Hi
I’m quite interested to build a BIB using Fostex FE206 E. However, since I can not accommodate the proper, tall version, I was thinking about a shorter variant. I came up with the following dimensions (in millimeters)
Height: 1800 mm
Width: 245 mm
Depth: 350 mm
A=B=C= 175 mm (depth/2)
Z driver= 75 mm
The numbers are rounded a bit, but are quite close to the recommended, except line length, but that’s a compromise.
Hope this will work.
Regards,
Vix
I’m quite interested to build a BIB using Fostex FE206 E. However, since I can not accommodate the proper, tall version, I was thinking about a shorter variant. I came up with the following dimensions (in millimeters)
Height: 1800 mm
Width: 245 mm
Depth: 350 mm
A=B=C= 175 mm (depth/2)
Z driver= 75 mm
The numbers are rounded a bit, but are quite close to the recommended, except line length, but that’s a compromise.
Hope this will work.
Regards,
Vix
Hi,
The spec's on Zilla's site state a line-length of 246.38 cm for my FE127s... With a Sm of 277 (18.5*15 cm) I end up needing an inner height of 125.23 cm..
Could I reduce this to 122cm, without altering the other dimensions?
(122cm is the Std. width of a board overhere)
I also thought making the 'ground plane' 20*15cm, having the divider subtracted from that on top (18mm thick) I end up having roughly 18*15 cm: Just about right. Right?
Thanks, Bibster
The spec's on Zilla's site state a line-length of 246.38 cm for my FE127s... With a Sm of 277 (18.5*15 cm) I end up needing an inner height of 125.23 cm..
Could I reduce this to 122cm, without altering the other dimensions?
(122cm is the Std. width of a board overhere)
I also thought making the 'ground plane' 20*15cm, having the divider subtracted from that on top (18mm thick) I end up having roughly 18*15 cm: Just about right. Right?
Thanks, Bibster
My plan is to tease half a pound of acoustuff from just below the driver to the top of the line. That works out to about .5 lb/cu. ft. I will also dacron sheets in the bottom. I'll see how this sounds, and alter as needed. This will be easy to reverse or alter.
The biggest problem thus far has been my warped double thick front baffle. I decided to laminate them first, and I cut the inside baffle with an eye shaped recess, thinking it might eliminate some resonances from a round hole. I think the larger hole in general, but especially this, bowed the baffles considerably. Most of my panels a bit warped, but my construction process made that fairly easy to deal with.
The enclosure in the back of the first pic isn't glued up yet, just screwed together. I can't unclamp the first until tonight, then I'll get the second glued. I still have to complete the bases and decide how I'll attach them. I'll also need to get the cables and stuffing in them. I'm going to listen to them for awhile before I decide to finish them. I'll probably use some color of duratex. I may put some decoration/stiffening panels on the sides, and possibly a supra baffle. I may wait for warm weather so I can do it outside.
Paul
The biggest problem thus far has been my warped double thick front baffle. I decided to laminate them first, and I cut the inside baffle with an eye shaped recess, thinking it might eliminate some resonances from a round hole. I think the larger hole in general, but especially this, bowed the baffles considerably. Most of my panels a bit warped, but my construction process made that fairly easy to deal with.
The enclosure in the back of the first pic isn't glued up yet, just screwed together. I can't unclamp the first until tonight, then I'll get the second glued. I still have to complete the bases and decide how I'll attach them. I'll also need to get the cables and stuffing in them. I'm going to listen to them for awhile before I decide to finish them. I'll probably use some color of duratex. I may put some decoration/stiffening panels on the sides, and possibly a supra baffle. I may wait for warm weather so I can do it outside.
Paul
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Thanks James! The old signs are really comfy to lay on; far softer and warmer than the floor, more durable than cardboard. Glue doesn't stick to them. Since they are slick, I can rock a speaker off the saw horses and drag it around on them. I can pick the cabs up, but I know I shouldn't.
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mix and match
Had my first listen to the sample build I made of the BIB for
FE127e today-- finally. It's just a dry clamp job so far. I laid in
some 1/2 in foam insulation on the front back and divider and then
clamped the unglued side on.
I call this mix and match because the other half of the stereo pair
is a GM MLTL with the other FE127e in it. Hell, I only have one
corner in this arrangement to play with anyway.
My first listen was to some organ recital and that not of the best quality.
I have an SS receiver that can play test tones for right and left channel
and the sound seemed to be at about the same level. But when playing that recital, I found I had to adjust right left separation off
of center to get balance on my soundstage. (I sit pretty close to
this rig and do not play at hight volume.) So what accounts for the
perceived level in volume difference between the 2 different speaks?
I'll keep the setup like it is and experiment some more with different
music pieces and some original cds rather than the dupes I've made
of things.
So what's the next step for treatment of the cabinets if any?
My MLTL runs bare-- nothing inside whatsoever. I tried a piece of
foam carpet underlayment behind the driver of the BIB but I removed it and so the BIB is bare as well.
I'm trying to figure out a way to snuggle up the BIB to the wall at the corner. Since the BIB has a false base to get the driver up, I thiought of making a base
with a cutout for the moulding and baseboard heating and trim the
BIB to sit on top of that.
It's been an exciting project and one that I can tackle where I live. But I'm thinking some tuning is needed.
Materials used: Fiberboard shelving ripped to make the front, back and divider, and glued up shelving for the sides which gives a
butcher block look.
Had my first listen to the sample build I made of the BIB for
FE127e today-- finally. It's just a dry clamp job so far. I laid in
some 1/2 in foam insulation on the front back and divider and then
clamped the unglued side on.
I call this mix and match because the other half of the stereo pair
is a GM MLTL with the other FE127e in it. Hell, I only have one
corner in this arrangement to play with anyway.
My first listen was to some organ recital and that not of the best quality.
I have an SS receiver that can play test tones for right and left channel
and the sound seemed to be at about the same level. But when playing that recital, I found I had to adjust right left separation off
of center to get balance on my soundstage. (I sit pretty close to
this rig and do not play at hight volume.) So what accounts for the
perceived level in volume difference between the 2 different speaks?
I'll keep the setup like it is and experiment some more with different
music pieces and some original cds rather than the dupes I've made
of things.
So what's the next step for treatment of the cabinets if any?
My MLTL runs bare-- nothing inside whatsoever. I tried a piece of
foam carpet underlayment behind the driver of the BIB but I removed it and so the BIB is bare as well.
I'm trying to figure out a way to snuggle up the BIB to the wall at the corner. Since the BIB has a false base to get the driver up, I thiought of making a base
with a cutout for the moulding and baseboard heating and trim the
BIB to sit on top of that.
It's been an exciting project and one that I can tackle where I live. But I'm thinking some tuning is needed.
Materials used: Fiberboard shelving ripped to make the front, back and divider, and glued up shelving for the sides which gives a
butcher block look.
In answer to a the queries raised in the previous two posts:
The BIB is a conical horn. To preserve the conical profile (i.e. the flare-rate) with parallel walls requires specific WxD dimensions; a ratio of 1:1.4142 at the terminus in this case, as pointed out by GM. People are well advised to follow Greg's advice. A conical horn has the lowest distorortion of any horn type. It's not usually used for domestic bass-horns because it also needs to be longer than any other type. Not a problem for the BIB of course.
Particle board is lossier than many other materials. It should help prevent unwanted HF leakage through the horn. Plus, it's cheap, which is nice.
Why the differences in volume between the MLTL and the BIB? Well, the BIB should be a fair bit more efficient -it's a horn after all (albeit a conical horn -the least efficient of the horn types. This is relative though), so it should provide higher SPLs for a given power input.
The BIB is a conical horn. To preserve the conical profile (i.e. the flare-rate) with parallel walls requires specific WxD dimensions; a ratio of 1:1.4142 at the terminus in this case, as pointed out by GM. People are well advised to follow Greg's advice. A conical horn has the lowest distorortion of any horn type. It's not usually used for domestic bass-horns because it also needs to be longer than any other type. Not a problem for the BIB of course.
Particle board is lossier than many other materials. It should help prevent unwanted HF leakage through the horn. Plus, it's cheap, which is nice.
Why the differences in volume between the MLTL and the BIB? Well, the BIB should be a fair bit more efficient -it's a horn after all (albeit a conical horn -the least efficient of the horn types. This is relative though), so it should provide higher SPLs for a given power input.
Hi everyone,
I've finished sawing my cabinets, and my drivers [Fostex 168's] are on their way.
But before I cut holes for them I need to clear something up. Scott, you originally gave
Zdriver as 30.25" for the 140" line length version, which is ~21.7% as GM said.
But when responding to a question from Samue Jayaraj you tweaked it to 29.25".
How come?
I planned on running the cable from driver to amp, [a KT88 SET]. What do you recommend
for wire? What have other people who have the 168 and tube amp combo used?
I've seen a single pair of wires stripped out of a CAT5 cable mentioned, but when I looked
they were very skinny. Can they really get the job done?
Thanks for the help, John
I've finished sawing my cabinets, and my drivers [Fostex 168's] are on their way.
But before I cut holes for them I need to clear something up. Scott, you originally gave
Zdriver as 30.25" for the 140" line length version, which is ~21.7% as GM said.
But when responding to a question from Samue Jayaraj you tweaked it to 29.25".
How come?
I planned on running the cable from driver to amp, [a KT88 SET]. What do you recommend
for wire? What have other people who have the 168 and tube amp combo used?
I've seen a single pair of wires stripped out of a CAT5 cable mentioned, but when I looked
they were very skinny. Can they really get the job done?
Thanks for the help, John
Thus the shorter one (front) = sqrt(Sm/1.4142), and the longer one (side) is 1.4142 times the shorter one. (14 and 19.8 in my case, thus).Scottmoose said:
Depending on how one mountes the internal baffle, should one add its thickness to the length of the sides? (Red vs. blue in the drawing)
(The diff. between the actual board thickness and its 'coupe' at the required angle can be neglected... 5 degrees, 1/cos(5) = 1.0038 )
Regrards, Bibster
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copperhead said:
Slight variations away from what's notionally optimal can sometimes yeild interesting results. For Samuel, I tweaked it to suit his own conditions. There's not a huge amount in it though. Generally, I'd stick to the ~optimal -the 21.7% GM identified.
With your amp, I'd probably use about 20AWG wire. The thinner stuff isn't ideal with SET as there's a danger you'll under-damp the driver and loose control in the bass. Magnet wire should do the trick.
I think ronc has a point. The horn transitions to the room walls which act as a final flare, and the walls probably don't match the flare of the BIB. So , if the flare expanded a bit at the end, it might transition better to the room walls. Certainly worth experimentation..
I have a question about the part of the path above the driver. Does it have to flare at all? or is it just a nice coincidence that that area tapers which makes a nice trap? So could I make it any shape as long as the length is correct? Hmm any volume change there would do what?
I have a question about the part of the path above the driver. Does it have to flare at all? or is it just a nice coincidence that that area tapers which makes a nice trap? So could I make it any shape as long as the length is correct? Hmm any volume change there would do what?