Terry Cain's BIB -why does it work and does anyone have those Fostex Craft Handbooks? - Page 21 - diyAudio
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Old 16th March 2006, 12:43 AM   #201
TC is offline TC  United States
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Allright, I get the 200th posts to this BIB thread. Now who is simming BIB subs?????

TC
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Old 16th March 2006, 12:55 AM   #202
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I was thinking that myself. This looks like a good candidate to me, given the price and friendly Qts.

http://www.ascendantaudio.com/assassin10specs.html
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Old 16th March 2006, 01:05 AM   #203
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Quote:
Originally posted by GM

If you want to 'burn' some wood, try this, it won't have the acoustic efficiency or super low F3 of the BIB, but should work fine in a corner down into the 30s without any BSC and is small enough to use a triangular cab:

L = 57.25"
CSA = 100"^2
driver around 36-38" from floor

GM
Thanks, this looks like fun. Speaking of burning wood, what is the cheapest grade of ply useful for experimenting? Some of these designs would cost a bit of money to build up with nice Baltic Birch (also, the genuine stuff in 5x5 sheets isn't of much use here). I've seen some 4 or 5 ply that doesn't look too bad; will it give one an idea of an enclosures merit? HD up here carries some 13ply veneered (oak or birch) stuff that has a few voids and sells for $35 a sheet. I know ply has been discussed before. As I recall, most discussions have been finding the ideal rather than minimum workable quality.
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Old 16th March 2006, 01:53 AM   #204
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Quote:
Originally posted by Godzilla
http://www.zillaspeak.com/BIB.asp

As this developes I hope it's useful. Comments are appreciated.

Godzilla

Excellent work! Really appreciate your efforts on this...all the options had just started to make my head spin.

Is there any way to present whatever FR info that MathCad spits on regarding each sim?
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Old 16th March 2006, 01:56 AM   #205
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Yes, more on the Assassin 10" please. This was the other I gotta do it project I bought some stuff for but didn't get the MCM amp
either.


Was hoping someone would actually go gor the Assassin.

It's $55 plus shipping.


I'm fence sitting as usual.
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Old 16th March 2006, 02:00 AM   #206
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>>> Is there any way to present whatever FR info that MathCad spits on regarding each sim?

I would like to see the FR charts too. I can't get mathcad to work on my pc... Whatever i'm supplied with i will find a way to put it onto the webpage.

Big thanks to Scott for the time he's spent and surely will spend checking all the dims. If everyone's really nice to him maybe he will supply FR charts.

Peace,
Godzilla
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Old 16th March 2006, 05:03 AM   #207
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GM,

What is the difference between a corner firing apex vent and a front firing port? Thanks
James
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Old 16th March 2006, 05:32 AM   #208
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Greets!

The former is loading the corner, which is an 1/8th space 90 deg conical expansion, over its entire BW and the latter's loading is frequency dependent due to being somewhat further from the apex. The apex loading has the additional benefit of compression loading the vent's output, a big plus with low Xmax drivers.

GM
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Old 16th March 2006, 07:03 AM   #209
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Quote:
Originally posted by pjanda1
Thanks, this looks like fun.

Speaking of burning wood, what is the cheapest grade of ply useful for experimenting?
You're welcome!

When I was building, I made my test cabs from large scraps and used concrete formers scrounged at building sites. If you buy, it just needs to not easily strip out since you need tight joints without gluing or caulking, so 23/32" sheathing suffices. Or use thinner wood/fewer screws and wrap it with Saran Wrap to get a good seal.

The finished product must be no-void or you run the risk of having one or more spurious resonances you can't locate without a mechanic's stethoscope.

GM
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Old 16th March 2006, 09:29 AM   #210
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Hi Terry -good to see you & hope you approve!

I haven't put the MathCad simulations up because as they stand, they're not particularly accurate representations of these cabinets in-room behaviour. The currently available sheets on Martin's site give a great 1/2 space simulation of their behaviour, but this is not an accurate in-room representation of their response, because they are designed for 1/4 or 1/8 space (rear wall or corner) loading, which flattens their response curve and increases their LF extension into the room, as Martin and Greg point out. In a 1/2 space simulation, they frequently look vile; in 1/4 or 1/8 space reality, they actually work very well. I'm currently working on using the lower, in-room half of Martin's new sheet to come up with a 1/4 space response simulation, and if I succeed, I'll post some curves as they will be a better representation. 1/8 space is not possible at present -that'll be for a future upgrade, but don't hold your breath; Martin's got enough on as it is without trying to add even more at this stage!

Subwoofers eh? I seem to remember someone raising that point elsewhere, though I can't remember where. I'll have a look at those Assassin (what a name!) drivers and perhaps those SEAS jobs that you use in the Bailey Terry for a start when I get a moment. Might give Nelson's El Pipe-o a run for its money. ;-)

Cheers
Scott
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