 'big' sound of a Dread or Jumbo is not simply the outcome of that pitch being low; in fact, many small guitars have a low 'main top 'pitch. That 'big' sound comes from the ability of the big guitar to move a lot of air, both through the soundhole and off the top.

You can use the back to help the top move more air through the soundhole by 'tuning' it's main tap tone to be about a semitone higher than the main tap tone of the top. This is quite effective: guitars that do this well can sound about a half size bigger than they really are. Making the box deeper only spreads out the effect; it can make the low-end sound more even, but not more powerful, and may even make it less powerful. But with all that, there's no substitute for a big top.

Making the top thin means that you will need to use heavier bracing to get enough strength to resist the bridge torque. I feel that there's a certain balance between the top and bracing that gives the best treble response, and sacrificing that to get more bass only gives a high-end sound that is muddy or fuzzy. You can get good trebles from any brace system if you do it right, so pick a profile, like scalloping, that tends to maximize bass response, and don't skimp on the braces, but get them properly balanced with the top.

Your thinking on this seems to me to be 'prosodic': one thing at a time, with each part or word having a seperate meaning and function. "I'll make the top thin to make it flexible, and then arch it to make it stiff", as if the sum of the two won't be a stiff top. You have to think 'poetically' about the guitar: it's not just a bunch of parts, but a whole thing that either all works together, or doesn't work. It's not about one finger brace or tone bar vs two, it's about how the finger braces and tone bars work with the top, and that with the rest of the box. It's hard to make one part at a time, and keep the gestalt in your head, but that's what a successful maker does. As you learn to see the whole thing, and role of each part in it, you can move the whole structure and function in a direction you want. But there are always limits; if OMs could be made that sounded like Dreads, they wouldn't have bothered to make Dreads.

Guys I know I can never make a OM sound the same a a Jumbo or Dreadnought and I really need to rethink my approach. If I understand you all and take your approach I'd have a standard thickness top lightly scalloped bracing I know with a box that's no deeper than normal? Or as Todd suggests use a different body shape.

Anyone here specialise in small bodied steel string like to jump in here and say how the get good bass out of an OM without destroying the mids and trebles?

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Formerly JJH

I learn more from my mistakes than my successes

I guess I mislead people when I said I wanted a dreadnought or jumbo sound and should of said I want am OM sized guitar that had very strong bass response that had long sustain with sweet mids and trebles. I would like to clarify that when I say I want a strong bass response I want it without the thumpiness if that makes sense. This would be my ideal guitar to build/play.

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Formerly JJH

I learn more from my mistakes than my successes

Choose your top accordingly, as well as the B&S.
Englemann, Carpathian and generally softer spruces tend to favour the low end. A rosewood such as cocobolo (or Honduran, even EIR), or equivalent B&S would help as well in the bass registers. I would look for individual sets with the lowest fundamental and resonance.
Then there is voicing, a flexible perimeter on the top lower bout will tend to increase bass response, as well as a thin, lightly braced and resonant back. 2 tonebars are standard for a 000, and make it easier to voice than a single one IMHO.
Stay away from brass and heavy materials on the top…
A stiffer and/or heavier neck material tends to increase sustain.
Increasing the body depth has limits, it usually allows a little more low end to be squeezed out from the box, but it incrementally favours the fundamental. I wouldn't go deeper than 4 1/2" on a 000, and that's plenty deep.
As Al points out, it's a whole system where every part affects the others and vice-versa.
The thinking needs to be holistic.

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Laurent Brondel
West Paris, Maine - USA
http://www.laurentbrondel.com/

I don't build Dreads any more, and only build Jumbos once in a while. As I say, tuning the back and using a 'normal' top goes a long way toward improving the bass response, and scalloping the top braces will also help. Thinning the edge works, but is actually less productive than thinning the center or scalloping the braces IMO.

IMHO, build the back active and the top very light.

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David White, Toronto

"All my favourite singers can't sing."

There's already a bunch of good advice on voicing the top and back. I'd recommend messing with the "box" a little too. Move the soundhole forward(toward the neck) a fret or 2. You could also make the soundhole a little bit smaller than normal. If it will still fit in the case you want to use I'd also make the waist a little bigger. I believe you could make the waist 1/2" bigger, and it would still look, and feel like an OM. All of these changes will make subtle differences, but the will make it a little more.....dreadlike.

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I didn't mean to say it, but I meant what I said.
http://www.brackettinstruments.com/

John,

For what it's worth I built a deep bodied Gibson L-00 and it delivered a strong bass, good mids and very nice trebles. I built it for fingerstyle as obviously it would be way undersized for a rhythm instrument.
I built it with a Nick Lucus build in mind and she was 4 7/8" at the tail and 3 7/8" at the neck. I used an adi top from John Hall and mahogany back and sides for the body. Thinned the top to about .095 and the B&S at around .100 with ziri bindings. I also used adi braces using only one lower tone bar.
I used the L-00 design as it has a large lower bout, for a 00, and I think that combined with the woods and bracing gave me the bump in bass response?
The little thing just sat in your lap and was easy to play (2 5/16" string space) and the soundport gave me an even better feel for the sound it was producing.
I had it for a whole week before a local music teacher took it away to fund my next build...Darn WAS disease is going to do me in!!!

Good luck and think deep body for a little extra thump.

Ray

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Guitar Building = Continuous Improvement Process

Found this lots of good info http://www.mimf.com/cgi-bin/WebX?128@12 ... @.2cb6ae05

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Formerly JJH

I learn more from my mistakes than my successes

That was a good thread!

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Steve Smith
"Music is what feelings sound like"