What can rattle/vibrate inside a double bass?

[Ken Smith]

Originally Posted by Bin Hire

Thanks for replying Ken,
The bass is a Christopher that was built in the early 2000s. It's fully carved. A very nice bass - I've played it. It is in good condition. My friend has booked it in to a luthier next week.
Thank you for your advice.

Is the rattle metallic sounding, wood-type sounding or a little of both?

The most common metallic problem is the endpin 'inside' the bass when it's long. Also, the tuner plates as well touching the pegbox.

Try and find out 'where' the rattle is, up, down, middle, like that. Like I said, an old bass I just got back from restoration had a rattle at the 'fret' of the tailpiece because the downward angle off the bridge was a tad shallow. This was only noticed if I played hard or if I raised the bridge which lifted the strings off the TP Fret even higher. It went in my mind from a top removal and internal search for something loose to an actual 5 minutes of slight 'filling' of which I have over 40 years of experience doing.