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

Greets!

Not having a clue what a 'Gant' chart is, I guess I do too. I don't know how much knowledge/effort is required to embed one, but may be too much to ask of Dave. I've been hoping he would at least put the info on the site though.

Hmm, I just noticed that I forgot to account for the baffle thickness, not that it will make an audible difference. Anyway, here's an Excel SS for those of us who suffer Windoze and hopefully he can embed it into the website without too much hassle or at least offer it as a download:

GM
 

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Hey folks. Been a while, as I've been overwhelmed with a lot of stuff lately. I wanted to offer up a set of mediocrely built BIB cabs I built a couple years ago. They're built to the original specs TC had on his page, only out of 3/4" MDF. Glued and screwed. Craftsmenship is far from perfect, but could be a good place for someone to start. Something to experiment with.

These are free, I'm in Columbus, Ohio and they just need to be picked up. If I don't hear from anyone, the go under the saw pretty soon, as I need the space.

Contact me if you're interested. Cheers!

layne_oh at yahoo.com
 
I have finished my BIB's using the FE168EZ. They have been running since Friday afternoon in my golf cart garage/workshop hooked to a Sony boom box. They definately require a break-in period. They were very constricted initially but have changed significantly as of this morning. They are mesmerizing....I stuck my head in the garage this morning and got "sucked in" to the music. I have no fill in them and the bases are not on yet; this will be done tonight after which they will be moved inside.
Pictures to follow.

Ray
 
A Gantt chart is a project management tool that shows the timelines of various tasks in the project. They might show the impact of one task getting delayed on the rest of the project, for instance. (If one task cannot start until a different task is complete, it will push the dependent task out, too.)

See also: Microsoft Project. :)

eL
 
Gantt charts were developed by Henry Gantt in the early 1900's.

There are also:
PERT Charts ( Program Evaluation Review Technique ) developed by the Navy for the ICBM program in the 1950's.
CPM ( Critical Path Method) developed for civilian use by DuPont
PPBS ( Program Planning Budgeting Systems) developed by the Defense Dept. under McNamara in the early 1960's

Ray
 
Once you move away from this ratio the bend becomes increasingly compromised with increasing aspect ratio

Hi GM!

If the Sm ratio is slightly off from the ideal calc.. Let's say for an Sm of 220"^2 = 11" x 20" instead of 12.4" x 17.7", would there be a significant effect in response that it would be quite audible and more difficult to tune (stuffing/lining)? Thanks!

fred
 
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
 
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. It’s all butt joined, glued and screwed like the amateur I am but it’s 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 it’s 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 site… the TB 871 3” BIB dims, the Visaton BIB by GM and a couple lovely pics of TC’s BIB contributions.

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

Peace,
Godzilla
 
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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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
 
GM said:
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
 
>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.
 
Scottmoose said:
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... :)

Gastón
 
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".