Bose 501 Series Info Please

[Airjmax]

Were there any Bose 501 series made with rubber woofer surrounds? I have read conflicting information about this. I know some of the 901‘s had drivers with rubber surrounds.

 

[Airjmax]

Ok, of course I found the answer shortly after posting the question. From the Bose website, they describe the woofer as having a foam surround. There’s a scan of the original manual with the information about the woofer construction.

 

[tarior]

Some 901s had doped cloth surrounds. AFAIK, all 501s had foam. BTW, foam is acoustically superior to rubber, but it degrades more dramatically and is a maintenance item. Modern foam formulations seem to last much longer than they used to.