Double Bass Should the bridge "sink into the top" at all?

[Chef]

When I first got my King, the soundpost was in there sooo tight it was "making a lump" in both the top and back of the bass where it sat. I used a contour guage to measure this, it showed about 3mm on the top, and maybe 1 or 2 on the back. It looked scarier than that! The treble bridgefoot also appeared to be "sinking into the top" as it was right next to the bulge the soundpost was making.
King Instruments suggested I pull the post and let the db rest for a week or so for the top's and back's shape to go back to form, and then trim and reset the post. So I did! The post was in there so tight, it took many well placed mighty whacks to pop it out!
The top and back came back to form nicely after a week, and I trimmed what I'd guess to be about 3mm off the post, carefully shaping it using an inspection mirror and post resetting tools bought for this purpose.
Now, after about two weeks, the treble foot of the bridge appears to be "sorta sinking back into the top."
Nothing like it was before. The bass foot rests on the bass bar, and that side's contour looks very normal. The treble side gets supported by the soundpost right? So if the soundpost is about "a soundpost width below the bridge", is this normal for the top to sink in a tiny bit at the treble bridgefoot, or is something really evil going on?

Additional question: the notches in the f-holes are used to set where the bridge sits, right? On the bass side, centering the bridge on the notch gets me a string length of 42", where King says it's supposed to be. On the treble side, either the f-hole or the notch is off, and centering the bridge on the notch results in a visibly crooked bridge, and a string length on that side of about 41 1/2"...Seems like the f-hole (or notch) on that side is outta place comparatively?

Thanks for reading my longwinded questions, Alan

 

[Bob Branstetter]

Ive not yet had one of the new Kings in my shop to examine, but the sinking condition you describe is not normal on other basses. I suggest that you take your bass to a qualified bass luthier ASAP for a hands-on diagnosis.

 

[Chef]

Here's a pic of the f-hole dilemma. String length set at 42" from nut to bridge, measure on both the treble and bass side of the bridge to make sure it's all square. I ran a string down the center of the bass, the left side foot centers on the f-hole notch, obviously the other side doesn't. It appears as though the f-holes themselves are cut right, but maybe just the notch is off?

 

[Chef]

Kinda hard to tell, but here's one pic...

 

[Chef]

Another, do these provide any useful info to you guys?

 

[Huy Nguyen]

Looks like you better call the doctor. That don't look good.

 

[Bob Branstetter]

Another, do these provide any useful info to you guys?

It does look like the notches are off. While this doesn't speak well for King's quality control, it is not a big deal. Call King and ask them what the proper distance is for the notches. Hopefully, one of the two notches will be correct.

 

[Brent Norton]

Looks like you better call the doctor. That don't look good.

+1. Bob, what's your take on that sinkage pictured in the 2nd and 3rd pics?

 

[Brent Norton]

You know, the more I look at that bridge, too, the more I think that IT'S the culprit in terms of not lining up between the notches properly, not the f-holes or nicks... It looks like the feet themselves are different heights, almost if somebody cut the feet off first, THEN drilled the holes for the adjusters individually into the feet and bridge?? Am I just seeing things?

 

[Chef]

You know, the more I look at that bridge, too, the more I think that IT'S the culprit in terms of not lining up between the notches properly, not the f-holes or nicks... It looks like the feet themselves are different heights, almost if somebody cut the feet off first, THEN drilled the holes for the adjusters individually into the feet and bridge?? Am I just seeing things?

I measured the bridgefoot blocks, and they're both ~ 7/8" thick. I think the reason they look different is twofold:
first, the bass side is adjusted up a few mm more, and second is just "photo-crap." Both angles are what we call "keystoned" in the photobiz, in other words taken from a perspective changing angle, kinda. At any rate, they measure the same, and the adjuster hole seems well centered in both blocks...

 

[Bob Branstetter]

+1. Bob, what's your take on that sinkage pictured in the 2nd and 3rd pics?

A picture may be worth a thousand words, but I would want to see the beast in person before I would venture a guess.

 

[Chef]

It does look like the notches are off. While this doesn't speak well for King's quality control, it is not a big deal. Call King and ask them what the proper distance is for the notches. Hopefully, one of the two notches will be correct.

As I said earlier, King said string length should be 42". Both sides of the bridge are set to that, so *something* is amiss with the f-holes, or notches...Bottom line for the f-holes, I guess, is that's an "inconvenience, and quality control flaw" as you noted, and doesn't effect playability. It also doesn't concern me nearly as much as the bridgefoot starting to sink again, which seems pretty scary in terms of the db's long term health....

 

[anonymous0726]

Looks to me like the neck might be mounted wacky.

 

[Bob Branstetter]

As I said earlier, King said string length should be 42". Both sides of the bridge are set to that, so *something* is amiss with the f-holes, or notches...

Rather than using the string length, ask King for the body stop length for their basses. That is the distance measured on the center seam of the top between where the neck joins the top (under the fingerboard) and the center of the bridge location (where the notches should be). Use a protractor (90 degrees) to extend that line from the center seam to the notches if you can see the center seam through the black paint.

 

[Chef]

Rather than using the string length, ask King for the body stop length for their basses. That is the distance measured on the center seam of the top between where the neck joins the top (under the fingerboard) and the center of the bridge location (where the notches should be). Use a protractor (90 degrees) to extend that line from the center seam to the notches if you can see the center seam through the black paint.

Indeed, I can't see the seam thru the black paint...I'll ask tho...

 

[arnoldschnitzer]

Your Q: Is it OK for the bridge to be sinking into the top?
Straight A: No!

 

[Chef]

Thanks Arnold. You, Bob, and Brent were some of the guys I was hoping to hear from.

 

[Steve Swan]

When I got this bass back from Chef the bridge was wobbling on very tall adjusters.

[Not-particularly derogatory but idiosyncractic information removed by moderator.]


I moved the soundpost to the proper position and the bass sounds great with Thomatic Spirocore strings. [More commentary removed.] The new owner of this bass is mighty pleased with it . . . [Yet more material removed]

Always seek out a fully qualified repairman to do your work!

Happy slappin'

Steve Swan

 

[Chef]

Steve, if you want to air the entire load of dirty laundry that comes with my dealings with both you and KDB, I'm happy to do so.

RIGHTO, SAYETH SAM, BUT I AM NOT. Material removed by moderator.

 

[M_A_T_T]

This may be abit late, but the first picture tells me the bridge is twisted, or the feet don't seem to line up, because that piece of string layed across the bridge feet is obviously not perpendicular to the center line of the instrument.