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Double Bass Acoustic/Hybrid Upright Bass Project

#21
Right.

There's about a 7-8" gap from where the replacement neck ends, and where the tub starts. So instead of coming up to the chest level, the tub will come up to about waist level.

In between, I've designed a structural section, that includes a compartment for preamp equipment.

I'll have to see how it behaves when it's done, but if it needs more support, I'll put a removable body brace piece up near where the neck joins.

The alternative was to create a larger section between the neck and the tub, but the current design has the advantage of easier access to the higher positions on the fingerboard.

But frankly, I don't know how the balance will feel. I think I've read that most double bassists prefer that the neck doesn't angle too far back, because it makes it more awkward to balance and play.

I also haven't figured out how to do the tailpiece. A regular ebony tailpiece will come closer to the bridge on my bass, than on a real double bass, and require me to find shorter strings. I'm wondering if (a) a cello tailpiece can handle the string tension, or if (b) I'll have to custom make a tailpiece, or (c) use something designed for an EUB.

(p.s. sorry I haven't updated anyone on the top, I've been really busy at work, and haven't had a chance to do it yet)
 
#22
"But frankly, I don't know how the balance will feel. I think I've read that most double bassists prefer that the neck doesn't angle too far back, because it makes it more awkward to balance and play."

Very good point, though all the balance should be centered at the shoulder of the bass, so you're free to play with the left hand instead of hold, this is obvious with newbie players, the angle of the neck would determine a lot of the balance.

Try not to use too short of a string, like a bass guitar 34/35". I believe you need at least a 38+ to achieve the sound quality timber of an upright bass. The small electric 35" upright on a pole, (Dean Pace style). They sound more like an electric bass because of they're short scale. So why not just play an electric bass so at least you can move around.
 
#23
Oh I'm absolutely doing a 41-42" mensure length (see original post).

I would just have to use shorter strings if I used a double bass tailpiece, because there would be less distance between the bridge and tailpiece on my design, than there would be on a double bass.

I do play an electric bass.

But what I'm trying to do here is build something unusual. It's obviously not going to have the sound quality of a double bass, but it will have a significant acoustic factor to it, it will be possible to play it arco, and since it will have the same mensure as a double bass, I will be able to learn a lot of things that I can carry over to a double bass when I am ready to purchase one that is worthwhile. And I am learning a lot by this project. And in the end, I am going to have something unique.
 
#24
Minor update:

Last Saturday I practice-bent a cross section of plywood successfully.

The process was similar to the one I mentioned earlier. I soaked a section of 1/4" aircraft grade birch plywood in hot water for 30 minutes, then set it up on the bending apparatus.

First was the base layer: a section of scrap countertop material.
Next came a round piece to push up in the center of the plywood.
Next came the plywood.
Next was a sheet of 1" plywood, out of which I cut an oval, about 2" smaller than the mouth of my tub. I hand-beveled the underside corner, so that it wouldn't press a line into the plywood.The overlap was for creating the recurve.

I drilled a series of holes through the plywood layers, outside of the perimeter of the oval, and placed a series of drywall screws with washers, in them.

I covered the plywood with towels that I kept moist with a kettle of hot water, and kept moving a hot iron over the towels.

Meanwhile, my friend started to screw down the screws with a power drill set to varying pounds of pressure (started at 5, and finished at 20).

After about an hour, the screws were all cinched flush, and there was a visible, but gradual, curve and recurve in the cross-section of plywood.

---

While the results were encouraging, I can't say that it will work on the actual piece yet. There are two major variables that will be different.

On the one hand, the piece I used was smaller than the actual piece, so it should be easier to bend a larger piece.

On the other hand, the test piece was only really bent along 1 axis, while the larger piece will be along two axes.

So I'm making a few modification that should increase the leverage of the apparatus. If the 1/4 inch ply doesn't work, I will try 1/8 inch ply. If that doesn't work, than I will either do a flat-top, or scrap the idea, and use the neck and fingerboard for less ambitious EUB build.

I expect to have an update in about 10 days.
 
#25
comparisons and thoughts before arriving at my decision. A carved bass would obviously be the best tone, but is far out of my price range. A plywood bass is a cool alternative, but for a decent setup, it is still out of my price range. I've searched, and it seems a good-quality EUB is going to run at least $1,000 (I know there are a couple models for slightly less, but have noticed that there are a lot of talk about tweaking or dealing with minor issues online), but that doesn't even include the expensive task of amplification to get a good sound out of the thing.
 
#26
If you are really planning to spend 1K...you should spend a little time researching the possibilities of finding a used instrument? Or since you are enthusiastic about building and are going to buy a neck anyways...you might want to put out an add to see if you could find a damaged instrument...to get the neck and maybe a body that can be modified? I found a castoff cello and am using the body and headstock.

I have seen used strings for sale...do check with musical students...

jp
 
#27
The $1,000 figure included amplification/equalization equipment. For the actual bass, it's working out to about $600 or so, which includes double bass replacement neck, FB, bridge, tuners, a decent set of strings, etc. Of course, one is better off, financially, buying a quality double bass, and this isn't an attempt to cheap my way to that, it's just a diversion/temptation that will probably end up costing more in the long run. C'est la vie. Of course, appreciate your tips on saving $. I might be able to shave that price down a bit.

----

I've been meaning to update everyone, but I've been swamped at work, and had the flu. We were actually able to arch the top using my aforementioned steam-bending technique. I'm actually a little bit in shock that it worked, as you're not really supposed to be able to bend good plywood along two axes, but hey it's not like I was making a dome out of it. Right now it has about a 1" arch, and a gentle recurve back to 0 degrees along the edge.

My co-builder has the pics on his camera, so I will have to post pics after I wrestle them from him this weekend. Sunday or Monday, I hope.

Next up I'm
-working on attaching the soundboard to the tub (it will be removable)
-fitting a bass bar
-ordering my neck and FB
-doing the math for the construction
(I have a rock-hard piece of Ipe that is going to be the main support beam)
-Assembling
-Ordering and fitting the bridge, soundpost, and putting on strings (to test sound quality, and structural soundness)
-Disassembling and doing finishes
 
#28
BigBeatNut said:
Something that works for old electric bass strings (I have no idea if this works for upright, so beware) is to boil them. It gets all the gunk out of the strings, and can make them sound quite fresh.

Andy
Click to expand...


You would want to soak them in denatured alchohol rather than boiling them. That's what I do and even though it does bring them back to life, it's not for very long because I often pop (break) them within a few weeks afterward..

However, this is on my EB. I haven't soaked my fretless EUB strings as they still seem to have a good sound to them, but I think the wear wouldn't be the same as on round-wound EB strings. So you probably would get a much longer re-life out of doing this.
 
#29
Here are the pictures I promised everyone.

First picture is of the mold. The bottom layer is a piece of scrap counter-top material, with an plywood oval screwed to the middle. My plywood top material went on top of that, and on the top of the plywood went this plywood oval ring. I used about 80 screws as clamps, and torqued them all down slow and even while I kept a steam iron on the surface, steaming the plywood through a towel. Eventually, they were all cinched flush.

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I let it dry for a couple days and popped it out. Below are two pictures of the arch, the first along the long axis, and the second along the short axis.

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Then I took a piece of scrap plywood, and jigsawed and planed it to fit the inside lip of the tub. I will use this to trace out the actual top.

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Next up, I'm going to either weld or epoxy some thick copper wire around the inside edge of the tub. This is going to be a lip that the top will butt up against. (The top is going to be removable.)

Then f-holes, bass bar, neck, fingerboard, etc. etc.
 
#31
Ah, finally an update for everyone. (it's hard to snatch the time away from work and everything to get moving). But major progris has bin made.

We took some heavy copper wiring and stretched it straight (using a chain block), and then epoxied it to the inside of the tub, about 1/4 inch from the lip.

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Then came the f-holes (I've been looking forward to them for a while). I printed a jpeg of one I liked, and then traced it out on a sheet transparency plastic, and cut it out, creating a stencil.

Then I used the stencil on the bass, and drilled guide holes at the ends. I took a coping saw and a jigsaw to cut out the outline, and various files to get a finer outline.

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Then I fit the top to the tub, using a sanding plane.

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And here are a couple of the arching. It's subtle, but definitely there.

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#37
Progris is a little slow.

Here's the area near the tailpiece. The support beam is a 100+ year old lawnmower handle that happens to be the *exact right length (it's very hard wood, I'm guessing ash). I planed 2 pieces of scrap hardwood (cherry, I think) to fit with the support beam and the bottom of the tub.

Since the bridge to saddle distance is a few inches shorter on this bass, compared to a double bass, I will have to use a smaller tailpiece (going to try a cello TP). The bottom section is designed to compensate, and make a shallower break angle from the bridge.

100_1080.gif


100_1083.gif


The laminate strip is there to distribute the pressure from the soundpost.
 
#39
Right now it weighs 17 pounds, without a fingerboard, bridge, tailpiece, endpin, or strings. So I'm guessing final weight will be in the low 20s. The tub is actually pretty light...

I'm trying not to overbuild it. As I bring strings up to tension, I'll watch for any issues, and add structural strength as needed. I can't imagine this thing weighing over 25-30 pounds in the end.

Plus, the neck is removable. So should be un-Frigidaire-like.
 

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