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-   -   BASS REFLEX ENCLOSURE/TUNING (http://www.diyaudio.com/forums/multi-way/226997-bass-reflex-enclosure-tuning.html)

murillollirum 3rd January 2013 11:32 PM

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

PeteMcK 4th January 2013 04:08 AM

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.

murillollirum 5th January 2013 04:52 PM

UNIBOX
 
Thx Pete for the info, I will look at Unibox to see what it suggests.

Inductor 5th January 2013 07:14 PM

1 Attachment(s)
Quote:

Originally Posted by murillollirum (Post 3310079)
...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.

murillollirum 5th January 2013 07:36 PM

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

Inductor 6th January 2013 01:07 AM

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).

bjorno 9th January 2013 10:17 PM

3 Attachment(s)
Quote:

Originally Posted by murillollirum (Post 3312475)
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 :o but here are some suggestions:

b:)

murillollirum 10th January 2013 09:47 PM

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.

murillollirum 27th January 2013 05:24 PM

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

bjorno 30th January 2013 05:41 PM

Quote:

Originally Posted by murillollirum (Post 3344686)
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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