Hi everyone. I have a pair of Fostex Fe126En. On the net you can find many cabinet plans for Fe126 but TS parameters for the two kind of Fostex are quite different. In particular, Fs. Qts and Vas that are very important to build BiB and iBiB enclosure. I have two questions.
1. Is iBiB configuration really better than classic BiB?
2. If so, does anyone have plans for Fe126En? The one you can find is for 126E and, as said, this driver is different from En one.
Otherwise, if in your opinion Bib and iBiB are equivalent, I've no matters.
Thanks to all of you
Ziocalepino
1. Is iBiB configuration really better than classic BiB?
2. If so, does anyone have plans for Fe126En? The one you can find is for 126E and, as said, this driver is different from En one.
Otherwise, if in your opinion Bib and iBiB are equivalent, I've no matters.
Thanks to all of you
Ziocalepino
I too have a pair of the new FE126En's and was looking at building BiB's for them.
GM's (BiB_166_GM) BiB calculator found on Godzilla's website is an auto-calculator. Once you plug in Fs, Vas and Qts it will give you the dimensions.
Bigger Is Better 'BIB' Cabinet Dimensions - ZillaSpeak
Using the GM calculator I got a 42" tall cabinet with a z-driver position 16.5" down, resulting in a 25.5" floor to driver height.
The only plans I could find for an iBiB were in the box plan library of Planet10's website.
planet_10 hifi
It's called the iBiBk because it incorporates a Karlson Slot. It appears to be a working drawing though, not a finalized design.
The issue I had was when comparing the two pieces of information (the info given from GM's calculator using Fostex published T/S numbers) and the dimensions given in the iBiBk plan sheet, I saw some pretty significant differences. The height difference between the two is almost 10" and the driver position (z-driver) is totally different.
Since I have 8' ceilings and mine would be against a wall but not necessarily tucked into corners, I'm pretty sure an iBiB would load better in my room. The issues mentioned above though have so far kept me from building a pair.
R/
Jim
GM's (BiB_166_GM) BiB calculator found on Godzilla's website is an auto-calculator. Once you plug in Fs, Vas and Qts it will give you the dimensions.
Bigger Is Better 'BIB' Cabinet Dimensions - ZillaSpeak
Using the GM calculator I got a 42" tall cabinet with a z-driver position 16.5" down, resulting in a 25.5" floor to driver height.
The only plans I could find for an iBiB were in the box plan library of Planet10's website.
planet_10 hifi
It's called the iBiBk because it incorporates a Karlson Slot. It appears to be a working drawing though, not a finalized design.
The issue I had was when comparing the two pieces of information (the info given from GM's calculator using Fostex published T/S numbers) and the dimensions given in the iBiBk plan sheet, I saw some pretty significant differences. The height difference between the two is almost 10" and the driver position (z-driver) is totally different.
Since I have 8' ceilings and mine would be against a wall but not necessarily tucked into corners, I'm pretty sure an iBiB would load better in my room. The issues mentioned above though have so far kept me from building a pair.
R/
Jim
I do not think they are that much different - not more than typical measured deviations from spec and between samples.
I therefore believe the same designs can be used.
SveinB
>>> Since I have 8' ceilings and mine would be against a wall but not necessarily tucked into corners, I'm pretty sure an iBiB would load better in my room. The issues mentioned above though have so far kept me from building a pair.
Without being in corners my BIBs using fostex 165k or even the 168s (older style with whizzer) are bass light. Placing them into corners fills out the bass beautifully. It's quite an amazing transformation actually and rounds out the sound nicely. I would not build BIBs if they cannot be placed into corners as designed. Placed correctly, they ROCK, especially when considering they use pretty small full range drivers. They also deliver a BIG soundstage... they are great speakers for corner placement.
Zilla
Without being in corners my BIBs using fostex 165k or even the 168s (older style with whizzer) are bass light. Placing them into corners fills out the bass beautifully. It's quite an amazing transformation actually and rounds out the sound nicely. I would not build BIBs if they cannot be placed into corners as designed. Placed correctly, they ROCK, especially when considering they use pretty small full range drivers. They also deliver a BIG soundstage... they are great speakers for corner placement.
Zilla
I've always had difficulty with those pesky online abbreviations too..........
IIRC = "if I recall" (if I'm recalling it correctly)
I really doesn't matter that much. The frequencies you are coupling with the horn won't be able to "see" the difference of small details like the curves exact shape. You could easily just make it a high triangle if that's easier. The basic idea is just to extent the bandwidth of the opening and make it less resonant.
The important thing is, that the combined opening at the exit area of the iBIB should at least be equal to final piece of the horn, just like with a normal ceiling firing BIB. You don't want to narrow the horn after expansion.
If you are doing corner or floor/wall loading (which you should to get the best effect of the iBIB), you should also consider doing a slanted plate at the bottom to help reflect the sound out at the wall and also to avoid standing waves that bounces off the floor back up the horn.
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FWIW, I've periodically posted that all of the few pipe horns I built were floor reflex loaded with Av = Sd with me and their owners being pleased with the results, though this was before there was any really low signal LFE available to consumers. Regardless, some Hornresp sims indicate that doing it and/or capping 'normal' top exit BIBs with a reverse cone will theoretically be a worthwhile tweak in at least some instances, though AFAIK, no one has tried it yet and reported back.
GM
The easy way is to just do the triangle area "math" (width x hight (perpendicular lines)) and add a bit of area to account for the curves. Or you can find the area formula for the kind of curve you choose.
The advantage of the iBIB is that you can make it smaller and maybe also get better ear level driver placement which is very important with FR drivers as they beam like crazy. With a normal BIB you want to get pretty close to the ceiling to get good loading. So you need a tall speaker if you have high ceilings. A small driver like the FE126 doesn't really warrant a large box anyway.
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