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

I have been throwing around the idea of building a BIB style subwoofer. For example, there is Scottmoose's
CSS TRIO12 design. While reading through the various BIB threads, I found this one, which has the driver
mounted facing into the enclosure. Please see the attached photo. Is there a reason to do ...or not do this?
 

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A couple of quick questions before I start ordering components for my BiB build:

No clue about their mids/HF sonics, though all else equal, I personally would opt for the 166 due to its stronger published motor as it's inherently better damped and also allows a bit more tuning flexibility.

Hmm, thought I posted some thoughts on theoretically optimum terminus/ceiling or floor spacings in this thread, but with my saved docs with links not being available to me for now, no way to quickly check what/where I posted it. IIRC, the rule-of-thumb way is to find the terminus effective radius, then multiply it x 0.613 to get the minimum distance. The more complex way is to calculate its rate of expansion to calculate a proper bend expansion. Done this way, corner loading may not be required.

Regardless, I recommend building it 'stock', but make the terminus with a minor recess such that you can drop in a flanged 'tophat' to both get it closer to the ceiling and mass load it a bit with this simple straight section if you feel the driver needs more loading on some music.

You may want to do it anyway as HornResp indicates it's a worthwhile tweak. I had planned to experiment/post results by now using TC's original 40-1354 BIB, but 'life' keeps getting in the way.

GM
 
Is there a reason to do ...or not do this?

Without taking the time to research it, I assume the driver is too deep to fit and since it's a 'sub' woofer app, the XO will roll it off long before it gets high up enough in frequency for the frame/motor to audibly affect its sonics.

The only real downsides AFAIK is having exposed wiring, so ideally need some shielding against contact, accidental or otherwise and of course it's hard to dust properly if you're not blessed with a very good home filtration system.

GM
 
I added some stuffing below the driver to provide some more loading, helped to bring out the bass. These BIB's are good with the infrasonic bass.

I built these in 2006 :) for whatever reason I change my audio system. I have some 2a3 monoblocks in storage and not used in years; just using an lm3875 chip amp to power these.
 
FOXYE,

Good bass means different things to different people! :)

The FE166en in the BiB works well. I built one last year. Please note, you will have to place BIBs near corners to bring out the bass. With corner placement bass is nice and powerfull. You will need to adjust the stuffing a bit to tune to your taste, so if the front panel has a removable part, it helps. You might also consider putting in phase plugs to improve the treble.
 
6.5 With Bass

It has probably been years since I posted anything on here. I just keep enjoying my Fostex 208 sigma BIB's in my spare time. I think the FE166 is a good driver. I used it in my first pair of speakers (Voigt Pipes). However, I remember once LONG ago Scottmoose had tried the FE166 and then the FE165 in a BIB. As I recall, he said he liked the FE165 quite a bit more, and that it subjectively had more bass. I believe the two drivers are about the same price. I don't have any experience with the 165 myself.
 
The 165 sounds very balanced in a BIB (and probably the C&C speakers) but i wouldn't call them bassy. They just provide the right amount of bass for smaller rooms IMO. I setup H-frames (using 15" Alphas) which enhanced the bass of the 165s alone in BIBs. I also used a rear firing super tweeter to enhance the treble but it was barely noticeable and probably subjective in need.
 
I just completed my Fostex FE168 Sigma BIB. The Fostex is the older style with whizzer. I actually built a trial box last December, and the results were good enough to try and make it pretty. BIB dimensions: line length - 125 in; zdriver - 27.125 in; internal width - 7.75 in; internal depth - 11 in; a-b-c - 5.5 in. I used two sheets of sandeply 3/4 in plywood from Home Depot. It's advertised as void free, but next time around I will look for something better. My samples had lots of voids.

I used solid ash for the front and very thin oak plywood veneer for the sides. I glued the ash to the front just proud of the sides, and butted up the plywood veneer to the ash. The ash has a 5/8 in roundover. I finished without stain, using General Finishes Polyacrylic water based topcoat - satin for a topcoat. The polyacrylic finish went on like a dream - no dripping or brush marks, without only light sanding between coats with a 3m superfine pad. I used a foam brush to apply the topcoat.

Thanks especially to Scottmoose for starting the thread and his many contributions throughout. I am enjoying the speakers immensely.

I use either Wright Audio Mono 25 monoblocks (williamson based) or Bottlehead Afterglow 2A3 amps. I listen to these all day without fatigue. No they don't make me like free jazz, or let me stay awake for a Sibelius symphony but the music always sounds good. Not the last word in bass impact but good enough. I don't use or feel any need for bsc.

Here are some pictures of the speakers:

This one show the construction details

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excuse my mess, i'm a bit of a slob while engaged in a project

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