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

[one1speed]

You are the man! Hopefully those of brilliance will help with the details.

[GM]

Originally posted by Godzilla
GM has so many sims all over the place it would be difficult to find them all but i feel GM should have a page as well for all his effort. Thank you very much GM! From MLTLs, ported, BIB's... amazing number of designs... I'd be happy to put a page together for you as well. You have many Fostex, TB, Pioneer, Jordan and Radio Shack dims out there that i know of.

Greets!

You're welcome and thanks for the offer! As you know SB started one then 'disappeared' without bothering to give me the access info to update it, so I started one on MSN only to have them delete it in an 'upgrade', so said to heck with it.

Yes, and for all that I've published, I've done many more privately, so have around 1300 total, though a goodly percentage are just variations of a basic alignment for a given driver.

Anyway, let me know which drivers you're interested in, and TIA for the effort! No drawings though other than whatever Dave p10 has done, so how they're handled is between you two. Hmm, now that I think about it, I do have a few sketches of some RS driver proofs-of-concept' I cobbled together, but I don't know if it's worth the effort to publish them at this late date though.

GM

[GM]

Originally posted by jimmyd53
GM thanks for all your input.

A few questions. Do you recommend that the height stays at 70” or should it be extended to better utilize ceiling/corner loading? Should I angle cut the top? Will I need a BCS circuit?

Greets!

You're welcome!

Increasing the length lowers Fp, hence ultimate loading up through the midbass falls, lowering the 'slam factor' capability, so all things considered I wouldn't. I mean this thing sims a half space ~32 F3 at 95 dB eff., so in a corner it's going to be lower. If your room's construction is really solid, it wouldn't surprise me if it did 64 ft pipe organ and movie special effects you can feel if a suitable SS amp is used.

No BSC required if up against a wall and may wind up being bass heavy if in a corner, so you'll probably have to experiment as to how close to put them in this case.

GM

[GM]

Originally posted by pjanda1
I'm pretty bummed that the hemps would require such enormous enclosures. 18x18 is just out of the question, I fear. I may buy some cheap ply to see just how bad the ripple is with a 12x18 jammed into a corner.

Greets!

It's not the ripple so much as the huge midbass suckout with the ~one note bass boom below it. The room will alter it of course, but you would have to find the best point to help fill in the suckout, which is typically somewhere around the middle of the room, not a viable location in a typical home.

If you want to 'burn' some wood, try this, it won't have the acoustic efficiency or super low F3 of the BIB, but should work fine in a corner down into the 30s without any BSC and is small enough to use a triangular cab:

L = 57.25"
CSA = 100"^2
driver around 36-38" from floor

Since the cab is triangular, cut off the lower rear tip at a 45 deg angle to create a corner apex firing vent with a CSA = ~19.63" and tune it either by moving the cab out from the corner and/or spacing it up off the floor to suit. I'd start with 3/4" away from the corner and up off the floor.

GM

[Godzilla]

I don’t want this to be a competition with Dave… I don’t have to have this info on my website. Dave has done a great job and makes much better drawings than I do. Since the BIB is the same basic shape every time all that’s needed are the dims.

I was motivated last night to do this because the thread had gotten so long I felt like reigning it in. Everyone’s comments are valuable but the dims Scott had been posting seemed to need a more organized place. Personally, a handful of these BIB’s look interesting to me and may be built for my home or office. Something more interesting than simming in WinISD for a change.

The DIY community needs fresh thinking… and tho this basic design may have been around forever it’s particularly well suited for full range drivers (our favorites!). If computer generated sims are available, pointing us in the right direction, then why not gather the info and offer it up to everyone as a community?

There may be no audio breakthroughs here but at least it’s solid math, experimentation and fun. I’ve not heard a subjectively negative comment on a BIB and since it’s all about the music and not the measurements why not offer up good sounding designs to grow and keep our DIY community strong. At least it’s another alternative project to a basic sealed or ported box and it offers something different than more difficult back or front horns. It fills the gap between difficulty and interest so I feel it’s important to explore. Of course there’s also open baffle, omni directional, etc….

Dave, I would be happy to help you organize and post GM’s designs on your website if you’d like. I have a handful on my PC regarding the Fostex 168S, 127e and a small TB I think. I also built the Pioneer/Piezo I love so much based on comments posted by GM from years back. I prefer mine simply sealed but I’ve seen GM had designed a large ported box for that driver too. GM’s database should be in an organized format for DIY’ers to view. Imagine how an organized library of his designs would benefit full range driver speaker builders!

[jimmyd53]

I mocked up the BIB enclosure that Greg modeled for the Hemp FR8 out of cardboard just to see how they would fit in my listening room. The external dims are 70"H x 18.5"W x 18.5"D. I haven't decided if I can live with them yet, but I can tell you thay take up a lot of real estate. I think we should change the name from BIB to DBB - Damn Big Box. I will leave them up a few days and see if they grow on me. Again thanks to Greg, Scott, Dan and everyone else on this board that freely shares their knowledge and experience. This really is a very special place. James

[GM]

Greets!

You're welcome, but I'm not all that sympathetic WRT to its size since my cabs have a 30" x 24" footprint, though they're only 60.25" tall.

GM

[blumenco]

alright, so I should be done with the things today, Ill let everyone know the results shortly.


mdf might be the antithesis of the need of this box.

also, the website looks great. Ill let you know if the 7/14/70 thing works out and or what I have to do to get it to work with the fx120.

see yas.

Clark

[loninappleton]

I like the layout. It's nice and legible


Since these are so large I'm going to experiment with
one only to see what sort of sound comes out.


Looking forward to your progress.

[apassgear]

Originally posted by Godzilla
http://www.zillaspeak.com/BIB.asp

As this developes I hope it's useful. Comments are appreciated.

Godzilla

Page looking really nice, easy to read too.

Thanks for your effort