Terry Cain's BIB -why does it work and does anyone have those Fostex Craft Handbooks? - Page 10 - diyAudio
Go Back   Home > Forums > Loudspeakers > Full Range

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 7th March 2006, 03:53 PM   #91
diyAudio Member
 
Scottmoose's Avatar
 
Join Date: Mar 2005
Location: UK
'Voigt', please, not 'Voight' -P.G.A.H. Voigt you know. Not that he had anthing to do with the vile 'Voigt Pipe'.

Terry's BIB on the other hand is basically one of Voigt's own designs, somewhat modified. It looks like a long Lowther Club of Norway Voigt pipe, folded in half, but in reality, it does not work in the same way. It's a folded, corner back-horn you see, with no mass-loading applied. It uses the rear boundary conditions of the room to flatten its response and produce lower bass, which the other type does not do.

Although they are both So=0 designs, in the case of the BIB, the mouth placement mitigates against the problems that would otherwise occur -see the last post on the first page of this thread by Martin. Interestingly, I've tried increasing the area of So, and it actually causes some problems the So=0 pipe dioes not have.

To answer how to accurately simulate these in MathCad -you can't. Yet. I do some simulations in it, using the TL offset driver sheet, and the rear-loaded horn sheets, but the response looks vile -that's where empirical knowledge comes in. Based upon my own experience with building several different versions of these pipes, I know when and where response issues will occur, and what to do to counter them if possible. Martin will eventually get around to adding a facility for modelling vertical ports or mouths, but he's a busy man, so don't hold your breath for a while.

General response is pretty good. They're no monitors, but if you wanted that, you wouldn't be looking at these, would you? They have a dip at around 100Hz (average), though it's never as bad as the giant hole the simulation suggests: 4db is about the lot, which isn't too bad (that's a consequence of the driver placement -nothing you can do about it). Bass is astonishing for a horn -from 6 1/2" drivers, expect an easy 30Hz in-room. Above 300Hz or so, they're pretty flat, ripple is contained to about 3db at the most. Below that is a bit ragged, but as GM points out, at lower frequencies, our hearing accuity drops off and we key off the peaks, being amplitude based animals, so you don't rreally notice. They're not for everyone. But they're great fun, and they make music, and let it breath like few other speakers. They are the one, and the only exception I make to my cardinal rule of speaker enclosure design, which is that enclosures should always be modelled done in Martin's MathCad sheets.

Best
Scott
__________________
Community site www.frugal-horn.com Commercial site www.wodendesign.com
  Reply With Quote
Old 7th March 2006, 04:45 PM   #92
MuaDibb is offline MuaDibb  United States
diyAudio Member
 
Join Date: Feb 2006
Location: Lawrenceburg Ky.
Thanks for the post Scott. Confirmed my darkest suspicions. So now for a completly subjective opinion. Which speaker and cabinet size have you been most pleased with? It would appear you have built several.
  Reply With Quote
Old 7th March 2006, 05:10 PM   #93
dmason is offline dmason  United States
diyAudio Member
 
Join Date: May 2004
Location: Republik of Kalifonia
If you are looking for refined, true full range sound, your very best bet would be either the Fostex FF225K, or the Hemp Acoustics 8FR.

Fostex FE168Sigma is also extremely musical, and a smaller load than the aformentioned 8 inchers, @ 66X7.5. HP @ 70Hz and add a sub. Uber dynamics.

Turns out hemp as cone material is about as good as it gets. My vote goes with the hemp. Pair of 'em playing in the background, as worthy a contender for SET as they come IMO.
__________________
"Pilau Buggah, Big Islan Mo Betta!!"
  Reply With Quote
Old 7th March 2006, 05:15 PM   #94
GM is offline GM  United States
diyAudio Member
 
GM's Avatar
 
Join Date: Jun 2003
Location: Chamblee, Ga.
Greets!

FYI, you can get a decent half space sim if you use the ML-TQWT WS, setting SO = (~0.125" x width), rp = (SL/pi)^0.5, lp = 0.0001, and the other values at whatever you want.

GM
__________________
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
  Reply With Quote
Old 7th March 2006, 07:22 PM   #95
diyAudio Member
 
Join Date: Feb 2004
Location: Appleton, WI
Could this be the next reference project?


For the longest time I didn't really know what
was going on with this design, now I'm intrigued.


Could the design be modified for standard board widths?


The original cab is 14 in deep.

With a different driver could the design be worked up
for 12 in and 6 or 8 in. lumber? I think Aspen comes in
those dims.
  Reply With Quote
Old 7th March 2006, 07:54 PM   #96
MuaDibb is offline MuaDibb  United States
diyAudio Member
 
Join Date: Feb 2006
Location: Lawrenceburg Ky.
Hey dmason, you said you were listening to the FR8's. Are they in a BIB cab. and if so what dimensions are you using?

Hey GM I might try your MLTL-48" but do you have a suggestion for a more "economy-minded" speaker than the Jordan?
  Reply With Quote
Old 7th March 2006, 08:02 PM   #97
dmason is offline dmason  United States
diyAudio Member
 
Join Date: May 2004
Location: Republik of Kalifonia
FR8 Hemps are in a 2.5ft^3 BR. Fostex 168 is in BIB. These are my living room speakers for the last several months. BIB for Hemps is coming this spring.

Good to see you Greg!
__________________
"Pilau Buggah, Big Islan Mo Betta!!"
  Reply With Quote
Old 7th March 2006, 08:37 PM   #98
GM is offline GM  United States
diyAudio Member
 
GM's Avatar
 
Join Date: Jun 2003
Location: Chamblee, Ga.
Greets!

Quote:
Originally posted by MuaDibb
Hey GM I might try your MLTL-48" but do you have a suggestion for a more "economy-minded" speaker than the Jordan?
Not really. I mean I've posted at least a hundred sims from 'mild to wild' across various forums/threads, but don't have time to browse them, and the ~obvious one, the CSS FR125S, too easily bottoms out in the design I did according to others, so Caveat Emptor.

Quote:
Originally posted by dmason
Good to see you Greg!
Same here! I (eventually) responded to your emails and re-sent some of them when you didn't respond.......... Anyway, just passing through, I'm in Dental 'doc-in-a-box' Hell right now.

GM
__________________
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
  Reply With Quote
Old 7th March 2006, 10:13 PM   #99
diyAudio Member
 
Scottmoose's Avatar
 
Join Date: Mar 2005
Location: UK
Quote:
Originally posted by GM
Greets!

FYI, you can get a decent half space sim if you use the ML-TQWT WS, setting SO = (~0.125" x width), rp = (SL/pi)^0.5, lp = 0.0001, and the other values at whatever you want.

GM
And he's still the Master! Never tried that one. I will do in about, oh, thirty seconds or so. And, as Dan said, great to see you Greg.

Regards
Scott
__________________
Community site www.frugal-horn.com Commercial site www.wodendesign.com
  Reply With Quote
Old 7th March 2006, 10:24 PM   #100
diyAudio Member
 
Scottmoose's Avatar
 
Join Date: Mar 2005
Location: UK
In reply to the other questions -yes, generally they can be modified. THe size depends on the driver used of course. Me, I've loved my pipes with the FF165K most. They work well in the original. Better still when widened fractionally to give more volume. Dan loves his FE168ESigma pipes (I can't afford Sigmas ). I note with interest his liking for the FF225K. Now I've tried that as well in a very large pair I built for some friends, to superb effect. My personal favourites tend to be whizzerless drivers. That's more a reflection of my own taste though.

A version with the B200 is a wild-card, though I'd need to do some more work with that, and some DSP is probably necessary.
__________________
Community site www.frugal-horn.com Commercial site www.wodendesign.com
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



New To Site? Need Help?

All times are GMT. The time now is 06:54 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2