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

Agreed.

It'd also need to be a hell of a big mouth. The BIB's open top is actually a terminus, as Greg pointed out to me in a private email, the mouth is actually formed by the room corner. So, the forward venting types, if they otherwise follow the BIB layout, will nominally require an eightfold increase in mouth area to gain similar performance. OK, so the other room factors come into play here, but you get the idea. Front horn mouth = fine, but not linked only to an otherwise unaltered BIB layout.
 
zek said:


...and how to get rid of this dip around 120Hz and zig-zag in upper region.

Greets!

Eliminating the dip requires either the driver be placed much further down the pipe or a separate tuned resonant pipe be added, both of which go beyond the scope of this thread.

The 'zig-zag' can be damped by stuffing the pipe, but the trade-off is you lose all of the pipe's gain, winding up with a low tuned classic TL.

GM
 
QUOTE]The BIB's open top is actually a terminus, as Greg pointed out to me in a private email, the mouth is actually formed by the room corner.[/QUOTE]

Hi Does this mean if the BIB concept is maintained and the terminus is still uppermost, the bi-folded version (see bibib.jpg) I am experimenting with will still "load" the corner even if shorter than the original? Thx.
 
hlj said:
QUOTE]The BIB's open top is actually a terminus, as Greg pointed out to me in a private email, the mouth is actually formed by the room corner.


Hi Does this mean if the BIB concept is maintained and the terminus is still uppermost, the bi-folded version (see bibib.jpg) I am experimenting with will still "load" the corner even if shorter than the original? Thx.
[/QUOTE]


Wait for the experts to answer here, but my take
on it is that the wall corner acts like nelson Pass's
'kleinhorn'. That's my best way to visualize it.
 
To piggyback the question further for the "experts"...

What is the minimum distance between the top of the horn and ceiling required for proper loading/creation of the horn mouth? Is there some relation to the size of the BiB terminus?

And, if the BiB is too short, what would the effect be by inverting and using the bottom corner of the room to complete the mouth (assuming the minimum distance does not change)? Perhaps, use some sort of "reflector" on bottom to difuse/low pass the output...

Thanks.
 

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I don't have enough hours on them to consider the drivers broken in. My first impression is that they sure don't lack for bass. If anything they are too full in the 40-50 Hz range. Some (maybe all) of that is the main resonance of the den they're in, but the same was true in the living room which is much larger. I need to make some short stands for them, the drivers are well below ear level now so the top end is rolled off. On axis listening will be essential. The well-documented dip above 100 Hz is in effect, too.

So, as they sit, they are somewhat flawed. Stands will help, I expect that some bracing in the mouth will be appropriate (as I said in an earlier post, the 3/4" pine boxes are hardly dead enough to please the cabinet resonance Nazis), and I'm sure that I'll be playing with both damping and some sort of filter network (treble notch or BSC, not sure which, maybe both?).

There's good stuff happening too. I'm enjoing listening to them, colorations and all. The only full-range drivers I've ever listened to have been headphones, and in some ways the sound of these reminds me of 'phones. I never thought about headphone sound in terms of having no xovers, but now I'm thinking that is a critical aspect in the clarity of sound from headphones. The prominent bass works like loudness compensation at lower listening levels, and I kind of like it. Turn them up and throw on some reggae (I've got Dub Side of the Moon on again as I write this) and they're ready to boogie. They won't go disco party loud, but they're plenty loud enough for my needs.

It's amazing just how much music (and how much bass!) you can get out of a tiny pair of drivers. I'm going to be playing with these for a while to see what I can get out of them.

Bill
 
Godzilla said:
Neat... i like the bases very much. What speakers are facing backwards?

Godzilla


Paradigm Control Monitors, late '80's vintage. The stands they are on are probably the nicest woodwork I've ever done. The rails and stiles are solid 5/4 oak, with mortise and tenon joints in all directions. I used a table saw to help with the tenons, but cut all the mortises with mallet and chisel. The panels are 3/4" ply veneered in ribbon cut white oak. They're sand filled and solid as all get out. I built them when I was recently divorced, dateless and looking to fill up some hours between parenting duties. I won't have that kind of time again until I retire.
 
Yes this one has me puzzled too? Is any horn loading going on here?, or merely using the db gain acheived by wall or corner positioning?

As the BiB is in essence a 1/2 wl voight pipe, a certain amount of horn loading is taking place? i.e. acoustic gain.

Another question that i wonder about, is I believe that the driver is positioned on th 1/5 harmonic, which is an anti-node, surely the 2/5 which is a node would be better?
 
It is a horn -Voigt (no 'h') style back-loaded. The intro I wrote on Jeff's wonderful BIB pages, which is heavily based on a number of Greg's emails to me and other posts, goes into this in a little more detail. It just happens to use the corner of the room to complete the horn mouth.

2/5? Swings and roundabouts really. You get some benefits, some other issues, but the real physical problem is it puts the driver too low down for practicality.
 
Many thanks SM.

It is a horn -Voigt (no 'h') style back-loaded. The intro I wrote on Jeff's wonderful BIB pages, which is heavily based on a number of Greg's emails to me and other posts, goes into this in a little more detail

Have just found the pages you mention, very informative, a little hidden away though? just thought there would be a list of names under the Site Contributors heading, sorry! will have to have to have a good look now.

It just happens to use the corner of the room to complete the horn mouth.

So technically a bifolded version would achieve a larger horn mouth being shorter?
 
IMHO the major site contributors are Scott (for working up most of the sims and dims, and kicking off this interesting thread/discussion, Greg (for his sims and dims as well as his private emails with Scott to confirm things were in working order, Martin (for creating the software used to generate this info… and Terry for pointing out the BIB design has merit… building a couple pair and writing an article about its sound.

Also everyone contributing to this thread is really a site contributor. LC for creating some additional graphics (thank you) and everyone that’s built and posted pics of their BIBs.

Peace,
Godzilla

http://www.zillaspeak.com/bib-Intro.asp
 
IMHO the major site contributors are Scott (for working up most of the sims and dims, and kicking off this interesting thread/discussion, Greg (for his sims and dims as well as his private emails with Scott to confirm things were in working order, Martin (for creating the software used to generate this info… and Terry for pointing out the BIB design has merit… building a couple pair and writing an article about its sound.

I have nothing but admiration, for people like yourselves who devote a great deal of time, enthusiasm, and effort in a bid to further or promote their hobby, for the benefit of all.

It is also nice to be able to contribute to a discussion irrespective of technical level or ability. I guess this is what makes hobby forums so successful.

My comment was not intended as a criticism, apologies if that was how it appeared.
 
well.....

it seems my esteemed colleague deleted all the pictures documenting the construction process of the 166 esr horns I built a while back without telling me. he deleted those photos to make space for pictures of drunk people. ahhh college. I recently finished my last final and the project of bringing a tutorial to the web of the BIB was one of the first things on the list.

I suppose that I could write text in a very detailed fashion. I tend to prefer text only manuals anyways, but we'll see...

here we go though. I have another set of drivers and plywood and some time on my hands. anyone want to give me dims for a fe126e? not tuned too low?

thanks...

clark