Terry Cain's BIB -why does it work and does anyone have those Fostex Craft Handbooks? - Page 11 - diyAudio
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Old 7th March 2006, 10:45 PM   #101
dmason is offline dmason  United States
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I would forget about the B200 in a BIB. DisQualified at .70. These things want mid Q .45 is perfect. The B200 was designed as a mid-high range for open baffle. BUild the right OB with it and kill BIB's. OB rules, but requires space, which most modern urban dwellings cannot provide. The great thing about these is that they can go into corners and fill the entire room easily.

I too prefer whizzerless FR drivers, but this one's okay; "if ever a whiz there was" ...look for a wideband non whizz Hemp cone good to around 10KHz according to Perry the P at Hemp Acoustics www.hempacoustics.com with similar SPL, bit lower Fs, more Xmax, a design with perhaps a small horn supertweeter a la Fostex, and you have it, The Arch-Lord of BIB's in my opinion, The reference project; super simple, and jaw-droppingly musical.

These are designs very worthy of the best woodworking you can undertake.
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Old 7th March 2006, 11:53 PM   #102
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Here is my contribution to this thread. These dims are from the Fostex Handbook #3.
I would think its copyright and not proper to scan the drawing. I am not sure if what I am doing is much better ... sigh......

The recommended driver is the FF125K so this is a smaller version. Of course feel free to try the FE103 or 40-1197 or whatever you have, after all its all about experimentation.

Wood is all 18mm
height 1818 mm
N.B. the cuts stand on a base hence the 1818 mm (18 mm thick wood in the plan)
width 180 mm (external)
depth 336 mm (external)
cutting plan
front & back 1800 mm X 180 MM
divider 1660 mm x 144 mm
sides 1800 mm x 300 mm
base 440 mm x 300 mm
Looking from the side (profile view) the divider lays against the front panel at the top of the cabinet and the centre of the of the bottom of the divider is 150 mm from the inside of the back wall. The bottom of the divider is 150 mm above the base.
Driver is located 1000 mm from the top of the base up, so its a little more than halfway up. Diameter for the cutout for the FF125K is 104 mm.
There is stuffing at the top of the speaker from the top down ~ two thirds the way down to the speaker so ` 500 mm from top down. There is a light covering on the entire base and another light covering on the back panel from the top down ~ 200 mm.
These specs are given
L = 3600 mm
Fc = ~24Hz
Foc =~ 48Hz

go here for a profile pic from Terry

Andrew
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Old 8th March 2006, 12:32 AM   #103
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Quote:
Originally posted by Andrewbee
These dims are from the Fostex Handbook #3.
I would think its copyright and not proper to scan the drawing.
If you want, you can scan the picture (nice and big!) and send it to me...I'll put it up on my web server. I don't think Fostex will mind, it'll just inspire people to buy more drivers.
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Old 8th March 2006, 12:58 AM   #104
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Quote:
Originally posted by MuaDibb
is that the SO ends at zero. It seems the general consensus is that this is not a good thing
Well more like alot of people repeating the accepted wisdom. GM designed an 1194 ML-Voigt that purposely have S0 = 0 to disprove the point, I believe Woody has the prototypes -- they placed fairly well at an Atlanta diyFest.

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Old 8th March 2006, 01:03 AM   #105
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Quote:
Originally posted by Scottmoose
Voigt', please, not 'Voight' -P.G.A.H. Voigt you know. Not that he had anthing to do with the vile 'Voigt Pipe'.
I do hope your tongue is firmly in your cheek...

Voigt Patent

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Old 8th March 2006, 11:26 AM   #106
MuaDibb is offline MuaDibb  United States
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Hey dmason, you said you were listening to the FR8's. Are they in a BIB cab. and if so what dimensions are you using?

Hey GM I might try your MLTL-48" but do you have a suggestion for a more "economy-minded" speaker than the Jordan?
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Old 8th March 2006, 12:05 PM   #107
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Quote:
Originally posted by planet10
I do hope your tongue is firmly in your cheek... Voigt Patent dave
Bit of both Dave. Mostly yes. However, for example figure 2 and his own comments indicate terminating in free space, and the implied use of corner boundary conditions, unlike the loathsome contrivance which is the semi-mass-loaded LCofN VP. Thanks for putting the pages into one pdf BTW -it took me forever to download them indiuvidually when I was looking into them a year or so back.

Regarding the So=0, I agree. Generally best avoided unless there are specific reasons for having it, like to increase pipe-gain, but it's not the great evil of the Western (or any other) World either. However, the LCofN VP can have its response mostly flattened by mass loading -it still cuts off too high though.

Andrew -if you think it appropriate, I wouldn't mind seeing that picture as well if you could send me a private email: I've been trying to get hold of those Fostex books for a long time, with 0 success. Naturaly, I wouldn't break copywrite though -it's been done to me in the past, though given the amount of time I've invested into playing with modelling and constructing these cabinets, I'd love to finally see the originals!

Dan -I agree about the B200 not being an ideal match with that hefty Q. Not impossible either; as I say, I tried it a few days ago with some interesting results. It wouldn't be my first choice either though -Fostex of hempsters for me.


Cheers
Scott
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Old 8th March 2006, 03:08 PM   #108
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AudioNewB,

sorry not for you since you intend to add to your web server. Call me an old fashioned if you wish but principles are principles.

ScottM, I will contact you.

Andrew
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Old 8th March 2006, 04:13 PM   #109
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Quote:
Originally posted by Andrewbee
sorry not for you since you intend to add to your web server. Call me an old fashioned if you wish but principles are principles.
Smacked!

Your principles are fine. Scott deserves them more than me anyway, he's given a great deal to the community regarding the BIBs.
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Old 8th March 2006, 04:31 PM   #110
dmason is offline dmason  United States
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FYI

The only commercially offered BIB that I know of is the Polish-built Acuhorn "125" model, which is 50 inches high, uses a Tesla 8 inch driver, which some report is actually the inexpensive Monacor driver. www.spectrumaudio.de

At any rate, the anecdotes by reviewers, available on the Acuhorn website are very impressive, and mirror exactly what I hear. BIG, open, throaty, effortless, full range, room-filling sound. And mine is with just a 6.5 inch driver. Gawd only knows what the 8 inch Hemp will sound like.

www.acuhorn.pl
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