speaker distortion?

[yoshi800]

Since upgrading to a smash preamp with upgrades, I notice more bass distortion at some of the preamp levels. I guess it's caused by my speaker's limitations, becase the mid and highs are clear. Would it be better to add in a subwoofer or go for upgraded  (more sensitive) speakers? My goal is to reduce the distortion rather than improve volume handling or bass response.
Thanks in advance
Fred

 

[yoshi800]

Oh I got it! One of the woofers is giving out. It's much noisier than the other one, so I guess it's time to replace it.
Fred