Terry Cain's BIB -why does it work and does anyone have those Fostex Craft Handbooks? - Page 518 - 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 29th January 2013, 04:32 AM   #5171
GM is offline GM  United States
diyAudio Member
 
GM's Avatar
 
Join Date: Jun 2003
Location: Chamblee, Ga.
Quote:
Originally Posted by xrk971 View Post
Does this look closer to a BIB? Horn output only.
T.C.'s original RS 40-1354 BIB, 2pi horn only:

GM
Attached Images
File Type: gif T.C.'s BIB 2pi_horn output only.gif (15.6 KB, 284 views)
__________________
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
  Reply With Quote
Old 29th January 2013, 04:51 AM   #5172
GM is offline GM  United States
diyAudio Member
 
GM's Avatar
 
Join Date: Jun 2003
Location: Chamblee, Ga.
Quote:
Originally Posted by xrk971 View Post
I am not sure what to do about it at this point - at least the two channels are somewhat balanced. I am open to suggestions as to how to fix.
What with no 1pi loading and no experience with the BIB per se [mine were all vent loaded and used a completely different design routine], much less a mid wall mounted one, no clue except to fiddle with stuffing and/or some sort of EQ.

Bottom line, a wall mounted one probably needs its own design routine.

GM
__________________
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
  Reply With Quote
Old 29th January 2013, 05:48 AM   #5173
GM is offline GM  United States
diyAudio Member
 
GM's Avatar
 
Join Date: Jun 2003
Location: Chamblee, Ga.
Quote:
Originally Posted by B00B00 View Post
Hi Greg,

Thank you again,
I have now gone through all 500 plus pages.
Greets!

You’re welcome!

You’ve got more patience than me to actually read a 500 pg. Forum thread. A good book OTOH……

Right, using a medium Qts is pretty much my standard response and design choice for a low Qts driver if for no other reason than it makes the cab large enough for plenty of tuning flexibility.

Less bass is well, less bass and the only option would be to use digital EQ to trade efficiency for a flatter response to a lower corner frequency.

Again, I saw no output impedance/DF spec for the SEX amp, so have to assume it will be high enough to possibly create a ‘bloated’ bass response in an acoustically small cab/horn, though the other amps will theoretically do fine overall except for having less really deep bass than in a larger one.

Yeah, I prefer acoustic solutions to acoustic problems whenever practical, so typically want at least a 30” wide baffle to avoid using any BSC.

Ooh, my kind of woodworker! No ‘sissy’ router chamfering. FWIW, I use a very coarse rasp as all those gouges and general irregularity help to further scatter any mids/HF reflections.

GM
__________________
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
  Reply With Quote
Old 29th January 2013, 12:26 PM   #5174
B00B00 is offline B00B00  Canada
diyAudio Member
 
B00B00's Avatar
 
Join Date: Apr 2012
Hi Greg,
For lack of a better word... BEURK

Hmmm... that's not very gratifying... My fault, I jumped in both feet.
Oh well, you pays your money and makes your choices.

What amp would you suggest to go with these?
Not afraid of getting my hands dirty and trying to solder a little.

If I'm not happy with the results, that this driver gives in this cabinet, I'll swap in another driver and
build a pair of Decaware HDT's for the Fostex206EN's

Audiophile Tube Amps and Tube Gear from DECWARE

Last night's progress:
Click the image to open in full size.
Big chunky file used.


-andre-

Quote:
Originally Posted by GM View Post
Greets!

You’re welcome!

You’ve got more patience than me to actually read a 500 pg. Forum thread. A good book OTOH……

Right, using a medium Qts is pretty much my standard response and design choice for a low Qts driver if for no other reason than it makes the cab large enough for plenty of tuning flexibility.

Less bass is well, less bass and the only option would be to use digital EQ to trade efficiency for a flatter response to a lower corner frequency.

Again, I saw no output impedance/DF spec for the SEX amp, so have to assume it will be high enough to possibly create a ‘bloated’ bass response in an acoustically small cab/horn, though the other amps will theoretically do fine overall except for having less really deep bass than in a larger one.

Yeah, I prefer acoustic solutions to acoustic problems whenever practical, so typically want at least a 30” wide baffle to avoid using any BSC.

Ooh, my kind of woodworker! No ‘sissy’ router chamfering. FWIW, I use a very coarse rasp as all those gouges and general irregularity help to further scatter any mids/HF reflections.

GM
  Reply With Quote
Old 29th January 2013, 02:51 PM   #5175
xrk971 is offline xrk971  United States
diyAudio Member
 
xrk971's Avatar
 
Join Date: Oct 2012
Location: Virginia
Quote:
Originally Posted by GM View Post
What with no 1pi loading and no experience with the BIB per se [mine were all vent loaded and used a completely different design routine], much less a mid wall mounted one, no clue except to fiddle with stuffing and/or some sort of EQ.

Bottom line, a wall mounted one probably needs its own design routine.

GM
TC's BIB sim doesn't look that pretty either but at least the lower bass is a solid range rather than a couple of peaks. Looks like a lot of output in the 100 to 500 Hz range that needs to be attenuated with stuffing.

I think one thing I failed to consider when I first started designing the BIB for flatness is not looking at where the simulation peaks are and designing to avoid having standing wave resonances at the same frequencies.

I will play around with the stuffing some more and maybe try adding damping liners near the internal walls at the bottom.
  Reply With Quote
Old 29th January 2013, 02:53 PM   #5176
xrk971 is offline xrk971  United States
diyAudio Member
 
xrk971's Avatar
 
Join Date: Oct 2012
Location: Virginia
B00B00,
Nice work! I love the antique wood approach. We don't need no stinkin' routers!
  Reply With Quote
Old 29th January 2013, 03:17 PM   #5177
GM is offline GM  United States
diyAudio Member
 
GM's Avatar
 
Join Date: Jun 2003
Location: Chamblee, Ga.
Quote:
Originally Posted by xrk971 View Post
TC's BIB sim doesn't look that pretty either but at least the lower bass is a solid range rather than a couple of peaks. Looks like a lot of output in the 100 to 500 Hz range that needs to be attenuated with stuffing.
No 'vent' only calculation looks very 'pretty'. What matters is the in room response of the combined driver/vent output once damped. WRT horn gain peaking, look at what can happen in room sim wise with a FE167E: http://www.quarter-wave.com/General/...BIB_Design.pdf

GM
__________________
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
  Reply With Quote
Old 29th January 2013, 03:44 PM   #5178
xrk971 is offline xrk971  United States
diyAudio Member
 
xrk971's Avatar
 
Join Date: Oct 2012
Location: Virginia
GM,
you are right about the vent only sim without stuffing is never pretty looking and the room integration is what makes it all come together. Perhaps this is why it still sounds good when I step back and listen to it.
Thanks,
X
  Reply With Quote
Old 30th January 2013, 04:57 AM   #5179
GM is offline GM  United States
diyAudio Member
 
GM's Avatar
 
Join Date: Jun 2003
Location: Chamblee, Ga.
Quote:
Originally Posted by B00B00 View Post
What amp would you suggest to go with these?

Big chunky file used.
Greets!

That's the ticket! Sometimes we need to be coarse.

Well, either amp should do fine, though I would ‘test the boundaries’ of bass extension with the 540A by using cheap 25 ohm pots to dial in however much [if any] series resistance improves the overall performance and replace them with a fixed grid of small resistors.

Long term, either a matching impedance SET or low DF PP amp is what this horn driver wants to ‘feel’.

GM
__________________
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
  Reply With Quote
Old 30th January 2013, 01:10 PM   #5180
B00B00 is offline B00B00  Canada
diyAudio Member
 
B00B00's Avatar
 
Join Date: Apr 2012
Brillant! Thanks Greg...
Now I just have to finish the things.

Any suggestions with regards to wing/supra-baffle shape?
Total of 30 inches wide. Earlier in the thread someone, I forget who had good results with a trapezoid (pic not to scale)
Click the image to open in full size.
but 6-7 inches wide (which would leave us somewhat short of 30inches.
Rectangular? Curved? (oblong oval)
Full length rectangle?
I'm gathering that round is bad.

I'll experiment but if pointed in the right direction it would save me time, material and money.

Pics of last night's progress...
Click the image to open in full size.
Making a pattern to *enable* inside of the cabinet.
Going to plasticize it, cut out the squares and use a putty knife and plaster to apply it. (I don't have the patience to apply 14billion little squares of tape)
At least that is the plan.
We'll see how well it works in reality.

Hoping to get these up soon.
-andré-

Last edited by B00B00; 30th January 2013 at 01:11 PM. Reason: spelling
  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 08:57 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