Acoustic bass guitar build

[jeffhigh]

No Pics yet no progress, just design brief and materials accumulation.

Ok well we all know that most acoustic bass guitars are fairly uninspiring unamplified, unless you get to the size of an ernie ball Earthwood or Graham Calderstone's monsters.
Specifically, they dont have a low enough body resonance to support the low E string. The ear sort of fills in the gaps but it is not the same.

This build will attempt to approach the problem from a different direction without the ergonomic problems of a large body.

34" scale length
Savarez classical bass guitar strings (nylon core)
Classical guitar body size +12mm width and +25mm depth
17th fret joint to body
High mobility falcate top 170HZ or so ( the savarez strings will allow me to do this due to their lower tension)
Heavy sides (particularly at the tail)
Live back
Tornavoz to get the main air down around 60 hz

Materials
Honduras Mahogany back and sides
Engleman spruce top
Qld maple neck
Ringed gidgee fretboard

[P Bill]

Excellent! Sign me up!

[DarwinStrings]

I look forward to hearing it Jeff and am sure you will put a big grin on a few Mariachi's faces. Just don't go pinching my bracing ideas will you.

Jim

[Kim]

This build does sound interesting Jeff. Hope you will share progress along the way with a few images.

Cheers

Kim

[jeffhigh]

Yes I will be fully documenting this for a change

[nnickusa]

Cool. One of Mottola's tinozza's is on my bucket list.....

[EricDownunder]

I must watch what your doing as I plan to build an acoustic bass 34" action and using rimu back and sides spruce top at this stage of planning I am looking forward to seeing the bracing method.

[jeffhigh]

Top and back halves tested for properties (gore Method) then edges shot and joined using HHG and tape
QLD maple neck blank prepared
Side taken down to 2mm thickness

[jeffhigh]

Back braced, sides bent and falcate bracing laminated

[EricDownunder]

Looking terrific, I am all eyes and ears.

[P Bill]

I like the no frills heat blanket bender.

[martintaylor]

One of my daughters plays bass and has been hassling me to build an acoustic bass for her. I am really interested in this build and will probably pick your brains as you go along. Love it.

[graham mcdonald]

Back 25 years ago Gerard Gilet, Jim Williams and myself all built an acoustic bass guitar at about the same time. We did some testing and I made some notes which disappeared into a pile of paper. They re-emerged a few months ago along with a couple of photos we took at the time. I have finally written up the notes and they will be published in the next (or the issue after) American Lutherie.

Attached is a pdf of the brief article, which may save a little time and offer some small assistance for those considering such a build.

cheers,

[Nick]

Nice article Graham, great when you have three differing designs, to compare. Thanks for adding more info to this great post. Interesting also to see that Gerard was using epoxy/CF laminate techniques even back then.

[P Bill]

Thanks for that Graham, another one for the archives.

re: guitar bass string tension. I built a solidbody guitar bass not long ago and was surprised at how little tension is needed
to go from floppy to pitch.

[graham mcdonald]

Nice article Graham, great when you have three differing designs, to compare. Thanks for adding more info to this great post. Interesting also to see that Gerard was using epoxy/CF laminate techniques even back then.

All three of us were playing around with lattice bracing and/or CF in one way or another. We had all met Greg Smallman over the previous few years and were interested/fascinated by his ideas. He compared what he was doing to hotting up cars, making then go faster. I first met him in 84 at a luthiers' get-together here in Canberra that was organised by Graham Caldersmith and Greg's ideas had my head buzzing for weeks. Adjusting the modes on a completed guitar soundboard with sawdust and bits of blutac was eye-opening.

cheers

[jeffhigh]

Thanks for that Graham
I am looking to get down to that 65HZ or so but with a small body, tornavoz, lower tension strings etc
Very much an experimental build, But trying a cardbord tube tornavoz in one of my classical bodies did get me about 23HZ drop.

[graham mcdonald]

Thanks for that Graham
I am looking to get down to that 65HZ or so but with a small body, tornavoz, lower tension strings etc
Very much an experimental build, But trying a cardbord tube tornavoz in one of my classical bodies did get me about 23HZ drop.

I have never tried one of those tube port tornavoz things (never knew they were called that), but it might be worthwhile digging out Graham Caldersmith's articles in American Lutherie on the classical guitar family instruments he was buuilding a while back. He tried a cardboard tube in the soundhole on his classical bass guitars and found they didn't work very well, or at least added something to the sound of the instrument that did not appeal. A half tube worked to lower the air resonance at least some of the way and didn't add anything unpleasant to the sound. The thing with acoustic bass guitars is that you have to accept that the bottom E won't work, but if the higher harmonics are there is the right proportions and the right relative positions the ear thinks it is hearing the bottom E.

cheers

[jeffhigh]

I guess I'm Just cantankerous and won't accept that the bottom E won't work.
I built a 7 string Classical/flamenco with 650 scale and it supports A on the low string quite well so I thought I would build something to try and achieve a low E.
It will have a fairly flexible top to work with the lower tension nylon core strings.
Anyhow we will see in a few months, I may be crying in my beer......

[jeffhigh]

Oh and it will have a pickup too.... but I am hoping for something with enough oompf to play unamplified with an acoustic guitar.

[DarwinStrings]

Well lets hope you are raising your beer in a toast rather than crying Jeff, I have been asked 4 time to build one of these but have declined (too scared), maybe in a few months time I will be chasing up those guys again.

Jim

[jeffhigh]

Laminated linings fitted to soundboard edge of rims
Rosette and tornavoz installed to soudboard (press fit)

[charangohabsburg]

Hi Jeff, I'm following this thread with great interest, thanks for sharing!
May I ask, what did you made the tornavoz of? And will it be removable on the finished instrument? If not, I'd like to see one or two pictures more of it before you close the box!

@ Graham: Thank you for sharing the article!

[jeffhigh]

It's 90mm pvc stormwater pipe with a section of bwb purfling glued to the top edge.
The outside is thinned a bit to reduce mass
At the moment it is a press fit, which I will either adjust with teflon tape or add a couple of small screws
It is removable and will be adjusted for length during the tuning process

[jeffhigh]

Falcate braces and CF glued on
Tomorrow shaping and CF overlay