Pioneer 8" BOFU BIB

[nuconz]

Hello GM,


I wanted to share with everyone what I did a few weeks ago. I bought a bunch of BOFU's when they were on sale at PE. I blew one of the speakers one night when my friends were over and we were blasting my ceiling speakers. I fixed it and it sounds great. I sent away to eBay for rubber surrounds.

2Pcs 8'' Speaker Surround Decorative Circle Repair Rubber for Bass Woofer Horn | eBay

Removing the old foam was easier with a heat gun, when the cone was clean I raised the cone with paper towels folded between it and the basket. The dust cap was already removed because I made phase plugs. I spaced the coil with paper to center the cone. I glued the with rubber cement the surround to the cone and let dry then later to the basket. It was easier than I thought. I'm going to buy from the ebay seller more surrounds and gaskets for the ones I have in boxes. I hope you give it a try, it should not dissolve even in your part of the country.

Here are a few pics.

Webber

the change to rubber surrounds will alter the response characteristics of the drivers.

so how do they sound?

 

[webber]

Hi Nuconz,


They sound fantastic !!

The speaker boxes I made when my dining room ceiling was open are about 4 feet long and add up to 3 cubic feet for volume and a super tweeter takes care of the highs. I'm driving it right now with a modified TDA7297 amp with the proper parts selected. I don't hear a difference from left to right, the bass is amazing in the sealed box. The rubber was thin and the old foam was thicker so they might be close in resistance.


Webber

 

[Variac]

Most places that sell the surrounds also offer foam, and it's the newer foam that doesn't degrade, or at least not so far. Now it still isn't guaranteed to be exactly the same as OEM, but probably a better bet as far as weight and flexibility than rubber, unless your drivers had rubber originally. Replacing the surrounds is really not so hard as Webber points out, and very satisfying. In San Francisco it's not too unusual to find a pair of speakers on the sidewalk. i found some epi's once, replaced the surrounds and they were much appreciated by the recipient.

 

[nuconz]

Most places that sell the surrounds also offer foam, and it's the newer foam that doesn't degrade, or at least not so far. Now it still isn't guaranteed to be exactly the same as OEM, but probably a better bet as far as weight and flexibility than rubber, unless your drivers had rubber originally. Replacing the surrounds is really not so hard as Webber points out, and very satisfying. In San Francisco it's not too unusual to find a pair of speakers on the sidewalk. i found some epi's once, replaced the surrounds and they were much appreciated by the recipient.

i got some epi 100c boxes & passive radiators 4 sale. boxes almost perfect. way in east coast, though.

 

[Scott L]

It's a real tragedy that Pioneer discontinued the BOFU. With the ACA amps the BOFU BIB with a small tweeter at the very high end isn't the ultimate in resolution, but just sounds great! Really Great!

I think I saw some on e-bay

 

[Variac]

I still have 4!

 

[GM]

Hello GM, Removing the old foam was easier with a heat gun........

Greets!

Thanks, good to know!

Still mired down with 'life', but finally starting to see the 'light at the end of the tunnel' after nearly two decades, so a timely update. The original Foster version I'm most familiar with had a gooped cloth surround like Altec, so still the plan if they are still available in 8"; not as much Xmax, but has the Altec's smoother overdrive I prefer when gooped with the Altec/JBL preferred clear dope, though been told its EPA mandated replacement isn't quite as 'syrupy'.

GM

 

[GM]

Most places that sell the surrounds also offer foam, and it's the newer foam that doesn't degrade, or at least not so far. Now it still isn't guaranteed to be exactly the same as OEM, but probably a better bet as far as weight and flexibility than rubber, unless your drivers had rubber originally.

Hope so, I've got some Philips drivers that need refoaming.

Rubber can be OK if the roll is narrow/'tight' like on GPA's 411 relatively high Xmax prosound/studio monitor wide range <sub>woofer, but these big half round donuts have way too much hysteresis at low excursions and visibly distort at high ones for anything but a narrow BW woofer app to my ears, especially cheap ones; though somewhat out of date now, so guess materials technology could have solved the worst of the problem by now, but if so, has it trickled down to the masses yet?

GM</sub>