Double Bass Keeping the bass in tune

[Rusty the Scoob]

I realized last night while practicing for my upcoming acoustic duo that my bass goes flat extremely quickly - about a quarter step flat after just a song or two, across all four strings - not perfectly evenly but fairly close.

What are the common things that would cause this? I'm not even sure where to start looking.

 

[Ed Fuqua]

But I would say the most common thing is the strings pulling the top of the bridge forward. This can pull the bridge over, which is No Fun. Which I know from Bitter Personal Experience. At a gig. Which was No Fun.

Check your bridge from the side to make sure it's perpendicular, check the bridge feet to make sure they're sitting flat on all 4 sides and corners of each foot. If you've got adjusters, how far are they extended? If they are too far out, the feet can be flat and correctly positioned but you can still be pulling the top of the bridge off the adjusters.

 

[Rusty the Scoob]

It's most definitely pulling the bridge forward. There are no height adjusters, it's bending at the middle. Crap, so that will be enough to pull it out of tune? I'm liking my Fenders more and more...

 

[KUNGfuSHERIFF]

Your bridge is warped. For a temporary fix it can be boiled until the wood is 100% saturated, clamped flat and left to dry under pressure over the course of a few days. Some warp again, some don't. Or you could lump it and have a new bridge cut. Plenty of fine bass luthiers in Boston.

Welcome to doublebass!

 

[tyb507]

Maybe check where the tailpiece is attached to the endpin as well...if it's wire and slipping that could conceivably cause this, yeah?

 

[Ed Fuqua]

Timely!

 

[Rusty the Scoob]

Maybe check where the tailpiece is attached to the endpin as well...if it's wire and slipping that could conceivably cause this, yeah?

I don't think it's slipping but it is gradually bending the endpin forward.

Welcome to doublebass indeed! I've had more trouble with this instrument than my 15 or so electrics combined! Then again it was free.

 

[scotch]

Timely!

Man! That video came at just the right time! My bridge took a hit on the road and got knocked about an inch diagonally out of place. This was a great video to help me make sure I put it back correctly! Thanks!

 

[tyb507]

I don't think it's slipping but it is gradually bending the endpin forward.

Welcome to doublebass indeed! I've had more trouble with this instrument than my 15 or so electrics combined! Then again it was free.

If the endpin is being pulled out of the block by string tension, it's time to loosen your strings and call your luthier!

 

[Jeremy Darrow]

If the endpin is being pulled out of the block by string tension, it's time to loosen your strings and call your luthier!

Before taking all the tension off of your bass; it is not unusual for the endpin to tilt SLIGHTLY towards the front of the bass due to the tension from the tailgut. That is, it doesn't sit perfectly perpendicular to the tail block and ribs. If it's actually migrating out of the bass, that's a different story.

 

[RSBBass]

And should you have to take the string tension off, be aware the sound post may fall.

 

[T-Bird]

Hi.

What are the common things that would cause this? I'm not even sure where to start looking.

I do not dispute the wise words from the pro's, but...

IMLE as a hobbyist, the most common causes for a DB to go flat while playing are:

#1 Slipping strings on the tuner barrels, ie. incorrectly strung.
#2 If using guts or weedwhackers, the strings stabilizing.
#3 the tail-wire slipping.

Especially on the basses from the lower end of the price spectrum.

Since the bass was free, I'd make sure that at least the sound-post is at its correct location, if not a full and thorough once-over.

Regards
Sam