Terry Cain's BIB -why does it work and does anyone have those Fostex Craft Handbooks? - Page 65 - diyAudio
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Old 12th May 2006, 04:51 AM   #641
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Quote:
Originally posted by oface
hey lousy ..


nice work,,,

is that a ryobi bt3100 Table saw??

i have the same aswell,,

btw they have their own website,,,http://bt3central.com


later,,


chris
BT3100 it is. Just about the last one the local Home Depot had, got it just before they discontinued them.
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Old 12th May 2006, 04:54 AM   #642
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Quote:
Originally posted by hlj
looking good! what are the overall dims, they look very sleek in the pic.

Posted

here.
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Old 12th May 2006, 05:14 AM   #643
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Quote:
Originally posted by MuaDibb
I see alot of people using pine for their speakers, has anyone tried poplar? It is denser than pine and more stable. Pretty easy to find, at your local hardware/lumber and since its pre-cut into boards you might find you won't have much cutting to do. Slightly more expensive than the pine, but I don't think its a big difference. Just a thought.

I thought about poplar. A better material in some respects I don't doubt, but the heartwood has a greenish color that I don't really dig, and I didn't see boards wide enough to use without jointing. I'll save that for a later project, as I don't have a jointer.

I'm using pine as a cheap (compared to nice hardwoods) and easy (no big sheets to rip, no splintery plywood edges to mess with, no MDF nastiness) way to play with the BIB concept. And to get better in the wood shop. I'm long out of practice, it's been over ten years since my last woodworking project (an ultralight canoe). I wouldn't recommend that anyone take my posts as any more of an endorsement than that!

I don't expect the pine to be particularly 'dead', or necessarily stable in the long run. If true Baltic Birch ply was available here in sheets long enough to build a BB I would have used it.

If I was looking for absolute accuracy and neutrality, I'd be building something other than a BIB. These are about building something inexpensive, different and fun, and hoping they will look and sound good. The next pair, whatever thay are, should look and sound even better!
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Old 12th May 2006, 05:01 PM   #644
GM is online now GM  United States
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Quote:
Originally posted by Tweeker


Im confused by this statements language. Could you please clear up what was meant. Pine is good until it gets weathered, or that weathered pine is good, or that unweathered Pine is fine, so long as extensive measures are taken? Thank you.

Greets!

Pine needs to be dried, preferably by being outdoors for a long time in a sunny climate. My best planks are from a 150+ yr old Central Ga. barn, but if you can still get kiln slow dried it will work too.

As Scott noted, typical 'green' #2 Yellow Pine isn't a good choice, so all this leaves is White Pine (at least around here), which is easy to work with and light, so needs serious mass loading to stiffen it up. Seems to me that TC mentioned there's another grade of Yellow Pine that works well, but I'm not familiar with it.

GM
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Old 12th May 2006, 05:28 PM   #645
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Quote:
Originally posted by peterbrorsson
Hi!
I'm pretty sure the midrange problem I have is due to the chip board I used. There's a lot of resonances when pressing ear to the side panels.

Greets!

Chipboard is very lossy, so you're actually hearing it doing a pretty good job of absorbing the higher frequencies. Most of what you're feeling are lower in frequency, which shows you why it's not a good material for any wide BW design, so 'skinning' these with something rigid will help a bunch.

Anyway, back to 'thinking outside the box' WRT damping these, obviously not everyone can/will have an acoustic tile ceiling, mush less at the optimum height, but spacing a damping screen above the mouth to 'slow down' the BW above ~400 Hz will go a long way towards improving clarity at the listening position without rolling off the LF nearly as much as when the damping is inside the pipe.

The downside to such a contraption is that it's a dust filter too, so will lose its effectriveness over time unless made to be removable/cleanable.

GM
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Old 12th May 2006, 06:05 PM   #646
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Quote:
Originally posted by peterbrorsson
Have had this idea steaming for a while with the extra pair of Monacor's I have. An apeirodical box where the whole back panel is made of two perforated plates, between the plates I would put damping.
In the corners of these would be screws so it would be possible to squeeze these together in order to adjust output of the back wave. The BIBs are excellent to try this on, at the moment I have two pillows on the mouths(this idea I got from listen to my mother in law way to long to keep hi freq in line

Office dividers have these plates and it is possible to choose amount of holes drilled.
I got this idea sitting examin a Dynaudio variovent which has this adjustment feature.
What do you experts say?
Greets!

Per my previous post, have you tried spacing the pillows up some?

Anyway, aperiodically loading the second half of the horn's expansion by venting one whole wall will in theory primarily roll off all of the BW below whatever the bottom corner frequency's F6 is, though it's bound to get the higher harmonics to some extent also since the horn will be controlling them via reflections off the walls, so seems to be going in the wrong direction overall, but only one way to know for sure.

GM
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Old 12th May 2006, 08:22 PM   #647
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http://www.zillaspeak.com/bib.asp

More BiBs!

Audio Nirvana and Jordan added.... click on logos to see dims and sims.

Peace,
Godzilla

GM designed BiBs here:

http://www.zillaspeak.com/bib-gm.asp
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Old 12th May 2006, 10:44 PM   #648
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Hi GM!
Well I can see when I reread my posting, that it could be misunderstood.
What I meant with a "normal" box was a small (15L) aperiodic box.
Anyway, I will try this on the mouth of my BIBs and if it works good, who knows if it stays there.
I don't have any problems with bass output with the pillows. As a matter of fact, it's too much with some records. So why should it be worse with a more esthetical solution.
The Naim CD3 I use has some grunt in the lower regions that makes dynamic music real fun to listen with the BIBs.

BTW dmason,
I remember some positive comments from you about the Monacor SPH60X. My opinion is that they need help in the treble region. I can still hear 15 kHz despite being a geezer
Read some recommendations from german builders that SPH 155X is better though I have not heard them personally.
However they claim the midrange is much more clear and crisp with SPH155.
Now Jordan looks interesting, but price....
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Old 12th May 2006, 11:24 PM   #649
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Amen re the price of the Jordans.

My own SPH-60Xs seem to motor up to 18KHz or so before dropping off.
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Old 13th May 2006, 12:41 AM   #650
dmason is offline dmason  United States
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The Jordan looks as though it needs to be explored. Do we really need to order them all the way from HK?? And that price...

There is a ~soon-to-be-released HempAcoustics 4.5 inch which was recently heard, and apparently won the hearts of many, many people. It is said to fit in the same hole as FE126/7E, and share the wonderful warm signature as the Hemp 8, but sans whizz...
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