Double Bass Un-notched F-holes - bridge positioning method?

[moles]

Just picked up a new bass, and I'm going through the minor adjustments it needs. Mostly it's pretty minor stuff that I can deal with (3-4 inches of popped seam at the bottom bout which has supposedly been stable for the 5 years the seller owned the instrument, some cleanup on the top of the bridge, the sound post could be a little more plumb, and I might take the Realist off just to hear it without). It's a fully carved bass, albeit no-name (factory?) - I was told German, maybe mid 90's. It plays well and the fingerboard is in fantastic shape, and I'm pretty happy with it overall.

So I noticed when I was looking it over before buying that the f-holes have no notches at all, and now I'm scratching my head trying to sort out how to position it properly-? Any advice where to start?

 

[turf3]

I'd look for the witness marks in the top finish where the feet were. Then once you get it positioned I'd run a pencil round each foot to keep track of where it is.

 

[Steven Ayres]

Put the bridge in and set it vertical to the table. Use a long ruler (easy) or tape measure (harder) to find the scale length for your instrument on the string; that's the point where the strings come off the top of the bridge. Make sure the bridge is vertical again, and you're there. Mark the position of the feet if you like, but the important measurement is the scale.

 

[moles]

Thanks for the ideas - these are all the starting points that I'm thinking... The problem is the top around the bridge feet is a mess of scratches etc. and there's no easy to judge exactly where things should be that way. Centering is a no brainer; I'd like to try to get it as close north/south to where the builder intended.

Put the bridge in and set it vertical to the table. Use a long ruler (easy) or tape measure (harder) to find the scale length for your instrument on the string; that's the point where the strings come off the top of the bridge. Make sure the bridge is vertical again, and you're there. Mark the position of the feet if you like, but the important measurement is the scale.

I'm not sure I get it yet. Usually I'd be able to measure the mensur once the bridge is in its proper place, but without knowing that, how do I know how long it is supposed to be? Can't find the bridge placement without the scale length, can't find the scale length without knowing where the bridge goes - see what I mean?

The smartest solution I can come up with is to figure out where the Eb on the G string intonates the "nicest" at the neck/heel and call it a day. But I'm hoping there is some rule of thumb the builder might have stuck with relating to the f hole shape / bass bar location.

 

[Steven Ayres]

how do I know how long it is supposed to be?

If it's a 3/4 bass, the mensure is usually 41.5-42". You can check this against the position of your soundpost, which is usually placed nutward of the foot by about one post diameter.

 

[moles]

Well sure it's *usually about* that long You're probably right thinking 1/2" isn't anything to worry about. I've had/played 3/4 size basses with everything from 41" to 42.5"; that's a bigger range that would make a difference IMO. (and I do appreciate the playability that comes from a bridge set exactly where it's supposed to be.)

I'm not going to drive myself nuts over it, but again I'm shooting for better-than-a-guess (if there is such a thing).

Sound post ain't in a good spot either, so we can't really go off that unfortunately. I suppose I'll have to just nudge it around and make a decision, stick with it, and set the sound post accordingly.

(I promise promise promise that won't drive me bats&^# crazy every time I'm working on intonation )

 

[Don Hergert]

If it's close and you have other 3/4 DBs with a scale length that you're used to, you may as well match them since it sounds like you're going to setup the sound post anyway.

Within a standard range, it seems that you have no other reliable landmarks to go by.

 

[overit]

Maybe if you share the make/model of the bass, someone may have one and can measure the scale length or might know what it is.

 

[moles]

Maybe if you share the make/model of the bass, someone may have one and can measure the scale length or might know what it is.

Unfortunately there is no label, and the 3 previous owners have no idea, other than the info I reported in the OP.

EDIT : I did find this http://www.platetuning.org/How_Strad-vs_positioned_his_ff_holes_-_The_Strad_part_2_8_sept.pdf
Whether it will be useful or not I can't say, but it's interesting nonetheless.

 

[overit]

Unfortunately there is no label, and the 3 previous owners have no idea, other than the info I reported in the OP.

EDIT : I did find this http://www.platetuning.org/How_Strad-vs_positioned_his_ff_holes_-_The_Strad_part_2_8_sept.pdf
Whether it will be useful or not I can't say, but it's interesting nonetheless.

oh my bad, i missed the no-name part in your post. interesting article, hope it helps.

 

[DoubleMIDI]

What about the obvious?
Middle of the f-holes?

i would not reposition the soundpost unless you tried the best bridge position with the current soundpost location. If the bridge is close to the middle of the f-hole then, measure and write down bridge and soundpost position and feel free to experiment after that.

Personally I would keep the soundpost where it is and try bridge position relative to the soundpost for best sound and keep it that way.

 

[Wasnex]

It seems reasonable that you would go off the current position of the sound post, since your description seems to indicate the bass sounds and plays well in it's current configuration.

I was under the impression that the sound post and bridge could be moved around a bit to vary mensure. For example if you have a huge old bass, you might install a false nut and reposition the bridge and sound post. Here's a related thread Is there a way to shorten scale length?

The point is it's probably not all that critical that you get the bridge and sound post in specific position, that would be indicated by the F holes. Instead you have a reasonable range of adjustability in which to make the bass sound and play well.

 

[moles]

I should clarify that the reason I'm saying the soundpost needs adjusting, is that it isn't straight - The top side has dropped 1-1/2 post-widths at some point. Probably been like that for awhile.

Actually when I went to try it out the first time I wasn't super impressed with the bass. It was very warm but lacked clarity - the fingerboard played very evenly and dragging a bow across the strings for the first time since 2015ish was surprisingly easy, but I couldn't get a bump up in volume by digging in like I'd expected. I came back because it did have something I thought could be workable., and it hadn't been played in awhile - the seller was pretty cool about spending whatever time I needed so I figured I'd try to loosen it up and check out what maybe could be tweaked. So that second day I noticed the bridge was leaning toward the fingerboard maybe 5-10 degrees (shoulda noticed that earlier) which made me start checking out the post. As soon as I adjusted that bridge perpendicular to the top - big change for the better. Getting that sound post up can't do anything but good. So long story longer - it plays well at this point, with an asterix.

Honestly I'm kinda super-thankful that I have a bass again, and one that's only going to take a tiny bit of work and some thought to get it happening. I think y'all have a good point though and I should stop sweating it too much (for now).

 

[GretschWretch]

Would there be anything to be gained by chiming the octave harmonic and moving the bridge around until the stopped octave and the harmonic matched?

 

[Wasnex]

Would there be anything to be gained by chiming the octave harmonic and moving the bridge around until the stopped octave and the harmonic matched?

??? AFAIK both will be at the mid point of the vibrating string. If you move the bridge, the mid point move on the fretboard, and so do both the octave harmonic and stopped octave.

 

[BobKay]

If it's a 3/4 bass, the mensure is usually 41.5-42". You can check this against the position of your soundpost, which is usually placed nutward of the foot by about one post diameter.

On every bass I’ve owned the sound post is set below the bridge - toward the tailpiece, not the nut.

 

[turf3]

Would there be anything to be gained by chiming the octave harmonic and moving the bridge around until the stopped octave and the harmonic matched?

Won't help, no frets.

 

[Steven Ayres]

On every bass I’ve owned the sound post is set below the bridge - toward the tailpiece, not the nut.

You're correct, of course. Me writing too fast again ....

 

[james condino]

Step 1) Checkout this video from Upton about setting your bridge

Step 2) Don't overthink it.




As a side note: I installed a few of those in house made Upton bridges several years ago. They worked great and I liked that they were manufactured at their CT shop. It sure would be nice to have them available again to other luthiers. Much (most?) of the country is sold out of the traditional European ones right now and I'm constantly asking all of the suppliers if we are ever going to be able to buy them again while empathetically listening to their current stories about viruses & customs & economics & the state of the world....

 

[David Potts]

Two observations not mentioned yet. The first is to check the inside of the belly (front table) for pencil lines drawn by the maker, using a torch and swivel-headed mechanic's inspection mirror. If there is a line across it may indicate one of two things. It could indicate the highest point of the bass bar or, less likely, the top edge of the sound post setting.

The centre of the feet of the bridge should be in line with the missing inside notches that are usually in line with the highest point of the bass bar. Assuming that the two sound holes are carved symmetrically you could approximate the inside notch with a square ended ruler on the bass bar side and make the same mark on the other side then connect them with a line across the outside of the belly. Stand the bridge in its (new) place and measure the string length. You can also measure the distance between the nut diagonally to the middle of the curve at the base of the neck. I have found that a comfortable neck-to-string length ratio is approximately 14 3/4" to 42" the puts the thumb opposite E flat. A shorter neck will oppose the thumb with D (or worse) and a longer neck will oppose E...... There is some wiggle room to move the bridge north or south without risk of harm. After that comes adjusting the sound post............