Terry Cain's BIB -why does it work and does anyone have those Fostex Craft Handbooks?

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#3,981
Anyone else notice we're about to crack the 4,000 post mark? Never expected that when I started the thread...

I just noticed that there were > 13K readers of my posts in the FR tech articles. DONT YALL PPL HAVE A LIFE?

Please sit back and enjoy your loved ones, enjoy the moment,/music, life is short and you never know when it ends.

ron
 
#3,982
kristleifur said:
Hi, I just got a pair of Omnes Audio BB3.01 drivers. They're rougly similar to Tang-Band W3-871, but not quite the same.

Roughly translated from the specs found here:
http://www.spectrumaudio.de/breit/omnesaudio/omnesaudioBB3.01.html

... the driver looks like this:
Nominal impedance / DC resistance: 4 / 3,6 Ohm
Resonant frequency: 95 Hz
Qms / Qes / Qts : 1,8 / 0,43 / 0,35
(Vas): 1,76 Liter
(Sd): 32 cm²
Antriebsfaktor (BL): 3,42 Tm
(Xmax): 1 mm
(Le): 0,09 mH

I was planning to build a pair of Cyburgs Needles or TABAQs. As I'll get some wood cut for me anyway, I'm going to ask -- Can you good people imagine that these would be suited for a pair of BIBs?

Thanks!

edit: notice the 4 ohm impedance - I'm hoping for a magical combination with a Tripath chip with this driver, whatever the enclosure.
Click to expand...

Greets!

Hmm, I noted this to do back on 12.28, but for whatever reason I forgot about it and don't see where anyone else did it, so at least for the record:

L = 70.866"
Sm = 16.332"^2
zdriver = 15.378"
a-b-c = 2.403"

Due to its size/high F3, best to floor load it IMO, though unfolded puts the driver too high for most folks and folded puts it too low, so I recommend moving it as close to the top as you can and add a supra baffle to space it out for the motor to just clear the internal baffle.

GM
 
#3,983
GM said:
Greets!

?? Why should there be any animosity?

Hmm, FWIW you used the FE166E published specs, not the special edition FE166ES-R, but that's fine since it's what you're buying. That said, since I did the design math I don't understand why the SS you used is so far off from mine, which assumes MJK's 342 m (13,464.54")/sec SoS:

L = 134.645"
Sm = 116.252"^2
zdriver = 29.218"
a-b-c = 6.411"

All things considered though, there's no good reason not to just use T.C.'s 'standard' height to get it a little closer to the ceiling/raise driver height:

L = 138"
Sm = 113.416"^2
zdriver = 30"
a-b-c = 6.332"

All that said, while those differences may not be audible in-room, there's the issue of either using a high output impedance amp and/or a BSC filter and/or tiny, resistive wiring which will raise Qts potentially enough to require increasing Sm/a-b-c that combined with your smaller calc'd size probably will be audible, especially down low where the driver needs all the acoustic protection the pipe can give it........

So, do you need to take any of these things into consideration or are you just going to drive it with an SS amp through relatively large gauge wire?

GM
Click to expand...

Thanks GM, I don’t know why other forums have nasty posts. Perhaps music does calm the savage beast.

I understand very little about speaker design and nothing of the maths involved. I probably shouldn’t even be posting here, anyway, I’m all for building the larger box considering how many times I’ve seen “bigger is better”.

I put Mr Cain’s “standard” height in the calculator and came up with these measurements (outside):

W 10.335”
D 14.065”
H 69”

Do these look accurate? Close?

I’ll power them with an old NAD 3020 25w/c intergraded amp w/ large wire for now and think about a T-Amp for later. I really don’t know what I’m doing and would like any advise from anyone willing to take the time.

Thanks in advance,
Mack

Will trade advise on small boat building for advise on audio. http://mackhorton.com/Sharpie web/BB1.htm
 
#3,984
Re: ordered FE166ES

tilroh said:
Thanks Zero One, I quickly ordered two FE166es before I thought too much about other speakers. As suggested, I'll bolt them face to face, out of phase and play radio white noise to break them in.

I found Godzila's spec.s on the FE166ES-R and entered these in to his wonderful BIB calculator and got the attached. Does it look correct?
Click to expand...

The VAS was not converted to Imperial from metric. Here is and updated view of the spreadsheet. Also, I plugged in the numbers from TC's original like GM suggested.
 

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#3,987
Re: Re: ordered FE166ES

zayne742 said:


The VAS was not converted to Imperial from metric. Here is and updated view of the spreadsheet. Also, I plugged in the numbers from TC's original like GM suggested.
Click to expand...

Thank you zayne!

I've just ordered the 18mm ply. It's interior grade Hoop Pine with harder pine on the outside and softwood on the inside. I think the duel density will cut down on resonance. At least the idea sounds good.

Thanks again.
 
#3,988
Scottmoose said:


Then you're going to need some series resistance on the driver as the 3020's output impedance is a bit low to suit the 166.
Click to expand...

Thanks Scottmoose,

I searched for "lower impedance" and found a suggestion to add a 5Ohm resistor in series for the 168's. Do you think the same value work for my FE166's? Are there other things I can try?

It looks like a Tripath amp is the way to go.

Thanks for your time.
 
#3,990
tilroh said:


Will trade advise on small boat building for advise on audio. http://mackhorton.com/Sharpie web/BB1.htm
Click to expand...


Mack,

I tried the URL for your Sharpie. Very nice boat and excellent workmanship. Believe it or not, there a few boatbuilders here on diyaudio. We had a thread going last year that essencially took a rather abrupt turn into an off-topic wooden boat thread. Finally the moderator even tried to stop it, which evenually did die down.
😉

Best Regards,
TerryO
 
#3,992
Neofone cabinet dimensions for BIB

Folks

Having come across some posts from an individual having a difficult time with a BIB BIB Problem I've postponed the order on my wood. I need some further advice.

These are the parameters of the Neofone that I entered into the spreadsheet...
Fr 53.7
Vas (litres) 11.6 (0.41)
Qts 0.42

This produced :
Line Length 125.37
Zdriver 27.2
Sm 76.36

I'm planning on using 3/4" (71mm) MDF for the cabinet.

I have 2 cabinet dimensions that I'm considering and need to know which is likely to give the proper result.

Option 1 is based on Terry Cain's original BIB.
Internal Dimensions
(H W D) 70" x 5" x 12" (1780mm x 127mm x 304mm)
The internal baffle centred 5.5 inches (139.5mm)
The driver 39" from the top (990mm)

Option 2 is having run the Neofone spec's through the BIB spreadsheet.
Internal Dimensions
(H W D) 62.5" x 7.35" x 10.39" (1600mm x 190mm x 260mm)
The internal baffle centred 5.25" (133mm)
The driver 27" from the top (686mm)

Any input will be appreciated.

Thanks

Brian
 
#3,995
Just spent about an hour listening to my 165k BIBs and loved them. Sometimes they sound warm and lush while sometimes they sound thin. Depends on the music selection i guess. Paul McCartney, Bruce Springstein sounded lush and warm as did Pink Floyd. Blondie and Queen sounded thin except for Another One Bites the Dust which is full of bass. Everyting sounded clear and effortless. Guitars and special effect sounds just pop out of nowhere with a surprising amount of life. Very cool. I would like to upgrade to the fostex 225k but don't have the room. My ceiling is only 76 inches high in the basement.

http://www.zillaspeak.com/systems.asp
 
#3,997
Godzilla said:
Just spent about an hour listening to my 165k BIBs and loved them. Sometimes they sound warm and lush while sometimes they sound thin. Depends on the music selection i guess. Paul McCartney, Bruce Springstein sounded lush and warm as did Pink Floyd. Blondie and Queen sounded thin except for Another One Bites the Dust which is full of bass. Everyting sounded clear and effortless. Guitars and special effect sounds just pop out of nowhere with a surprising amount of life. Very cool. I would like to upgrade to the fostex 225k but don't have the room. My ceiling is only 76 inches high in the basement.
Click to expand...

So upgrade to the 225 Jeff. 🙂 Nothing to stop you. You don't necessarily have to make them taller / longer or match to the driver Fs. That just sets the frequency it's tuned to (bit simplistic, but close enough. OK, so it's not optimal, but it still works fine). Just tune to whatever frequency you like & use WxD dimensions to provide the appropriate volume. Won't go much lower than your 165s, but you'll get better power handling & a much greater scale.

Just for you mate: a Godzilla shortened BIB for the FF25K. 136in line for a 68in tall box. W = 10in, D = 14.5in (including a 0.75in thick internal baffle). Zdriver 29.5in. About 2 years back I made a pair with 225s using roughly similar dimensions (few inches taller, bit narrower) for some friends. Suffice it to say, they work. Really rather well.
 

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#4,000
Godzilla said:
Thanks Scott! That will fit my room like a glove. Now someone has to pick up my 165 BIB and give it a happy home so i can build the 225 BIB.

Godzilla
Click to expand...

have you reconsidered my offer then?

and since i picked up a pair of the 165's over the holidays you would only have to mail the cabs!
🙂

good to see you're up and around and in a speaker building state of mind. now somebody please take these 165 bib's off jeff's hands!:smash:
 
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