Terry Cain's BIB -why does it work and does anyone have those Fostex Craft Handbooks? - Page 411 - diyAudio
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Old 11th June 2008, 10:20 PM   #4101
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Location: Appleton, WI
Quote:
Originally posted by zayne742
You need to convert the VAS from liters to cubic feet. 9.9l = 0.34 cu. ft. The confusion has happened before. I may try to go back and create a switch on the sheet to flip between Imperial and Metric and resubmit it to Jeff. Your measurements should be:
Yes, I looked at the Liters converter but wasn't able to
put any values in the highlight.

also don't know how the folded line length (48) plus the
a-b-c of 5.4 looks "in wood".

Recall the illustration for the BIB where the line length follows a
a center path and does not conform to any measures for wood. Also my pieces are under 3/4 thickness but not all the way down to .5 as the example shows.

Zdriver is also a concern since I used my old measurment of 19.5" at center off the previous build. I can make a dutchman or something to change it but I'd rather leave as is. \\as is, the driver clears the
slat with my double front baffle.

Overall, the line length plus a-b-c dimension is longer if I'm looking at it correctly.

So what is the absolute length of the slat and the absolute value of a-b-c?

I'm not going to recut the front baffle because I got this really primo flush cut to mount the driver that I had to do free hand. I'm saving that and doctoring the rest. There's extra length below the driver hole as cut.


You'd think there wouldn't be all these questions with a calculator.

I am using 6 3/4 front baffle width.
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Old 11th June 2008, 11:15 PM   #4102
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You are correct about the liters. Jeff, if you are out there, can you unlock that cell? If not I can resend the sheet.

GM would be be the expert on this one, but I do not believe that you add a-b-c. If anything, you would measure from the midpoint along the line. So with a depth of 12 inches, divide by 4, getting 2. So if it adds any line length it would be 6 inches. This would be just slightly different using inter dimensions. Then you need to compensate for the width of the slant. All in all, in the grand scheme this added amount is very little to worry about. Also, z is 20.87 on the sheet. If the memory is correct, Scottmoose had mentioned before that an inch or so in either direction should not affect the sound too much.

As for the slant, the length in the sheet should be absolute based on pythagorean theorem. The last set I built was by the calculator, and turned out perfect.

Try putting .625 in for 5/8" wood. Should get you close.

By the looks of your earlier post, your BIB should be fairly spot-on. Not sure if it is worth the trouble of re-doing. But, you must be as I, always looking at them knowing, and thinking about the saw!

Do you have any pics?
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Old 12th June 2008, 01:01 AM   #4103
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Quote:
Originally posted by zayne742
You are correct about the liters. Jeff, if you are out there, can you unlock that cell? If not I can resend the sheet.

GM would be be the expert on this one, but I do not believe that you add a-b-c. If anything, you would measure from the midpoint along the line. So with a depth of 12 inches, divide by 4, getting 2. So if it adds any line length it would be 6 inches. This would be just slightly different using inter dimensions. Then you need to compensate for the width of the slant. All in all, in the grand scheme this added amount is very little to worry about. Also, z is 20.87 on the sheet. If the memory is correct, Scottmoose had mentioned before that an inch or so in either direction should not affect the sound too much.

As for the slant, the length in the sheet should be absolute based on pythagorean theorem. The last set I built was by the calculator, and turned out perfect.

Try putting .625 in for 5/8" wood. Should get you close.

By the looks of your earlier post, your BIB should be fairly spot-on. Not sure if it is worth the trouble of re-doing. But, you must be as I, always looking at them knowing, and thinking about the saw!

Do you have any pics?

Well I noticed the difference in width big time _unless_ that is an
outside dimension. Looking at the slant value of 43 way down the
page is closer to my material size. The over all length (where the bottom is is the actual question I guess) is at 48.

Regardless, I have the psychology of previous investment going on this one and am using up some recuts from another build.

No, no pictures. I never learned to use a digital camera.

The previous build is 6 3/4 wide by about 9 deep. The sides are
glued up shelving which looks like butcher block. The insides,
front and back are particle board. (This was in the days when mixing materials was the rage. ) I make my own grilles and I've used some shoe molding to trim out the front giving a round-over look.

This Frakenbuild will have to last me a while. I don't like to pester my cutter too often. And the local home store hasn't got any good deals on either.

With this one I'd like to make the stuffing parts with bamboo (used for pillows that you get at the fabric store) or native fiberglass--
the kind you have to careful of. The bamboo is likely better for my usage because I'm in 'em all the time playing with stuff.

I'm also using the thin wire tweak. And the GM pennant tweak.

Thanks for helping with this. I'm just glad I finally was able to
use the calculator. I may have more questions on it's usage.
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Old 12th June 2008, 02:04 AM   #4104
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Nothing like a neverending project! Have been the same with my set. Found some inch thick cut your own size industrial filter that seemed great for stuffing. Works decent, still playing. Would be glad to answer any more questions, even though I am not an expert. That is what has made this forum particularly interesting and fun. It is also the reason why I have 4 BIB's, tuned to the room wavelength in the living room now. Used for music, movies whatever. Not perfect, but makes people drool, and think twice about purchasing an acousticrap system! Build your own and be proud!
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Old 12th June 2008, 02:15 AM   #4105
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Quote:
Originally posted by loninappleton
No, no pictures. I never learned to use a digital camera.
Hi Lon, you are using Linux, yes? Just plug a recent-vintage camera into the USB and it should "automount," just like a thumb drive, with a folder displaying the images. Ditto for anything that acts like a "USB Mass Storage Device," like generic MP3 players, external HD's etc. You probably already know all this!
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Old 12th June 2008, 04:15 AM   #4106
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Quote:
Originally posted by rjbond3rd


Hi Lon, you are using Linux, yes? Just plug a recent-vintage camera into the USB and it should "automount," just like a thumb drive, with a folder displaying the images. Ditto for anything that acts like a "USB Mass Storage Device," like generic MP3 players, external HD's etc. You probably already know all this!
Ok, you found me out. I'm too cheap to buy a camera.



And yes I've asked around about how the pix get into the
computer from people who do it all the time.

But in reality I have far fewer of the electronics than other people.

However if a 5 megapixel camera went on deal for $50
I could be persuaded.

A note on the Linux: I follow Marcel Gagnes listserv daily but just as a lurker. This is where I say "Don't get me started on Linux."




Thanks for answering. In truth, I do so few builds and of such
low grade (but well-performing) material that not much is lost.
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Old 12th June 2008, 02:07 PM   #4107
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>>> Jeff, if you are out there, can you unlock that cell? If not I can resend the sheet.

I'm here. Please send the modified file and i will replace the old one. Thanks.

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Old 12th June 2008, 08:05 PM   #4108
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Quote:
Originally posted by zayne742
You need to convert the VAS from liters to cubic feet. 9.9l = 0.34 cu. ft. The confusion has happened before. I may try to go back and create a switch on the sheet to flip between Imperial and Metric and resubmit it to Jeff. Your measurements should be:
zayne742,


I have entered the values you've given and am ready to apply some glue.


The slant in the calculator which you say is the critical measurment
is 41.9 something so I cut it at 42". If you change your mind, I made
extra pieces or can use a block plane.

abc is 5.4 and change so I marked ab at 5 1/2 and 11 for the back.

Other info in this build so far. It has a double baffle-- outer baffle
6 3/4 with 4 in cutout for FE127e.

A note here for anyone using the same components: Harbor Freight in US has a hole cutter set with 5 pieces including 4 " and
a 5 ". The four inch will give a just right fit for the Fostex. The run of the mill red or white jobs found in the home store do not give this nice fit. The dimension is just a shade wider on these. Cost $2.50 or so at the HF. Yes they really are that cheap.

Inner baffle I used the 5 " hole cutter from above and have not
chamfered on this build. It's just 2 stepped holes for the backwave to travel through. GM said this arrangement may enhance the build with this wave guide effect, but I've done it for driver clearance on thinner stock.


Overall length minus bottom plate will be 49 1/2 to visually match the one I made a while back.

Some of the dimensions on the calculator are still confusing down by the cut list. I'm using most of my sizes the same as the first one
for which there is already a grille form a previous experiment. It just happens to be the right size.
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Old 15th June 2008, 05:26 PM   #4109
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This thread has been on the front page for at least a year and a half so.................bump.
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Old 15th June 2008, 06:58 PM   #4110
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Quote:
Originally posted by G
This thread has been on the front page for at least a year and a half so.................bump.
Well I've followed most of the thread over the years. Right now, waiting for the new BIB calc with the changes.

I'm holding off on doing my final cuts for that. Not going to hold off forever though. I have to get this one standing up pretty soon.


I'm wondering what the noticeable difference will be with the
new slant length of 42" over the original BIB I made with 45" slant

There was lots of discussion then and I took all the measures
from posts here. So there must have been some change when building the calculator. Either that or some signals were crossed.
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