Advice needed on open string buzzing on acoustic bass

[Jimothey]

Hi all

 

I need some advice please I’ve just pickup an acoustic bass and I’ve got buzzing on the open A and slight buzzing in the open D it sounds like it’s coming from the bridge?
 

Am I right in thinking that it could be an issue with the string angle being too shallow as it comes over the saddle? The problem is the action is really high so I can’t raise the saddle up any higher! I want to lower the action as well but am struggling to think of any other way to do it other than change the whole neck angle? 
 

Any advice would be great!! 
 

Thanks 

[Doctor J]

Sounds like it's coming from the bridge? Find out where it's coming from for sure. Does it happen if you play at the first fret? Does it happen if you play the E string at the 5th fret, is it a resonant vibration?

 

Start with the basic setup. Check the neck relief. Check the strings are wound properly on the tuners so there is good pressure on the nut. Check the string clearance from the nut over the first fret.

 

Add pictures of the bridge.

[Jimothey]

3 hours ago, Doctor J said:

Sounds like it's coming from the bridge? Find out where it's coming from for sure. Does it happen if you play at the first fret? Does it happen if you play the E string at the 5th fret, is it a resonant vibration?

 

Start with the basic setup. Check the neck relief. Check the strings are wound properly on the tuners so there is good pressure on the nut. Check the string clearance from the nut over the first fret.

 

Add pictures of the bridge.

When I hold the guitar up to my ear the buzz is definitely coming from the body end and not the nut end 

 

I did a basic set up when I changed the strings the neck is virtually flat with not a lot of relief 

 

As you’ll see from the pictures the action is very high it’s approx 5mm, the strings are breaking from the nut nicely so I think it must be the bridge?? The 

[Doctor J]

If you loosen the strings, that saddle bar probably comes out and you could sand the bottom of it to get the action you want.

 

However...

 

I'd take all the strings off except the A string, since that's what's readily causing the buzz and try to isolate the source of the buzzing first. Hit the string, make it buzz, then put your fingers on what you suspect is vibrating and causing the buzz. Apply pressure to stop the different bits vibrating, e.g. the saddle, the ball ens of the string, the ends of the bridge against the body, check the truss rod isn't slack, strap buttons, tuner keys, even the bracing inside the sound hole. 

[Geek99]

Worth drawing a line on the saddle bar with pencil before you start and then measure to bottom so you know how much you’ve removed 

[Andyjr1515]

On 08/11/2023 at 22:36, Doctor J said:

 

I'd take all the strings off except the A string, since that's what's readily causing the buzz and try to isolate the source of the buzzing first. Hit the string, make it buzz, then put your fingers on what you suspect is vibrating and causing the buzz. Apply pressure to stop the different bits vibrating, e.g. the saddle, the ball ens of the string, the ends of the bridge against the body, check the truss rod isn't slack, strap buttons, tuner keys, even the bracing inside the sound hole. 

This ^

 

Personally, I wouldn't lower the saddle any more.  Because it is a top string through bridge, the break angle  over the saddle is quite low to start with...and that may be contributing to the buzz (although Doctor J's method should confirm this or not).  

Edited November 12, 2023 by Andyjr1515

[PaulThePlug]

Some of the blah blah in my experience may help... here is my Diesel...

What is it?

Problem with 'just the A string' is the neck is not under the correct tension...

I'd start with the tuner nuts, then neck relief, then check the nut... fret third, slight tap clearance to string and 1st fret - I did a post 'Nut Job'... then bridge blade out...

Sorting the Ball ends is a worthwhile chore...

Post back your findings with pix...

 

Edited November 12, 2023 by PaulThePlug

[Bafflegab]

Is the buzz still there if you put a bit of pressure on the string behind the nut, then pluck it?  I had a very similar problem that was solved by adding a string tree

[Bigguy2017]

First adjust truss rod to set neck to be straight, no relief.

 

With a straight edge check the whole neck is straight, including the upper frets over the body. 

 If there is a hump or ski jump, this can be lessened (a bit) by a fret level (if sufficient meat on the frets).

Otherwise it's off with the fretboard, level the neck and re-attach fretboard.

 

Lay straight edge on top of the frets and extend it to touch the bridge - ideally it should just lay on top of the bridge (not the saddle).

If it arrives more than a mm or so under this you need a neck reset. This is the most likely situation with an older instrument.

 

The present saddle could be lowered a little (maybe 1mm), but not more due to break angle.

As the 12th fret action is 4mm(?) you can only gain 0.5mm by shaving 1mm off the saddle, and that leaves the action at a high 3.5mm.

(Remember that 1mm lower at the 12th fret needs 2mm off the saddle).

 

Looks like it needs a neck reset.

 

For the buzzing check for a loose brace, top or back.

[Maude]

I spent a long time trying to locate a buzzing on an electro acoustic guitar. 

Turned out to be the wire between the pre amp and the piezo element. It had a plastic square clipped to the wire that was supposed to be double side taped to the inside of the body, it was floating and vibrating against the body on certain frequencies. 

Worth a look?