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

I gather Terry started the internal baffle 3/4in down from the top deliberately in order to install a grill. I ran across a post in the archives commenting something to the effect that it was to prevent it from becoming a rubbish bin... pretty tall one. 😉

Horrible news about Terry. I heard about it this morning, but didn't like to go public at that point. Living in the UK, I can't do much, but I do now have an object very firmly in the forefront of my audio mind. Dave and Dan know about it already as I've discussed it with them. Greg, you have mail. 'Can't make it public yet -hope you understand; and guys -if I'm a little sporadic on the thread for a while, please accept my apologies in advance.

In the meantime, I'll publically say it: Terry is the person who first properly sparked my interest in DIY cabinets, even though the BIB was not the first box I made. I have enormous respect for him as a designer, but also as a person. He's encouraged people to experiment and think laterally; in audio, and other fields, and always offered help whenever he could. Although we only had brief contact via email some time ago, for my part I consider him a friend, as he was to the whole DIY audio community. We all owe him a massive vote of thanks, and our best wishes and love go out to him, his wife, and his close friends.

Not well put, but it's sincerely meant.

My very best regards to you all, but especially Terry and his wife Leslie

Scott
 
If those in the know don't mind, maybe you can post the info here and start a new thread.

The BIB is the first cabinet I built and sold me solidly on DIY. They were a crappy build, but I continued with them for some time. I had consulted via email with Terry on several things over the past couple years and he has always shared his honest opinion, which I value. His work always makes me drool, just wonderful. Here's to a thorough, speedy recovery!! :drink:
 
Hi Scott – do you think meeting approx in the middle at 145 line length would be a good compromise for a Hemp FR8 and/or Pioneer B20 BIB?

I’m just wondering what else I can do with my B20’s… but thinking of an easy upgrade path. I like rolling drivers!


Hemp Acoustics FR8
L = (Line length) 150.5"
Zdriver = Driver 30.1" down from sealed end of cabinet
Sm = 200"^2

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


Pioneer B20FU20-51FW 8" full range
L = (Line length) 138"
So = Driver 30" down from sealed end of cabinet
Sm = 200"^2

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

Peace,
Godzilla
 
I'm sad to hear about Terry Cain. He has contributed so much to the community and the fullrange cause.

In regards to the recent discussion, I've been curious to see what the response of non-optimized BIB's looks like. What does the response look like if you screw the dimensions up a bit (say, if the CSA or length is 10% off)? I think I remember seeing graphs in some previous post showing what a severely undersized BIB would look like, but how about a severely oversized BIB?

I know the sims take a great deal of time. GM and Scott have gone above and beyond running all of these simulations for people. I'd try some combinations myself if only I had a PC.

Paul
 
It depends on the driver as well as to how bad it would be. I don't have time to run a MathCad example sim right now, but generally, you'd get a large peak at Fc, followed by a dip, then heavy ripple. That said, the decrease in pressure after it leaves the terminus will probably go some way to mitigating this. At least, I think so. Will probably depend on the cab / ceiling height ratio. Greg?

Jeff -I don't see why not. You'll loose a little LF, but driver rolling is something I'm looking into at the moment, in the hope of creating a generic BIB that should suite a wide range of drivers in the 5in - 7in range, possibly a few 4 1/2in units too.
 
I have been leaning towards the 2001 BIB with the B20's to justify a cheap project... get them into the basement against the walls/corners... no need for a sub (save money)... then next birthday/holiday season/fathers day... SWAP FOR THE HEMPS!

The B20's have been a GREAT test mule for me over the years... sealed, ported, future BIB... a bargain for $25 IMO!

Helper tweeter on back/front of course.

Thanks Scott!

Godzilla
 
I may do just that… but first I must finish up my BIB which remains 75% complete in my garage. My goal is to finish them before December and get them in my office!

The next project will probably be another boring TB in a sealed or ported box and a small sub for the new small den.

The 2001 would be in the basement which has short ceilings… but I may build anyway and stuff the BIB openings to compensate. I’m just thinking things thru now.

Peace,
Godzilla
 
Well, I'm just going to project some positive energy out there to help you get through your current BiB construction. I've been waiting to hear your impressions for some time now, and now that I know there might be a pair of monoliths with B20s down the line after, I'm more anxious than ever ;-p

Oh, and Scott, you'd mentiones some sundry pages back that you'd decided to K-Slot the back of your BiB . . . did that get put on hold due to your BiBs being speakernapped?

Kensai
 
FWIW, I mentioned the K-Slot thing to Bill Wood, an Arch-Lord of the horn speaker, Jedi wunderkind of Yorkville Sound, in Toronto, and his gut feeling was that the slotback BIB was a Good Thing, ----based only on years and years of experience, and its resultant instinct.

My BIB168's are cut down on a 20' wavered angle, to increase the effective width of the mouth, plus, it adds greatly to the lines, the horizontal perimeter reminiscent of the tail of a quarter note, and overall physical perspective, especially when seated, they are fairly "tall," at 66 inches. I liked that design, as I see the BIB speaker as a musical instrument, as opposed to a box with a bunch of drivers, all connected with metallo-ceramic prosthetics, which at this point are guaranteed to ruin the sonic fun...

I think for the 5 inchers I will measure a K-slot. Just thinking out loud here.
 
dmason the Dutch are in the groove...

found a couple of designs on Dutch site
 

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