Double Bass Homebuilt EUB build thread

[ctmullins]

I am building the bridge for my EUB, and was wondering if staggering the bridges was essential for a fretless bass. I hadn't really planned on it, but before I get too far, figured I'd ask.

If by “staggering” you’re referring to the slightly different string lengths (longer for the lower strings), then my answer is No, it’s not strictly essential, but still recommended.

The physics of string intonation apply whether the instrument has frets or not. Thicker strings are less flexible at their termini than thinner ones. And while a fretless instrument can theoretically be perfectly in tune for all notes, not intonating the strings means your fingering positions would necessarily be in slightly different positions for the different strings.

Single string bridges should have some adjustment built in though. So even if the actual bridges aren’t staggered, you should still have some room to move their saddles fore and aft. Whether there is enough range of motion is the question.

In practical terms, for a fretless instrument, especially one with a scale length as long as this one, approximate is good enough. So if the bridges have enough adjustability to make each string approximately its width’s amount longer than its neighbor, you’ll be fine. If not, then I would recommend staggering them.

 

[Videojunkie]

So if the bridges have enough adjustability to make each string approximately its width’s amount longer than its neighbor, you’ll be fine.

There's about 3/4" of adjustment in each saddle. So I should be OK.

Thanks!

 

[T_Bone_TL]

"Bridge staggering" - Depends (in part) where you are coming from. The big hunk of maple on the Lidl is basically straight across on top, and that's fairly normal for upright bridges. Being in tune (or...not) is between your fingers and your ears, and does not involve mythical straight lines like frets.

If you are coming at it from a more EBG background you would probably prefer the EBG-stock bridge saddle locations staggered for intonation approximately straight across like a fret, but that is usually within the adjustment range of the saddles on the bridge.

Unless - this is your gateway instrument to the land of large hollow-body noisemakers, in which case you might as well start getting used to the way a hunk of carved maple intonates. (I have obviously not read the whole thread yet, or I might know your intent better.)

 

[Videojunkie]

Unless - this is your gateway instrument to the land of large hollow-body noisemakers, in which case you might as well start getting used to the way a hunk of carved maple intonates.

I think of this as an adventure into familiar, but unknown territory. I am really looking forward to playing this beast and hearing how it sounds. My buddy who got me into playing bass had a defretted EB, and it was a fun thing to mess around with.

I am mostly familiar with fretted instruments coming from guitar, to bass, to this, so I think my fingers will be happier if the notes are relatively stacked in a familiar pattern. (Hence the plan to tune in BEADG. Also the scale length) I know there will be a learning curve to get my fingerings from 'between the frets' to 'on the note'.

 

[ctmullins]

There's about 3/4" of adjustment in each saddle. So I should be OK.

Thanks!

Good deal. In that case, the approach is to run the saddle 95% out (towards the nut), and place the saddle slightly behind your scale length. Intonating almost always involves lengthening the string, not shortening it.

 

[Videojunkie]

I am a bit concerned about the string action based on my straight edge approximation, it looks like there would be almost a 1/2" at the end of the fingerboard. I think that should be lower... there's pretty good vertical travel in these saddles but that measure was from the lowest position.

I think I need to remove at least 1/8" from the thickness of the purpleheart piece.

 

[Jeff Siddall]

In a single scale instrument almost all have a straight bridge. A notable exception is TOM bridges given the limited range of movement of the saddles.

But those are for fretted instruments. For fretless it's generally not an issue since the intonation is taken care of by the player. If you wanted to adjust out some of that error on the instrument you can use adjustable saddles, as you are doing. Staggering adjustable saddles in a case like this would look odd to me, but my opinion isn't the one that matters!

 

[Videojunkie]

@Jeff Siddall, I was just making sure I wasn't missing something that was obvious to other users of these bridge saddles. I will mount them in a row as planned.

Now I just need to get the height taken care of...

 

[Jeff Siddall]

@Jeff Siddall, I was just making sure I wasn't missing something that was obvious to other users of these bridge saddles. I will mount them in a row as planned.

Now I just need to get the height taken care of...

Yeah, 1/2" seems too high to me but I have never taken a ruler to an upgright to see what "normal" is. When you say "I think I need to remove at least 1/8" from the thickness of the purpleheart piece" I expect you mean the piece that the bridges are attached to? If so that makes sense to me, although I don't know if 1/8" is the right amount. I would say mount the bridges at a height that puts the strings at your ideal action when they are in the middle of their travel.

 

[Videojunkie]

Yeah, the tricky bit, is that I kinda like the idea of bolting all the bridges to the purpleheart block, and then bolting that to the maple underneath.

The issue is that the edge saddles will basically be right on the maple. So I get to re-think the joint between the nicely curved bit under the fingerboard, and the bridge which will probably wind up being 2 thicknesses of purpleheart stacked.

 

[Jeff Siddall]

Were you planning on making a half-octagonal (or decagonal?!?) bridge base, with the bridge angle matching the fretboard at each string, or more of a vertical step type thing?

 

[Videojunkie]

I was going to step the bridge saddles to match the fingerboard radius. Trying to arc them seems both unnecessarily complicated and difficult.

I was planning on leaving raised areas between each saddle that I could radius to match the fingerboard.

 

[Jeff Siddall]

That seems like it should work, but if the base at the edge saddles needed to be very thin it might look better to mount the bridges on angles instead. You could always mock it up on scrap blocks to see if you like it before finalizing the purple heart version.

 

[Videojunkie]

At the edge, it will blend with the mahogany sheeting of the body, the only visible part will be on the maple between the bridge and the fingerboard.

I am rapidly reaching the point where I just need to start building the body out... there's a lot of complex joinery magic that needs to come together...

 

[T_Bone_TL]

I am a bit concerned about the string action based on my straight edge approximation, it looks like there would be almost a 1/2" at the end of the fingerboard. I think that should be lower... there's pretty good vertical travel in these saddles but that measure was from the lowest position.

I think I need to remove at least 1/8" from the thickness of the purpleheart piece.

Not finding my good ruler at the moment, but on my 4 string upright, the E string is about a centimeter off the board, and can still rattle/clack if I pluck it wrong (but has not been rattling with the bow) while progressing to the G side is (as typical on an upright) quite a bit lower to the board. ADG don't rattle despite that. E flops a lot more, I assume a B would be even more so. Honestly action-wise, I never even get to the octave on the lower strings. Sounds better to jump up a string or two. If I build one I'll probably just make more room for string movement down at the bridge end by not bothering to put a board under that side, that high. But that's me, not you.

Looking ahead to when you have it playable and dive off the bow (arco) cliff, don't get discouraged if there'a few months of horrible screeching. That's just dues, not "I can't do this." Just do that in private until it starts to improve.

 

[Beej]

Thanks for the invitation to the electric lutherie crew for input I popped over to see if I could offer anything though I'm not a fretless master by any stretch, but great to see that some regulars have you covered. I've got nothing to add other than this is coming along beautifully and has so much cool content I plan to steal. My upcoming EUB will be all your fault!

 

[Videojunkie]

So what with errands and such I didn't get very much done, but I did see if the piezo worked with the bridge alignment.

I cut an 1/8" wide shallow trough under the saddle, and drilled holes at either end. The one towards the back is blind and ends about 3/8" into the wood. The one at the front goes all the way through.


Then feeling bold, I decided to try to string up a single string and see if it works!

Using some 20 year old round wounds I found, I was able to string it up, and plugged the piezo into the electronics and then into an amp.



It worked!
Not going to judge the sound as nothing is finished, but it sounds pretty good.

I discovered that I need to deepen the holes under the center of the saddle so that the ball ends of strings will clear.

 

[ctmullins]

That's gratifying!

 

[Videojunkie]

Thanks for the invitation to the electric lutherie crew for input I popped over to see if I could offer anything though I'm not a fretless master by any stretch, but great to see that some regulars have you covered. I've got nothing to add other than this is coming along beautifully and has so much cool content I plan to steal. My upcoming EUB will be all your fault!

@Beej I can't wait to see what someone with your skills and lumber library can do from my ideas...

 

[Beej]

@Beej I can't wait to see what someone with your skills and lumber library can do from my ideas...

Probably screw them up... seems to be what I've been doing best lately