Advice needed: Bridge rattle on Sire bass

On my Sire V7 Vintage 2nd generation bass, I am noticing a weird rattling, buzzing sound whenever I play loud on the D and G strings. The rattle is most noticeable when slapping/popping these strings. It doesn't sound like a fret buzz, instead it sounds like a screw is loose or something and it kind of destroys the pop sound.

The bass is about 6 months old, and I didn't really notice this until now.

I went through and checked all of the screws on the bridge, pick guard, etc and they all seemed tight enough. I also tried mounting the strings through the underside of the bass instead of through the bottom of the bridge, and that didn't help.

The noise is very difficult to track down, but it sounds to me like it is coming from the bridge.

This is starting to drive me nuts. Anybody ever run into this problem?
 
I know it sounds like the bridge but check everything else as well. I have had a noise coming from a tuning key or something that sounds like it’s from the other end of the bass. If someone else can get it to make the noise while you check / touch various parts of the bass that might help.
 
Make sure the bridge saddles are level side to side. They can follow the bridge radius but they need to be level. Like this:

upload_2020-8-22_16-20-8.png


Not like this:

upload_2020-8-22_16-21-23.png


When the edges of the saddles touch they can vibrate against each other and buzz.

If your saddles are level, the mounting screws on the bridge are tight and both height screws on each saddle are firmly planted on the bass plate, you might want to start looking elsewhere for the rattle. The next thng I would look at is the tuners.
 
I know it sounds like the bridge but check everything else as well. I have had a noise coming from a tuning key or something that sounds like it’s from the other end of the bass. If someone else can get it to make the noise while you check / touch various parts of the bass that might help.

Wow, Turnaround, what an excellent diagram! That is one of the most clear drawings I have ever seen. Very impressive, thanks a lot for making that!

Based on your diagram I inspected the levelness of the bridge saddles and I noticed that 3 of them were fine but the saddle on the G string was quite a bit out of whack so I evened it out and it helped a lot. But even after leveling it I think I am still hearing a little rattle. I tried tightening everything else I could find, including the tuners (thanks Matt for the tip), and it still doesn't sound quite as "tight" as my other basses on the pops. I think it sounds acceptable now though, especially when I listen through headphones.