Liutaio Mottola Stringed Instrument Design



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Uccello Grasso Archtop Acoustic Bass

This is an archtop acoustic bass guitar that uses the same body outline as that of the Elastico Ashbory Style Acoustic Bass.  I build a number of different archtop basses, enough to detect a strong relationship between the overall size and mass of the instruments and their similarity in tone to that of an upright bass.  The bigger and heavier they are (that is, the more they resemble an upright in their gross physical characteristics) the closer their tone is to an upright’s tone.  This should probably come as no surprise.  With this instrument I wanted to see how much the tone would be compromised by having a smaller upper bout.  The answer is that it is hardly noticeable.  The reason this is something worth experimenting with is that, the bigger and heavier a bass guitar is, the harder it is for the player to play it.  So any way you can make the instrument lighter and smaller without messing up the tone is a good thing.

Last updated: Tuesday, May 08, 2012



This instrument is quite comfortable to play standing up, but its (practically) teardrop body shape makes it tough to play while sitting.  I’ve added a fold out leg rest to this so it is actually possible to set the thing on your leg.

Another experimental feature of this instrument is a small additional sound hole in the upper bout.  Due to a combination of where the player is positioned relative to the vibrating top of the bass and the length of the sound waves in the bass range, what the player of a bass guitar hears bears only a passing resemblance to what the audience hears.  The small sound hole is positioned close to the player’s ear and I had hoped this would provide more characteristic sound for the player.  But in fact it really provides no benefit in that regard at all.  It does look cool though.

The bass is made of traditional violin family materials – soft maple for the neck and ribs, spruce for the top, and poplar for the back.  The fingerboard and tailpiece are made of Pau Ferro.  It uses extra long scale flat wound electric bass strings.  I’m currently using a polymer piezo transducer under the bass side bridge foot to amplify the instrument and it works extremely well.  The transducer is made by Measurement Specialties and is available from Experimental Musical Instruments.

The downloadable instrument plans are available for non-commercial use and licensed under a Creative Commons License. Please read the license for restrictions on use of these drawings.


 Download Uccello Grasso Archtop Acoustic Bass Plan (zip contains .dwg and .dxf)
Cad Files.

 View or Download Full Size (42”x60”) Uccello Grasso Archtop Acoustic Bass Plan (.pdf)
Use this plan if you have or have access to a large format printer.

 View or Download Tiled Uccello Grasso Archtop Acoustic Bass Plan (.pdf)
This is a tiled version of the plan above. It can be printed out on any printer and assembled into a full-sized plan.