A string "buzz"

[growlypants]

Not action related, my A string, on any fret, was creating this slight buzzing from somewhere inside!  (This was a slight, un-amplified sound which grew more and more irritating!) I loosened the A string, wiggled the bridge thing to no avail, retightened the string, and the problem was gone!!  Any educated guesses on what the problem was??

[tubeperson]

Perhaps there is something loose in the control cavity that is resonating with your A string.  Could even be an isolated small crack in the wood.  Good time to do a spring cleaning check of all connections, pots etc.  Good luck.

[5a_quilt_top]

Check that and also check the brass plates that cover the control cavities. If any of them are even slightly warped, they will not make good contact with the wood and will buzz - even if the screws are tight. You may need to install some small pieces of foam along the edges of the plates where they contact the wood to dampen the rattle.
 
I discovered this myself because the open A string (and to a certain degree, any fretted A) on my Spyder resonates so intensely that the entire bass vibrates, including the brass plates.
 
Initially, I thought it was fret buzz, or something loose on the bridge. A few bits of foam later, all was well.
 
On the positive side, this is a minor inconvenience that is completely overshadowed by the resonance & sustain these instruments produce.

[growlypants]

Good advice - I'll check all the wiring for potential rattles as well as using some foam on the brass plates.  Thanks!  (And I swear, I did absolutely nothing other than loosen and then tighten the A string!)  It was weird because usually a buzz or rattle is caused when only one note is played, but this was on any A string note!

[mica]

Weird. It seems like anything that is limited to a single string would have to be either the string or the saddle for that string. Sometimes it is really really hard to figure out where a mechanical buzz originates. You can be sure it's in one place and then figure out it was really somewhere else. I bet it was the saddle, and your slight wiggle just nudged it from the precarious place it was adjusted to.  
 
It can't really be resonance-related since it doesn't happen on other notes of the same value (like on David's hyper-A bass).

[5a_quilt_top]

Maybe your bass shares a little DNA with my Spyder...
 
FWIW: I have a theory that all instruments have an inherent resonant frequency. If true, it may explain why some notes seem to jump off the fretboard while others need a little more coaxing to bloom and sustain.
 
Although I have no way of proving this, I do know that I've never had an instrument with such a strong bias to a frequency as that Spyder has to A.
 
As a test, I recently plucked the open A string at practice volume through my AER Amp One (volume about 1/4 up, no compression)and it sustained audibly for about 90 seconds.
 
Ridiculous.

[bigredbass]

I once had a single-string buzz/rattle/'what the hell is THAT' unplugged sound.  I forget which string, but I reached around to the bridge saddle where it was originating and turned it very slightly with the allen wrench, and it was gone.  
 
J o e y

[terryc]

Yeah..the battery in the cavity did the same on some notes, a bit if thin foam cured it. Can be bloody annoying though!!!!
It must be expected since we play and gig our instruments and they wear a little bit

[mario_farufyno]

Truss rod can ressonates  and rattles inside its housing, but it would be expected that this occurs only in one specific frequency, not on any note of a single string, though. May be the problem resides in a not so tight saddle/screw/fastener at the Bridge...
 
(Message edited by mario farufyno on May 17, 2013)
 
(Message edited by mario farufyno on May 17, 2013)