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Old 3rd January 2013, 11:32 PM   #1
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Location: Brasil
Default BASS REFLEX ENCLOSURE/TUNING

Hi folks,
I have a pair of 15 inch Dayton ST385 and plan to build a enclosure for it.

I listen to all kinds of music, specially classical and jazz, so it needs to get a low bass and without boomyness, a tight bass that get low to 20Hz is all I want.

I will use active crossover with a scan speak 8545 crossed at 300Hz and a SS Ilumminator 6600 TW crossed at 2Khz

So I;m planning to build an bass reflex enclosure. The programs I'm working, winISD and the german site (forgot the link), troelsgravensen, all give me different volumes and port sizes, what is the most accurate?
Fs - 18.8Hz
Vas - 301
Qts - 0.32

WinISD
Vb 140,4
Fb 23.82

German site:
Vb 171.57
Fb 22.02Hz

troelsgravensen does not gives me a result but in his projects he uses a number between this two.


in what should I trust? Does transmission Line give me better results?

Thz to all and a happy new year.

Murillo
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Old 4th January 2013, 04:08 AM   #2
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re:"what is the most accurate?" - depends on what alignment the software designer has chosen, in practise there won't be much difference in the outcome. FWIW I use Unibox.
The price for getting down to 20 Hz is a huge cabinet - a smaller cabinet (say 70 - 90 L tuned to the high 20s) will get you to the low to mid 30s, which is more than is needed for good music reproduction.
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Impedance varies with frequency, use impedance plots of your drivers and make crossover calculations using the actual impedance of the driver at the crossover frequency
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Old 5th January 2013, 04:52 PM   #3
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Default UNIBOX

Thx Pete for the info, I will look at Unibox to see what it suggests.
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Old 5th January 2013, 07:14 PM   #4
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Quote:
Originally Posted by murillollirum View Post
...Does transmission Line give me better results?

Thz to all and a happy new year.

Murillo
TL it's not a good option for this driver.
BR it's a better choice.
Your alignment as to do with your options or type of use.
Let's say that a simulated ideal one it's this here,
DAYTON ST385-8, VB = 138.2 L, FB = 18.7 Hz, 86.7 dB/2.83V/m.
F-3 dB 28 Hz
F-6 dB 21 Hz
F-12 dB 15 Hz
Each one will measure it's different T/S parameters for his driver (not the standard) and will choose also different alignments.
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Old 5th January 2013, 07:36 PM   #5
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Default TROELS

I think I will use a 155 liters with fb of 22Hz based in the troels project Jansen 1071 adapting it to a 15 inch version as he uses a 10 inch.
My measuring for the woofer cabinets in the unibox are of 136,4L with fb in 24Hz, but as winISD gives me 141L and mh-audio gives me 170L, 155L is in it's range.
The dimensions are external, 18mm wood.)

Woofer box:
H 87cm
W 42cm
D 52cm
155L internal

MID/TW box
H 38cm
W 25cm
D 33cm
21,5L internal

Jensen-1071
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Old 6th January 2013, 01:07 AM   #6
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Quote:
155 liters with fb of 22Hz
You have plenty of room to play with alignment. Just lower a couple of Hz for Fb if you don't want a very abrupt curve in the lower end (use longer port).
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Old 9th January 2013, 10:17 PM   #7
bjorno is offline bjorno  Sweden
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Quote:
Originally Posted by murillollirum View Post
I think I will use a 155 liters with fb of 22Hz based in the troels project Jansen 1071 adapting it to a 15 inch version as he uses a 10 inch.
My measuring for the woofer cabinets in the unibox are of 136,4L with fb in 24Hz, but as winISD gives me 141L and mh-audio gives me 170L, 155L is in it's range.
The dimensions are external, 18mm wood.)

Woofer box:
H 87cm
W 42cm
D 52cm
155L internal

MID/TW box
H 38cm
W 25cm
D 33cm
21,5L internal

Jensen-1071
Hi,

Late post but here are some suggestions:

b
Attached Images
File Type: jpg Dayton-ST385-8.JPG (883.0 KB, 250 views)
File Type: jpg SS-18W8545-00.JPG (803.9 KB, 232 views)
File Type: jpg SS8545-ST385.JPG (889.2 KB, 222 views)
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Old 10th January 2013, 09:47 PM   #8
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thx for all info. I will try first in an enclosure of a speaker that it's already done and it's very near your measures, 167L.
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Old 27th January 2013, 05:24 PM   #9
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I just came with a ption of installing it in 2 different boxes

BOX 1
VB 220L
Fb 20,78Hz
F3 21.99Hz

BOX 2
VB 160L
Fb 23Hz
F3 25.79Hz

What is the recommended by you guys???

thx
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Old 30th January 2013, 05:41 PM   #10
bjorno is offline bjorno  Sweden
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Quote:
Originally Posted by murillollirum View Post
I just came with a ption of installing it in 2 different boxes

BOX 1
VB 220L
Fb 20,78Hz
F3 21.99Hz

BOX 2
VB 160L
Fb 23Hz
F3 25.79Hz

What is the recommended by you guys???

thx
Hi,

Box # 2 is IMO the best choice.

b
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