How can I tell if I blew my speakers?

[Rods]

Hi, I have been running my SVT4-PRO through my SVT610-HLF and it sounds a little strange when playing just about any note on the 'E' string. I've tested the cab with other basses and other heads and I'm getting the same problem. Could something be wrong with my cab or am I just thinking about it too much and I'm playing too loud?
Thanks.

[rust_preacher]

If you are playing loud, it could be a resonance effect with the bass and the speaker output. Does the same happen with other basses? How about playing the same notes on the "A" string? Does the problem remain when tweaking pickup height? Can you try another head to see if it's the speakers? Can you try another cabinet? Troubleshooting may not be easy if you don't have these alternatives at hand...