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Old 22nd March 2013, 08:51 PM   #1
diyAudio Member
 
Join Date: Mar 2013
Location: Ontario Canada
Default ABC enclosure

I am currently working on a build and I'm looking for help on designing an enclosure. Could someone with experience comment on size and tuning for these or useable software.

does the tuning shelf extend from the lower tuning all the way to the upper tuning freq or does it peak in between?

also difference between 3:1 and 2:1 ratio?

optimal tuning for a 12w7

specs:

Free Air Resonance (Fs) 27.2 Hz
Electrical Q (Qes) 0.514
Mechanical Q (Qms) 7.807
Total Speaker Q (Qts) 0.482
Equivalent Compliance (Vas) 2.33 cu ft / 66.0 L
One-Way Linear Excursion (Xmax)* 1.15 in / 29 mm
Reference Efficiency (no) 0.249%
Efficiency (1 W / 1 m)** 86.2 dB SPL
Effective Piston Area (Sd) 84 sq in / 0.0542 sq m
DC Resistance (Re) 2.47 Ω
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Old 22nd March 2013, 11:51 PM   #2
Zero D is offline Zero D  United Kingdom
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Join Date: Aug 2009
Hi,

One source for FREE software that does ABC = WinISD v0.7.0.809

Quote:
does the tuning shelf extend from the lower tuning all the way to the upper tuning freq
Yes

Quote:
or does it peak in between?
It depends on where the low & high tunings are placed, & the volume of both cavities, & the ratio of both to each other. Often there can be a dip in the middle.

Quote:
also difference between 3:1 and 2:1 ratio?
See above

Quote:
optimal tuning for a 12w7
That depends on what you want from the design. For eg, Max Power, f3, SPL @ 1W, Max SPL, etc etc.

Let us know how you get on
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Old 23rd March 2013, 10:51 PM   #3
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Join Date: Mar 2013
Location: Ontario Canada
I want the cabinet to have a very flat response, will being a little bit more efficient than my current ported set up. A huge problem i'm currently having, and something I'm shooting for is excellent transient response, without using a sealed enclosure.

low tuning - 27 Hz
high tuning - 53? I think it's just under an octave, correct me if i'm wrong.

how fast will it roll off below 27? If my x-over is set at 20... would it be recommended to tune lower?

can you further explain the effects of a 2:1 or 3:1 ratio? I've only ever seen these two recommended but never why...

I have space for around 3.5 ft3, maybe more. (I'll be using two woofers, so read 7 ft3)
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Old 23rd March 2013, 11:09 PM   #4
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Join Date: Mar 2013
Location: Ontario Canada
btw, thanks so much for pointing out version 0.7 I was getting so frustrated with the new one...
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Old 23rd March 2013, 11:40 PM   #5
Zero D is offline Zero D  United Kingdom
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Join Date: Aug 2009
Have a look at these designs i've in done, with the software i recommended to you earlier.

The Reflex is Orange & the ABC is Yellow.

Reflex

Vol = 4.670 ft3 - fb = 30Hz

ABC

Vol = 3.178 ft3 = 1.589 ft3 = 4.767 ft3 - fb's = 15Hz + 40Hz

Both with a LR 24dB 20Hz HPF

Speakers are, mainly, limited by 2 things, Power & Excursion limits. One is usually reached before the other. So even though this driver lists Xmax as 29mm, it can Only take 1000W Max. So it has more excursion than it needs, before Max Power is reached. Which means you won't be able to take advantage of all of it !

I was going to strongly suggest you install the software, & experiment for yourself with various different options/designs etc. Post back with your results, hopefully with some screen shots "screenies"

Unfortunately i've just checked the DL link for you, & seen this

Quote:
www.linearteam.org • Information We have taken down the forums because not being able to fight against extensive spam.
Very sad

The version of WinISD = v0.7.0.809 that does ABC's was only available via their forums. The other 2 versions still available on their home page, don't. If you like though, i can upload somewhere 7 PM you the DL link
Attached Images
File Type: png TFM.png (6.3 KB, 140 views)
File Type: png Max spl.png (5.2 KB, 140 views)
File Type: png max pow.png (3.5 KB, 137 views)
File Type: png ex.png (5.5 KB, 136 views)
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Old 24th March 2013, 12:16 AM   #6
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Join Date: Mar 2013
Location: Ontario Canada
there's no way to utilize that x max then? I have seen these woofers fully exursioned (sp.?) and it looks intense...

Click the image to open in full size.

JL only recomends 1.7 ft3... there's no way that could come even close to 29mm.

Question, If I were to remove the LP, and tune the enclosure so it approached xmax around 19-20 hertz, is there a real chance it will reproduce something below such as 15 hertz and bottom out? I listen to regular mp3's. rap, rock, radio...
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Old 24th March 2013, 12:18 AM   #7
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Join Date: Mar 2013
Location: Ontario Canada
was the reflex a standard ported enclosure? Because I was looking into doing a triple chamber double reflex.. that or the ABC. My only concern is transient response. I want clean tight bass, and then I want it to be loud.
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Old 24th March 2013, 12:39 AM   #8
tb46 is offline tb46  United States
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Join Date: Jan 2006
Location: Texas
Hi Zero D,

Thanks for the tip ref.: WinISD v.0.7. I downloaded it from Facebook (had to join, but that had to happen sooner or later anyhow).

Regards,
__________________
Oliver
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Old 24th March 2013, 12:40 AM   #9
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Join Date: Mar 2013
Location: Ontario Canada
As the volume of the enclosure rises, so will cone excursion correct? resulting in more spl? In this case, could I create a cabinet that is 7.0 or 8.0 ft3 rather than previosly stated, and use an isobaric setup?

I would lose the 3db from the second speaker, however would I gain 3 db from the larger enclosure?

Does isobaric loading increase sq (transient response, lf response, etc..) ?
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Old 24th March 2013, 01:27 AM   #10
Zero D is offline Zero D  United Kingdom
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Join Date: Aug 2009
Quote:
there's no way to utilize that x max then? I have seen these woofers fully exursioned (sp.?) and it looks intense...
Mental is how i would describe it Don't expect nice clean tight bass etc from ANY driver pushed that hard, or anywhere near, or expect it to live long either

Quote:
Question, If I were to remove the LP, and tune the enclosure so it approached xmax around 19-20 hertz, is there a real chance it will reproduce something below such as 15 hertz and bottom out? I listen to regular mp3's. rap, rock, radio...
You mean HP ? Yes you can remove it, but i wouldn't, instead if you can, have one that is at or just below your lowest tuning. For eg, if you tune it to 20Hz make the HP 20Hz - 15Hz. You're confusing tuning with Xmax. Just because a box is tuned low, does not mean it will atomatically reproduce down there, if there are no such frequencies in the material being played. Also even if there are, if the boxes low frequency is tuned too low for the driver, the response will be tailing off by then, sometimes by quite a bit !

Quote:
was the reflex a standard ported enclosure? Because I was looking into doing a triple chamber double reflex.. that or the ABC. My only concern is transient response. I want clean tight bass, and then I want it to be loud
Yes it was, because you stated "My current setup is 1.67 cu ft ported at 31 Hz." I did that for you so you could compare what you have now, with what you initially posted wanting, an ABC with that driver.

Here's the ABC @ 1000W tuned to 15Hz & a 15Hz LR 24dB HPF. It's run out of power @ 20.5Hz & Xmax is near Maximum now.

Quote:
As the volume of the enclosure rises, so will cone excursion correct? resulting in more spl?
No, the excursion will be less, & the box will be able to be tuned lower, so it will be able to produce lower frequencies better. The SPL could actually be less !

If you want to discuss other options, such as isobaric etc, you should start a new thread/s.

@ tb46

Hi, pleasure, it's nice to be appreciated Though it's a pity you had to join FB to get, as i would have uploaded it for you Unless you delete your account @ FB, i would Strongly advise you to check out these links, Before you venture on with it.

Search for "facebook privacy guide" just one for eg, The Always Up-to-Date Guide to Managing Your Facebook Privacy You won't regret it, Regards
Attached Images
File Type: png maxspl3.png (3.4 KB, 10 views)
File Type: png maxp3.png (2.3 KB, 7 views)
File Type: png ex3.png (4.0 KB, 4 views)

Last edited by Zero D; 24th March 2013 at 01:30 AM.
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