Amp or Speakers broken?

[Daan32]

Hi,

 

So yesterday I tested my subwoofers with a 9v battery.

They both are 800w RMS 8ohm subwoofers connected in parallel.

I held the 9v battery onto the terminals multiple times for at most 3-4 seconds at a time.

 

I also tested my amp (Behringer EP4000, operating in bridged mode) WITHOUT any speakers connected for about probably

5-10 minutes, I also drove it into clipping as that was what I wanted to prevent by lowering the input volume.

 

 

Now my problem is that those 2 subwoofers sound a little quieter (not much, but it is noticable), what could be the 

most likely cause of this, having tested those subs with that 9v battery or running the amp without any speakers connected?

 

Thanks in advance!

 

-Daan

 

Amplifier Specs:

https://media63.music-group.com/media/sys_master/h27/haf/8849441357854.pdf

 

Subwoofer Specs (LX-18B(E)):

https://www.manualslib.com/manual/623327/Wharfedale-Pro-Lx-Seroes.html?page=9#manual