Do you know what these little horn knobs do?

[cruiser]

Here's a photo of my dual horns after bead blasting and before I painted them. Does anyone know what those little knobs on the horns do? They appear to be adjustable. Would this in some way adjust the tone of the horn? Have you ever tried adjusting these, and if so did it change anything (tone or volume of the horn)? Thanks.

 

[1 Wild R/T]

Yes that adjusts the horn.. hope you didn't get blast media in the horn, they usually don't work after that... I stuff a paper towel inside the snail before blasting...

 

[Nacho-RT74]

Just like a points adjustment on a distributor, those knobs adjust the horn diaphragm tension to get them work properly.

they don’t actually adjust the tone or volume but the gap to make the diaphragm buzz correctly into the magnetic field. These pieces are not CNC build LOL, hence why need to be adjusted after assembled.