Terry Cain's BIB -why does it work and does anyone have those Fostex Craft Handbooks? - Page 90 - diyAudio
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Old 20th June 2006, 01:27 PM   #891
GM is offline GM  United States
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Greets!

'Beats' me, when I was experimenting with foldings it never occurred to me to try other than theoretical optimums since both theory and common sense says to keep the expansion constantly expanding to ensure there's little/no reflections back to the driver/throat. FWIW though, my SWAG is that any differences will be swamped by the room's interaction until the impedance mismatch between the front and back sections becomes great enough to make it a bone-fide 'big vent BR' BLH alignment.

GM
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Old 20th June 2006, 05:20 PM   #892
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Here are my BIBs under construction. Cheap plywood sides ($30 for a 4x8) and even cheaper particle board ($20 for a 4x8) front back and internal baffle. Home Depot butchered it all up and left me with lots of sanding and another project of building a base with adjustable spikes to balance the cabinets out evenly. For me part of the fun is the challenge of getting all the pieces to fit. Itís all butt joined, glued and screwed like the amateur I am but itís all in good fun (and good sound of course!). I will double up the front and back which will add another butt joint, strengthening the cabinet further. This will be a heavy cabinet when itís done.

http://www.zillaspeak.com/bib-godzillabib.asp

My plan is to simply sand and paint the cabinet then add a lovely stained piece of pine as the front baffle. I hope to route the edge if I can get my hands on a router.

At least I finally have two cabinets!

Some additional things have been added to the siteÖ the TB 871 3Ē BIB dims, the Visaton BIB by GM and a couple lovely pics of TCís BIB contributions.

http://www.zillaspeak.com/bib-pics.asp

Peace,
Godzilla
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Old 21st June 2006, 02:57 AM   #893
GM is offline GM  United States
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Quote:
karlsonkab


sorry not FR - Like to have good (not reflex if possible) enclosure for Beyma 12CX whose woofer section is at least as wideband as Beta 12LT - goes to ~7Khz on-axis. (tweeter is ~ like APT50). wonder if TQWT would work well? What enclosure might be good for this Beyma?
Greets!

L = 138"
Sm = 440"^2
zdriver = 30"

So, assuming 3/4" (19 mm) material thickness (all dims i.d.):

h = 69"
d = 24.96"
w = 17.625"

GM
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File Type: jpg beyma 12cx t.c. bib done in blh ws.jpg (22.8 KB, 735 views)
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Old 21st June 2006, 08:00 AM   #894
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Impressive. That Excel calculator you've put together is a Godsend BTW Greg. Many thanks.

Jeff -looking pretty good to me so far. Good compromise too in the dimensions. I like the material combinations too. What are you planning -veneer or paint the fronts? One idea I've been toying with is a thin sheet of coloured perspex, but I'm not convinced about the vibations. (Or the price -why is everything so expensive in the UK?)

Cheers
Scott
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Old 21st June 2006, 09:44 AM   #895
fred76 is offline fred76  Philippines
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Quote:
Originally posted by GM
Greets!

'Beats' me, when I was experimenting with foldings it never occurred to me to try other than theoretical optimums since both theory and common sense says to keep the expansion constantly expanding to ensure there's little/no reflections back to the driver/throat. FWIW though, my SWAG is that any differences will be swamped by the room's interaction until the impedance mismatch between the front and back sections becomes great enough to make it a bone-fide 'big vent BR' BLH alignment.

GM
Thanks GM!

I guess it's best to be on the safe side ratio-wise, and go with the nearest rounded off dims.

SWAG = scientific wild-assed guess.. I just found out what it meant.

regards,
fred
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Old 21st June 2006, 11:11 AM   #896
Colin is offline Colin  United Kingdom
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>One idea I've been toying with is a thin sheet of coloured perspex

You could try one of the formica finishes - there's a wide and wacky range available these days (though you'd need to glue it down well to avoid any buzzes).

A BIB made entirely of transparent perspex or acrylic might negotiate the WAF problem. My parner has produced engraved display panels in 1 inch thick acrylic and it's pretty solid stuff. I like the idea of the driver appearing to float in mid-air.
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Old 21st June 2006, 11:17 AM   #897
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Quote:
Originally posted by Scottmoose
One idea I've been toying with is a thin sheet of coloured perspex, but I'm not convinced about the vibations.
I think the vibrations are one issue to consider unless talking of thick perspex, what's the same to say *very* expensive perspex.
But even if it were affordable, I don't know if I would use perspex for complex labyrinth speakers (TQWT, BLHs, etc...). Just the mere thinking of all the innards of the speaker getting full of lint and being unable to clean it makes me shiver...

Gastůn
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Old 21st June 2006, 12:05 PM   #898
Colin is offline Colin  United Kingdom
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Add a coupling attachment at the throat and voilŠ, the hooverhorn.
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Old 21st June 2006, 12:56 PM   #899
croat47 is offline croat47  United States
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Default B3S?

What would the numbers be for the Hi-Vi B3S? It seems to do well in various permutations (small OB, Cyburgs Needle, Zaph's sealed) with the same notch filter in most cases. It is comprable to the W3-871, so may make a nice little (high WAF) BIB?

Of course, I have all filter components and a couple of drivers due to arrive today for experiments .

Power handling: 15 watts RMS/30 watts max
VCdia: 3/4"
Znom: 8 ohms
Re: 6.5 ohms
Frequency range: 300-15,000
Fs: 80 Hz
SPL: 81dB 1W/1m
Vas: .06 cu. ft.
Qms: 4.29
Qes: 1.19
Qts: .93
Xmax: 3 mm
Dimensions: Overall Diameter: 3", Cutout Diameter: 2-3/4", Mounting Depth: 2-1/8".
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Old 21st June 2006, 02:32 PM   #900
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Give me ten minutes.
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