On Mon, 4 Dec 2017 13:14:31 +0000 (UTC), harry newton
wrote:

I haven't worked on speakers in decades.
http://wetakepic.com/images/2017/12/04/speakers1.jpg

How do we debug a scratchy sound?
We can isolate it with the balance to a single speaker.
But is it the speaker? Or something else?
If it's the speaker, where is a good place (other than the dealer) to get
speakers to fit a car rear deck? Are they all standard sizes nowadays? Or
is each unique?
I'm helping the neighbor's kid refurbish a beat-up 2005 Camry where I
helped her kid put in new speaker covers this weekend but the scratch sound
persisted (we thought it might have been the crud or vibration from the
crumbling melted-in covers).
The scratchy sound persisted even with the newly replaced covers.
http://wetakepic.com/images/2017/12/04/speakers2.jpg
Any suggestion on how to debug the cause of the scratchiness?
If it's the speakers themselves, are these things standard sizes nowadays?


Interchange the wires at the speakers - you'll prove that it's the
speaker and not the stereo or wiring.
Pull out the bad speaker & look for a tiny tear - try fixing it -

http://www.300guitars.com/300s-tips/...speaker-cones/

or shop for a replacement.
John T.