Acoustic/Hybrid Upright Bass Project

[zeytoun]

Hi all.

This is my first post, so here's a little background.

I'm a 28-year-old self taught musician in Portland, Oregon. I started out on guitar, piano, harmonica, etc., and the last few months have been playing electric bass guitar in a trio that me and two buddies formed (we have a lot of original songs, with some flavors of bluegrass, indie, baroque pop, grand hall, jazz/blues).

I've always loved double/upright bass, and am hoping to migrate to it over time (obviously not a straight transition - I will probably take lessons).

I did a lot of price 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.

So I decide on making my own. With a twist. I'm making a hybrid, acoustic upright bass, using an oval washtub as the back and sides. I'll be using actual double bass parts for quite a bit of it, and have priced the whole thing (sans amplification, at just under $1,000).

Anyways, I wanted to start this thread to chart my progress, and ask for some advice.

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Here is a rough, but proportional drawing of the current tenative plan.



Current design details:

String length will be 41.5"

The soundboard will be made out of 1/4" aircraft grade birch plywood. I am steam bending it to create an arched top with a re-curve. (I've engineered a simple process for this)

The back and sides will be a 16.25 gallon, oval washtub. 32.5" by 16.5" by 10.5".

I'll use spruce for the soundpost and bass bar.

I will purchase 3/4 size double bass neck, ebony fingerboard, bridge, strings, tailpiece (most likely)

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I've got a couple contingency plans. If the thing is an abysmal failure, I can re-use most of the parts in a standard EUB project. I've figured out how to make the soundboard removable, so I can tweak the internals if needed, after I make it.

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Feel free to ask me any questions about design details, and give me unsolicited recommendations. (Constructive, please )

And now to request a little advice, for some of those as-of-yet undecided areas?

Soundholes: I've read up on the acoustics of soundhole placement and size. My current understanding is that soundholes with a total surface area equal to a circle, who's radius is one-quarter the radius of a sphere with a volume equal to the volume of the body of the instrument (roughly), provides the loudest volume.

However, I've what I've read seems to imply that this volume increases the treble, but sacrifices power in the lower frequencies. I notice that double basses tend to have somewhat smaller f-holes (proportionally) than violins, so I'm currently planning on going for someting a little smaller.

Tailpiece: I think that a sandard tailpiece will be a little too large for my needs. The distance from the bridge to the bottom is going to be about 16.25", so to fit most bass stings properly, I will probably need something a little smaller. I will either make something myself, or look for alternatives. One idea was to use a cello tailpiece. Can it handle the string tension? Are there other issues I should consider? Other alternatives?

Strings: I will play mostly pizzicato, but will probably want to play arco sometimes. Although we tend to play a few songs that are 1-5, blue-grassy, my playing style is migrating in the direction of Jazz (which I've always loved). So I think I'm going to want a little lower action, and a little higher string tension. I'm also probably looking at improving the lower end power, and increase warmth, through every choice I can. I'm looking at the Evah Pirazzo strings. Is this the right direction? Other advice?

I'll eventually need advice on pickups, preamps, amps, etc. We'll have played our first sets by the time this is done, but will mostly just be playing rather small venues (it's more of a hobby/passion - we all have day jobs).

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Thanks for reading this long thing, and I look forward to sharing the process with you all, as well as getting to chat with you all in the future.

Zeytoun

[Francois Blais]

Good luck with the project!
As for strings, I think it'll be necessary to try at least a set to get an idea how the instrument reacts, and go from there.
Otherwise it's pure speculation.

[zeytoun]

Originally Posted by Francois Blais

Good luck with the project!
As for strings, I think it'll be necessary to try at least a set to get an idea how the instrument reacts, and go from there.
Otherwise it's pure speculation.

I think this is a good point.

So what is the best way to see how the instrument reacts, without buying a set? Do you use weedwacker, or search craigslist for a cheap set? Or are there other methods?

I've listened to a few recordings of variations on this design, and the sound has often been a little hollow and thin and flat (timbre, not pitch) and lacking warmth, IMO. So I guess I'm speculating, and trying to design things to avoid this (using an ebony FB, a real bridge, arching the top, making smaller soundholes than what I've seen). So you're right that it is too early to decide, I'm just anticipating the acoustical issues.

[BigBeatNut]

Originally Posted by zeytoun

So what is the best way to see how the instrument reacts, without buying a set? Do you use weedwacker, or search craigslist for a cheap set? Or are there other methods?

Don't overlook 2nd hand strings. They sometimes come up on eBay, but probably a more likely source is to scrounge an old set from another double bass player, or from a school orchestra, or a shop/luthier ... assuming they've kept an old set around as spares.

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

[akmusicfreak]

Your profile doesn't say where you live but if you live near Anchorage, AK I will give you an old of set strings free. My collection of old strings is building up.

[zeytoun]

That's quite generous of you.

I'm in Portland, Oregon. I'd happily pay for postage, if you are game to mail them.

[akmusicfreak]

Originally Posted by zeytoun

That's quite generous of you.

I'm in Portland, Oregon. I'd happily pay for postage, if you are game to mail them.

Hey Z,
I sent you a PM

[hdiddy]

Looks just like a guitarron.

[zeytoun]

It does?

A guitarron has a very short string length.

[bassbob]

I'd love to know what process you plan to use to bend the plywood for your bass. Would you be willing to share the info with us?

I've bent sides with a silicon blanket and water but a top is a big step. Thanks in advance.

[zeytoun]

Absolutely.

I'm using 1/4" aircraft-grade birch plywood (which arrived Thursday).

I'm using a bucket of water, rags, and a regular iron, for the steam.

From what I've read, the re-curve is critical. If the arched top is simply parabolic, then the vibrations are halted when they reach the edge of the sound board. The re-curve allows the top to vibrate, (like a musical saw). (This is a mix of research, conjecture, and very possible bull****).

So for forming I have the following elements, :

1) A workshop table against which to clamp everything. (Any block would do, I imagine)

2) A raised piece in the middle to create the curve. (Since my oval has an almost perfect 2 to 1 ratio, I'm just using two shallow steel bowls in line with each other, set upside-down on the working table.

3) the half sheet of plywood, cut down to a rectangle just a few inches larger than the eventual oval.

4) The re-curve mold. Which is just an oval ring traced out of thick plywood. The outside edge is the size of the tub, the inside edge is about 2 to 3 inches smaller. The bottom inside edge is planed off (to prevent a sharp crease in the soundboard).

5) Clamps on top of the re-curve mold.

I soak the wood down for a few minutes, then stack everything up in the order above, and put the clamps on to slight tightness. I iron through wet rags, and slowly start turning the clamps down until I get it to where I want it.

I then let the plywood dry for a few days, and unclamp.

I order more plywood as needed.....

[bassbob]

I hpe your method works well for you. I wonder if the plywood would go back to it's original shape after the clamps are off.

[Marcus Johnson]

One of the problems I've always had on the road is keeping my gig clothes looking clean and fresh. It looks like you've come up with a solution.

[zeytoun]

Originally Posted by Marcus Johnson

One of the problems I've always had on the road is keeping my gig clothes looking clean and fresh. It looks like you've come up with a solution.

Solution = solution ????



(you made a double entendre in a double bass forum? That's redundant - and repetitive.)

I hpe your method works well for you. I wonder if the plywood would go back to it's original shape after the clamps are off.

What was your experience with bending? Any tips?

[hdiddy]

Let me get this straight...

You're going to soak 1/4" plywood for a few minutes....
Then press it down using an iron to heat the wood through rags....
and then clamp it to a form on top of a table....

I've never bent plywood before but let us know how it all works out.

I suggest you use teh Google when you get the chance on bending wood.

[zeytoun]

Originally Posted by hdiddy

Let me get this straight...

You're going to soak 1/4" plywood for a few minutes....
Then press it down using an iron to heat the wood through rags....
and then clamp it to a form on top of a table....

I've never bent plywood before but let us know how it all works out.

I suggest you use teh Google when you get the chance on bending wood.

That's what teh Google told me to do. (although some sites recommended soaking up to 24 hours in water of varying warmth)

Heck with enough moisture and heat you can bend solid wood. They key is whether the specific plywood will retain structural strength after it dries. So I selected aircraft grade birch, because it supposedly does.

But I guess will find out in a couple of weeks...

My guess is that the main issue might be that the outer layer on the outside curve will split, and the inside curve will crinkle, but who knows.

And then, 6 months from now, when I post pictures of the garish thing with it's home-made black cherry sunburst and steam-punk preamp knobs, and it revolutionizes the double-bass world, you'll want one too....

[rllefebv]

Originally Posted by zeytoun

And then, 6 months from now, when I post pictures of the garish thing with it's home-made black cherry sunburst and steam-punk preamp knobs, and it revolutionizes the double-bass world, you'll want one too....

6 months from now?? Heck, from that description I WANT IT NOW!!

Seriously, I know you mention the issues with getting a budget EUB and having to mod to suit, plus the expense of amplifying, but I am getting decent results out of a Palatino with minimal mods... Amplifying is fairly straighforward through a variety of amps, though admittedly, and Acoustic Image is giving the best results... If you're interested, you're certainly welcome to try it out for a time to see if it suits your needs...

-robert

[hdiddy]

Originally Posted by zeytoun

That's what teh Google told me to do. (although some sites recommended soaking up to 24 hours in water of varying warmth)

Heck with enough moisture and heat you can bend solid wood. They key is whether the specific plywood will retain structural strength after it dries. So I selected aircraft grade birch, because it supposedly does.

But I guess will find out in a couple of weeks...

My guess is that the main issue might be that the outer layer on the outside curve will split, and the inside curve will crinkle, but who knows.

And then, 6 months from now, when I post pictures of the garish thing with it's home-made black cherry sunburst and steam-punk preamp knobs, and it revolutionizes the double-bass world, you'll want one too....

Take a look at the Setup & Repair forum. Use the search tool and you will find discussions about making laminate ribs. IIRC they use veneers, a form and a heating iron/band thingie that heats the wood for several HOURS if not overnight. The only other two methods I know of is to build a steam box to which you would have to steam the wood for some time so that it is pliable, or building the plys yourself from veneer, soaking the wood and applying a form using weight and possible a vacuum bag. And even after it cools and sets I think it still might spring back a little bit.

Bending 1/4" plywood just doesn't sound right to me but what do i know?

[zeytoun]

Oh, I'm sure I'll want an entry-level EUB to supplement. I just priced my parts for this project at about the same as something like the Palatino, and am excited to have a unique franken-bass.

But seriously, you guys need to stop being so nice, otherwise the word might spread...

(and I'll let you play mine when it's done, Robert)

[Bassmickeyd]

Stop me if someone has already mentioned this, but what about the shoulder? It doesn't look like it will be big enough to rest on your chest. Maybe you plan to stick on a stand and stand beside it. But I would consider this point before building the body.