In the late 1990's, the foam surrounds of my 901 Series IV's were totally rotted out. I exchanged them with Bose for a set of VI's at a discounted cost.
They are still working great -- driven by my sterling Yamaha AX-592 amp (100W per channel at 8 ohms).
But....It's been about 20 years that I've had these VI's and I'm afraid to look at the driver foam surrounds to see if they have started to rot. I read somewhere that the VI's had improved, rubberized foam surrounds and they had a much better longivity.
Can anyone verify if the VI foam surrounds are improved from the IV's foam surrounds?
I think I'll wait for my drivers to fail, like they did on my Series IV's, and/or definitive advice from competent authority on the composition of the driver surrounds. Based on the browsing I've been doing, it looks like the surrounds were probably improved after Bose must have gotten inundated by folks requesting exchanges from earlier series of 901's having foam rot.
They sound very good right now, so no rush to tear things up.
Thanks for your response.
Yes, I've seen that video. Very good. If I ever have to do this project, I'll watch a few more episodes of Monk so I can bring out more of my latent OCD traits. Looks like a great project - one driver per day, 18 days! ;-)
I was able to pry open my rear grilles and take a peek at some of my driver foam surrounds. Still intact after 20 years!
I was hoping that I had the Series VI Version 2, which have cloth surrounds and 'improved' drivers. But, alas, I saw the blue drivers of Series VI Version 1.
Still sounding great. No worries for now.