TWO radio speaker distortion questions

[JKent]

Two radios. Same symptom (distortion). Different causes (I assume):

Radio #1 is a KLH Twenty-One. The 21 is a solid state unit in a single cabinet. If I play at normal levels it seems OK but if I crank up the volume it distorts, and I "think" I'm hearing another station mixed in. If I attach an external speaker I get the same distortion. I'm guessing it needs alignment? I have replaced the power supply cap (preventive maintenance).

Radio #2 is a KLH Model Eight. Tube receiver, separate speaker. If I crank it up it distorts--bass notes primarily. Sounds sort of "ragged." BUT if I use a different speaker it is OK, so I assume I have a bad driver. Two problems with this: The grille cloth is very difficult to remove and it is irrepalceable. Also, this is a 2-driver speaker and I do not believe the 3" driver is available (it is smaller than the common full-range driver used in the 21). Is there any way to test the driver(s) without tearing into the box?

Any ideas welcome.

thanks

Kent