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

Hi Scott!
The Monacor SP200MX8 must be a TVM ARZ 6608 which sells for about 9 euro here in Cz Rep.
Check out the Monacor SP155X with a 91.5 db efficiency. Looks like a candidate for BIB.
Regarding the SPH60x being a bit polite in the highs, there is a version SPH68X/AD which sports a rise around 8 k.
Also a whizzer free version added below. Albeit a low efficiency.
All these under 25 euro/pcs
Cheers



http://www.tvm-valmez.cz/index.php?id=110&catit=186&l=1&catg=27

http://www.spectrumaudio.de/breit/m...rumaudio.de/breit/monacor/monacorSPW1168.html
 
loninappleton said:
I have some 127e's... Is that what you meant up there?
GM said I'd need an Fs of 45-50. I checked out the FX125 which I considered purchasing but the Fs on that is 70. .... doing a quick search on the 127e.... nope 70.4 Fs f

Typo: I meant the FE167E. Once I've had my usual 3 hours of sleep I'll get some dimensions for the 164 up. The other Monacors look interesting...
BTW: the original enclosure was intended to house the FF125K, Fs 72Hz. But MathCad says that Fostex claimed response limits are spot on. Wouldn't be my first choice, but it doesn't look too bad either.

Best
Scott
 
Re: Output Impedance

jimmyd53 said:
GM,

Good Morning. I am currently running an Antique Sound Lab Orchid 3.5 wx2 2A3 integrated amp. It has output taps for 4, 8 or 16 ohms. I have not measured the actual output impedance. Hope that answers your question.

James

Greets!

Not really, so I assumed 4 ohms and you can try the different taps to see what sounds best. Unfortunately, I couldn't come close to meeting your dims in a triangular cab and still get down to Fs with any authority, so at this point I suggest making the tallest triangular sealed cabs you can tilt into place (at least 88") and position the driver at whatever height you want. For a nominal ~18" wide baffle, using 3/4" material means the sides will need to be ~11.66" i.d..

GM
 
Scottmoose said:
BTW: the original enclosure was intended to house the FF125K, Fs 72Hz.

Greets!

Without compression loading, running a driver much below 0.707*Fs isn't a good idea, especially a low Xmax one, rising rate suspension system or not. It must have been designed with tiny apt. or Japanese paper house construction in mind.

GM
 
my BIB!

Ok, so I dropped by home depot yesterday and cut some wood. they will be 14 3/4 deep, 7 in wide, and 70 in tall. the interior panel i will space equidistant from back wall and bottom and attach the other end to the top of the baffle. I am throwing around numbers here, but i am pretty sure i will go with 7 inch clearance between the interior panel and back and bottom.

I did not taper the rear of the horn. it is a rectangle.

the drivers I will be using will be the fx120.

any opinions on the horn dimensions?

Clark
 
rather i might make that interior panel at 7 and 7 and use a small peice of plywood near the back corner placed at an angle to the bottom to get the 5.5 and another small peice angled against the baffle and bottom to get 5.5 inches there.

or i might just use the back peice (most likely). who knows?

i will no doubt use a few small peices here and there where there are large openings (like the mouth) in the direction of air flow to get a little more laminer (spelling?) flow and to stiffin these little guy up.

I probably won't get to the horn tonight, but advice, experiences are appreciated.

as far as the horn discussion goes,
I have found that most of terry's designs strategically use the room in some way or another to make the bass flat and real. his own listening room in the shop is purpose built for bass reinforcement, as the one shown in the photo of the BIB on mellhuish has wooden ceilings, floors, and walls (though there is some hallway induced weirdness here and there). when building this design, terry mentioned to experiment with the dimentions. in light of many of us having dry wall (or god forbid the #$#%#%@!!$^%^%& freakin acoustic ceilin tiles in my place) the horn angle ought to be considered. I would imagine it would be best in general to point the wave slightly towards the most reflective object, either wall or ceiling? I kindof like it being angled outwards towards the listener as in the original. eh who knows?

clark
 
GM said:
Greets!
Without compression loading, running a driver much below 0.707*Fs isn't a good idea, especially a low Xmax one, rising rate suspension system or not. It must have been designed with tiny apt. or Japanese paper house construction in mind.
GM


Oh I agree 100% -I remember you observing this to me before Greg, and I took your comments to heart -that's why I was so surprised that it was the original unit, and why I say it's not exactly my first choice. The model figures match their stated response curves, but I wouldn't care to try it in practice. The poor little thing must be screaming for mercy.

Tony, two ideas you could try this for the FE164, a 'small' and a 'large'.

Small version:
65.75" tall
Driver 26.25" down from top
14.75" deep
8.5" wide
Terminate baffle 6.25" above floor and centred between front and rear baffle walls

Larger version:
65.75" tall (131.5" total line length)
Driver 26.25" down from top
17.75" deep
10" wide
Terminate baffle 7.75" from base and centred between front & rear baffle walls. These both assume 3/4" material as usual and W & D are external.

There's a bit of suck-out in the midbass, but it's not huge; 4-5db or so, and with luck the room should help out there with them pushed into corners. Better to go with the increased Vb if you've the room, but both should do pretty well.

Clark -that box is too tall IMO. You're just looking for trouble tuning it that low. I know Fostex did with the FF125K, but as Greg notes, that's not the greatest idea (unless you're in very specific circumstances). Chop it down to 50" tall, with the driver centre 20" from the top. You'll stand a better chance of it working. I wouldn't worry about the interior strike-plates, unless you have them handy and they're not costing you anything: it's very unlikely to make a difference. Try angling the horn mouth toward the rear wall / corner.

Regards
Scott
 
wow

ok, so i have sawdust all over me and it is really late here, but i just got done with the "minis" - a small tl for a freind, using his pair fx120s. this is spring break for me. I am a geek.

in either case, the cabinets are already cut and starting to paste. so any changes will come after i am done building them. I guess it would be easy to chop off some of the back horn at a diagonal with a router.

course, I will modify it only if it sounds bad the way I am buidling them.

Clark
 
An LE8 BIB? Now that really would be worth listening to, if that driver is as good as its reputation suggests. Thanks for letting us know.

On the sim, there isn't a massive amount of difference Tony -about 3db or so of extra extension with the larger box. However, remember that those are 1/2 space sims, and with wall or corner postioning, differences will be greater. Both should work pretty well I suspect, so it's down to your space.
 
Scottmoose, if you are interested i can start sifting thru your threads to find all the BIB's you've simmed and put a web page together on my website with all the dims and sims. You've dedicated lots of time and effort... and simmed many drivers. Let me know if you want this done?

I know you've simmed BIB's for:
Fostex 167
Fostex 168S
Fostex 168es
Fostex 164
B200... and others... what am i missing?

I would title the page 'BIB by Scottmoose' or whatever you like.

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.

Since Scottmoose has been focused on BIB's and seems to enjoy simming them... well, just let me know and i will begin gathering the dims for all the diff drivers.

Peace,
Godzilla
 
Hempsters

Good Morning All,

GM thanks for all your input. I am struggling with a dilemma. I am a perfectionist by nature and it is difficult for me to accept the sound compromises that result from my foot print size constraint. My goal should be to build the enclosure that extracts the best a given driver is capable of given my operating constraints, but irrigardless of size. The Hemp FR8 has an 88 liter Vas that is going to necessitate a very large enclosure. I am mocking up your recommended BIB enclosure (303 in^2 crossection) for the FR8 out of cardboard to see if I can coexist with it. I will build it if I can live with it or else I will look at other driver possibilities. 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?

James
 
Hi Godzilla

Agreed wholeheartedly that we all owe Greg massive thanks for his thousands of contributions and designs over the years. It's rare I read one of his posts without learning something, and I reckon a page dedicated to a selection of his designs would be fantastic, if you're willing Greg.

A BIB page on your site? Great idea, and could be very useful for prospective builders. If you think my variations are worth putting up there, I'd be delighted -that's a really generous offer. I'll probably have to re-check a few of the early variations as some can be improved upon now, but there's plenty of them. By memory, there's some for quite a few other Fostex units, some Tang Band's, Monacor's, Supravox, Hemp etc. (he's let himself in for it... ;-) The ML BIB for the B200 wasn't mine though -all Greg's that one. I just tried a pair out in an enclosure I'd built for the FF225K and found they worked rather well.

Cheers for now
Scott
 
frugal-phile™
Joined 2001
Paid Member
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.


Agreed wholeheartedly that we all owe Greg massive thanks for his thousands of contributions and designs over the years.

I have text clippings of GMs designs scattered all over my HD. might be a helpful start if i can gather them all together.

dave
 
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. Perhaps the hemps just need to stay in regular old sealed or BR enclosures.

I am interested in trying the Neo-fone drivers in a BIB. The specs don't seem entirely different from some folks measurements of the 1354 (at least to my eyes.) They aren't cheap, but they have a serious displacement advantage over other small drivers.

http://www.diyhifisupply.com/diyhs_speaker.htm

FWIW I think Godzilla's idea of collecting some designs is fantastic. Many have contributed a wealth of information on this site, and organizing some of it would both contribute to the public good and recognize the individuals efforts.
 
>>> For the price the Pioneers are an excellent driver, though stock they do lack a bit of treble, and they'll need a hefty cabinet. Approximate dimensions (assuming I'm correct in how these things are sized): 78" tall, 8 1/2" wide, 21 1/2" deep (external). Driver at 41 1/2" from the base. Internal baffle terminates 9 10/16" from the base and front and rear walls. Bass will be very heavy -probably overly so.

I see Scott did one for the B20's... one of my personal faves!

Are you sure a smaller cab cannot be designed for these?

I have already begun collecting the measurements and have a handful done already... just need to figure an easy way to display on the web so we can all start building these neat cabs... and get bass from some of our beloved full range drivers.

Peace,
Godzilla