Pioneer 8" BOFU BIB

[Variac]

This thread is regarding the popular BIB speaker built using the Pioneer full range driver and a tweeter. It really sounds quite good, is full range, and the drivers are about $25 per speaker .

We built a pair out of OSB (oriented strand board ) or as it is sometimes known- flakeboard. With this were able to keep the total cost under $100 a pair. Of course other materials such as plywood
can also be used..

Attached are plans that allow it to be cut from three four by eight sheets.

Mark

[Variac]

Here is the Pioneer BOFU 8" driver

If you ignore the "2" in the model # you can see how it got its name


Part# Pioneer B20FU20-51FW "8" Full Range Driver"


http://www.partsexpress.com/pe/showd...number=290-045


I then ordered this tweeter as recommended by Mr. Chang:

http://www.partsexpress.com/pe/pshow...TOKEN=34028700


Man!! that tweeter is great with the Pioneer!! I tried other values for the crossover cap (1.75uF, 2.25 uF , etc.) and 2.0uF is spot on for my room!

[gychang]

Originally posted by Variac
Here is the Pioneer BOFU 8" driver :

http://www.partsexpress.com/pe/showd...number=290-045

I then ordered this tweeter as recommended by Mr. Chang:

http://www.partsexpress.com/pe/pshow...TOKEN=34028700



Man!! that tweeter is great with the Pioneer!! I tried other values for the crossover cap (1.75uF, 2.25 uF , etc.) and 2.0uF is spot on for my room!

When I built mine I was just a jaw dropping experience. Until I put in the tweeter with 2uF caps, it did not sing...

It is nice to verify this has to be a sleeper combo on the internet. Gurus here has to take the credit, I just followed their instructions, thanks Scott, Dave at Planet 10, Ron, etc.



gychang

EDITOR'S NOTE:
This isn't a BIB. It is Mr. Chang's horn which you can find out about here: http://www.diyaudio.com/forums/showt...92#post1334492
He uses the same drivers as Variac is using and was the first to try that particular tweeter.
END EDITOR'S NOTE

[danielm]

Is there any probem with mids coming from the rear of the driver and exiting with the BIB or does stuffing take care of that issue?

How is it stuffed?

Does that little tweeter keep up?

Fascinating project.

[davidallancole]

Hi Variac,

Do you have any pictures of the BIB you build? How does it sound with the OSB board? Is it a pretty sturdy cabinet using the OSB?

Gychang,

You said something about putting the tweeter in line with the center of the B20 at one point in time. Have you done this? Does it sound any better than the tweeter that is off to the side like in your picture?

Thanks guys.

[Scottmoose]

Originally posted by danielm
Is there any probem with mids coming from the rear of the driver and exiting with the BIB or does stuffing take care of that issue?

How is it stuffed?

Does that little tweeter keep up?

Fascinating project.

Anything over about 250 - 300Hz should be damped out. The 180 degree bend at the base should help. Typically, the best starting point is to line the front of the sloping internal baffle, and one side-wall from the point to a few inches below the dirver, and also line the internal base.

[Variac]

Also we filled the tapered area above the driver..
For smaller rooms other areas might have to be even more stuffed as the bass can be excessive..

A good thing about all that bass is quite likely they don't have to be all the way into corners.

[Variac]

The very first shot in this clip is the BOFU BIB

http://www.youtube.com/watch?v=4xibbmBc5fI

I think that the OSB could look really nicewith a color stain and clear finish... It has cool 3D look

[danielm]

What thickness of OSB did you use?

[Variac]

3/4" BUT with NO tongue and groove edges. If you get T&G it won't work with the cutting plan. Cost us about $16 a sheet. OSB seems harder and stiffer than softwood ply. It doesn't make complicated joints well but we just butt glued it and it seems very strong and rigid. Although I've never heard of it being used for speakers before, I like it..

Here's a photo with me and a speaker. The other BIB is MDF with a 6" Fostex, but really should have been used in the smaller room:


Mark