I purchased an ET65 for my Blues Jr III and I was wondering if the installation affects the sound?
I mostly love the sound of my new speaker, the only issue I have is a ghostly high pitched harmonic like sound when playing chords with the high strings. It's a little hard to describe but I guess it's like a mild ring modulator on top of the regular guitar sound.
Could this be because I didn't add the foam liner that came with the speaker? Could it be that I over tightened the screws? Is it a characteristic of the speaker?
The foam is only for if you FRONT mount the speaker (did you?).
If not ... two possible issues:
1. the speaker needs to be sent back for an exchange.
2. the speaker is so much better than the one it replaced that it has shown a weakness/problem in the amp.
Oh ... and yes, it is possible to physically distort a speaker enough to cause issues by over tightening the mounting screws (usually just a half-turn or so more than "finger-tight" is recommended). But generally, you need to crank down pretty hard to do that (hope you didn't).
In any case ... if you are not 100% comfortable with speaker swaps, might not be a bad idea to schedule a trip to a tech who is!
For the instalation I did a straight swap for the lightning bolt speaker that was in there. The lightning bolt had four screws so I used four screws. I noticed that the ET65 has 8 holes, do I need to get 4 more? I also didn't crank down on the screws, I sort of tested how much tension there was on the factory installed speaker and then screwed back to a similar tension.
I tried using the speaker with a different amp and had the same issue.