Watson Guitars
Idyllwild
California, USA

33" scale 7-String Chambered Fretless Bass (Serial 09B029)

Materials: Curly Koa top. Maple neck and body core with curly Mahogany stringers
Fingerboard: Ebony with a special epoxy hardening coating
Pickups: Piezo in bridge + Watson Humbucker - Split coil + Serial + Parallel
Electronics: Watson 3-band active/passive electronics system
Bridge: Hardwood custom bridge with piezos
Hardware: Bridge saddles Graph-Tech
Tuners: Hipshot Ultra Light
Finish: Polyester resin with a special hard coating on the fretless neck surface

The plan for this bass was a 7-string fretless with a chambered body. The body should have the look and feel of an acoustic bass and to that end we used a combination of piezo and wound pickups to give us a wide spectrum of available sounds. We used a wooden base for the bridge assembly, as its essence is based more in the acoustic sound than electric.

The top and headplate are made of a beautiful Curly Koa, setting this bass apart from the average instrument. For a 7-string, the instrument is quite lightweight. The technical challenge was to keep the neck weight to an absolute minimum.

We have been very pleased with the resulting feel of the bass, and the sound is very sweet. Using the 4-band eq and the mix of magnetic and piezo pickups we can dial in anything from a Jaco type sound to a subtle acoustic bass feel.

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Back view showing the continuous maple and mahogany stringers.
(1/13/10) These two photos show the instrument from the back. We wanted to maintain the look and feel of a neck-through instrument although our customer requested a bolt-on configuration. We needed to allow as much access to the top of the neck as possible by removing material for the player's hand at the joint area.
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This is the body/neck joint where it has been sculpted to allow the players left hand to have access to the upper end of the fingerboard.

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Almost done here - neck has been bolted on and we're ready to string her up!.
(1/13/10) Almost done here. The neck has been bolted onand the bridge (made of Kingwood) has been secured onto the body of the instrument. The bass has a 4-band EQ built in just behind the bridge. The picture on the right shows the fully assembled bass strung up and ready for the 2010 NAMM show (and our customer who will be there.)
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This is the finished instrument as seen from the top. We put a subtle sienna sunburst on the Koa top.

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This is the custom kingwood bridge we manufactured especially for this project.
(1/13/10) Left: we decided to make a bridge for this bass out of wood rather than using a commercial brass or aluminum bridge. This should yield a more organic tone from th ebass. Right: The wiring in the control cavity is sligtly more complicated than usual based on the piezo cabling and the blend with the magnetic pickup.
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This photo shows the control cavity with all the wiring involved.

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The body and neck have been finised, bringing out all the beauty of the woodgrain.
(1/10/10) The finish process has been completed. We applied a polyester resin over the body and neck, and at our customer's request, also applied an extra-hard and wear-resistant coating to the fingerboard. Now we have to work on making the body and neck fit together again correctly, as overspray always gets into these areas. The assembly process will be slow and meticulous as we have to handle the finished instrument very carefully.

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Body is assembled and the neck is on.
(12/29/09) This photo shows the instrument with the assembled body and the neck attached. Much work has been done to it over the last few days. We have drilled and counterbored the holes for the string ferrules, cut the pickup cavity, applied the headstock veneer (also Koa), established the bolt pattern for the neck attachment and carved the body/neck joint. Quite a lot of work still left to do but we are planning to get this bass to finishing this week.

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Gluing the fretless fingerboard onto the neck blank.
(12/22/09) Next step in the evolution of this bass is to get the fingerboard glued onto the neck. This will allow us to more easily shape the neck to the desired profile. The fingerboard is secured onto the neck with high-grade epoxy in our vacuum press. This will stay in the vacuum press overnight to ensure the best possible joint integrity. We have also glued the Koa top onto the body of the bass in the last couple of days.

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Cutting the f-holes into the top plate of the instrument.
(12/21/09) The block of Koa has been resawn into flat pieces which we then sanded down to a consistent thickness and finish. next, we prepared the edges so that they were perfectly square and straight and glued the two bookmatched pieces together. Having done that we rough-cut the shape of the top of the instrument into the material and set it up on our CNC machine where we machined the two f-holes through the top.

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This is the billet of Koa we're using for the top of this bass.
(12/17/09) Today we cut the Koa we are going to use for the top of the instrument from a board we have been keeping in the shop for creations such as this. We will have to cut two pieces off this billet to create a beautiful bookmatched top. The wood is curly with a lot of figure and will make a very impressive top for this unusual bass. We expect to start resawing tomorrow and thereafter, sanding the pieces flat.

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Both body halves are now glued to the core. Control cover cut.
(12/17/09) The assembled body has been sanded flat and we then put it up on one of our CNC machines to cut the cavity which will ultimately allow access to the controls, batteries and through-body string ferrules. In a previous operation we carefully harvested the material from the body from which we will make the cover for this cavity. All the woods and the stripes will match perfectly! In this photo you can see the belly-cuy which has been carved both on the outside and the inside of the instrument.

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Gluing the second body bout to the core of the body
(12/16/09) Some progress today on gluing up the body of this instrument. The two body halves are attached separately to guarantee the proper alignment to the center core and to each other. The body spent most of the day in various clamped conditions but we managed to get both halves glued up in the same day! Nice to see the instrument start to take shape! Next we will clean up all the edges and machine the control cavity.

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Fret lines in the fretless fingerboard have been added.
(12/9/09) At the request of our valued customer we installed lines on this fingerboard. Since they need to be seen in low-light conditions we were able to find oure white binding at just the right thickness to do the job. Worked out very well and although we are still cleaning up the fingerboard the lines look great! We'll have to add markers to the side of the fingerboard and we'll make sure those too are visible in low-light conditions.

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Upper and lower body bouts ready for gluing.
(12/8/09) The elegant sculpture in the photo to the left is actually the upper and lower bouts to this bass. This photo was taken very shortly before I glued the back piece onto the upper bout (pictures to follow soon). I did my best up to this point to relieve as much weight as physically possible from the components that will make up the body section of the bass. I am hopeful that the end result will be a surprisingly light instrument!

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We are now removing material to lighten the assembly
(12/5/09) The plan right now with this bass is to relieve as much weight as possible from the pieces that will combine to make the chambered body. The trick is to remove as much wood as possible from the places where it is either not needed or does not substantially contribute to the strength of the body. Lots of calculations to make sure we leave enough woood to accommodate the pickup and control cavities.

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Starting to work on the shaping of the neck.
(12/3/09) Back to the neck of the bass. We are cleaning up the bottom surface of the neck so that we can start shaping the back of the neck blank and working on the headstock. The fingerboard will soon be ready to be attached so we have to make sure the neck is caught up! We are currently adding light colored fret lines on the fingerboard. Then we will work on the side dots. Should all come together fairly quickly.

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Getting to the fun part, shaping the body..
(11/30/09) Next stage of this bass has now started. I cut some material off the back of each of the upper and lower body bouts so that I could re-use them as back plates. Next the rough cutout areas were marked and the wood in the center was band-sawed out. Following that was quite a lot of time on the spindle sander to refine the shapes both inside and outside. We now have to calculate how much of the center core we can safely remove!

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We are currently working on the parts for the body.
(11/21/09) We're now working on the various parts that will assemble together to become the chambered body for this bass. The first task was to make sure the back of the body had enough space behind the bridge to accommodate the controls we will be intalling there. Then I cut the external body shapes and we are now making plans to cut out center of each of the upper and lower bouts which will relieve most of the weight. More photos soon!

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Time to glue and clamp the Carbon Fiber rods into the neck.
(10/29/09) We mixed up our special epoxy and glued and clamped the two Carbon Fiber reinforcing rods into the neck. This epoxy takes a while to set completely but when it does - it's extremely hard. We leave the assembly clamped like this overnight tp make sure the joints are 100% bonded. We'll remove the clamps tomorrow and clean up any gule that has squeezed out from the joints.

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The internal features of the neck are being machined on the CNC.
(10/21/09) We are currently machining some of the features of the neck on this bass. The neck blank is set up on the CNC and we machine a datum surface on the top which becomes our joint face with the fingerboard. Then we machine the headstock angle and lastly we cut slots in the neck for the truss rod and the carbon fiber re-inforcing rods. We finish bt cutting some relief for the truss rod nut to provide allen key access.

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Here we are gluing laminates together to create the center core section of the body.
(10/8/09) No this is not the landing strip on a modern aircraft carrier - it is part of the Maple/Mahogany block that will become the centerpiece of the back of the body of this bass. All the gluing of the numerous laminate pieces for the body and the neck have now been completed and we can now look at how we are going to approach the assembly and machining of the chambered body. Quite an exciting project as we are, in many ways, breaking new ground!

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Here we are gluing laminates together to create the center core section of the body.
(10/2/09) We are still working away gluing tapered laminates together. The neck is almost complete and in the photo to the left you can see some of the laminates for the body of the bass being glued and clamped together. This is a fairly slow process as we want to ensure that every joint is perfect. The net result will be very impressive. Since it will be a 7-string with a relatively thin neck, we're building in as much strength as possible!

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This is the board of Hawaiian Koa we will use to make the bookmatched top.
(10/1/09) This is the Koa we are planning to use for the top of this bass. It will be resawn and bookmatched, and as you can see, it has a beautiful natural golden glow and some nice curly figure. We'll start cutting this Koa up probably next week if time allows. The cherry back and sides will have their own complimentary color. Combined with the ebony fingerboard, this bass will be quite a looker!

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Getting started on the many glue joints necessary to fabricate the neck and center body section.
(9/24/09) We are now gluing the various laminates of the neck together. This is done from the center outwards, one laminate at a time to make sure we have good alignment and the best possible joints. Over the next couple of days we will assemble the neck and the center core section of the body. We have to allow for a good-sized overlap between neck and body because the body will join the neck at the 12th fret.

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All the various tapered components for the center sections of the bass are now ready to be glued together.
(9/13/09) This photo shows some of the parts that are going into the neck and center of the body of this bass. Each of these pieces has been machined to a taper and veneered both sides over that last several days. The are now ready to be progressively glued together. We will start from the center laminates and work our way outwards. The back of this bass is going to look amazing and its construction should yield a great sound.

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here we see three of the mahogany stringers which have just been machined on the Ornamental Mill.
(7/12/09) Today I got started on the work on the ornamental mill - a very valuable piece of equipment which I use to cut accurate tapered sections on my wood laminates. Here we see some of the components after they were machined. Once all the parts are cut to the correct tapers I will be able to start assembling some of the central neck and body parts which will combine to create the core of this bass.

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This is the total amount of wood for the center core sections of the neck and body of our 7-string chambered bass. We're making progress!
(7/29/09) Well, believe it or not, it takes this much wood to build just the core section of a 7-string chambered bass. The light stuff is curly maple and the dark stuff is curly filipino mahogany (quite dense - a great find) and all of it has now been run through the drum sander and is flat and straight on both sides. This gets me quickly to the next stage in the process which is cutting tapered sections on the Ornamental Mill.

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yes - you would be correct in thinking that we are building a Bo Diddley bass but we have to start somewhere! Cherry and maple body parts have been rough cut..
(7/15/09) Today we got busy on the bandsaw and cut out several of the component pieces that will make up this bass. I split the huge piece of cherry in two for the upper and lower body halves and then cut several pieces of curly maple which will combine to become parts of the neck and body core of the instrument. We are very excited to be cutting wood on this very unique project. Next we will cut some material for stringers in the neck/body core.

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I completed a template for the neck components and we're now ready to cut up some Maple and Brazilian Cherry for the neck laminates.
(7/11/09) I had to make a template for the neck parts of this instrument, based on its cross-section. The body will be thicker than a solid body bass but since it's a bolt-on and the upper bout will meet the neck at the 12th fret, the transition from neck to body is relatively complicated. I drew a cross-section of the bass in a vector drawing program and from that made the template. You can see it here laying on some of the curly maple which we'll use for the neck.

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Revised body design showing f-holes and single cutaway.
(6/10/09) Through some detailed discussion with our client we have been able to further refine the body design of this bass. It will have a distinctly single-cut shape, with the lower bout cutaway deep enough to allow full access to the upper end of the fingerboard. We're including double f-holes for a more balanced look. Neck will be curly maple with stringers of another wood yet to be decided. We are now ready to cut wood on this bass so keep checking back for updates!

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We just picked up a very nice slab of Cherry for the body of the chambered bass.
(5/1/09) Here we have a very nice piece of 12/4 Cherry which I picked up at one of our wood suppliers recently. This material will play a part in the construction of the body of this unique bass. Having looked at Alder and Mahogany, I decided the cherry was a better option both sound-wise and aesthetically. It has a very nice color and grain and will definitely look good on the finished instrument.

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This is the Koa we are going to be using for the top plate of this bass.
(4/21/09) We have established that the top wood on this bass will be curly Koa. The material has a beautiful honey colored grain with lots of figure. Koa is becoming a very difficult wood to find in highly figured cuts, so this bass is starting off with head start. Our neck will be constructed mostly of curly Maple. We still have to decide on the best combination of woods to yield the tonal qualities we are looking for.
Last update January 19, 2010