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Terry Cain's BIB -why does it work and does anyone have those Fostex Craft Handbooks?
Terry Cain's BIB -why does it work and does anyone have those Fostex Craft Handbooks?
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Old 6th November 2018, 05:28 AM   #5761
soundnovice is offline soundnovice
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oh. i could have never imagined that BiB's top needs to be that close to the ceiling. all the while i was thinking to let the terminus have some breathing space!

i didnt quite get how the 'tophat' looks but i think all that you meant was to add a extension tube. i think a thick pvc pipe will do with the leaks at four corners sealed
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Old 6th November 2018, 05:42 AM   #5762
GM is offline GM  United States
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It's literally just an extension of the basic rectangular BIB perched on top with some way to gasket/firmly attach it. If a smaller area pipe were used it would be tuned lower than the tophat, which is already pretty much at the limit below Fs this driver's specs will tolerate: [56 Hz*0.59 Qts]/2 = 16.52 Hz Vs the tophat's ~18 Hz.

GM
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Old 8th November 2018, 06:02 AM   #5763
blumenco is offline blumenco  United States
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At this point, is a community favorite BIB horn/driver combo becoming clear? My mentor Terry Cain was developing a few different BIB horn concepts towards the end of his life. But first before sharing those designs I am curious what direction the community has gone during these years since his untimely passing. Apparently, many directions have been tried! But.. catching up on the many, many pages of threads is daunting... I am just asking for a few favorites... a few "best of's" To save me from having to try a million new drivers out!

-Clark
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Old 8th November 2018, 06:52 AM   #5764
Vix is offline Vix  Yugoslavia
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Quote:
Originally Posted by blumenco View Post
At this point, is a community favorite BIB... I am just asking for a few favorites... a few "best of's" To save me from having to try a million new drivers out!

-Clark
I dot't know the answer, but I guess that an fullrange 6.5 " driver would be closest to the best choice for this design, and that Terry would be proud to see this thread still going strong in 2018, with hundreds of pages, enough for a dedicated book about BiB
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Old 8th November 2018, 02:52 PM   #5765
Jim Shearer is offline Jim Shearer  United States
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@clark,

I have only built and listened to one pair of BIBs, but I can say that the Alpair 10.3 seems to work very well. My A10.3 BIBs give me a flat octave from 25 to 50 Hz in my room, something I have never seen from any of my other speakers. Perhaps this is due to the horn mouth being only 7.75" from the ceiling. The result is excellent concert hall type bass--not chest thumping club type bass. Since my interest is in classical and jazz, this works for me. As always: YMMV.
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Old 8th November 2018, 06:49 PM   #5766
GM is offline GM  United States
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Quote:
Originally Posted by blumenco View Post
At this point, is a community favorite BIB horn/driver combo becoming clear?

I am just asking for a few favorites... a few "best of's"........
Doesn't appear to be beyond small[er] 'FR' drivers, but 'best of', I've no clue, especially since so many different sizes, specs have been built or at least simmed, though from a technical POV, higher Qt drivers [max ~0.707 Qts'] with an Fs/2 that puts the terminus near the ceiling or driver at an appropriate ear height if inverted for floor loading would be prime considerations.

Qts' = Qts + any added series resistance [Rs]: mh-audio.nl - Home

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Old 8th November 2018, 07:23 PM   #5767
Maddin37 is offline Maddin37
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Thumbs up A very special BiB

Time to say THANKS!!!



I haven't been building loudspeakers for 30 years (as a 20year old newb), but when moving to our new appartement I wanted to give it a try. The hearing room is somewhat special concerning it is a roof chamber with three different pitches of the roof, a door at the back wall hindering a symmetrical speaker placement and a pillar in the middle of the room. That's when I stumbled upon this MEGA-thread and was instantly infected with the idea that a speaker loading into the ceiling could be optimal for this kind of room. So I read through the whole (!) thread and that was quite an enlightenment: So many nice people, so many interesting ideas!!! My main problem: Corner placement was not possible because of other furniture that could not be placed elsewhere and for placement at least near a wall the maximal height of the speaker would be 120 cm (47.2") because of the droop going that far down => Not quite a BiB in the common sense! I didn't need a bass down to 30 Hz or so cause I have a dedicated Subwoofer, so I ran the BiB Calculator with some Full Range Speakers, but they didn't quite fit the bill. The speakers were all too tall and slim, mainly because of fs beeing too low for my special case. So I switched to musician/PA coax speakers and found some that came quite near, the best but also the most expensive (for my budget far too expensive) being the BMS 8CN552 (fs = 87.6 Hz, Qts = 0.29, Vas = 10.08 l / 0.356 ft3). That also correlated with my musical habits hearing mostly dub/electronic music at sometimes quite loud levels. What a lucky coincidence that a few weeks later I found (and was able to pick up) a quasi new pair of these exact speakers on ebay for half the price! So I did some further simulations with Martin J Kings spreadsheets and these are the (inner) dimensions I ended up with (because of cosmetical and practical considerations there are some small deviations to the results from the BiB calculator, but the simulations were rather promising):


Height: 117.8 cm / 46.4"

Width: 19.6 cm / 7.7"

Depth: 33.7 cm / 13.3"

Z driver: 45 cm / 17.7"



The housings are made of the best birch ply I could find here in Germany (not so easy and quite expensive) in 18 mm (0.7"). The internal divider is made of 19 mm (0.75") MDF. Because the depth of the speakers was to big for this enclosure I needed a supra baffle and they are the very fine work of a local wood turner (made of alder). Side note: I love frisbees and a frisbee was the model for th wood turner! As you can see in the photos I rasped out the back of the supra baffle to give the speakers more room to breathe as was suggested in this thread. As far as damping is concerned I lined up the front side of the internal divider and the front part of the side walls from the tip down to a bit below the speaker (sorry, can't remember what kind of material that was) and two layers of rock wool on the ground. I also made a frame with some speaker cloth for the top (mainly to not collect dust or childrens toys in the cabinets). The finish is three layers of slightly coloured (mainly to emphasize the contrast between alder and birch) oil wax and a final layer of a glossy clear oil wax. I'm very content with the look of the speakers!


Now to the most important, the sound: I use a miniDSP for the crossovers and the room correction. I made some measurements with REW and after the first iterations I didn't feel any need to further fiddle around with measurements and DSP settings, I just wanted to enjoy the sound. I have not much experience with high end speakers but these ones for me have it all! The bass even without the subwoofer goes quite deep (at least for what I expected from a BiB that small; measurements say ca. 47 Hz @ -3 dB) and sounds very warm and natural as often described here. The locating of voices and instruments is fantastic with these coaxes and they have POWER without end! Even at higher levels no signs of distortions, just clear, crisp sound!


I have these speakers now for nearly one year and it seems that they still improved during that time. I have spent quite some time and money on these, but for me they are worth every bit of it. So I thought it was time to say thanks to all the contributors here on the forum, nice work!
Regards,


Martin
Attached Images
File Type: jpg Inside.jpg (657.6 KB, 75 views)
File Type: jpg Suprabaffle back.jpg (970.5 KB, 76 views)
File Type: jpg Whole Box.jpg (636.5 KB, 74 views)
File Type: jpg Suprabaffle.jpg (914.1 KB, 69 views)
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Old 9th November 2018, 09:46 AM   #5768
Ivo is offline Ivo  Netherlands
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Quote:
Originally Posted by blumenco View Post
I am just asking for a few favorites... a few "best of's" To save me from having to try a million new drivers out!

-Clark
To be honest, there does not seem to be something like a top ten or absolute winner. I do think smaller Fostex drivers have been used most often, and Tangband. I did read the thread in one go, and initially people seemed to come here to get something Cain&Cain related on a DIY budget. So always Fostex. Over time, BIB has become more of a flexible design algorithm. People use whatever they have for a first build, or get something cheap and popular. Occasionally, someone has a Lowther, or a Voxativ, or some ultra-rare vintage thing and build.for that.

I am sort of OCD and prepare way too much, and have a hard time choosing between drivers, so I simulate a lot in Hornresp. You can get a a lot of drivers to work in a BIB, you just need to tweak it with love and enthusiasm.
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