Altec studio monitors

I have traded for some altec 9846-8a speakers, can some one tell me about how old these are and what they might be worth. The story goes they came from an old rca recording studio but everything has a story.

I listened to some of the voice of the theater speakers but I liked these better.

The bass speaker has been replaced with I think a 15" cerwin vega. The bass isnt what Im use to. can I change the bass speaker of better quality. if these are very high sensitivity is the changing of this speaker very critical.

Hey if nothing else they are grey and black they look cool in my black listening room and they are cool at pool for parties.
You may visit the site link I have provided below for information on this speaker. Most likely the Cerwin Vega was used as a cost savings when the original Altec bass driver failed. Neither brand driver in this cabinet will produce flat bass much below 100 HZ.

The Altec driver would be a better match for the crossover circuit and may be found as good used stock or possibly rebuilt.
Vintage 1975, the 9846-8a woofer was model no. 411-8A.
Specs. for woofer 100 watts frequence response 20-1000 Hz
sensitivity 93 db/1 watt. 8 ohms impedance. Foam surround
woofer. Had a pair a few years back and changed the woofers
to JBL 2235-H which has the same sensitivity and higher
power handling. Port cabinet out the back of speaker. Made
it sound 100 percent better with much better bass extention
F3 was 35 Hz checked with LMS program