Terry Cain's BIB -why does it work and does anyone have those Fostex Craft Handbooks? - Page 101 - diyAudio
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Old 12th July 2006, 10:51 AM   #1001
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Hi

Nanook, funny enougth your post is post #1000 in this thread

As little service for y'all here is a pdf to download, containing post #1 too post #1000

BIB-1000.pdf - 2.3 MB, 198 pages.

best, LC
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Old 12th July 2006, 02:17 PM   #1002
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Location: Santa Fe, New Mexico
Default Lemo's

I use two types:

I like the Lemo Series "B"
This is thier standard design.
Aluminum housing, 2 contact, soderable.
panel mount females

You an get the Lemo catalog from 707 578 8811 (Lemo USA)(these guys are really nice)

And of course, from our friends at Digikey: 800 344 4539
a Lemo knockoff... Rohs Corp.
Digikey part number:
SC1204-ND (cable end) male 3 pin solder
SC1209-ND 9 (panel mount) female 3 pin solder

These are plastic housings and gold plated brass for the contacts.
These are WAY less money than the Lemo's but I do love the real thing.

In truth, Ill never use the "RCA" crap again. It is simply the wrong solution. Plus even the Rohs plastic sound way better than the best RCA.
Try them. You might like them.
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Old 12th July 2006, 02:36 PM   #1003
fred76 is offline fred76  Philippines
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Great work Phil

With that thick solid wood baffle, you might want to try cutting the driver hole at an angle if you haven't done yet, so that the back of the driver within the chamber could "breathe" better. T'was suggested some pages back by Scott and GM.

fred
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Old 12th July 2006, 03:11 PM   #1004
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Perhaps this thread should be closed at 1000 and new BIB threads should be started since many of us have begun or have built BIBs to date. Perhaps not…

I still have work to do on the BIB site... stuffing options... some of you have sent great pics and i will try to get around to posting them all. Scott has sent me some BIB bass horn concepts which seem worthwhile because they are tall and thin and can be corner loaded as a small footprint subwoofer.

My BIBs are half finished in the garage but construction on my house has prevented me from working on them.

Thanks Scott and GM for making this fun and generously spending your time designing! Thanks to everyone posting on this site and providing motivation and purpose.

Peace,
Godzilla
http://www.zillaspeak.com/bib.asp
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Old 12th July 2006, 03:22 PM   #1005
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Default Speaker cut outs

Yes, the holes are cut at angle for easy breathing.
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Old 13th July 2006, 03:15 AM   #1006
GM is offline GM  United States
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Quote:
Originally posted by fred76
http://www.diyaudio.com/forums/showt...481#post877481

Seems that too small a Vb would have this type of sound/response for high Vas drivers like the B200. But is it the biggest factor, or are there other parameters in the T/S that would contribute to this type of response?
Greets!

It can be just Vas or high Qts, or a combination of the two.

GM
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Old 13th July 2006, 03:29 AM   #1007
GM is offline GM  United States
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Quote:
Originally posted by zek
Please someone (Scott, GM, ..) to post the formulas how to calculate L (Line lenght), So (Driver down) and Sm (Terminus area) for BIB sims.

Thanks in advance.
Greets!

No 'cast in concrete' rules, just in general the full length is ~1/2 WL below Fs with a mouth area that yields sufficient Vb. T.C.'s BIB driver is at L*~0.21, but there's some 'wiggle room' to adapt it to ~ear height. Obviously, as Fs decreases, it becomes so large that it needs to be tuned as high as 1/4 WL of Fs.

GM
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Old 13th July 2006, 05:57 AM   #1008
zek is offline zek  Serbia
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Thank you Greg for your kind explanation.

If I understand mouth area is

Sm = (2*Vas)/L

or I'm on a bad track
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Old 13th July 2006, 02:26 PM   #1009
GM is offline GM  United States
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Greets!

You're welcome!

Never seen this formula, but haven't studied the Japanese way of designing these things. Anyway, the ones I did long ago were based on nomograms published in some early DIY books and some basic mechanical resonance theory, which don't 'translate' well to the BIB, so not being able to 'do the math', I'm at the mercy of MJK's WSs to arrive at a similar alignment to T.C.'s original with other drivers.

That said, in a straight pipe this type of simple correlation works well enough, but with a horn, the flare rate has to be factored in, hence much more math intensive if not mass loaded (ML-TQWT). When mass loaded with a vent area = Sd, mouth area can be approximated 'close enough' using a fixed value referenced to an estimated Sd, with length based on a fixed percentage of Fb that's somewhat longer than the commonly used closed pipe's 1/4 WL.

GM
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Old 13th July 2006, 02:36 PM   #1010
GM is offline GM  United States
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Quote:
Originally posted by Andrewbee
Since the BIB is a simply a horn how about using it for bass and then add an outboard FR driver.
Greets!

I agree, the ~ML variant I built were all strictly LF/midbass horns.

I assume this is the FW208N.

If so, then use the 'stock' BIB to keep size reasonable and 'close enough' to other BIB alignments, or for lower tunings, increase Sm and Zdriver proportionately to it with increasing length. This unfortunately will put the driver too high, so flipping it upside down and floor loading it makes more sense to me.

GM
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