Double Bass Is this bridge correct size (measured photo)?

[stefaniw80401]

I have a 2003 Romanian (Gyorgi) flatback I got from Robertson's. It has a 42" vibrating string length, so I think it's a 7/8 bass. The center of the bridge leg is well inside the center of the bass bar, by 10.32 mm. Would you experts recommend a larger bridge, and where would I get such a beast?

Click on image below for larger view.

 

[JoeyNaeger]

I can't quite make sense of the measurements you've posted. Generally, you want the width of the outer toes of the bridge to match the space between upper eyes of the f -holes. The bass bar should be placed in such a way that the bridge over hangs the bass bar by about 8 mm(IME). If the bass bar is closer to the f-holes, I wouldn't go much wider than the upper eyes of the f-holes. If the bass bar is closer to the center joint, I would use the bass bar placement to determine the bridge size. Sometimes, there is a significant discrepancy in the f-hole layout and the bass bar location, in which case a new bass bar will likely give better results. A luthier would need to evaluate the bass in person to determine if the bridge is appropriate for your bass.

 

[Eric Hochberg]

Why don't you discuss this with Robertson's? FYI, a 42" SL doesn't necessarily mean you have a 7/8 size bass. There are 3/4 size basses with 43" SLs. Length of the back and bout widths come into play, too.

 

[Greg Clinkingbeard]

Why don't you discuss this with Robertson's? FYI, a 42" SL doesn't necessarily mean you have a 7/8 size bass. There are 3/4 size basses with 43" SLs. Length of the back and bout widths come into play, too.

Good idea. FWIW, that bridge is already fairly wide, and tall. For reference, a bridge on a 3/4 might be closer to 155mm wide and (assuming a projection of 150mm) 160mm tall. Based on this, 7/8 might be appropriate. String length is behind bout width and body size in calling a bass 3/4, 7/8 or whatever.
You are correct in that ideally, the E bridge foot should be centered over the bass bar. If I understand correctly, the bass bar is centered more toward the outside edge of the bridge. If the bass sounds good and the bridge is otherwise good, I wouldn't worry much. Wider bridges are usually taller bridges. Getting everything exactly right is difficult.

 

[Don Kasper]

At the risk of "piling on", it is my understanding that bridge adjusters should be drilled "parallel" to one another. These adjusters were drilled "converging" (non-parallel), and will result in (slight) variations of foot placement as the height is adjusted up/down. It looks like this bridge design doesn't lend itself to the (parallel) installation of adjusters. (...and it's "fugly", IMHO).
Thanks.
don kasper

 

[stefaniw80401]

Thank you all for your replies. I've uploaded an image update in my original post (above) that hopefully clarifies things. Yes, the outer edge of the bass bar is just barely inside the bridge toe, and overall the bridge leg is not centered over the bass bar. I'm wondering if Robertson's "settled" on using this bridge when they setup my bass 11 years ago.

The bass sounds just OK. The A string has always been weak regardless of what string I put on. The sound of the bass is generally unfocused and wolfy (G) ... and currently, I've got the soundpost half-way under the treble side bridge foot. The tone character of this bass is very nice, but it lacks power in the upper AND lower register. My best string is the D string, and midway up the E string. My current string setup is Olive G over Spiro weichs -- including on the extension. I've had spiro mittle on as well (and EP's, Oblis, Permanent, and Corelli) , but the response is not as good as when I use lighter gauge strings. This bass always has felt tight to me -- being slow to respond.

I've had multiple luthiers here in Denver fiddle with three different sound posts. The last luthier raised an eyebrow about the bridge. Another (respected) luthier says that the bridge width is just OK -- citing it being the SAME width as the ff-hole eyes. That's why I'm barking up this tree.

I can feel the top plate has flatted on the inside of the bass bar, and that's why I think I need a wider bridge.

Please continue your input on this thread.

 

[Jake deVilliers]

I've got the soundpost half-way under the treble side bridge foot. The tone character of this bass is very nice, but it lacks power in the upper AND lower register.

This bass always has felt tight to me -- being slow to respond.

I'm not surprised! Who put the sound post in that extremely unorthodox position?

 

[stefaniw80401]

Originally, the SP setup by Robertson was placed much lower ... a good width of the SP below the bridge foot. The feel was a little looser, but still very resonant and unfocused. My wolf is a G, and it really howls with the SP down south. The SP has been slowly creeping closer/under the bridge foot in the last three tries by Denver luthiers Robert Ross, Eric Trujillo, and even the late Jerry Buffa when he was in Boulder for CU Bass Fest a few years ago. The first time I had someone fiddle with the SP was Don Robertson when they were here in Denver 8 years ago ... funny story ... he looked at the SP (his original setup from back in 2003), plucked a few notes and exclaimed "it's too tight". He took out the SP, cut about 1mm off the bottom (flatback bass) with his hand saw, and popped it back in. It was a little better (I think), but still not great.

This bass has a good spread of sound, which fills the room, but it's not very focused.

 

[stefaniw80401]

Here's a measured photo of my bass. According to all-hail Bob's site, the upper bout is 1/2 sized, and the lower bout is well into the 4/4 range, and the body height is in the 7/8 range. My scale length is 42"

Check out how the treble foot is well over the ff-hole eye, yet the bass foot is just to the inner edge. My neck is set straight, but the bridge looks like it's clocked towards the bass side. I'll try raising the bass side adjuster and bumping the bridge more over the bass bar....
... well (10 minutes later) ... that helped a bit ... seems to be more alive. I raised the bass adjuster a couple of turns which straightened/clocked the bridge toward the G foot. Then I nudged the bridge towards the bass bar about 1.5mm which recentered the strings over the fingerboard. This maneuver covered more of the bass bar (~1.5mm). The E and A strings seemed to have a bit more power and focus, but the G string got duller.

 

[stefaniw80401]

Oh ... and this image is a close-up of my feeler gauge to show the edge of the bass bar in relationship to the bridge foot. You can see the that the bridge leg is not centered over the bar...it's maybe 10mm too narrow? And that most of the bass bar is under the extreme flare of these bridge feet. Refer back to the image in my first post to see what I mean by extreme flare.

 

[stefaniw80401]

Here is an email response I got from Jonathan over at Lemuel violins:

Hello Mark,

Thank you for your detailed diagram. It really helps. You're right about the bridge legs being too narrow but it's not by that much. The edge of the bass bar should be in between the edge of the leg and the edge of the foot. The current bridge you have has very large toes so the bass bar needs to be closer to the edge of the leg. At this point the width of the legs would be a bit too narrow. The bridge that we selected which would work best is the Invalid Link Removed in 165mm. Bridge size is determined by the foot span from the edge of one foot to the other. The width at the legs is 140mm which should work just right since the toes are not so large. The height shouldn't be a problem if you have bridge adjusters installed. We have 165mm Despiau bass bridges available in 3 grades depending on the wood quality you want.

Regards,
Jonathan
Lemuel Violins Representative​

 

[JoeyNaeger]

If the bass sounds just OK and you want it to sound great, it's going to to take more much work than a new bridge I expect. It sounds like you might have a stiff top/stiff bass bar. It's technically possible to have these problems corrected, but I have to wonder if it would just be easier to find a bass you like. Of course, without having seen the bass, this is all conjecture, but I don't believe replacing the bridge is going to yield the drastic change you are hoping for.

 

[jmpiwonka]

i'd consider a new bridge for a few reasons, you suspect the bridge width might be able to be better. also, you mentioned the top under the bass foot and i noticed when i looked at the original picture you posted. it seems the adjusters are drilled at an awkward angle and it's deforming the top. raising the bridge on only the bass side is only going to make that worse.

^ edit: honestly i'd just talk to a good luthier about it. i can't imagine the bridge being too far off if robertsons did it. maybe the top settled in or something.