Terry Cain's BIB -why does it work and does anyone have those Fostex Craft Handbooks?

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#4,861
Greets!

One more time, while the original BIB is tuned to a half WL of Fs, it's no 'hard & fast' rule, so one can adjust the desired driver or total folded height by changing Fs.

Note too that very low Qts drivers such as the FE206E typically need some form of shelving EQ [baffle step compensation [BSC]] to go low with authority, so use a higher Qts of between ~0.35-0.4 to get the necessary net cab Vb required to maximize in-room fine tuning with EQ.

GM
 
#4,862
Greets!

One more time, while the original BIB is tuned to a half WL of Fs, it's no 'hard & fast' rule, so one can adjust the desired driver or total folded height by changing Fs.

Note too that very low Qts drivers such as the FE206E typically need some form of shelving EQ [baffle step compensation [BSC]] to go low with authority, so use a higher Qts of between ~0.35-0.4 to get the necessary net cab Vb required to maximize in-room fine tuning with EQ.

GM
 
#4,864
Other than having to use a driver with specs suitable for up/down firing [low compliance] if one doesn't want the driver on its vertical face and/or the loss of one boundary loading if not long enough to span ~80% of the distance between two corners, this makes for a space efficient platform for speakers, equipment which is what I sometimes used them for after reading about this early '50's variant [now considered a tapped TL]:

GM
 

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#4,865
I'd wonder if you were wanting to use a BIB as a sub-woofer, that maybe a Tapped Horn may be the better option in the long run? Thinking about size and delay issues with a BIB used as a sub?, not sure etc..

Oops, beat me to it GM 🙂
 
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#4,867
Since H-frames use larger woofers than BIBs i think it's not quite a fair comparison. Yes, two BIBs using 6 or 8" woofers will deliver bass with a small footprint anywhere from 45 to 55hz. But H-frames using 15 or 18" woofers taking up larger footprints as well as sitting out into the room provide deeper, more powerful bass down to 30hz... to my ears anyway... and i have both.

Both have their appropriate places in a home environment.

Zilla
 
#4,868
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#4,870
Agreed, I keep mine close to about 70hz for that same reason.. I had one on a sheet of ply about 4'x6' for a bit while constructing my H-Frames, and a higher x-over was okay, but in the H-Frame I like them best at about 70hz for my room 🙂

Going to one day get another pair and put them on a Carver Amazing styled OB baffle with some other driver doing the 100hz and up parts, or just left full range like the BIB's are running along with the H-Frames😎
 
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#4,871
I am soon ready with a BIB with FF165K:
H 173 cm internal
W 20 cm "
D 27 cm. "

Maybee i should make the round baffle? Is it neccecary? Whats the measures? Is it difficult to get the perfect freesbee shape?

And the Terry Cain feets. They are nice. Does anyone have a drawing?

🙂

Hans Erik
Norway
 
#4,874
I would suggest the $35 fostex from madisound plus a 1uf cap mounted on the rear. You will need a few inches of space to hear the tweeter so make sure you want the speakers positioned like that. If it's not enough treble try a 1.5uf... too much treble try a .68uf... or you can mount the tweeter on the front and try a .47uf or .33uf... I prefer it with a tweeter.

Enjoy
 
#4,875
GM has suggested a pennant at the BIB mouth. Can someone provide a link with that illustration? I had seen it and noted that the pennant was different from the one I used.

Currently I'm looking to upgrade my BIB to CHR 70 or similar when they are restocked at Madisound. The BIB is a very satisfying build. Various tweaks over time have been added.
 
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