Dual Chamber Speaker Box

[suministros]

hello friends

I Carlos From Colombia, i already buy almost 6 months a DB II from DECWARE, that is playing in my Susuky Twin Cam car, with a cheap 10 " DVC subwoofer, thats sound Good but now I like to make a new Box. Myabe a Dual chamber Box or a TL box.

Someone tell me that i have to do it this way :

" The first (larger) chamber is twice as large as the second side and all ports are the exact same size. They have two tuning frequencies and get very loud at all frequencies between the two. when designing them, design them as one large box with 2 ports, then split them 2/3 and 1/3. when building, remember to account for port and sub displacement. The bigger the box, the louder it will get, but mechanical power handling may be impaired (similar to a large ported box). "

I have a few Questions :

What it mean "but mechanical power handling may be impaired " ???

Do i have to use stuff in both chambers ??

Does this box sound better than a TL Box. ??


Here you can see the diagram of the Box Is somone car page NOT Mine. So I give all the credits to him.


http://www.sounddomain.com/member_pa...=318757&page=2


Sorry for my english ....

AND THANKS

CARLOS GARCIA

Final question How can I insert a image form my computer

[claudio]

Hello,
try reading those : http://www.diysubwoofers.org/prt/dual_chamber.htm

article about double chamber speaker enclosure

Regards

Claudio

[kelticwizard]

Claudio, did you get the chance to go ahead and build the double chamber reflex you mentioned in the other thread?

[suministros]

I show you my speaker Box plot in WINISD, i calculate the vents the way you explain in the past post.


Driver : PIONEER TSW 304 F 12"
Project by : Carlos
Project for : you
--
Number of drivers : 1
Box type : Vented
Box size : 125,3 l
Tuning frequency : 28,82 Hz
Vent : 2 vent(s)
3,05 in length for each
2,00 in round


Relative
Freq Gain SPL
[Hz] [dB] [dB]
20,00 -12,60 -12,60
25,00 -4,90 -4,90
30,00 -1,24 -1,24
35,00 -0,29 -0,29
40,00 -0,10 -0,10
45,00 -0,06 -0,06
50,00 -0,04 -0,04
55,00 -0,03 -0,03
60,00 -0,02 -0,02
65,00 -0,01 -0,01
70,00 -0,01 -0,01
75,00 0,00 0,00
80,00 0,00 0,00
85,00 0,00 0,00
90,00 0,00 0,00
95,00 0,00 0,00
100,00 0,00 0,00

[claudio]

Hi Kelticwizard,
here's a pic but I have stopped the testing cause I was working on my home page, that speaks about Speaker Workshop and double chamber reflex.

Suministros, the ports looks right, but Iwould use a larger diameter since it's a 10 inch woofer.
However I am not familiar with car speakers, maybe someone else could help you. Maybe a closed box would prevent too bumpy lows.

[nobody special]

Claudio,
how do they sound? Very nice.
Steve

[claudio]

They sound awful !!
Really they are just burning in, I need some more time to start listening sessions.

Claudio

[suministros]

I will try it and post some photos, and then tell you how they sound......

THANKS AND NICE SPEAKER CABINET GOOD JOB.

[kelticwizard]

Claudio:

Well, the double chamber reflex boxes you made are certainly stylish. Nice job.

The double chamber reflex design is an excellent choice if you are going to use a two way design that still gives out deep bass. The more the cone has to move at bass frequencies, the more the midrange gets muddied. This is called Intermodulation Distortion and it is audible as the "fuzz" an overdriven speaker gives.

A closed box speaker gives no excursion relief at bass frequencies, and therefore the midrange frequencies get muddied. The conventional single chamber reflex, (ported) gives substantial excursion relief, (ie, the cone must move much less to produce the same bass output as the Closed Box). This excursion relief is given through the lowest octave of the speaker's range-where the speaker will be moving the most.

The double chamber reflex extends this relief upward another octave, making the midrange even less distorted than the single chamber reflex, which itself was quite an improvement over the Closed Box in this respect!

It is sort of a tradeoff. The port adds a certain degree of distortion over the closed box at bass frequencies, but it cuts down on the cone excursion that muddies the mid and high frequencies.

Having never heard a double chamber reflex, I would speculate that the tradeoffs favor the double chamber design. That is because the ear is less sensitive to distortions at the bass frequencies than it is at the midrange frequencies. Therefore, you are better off keeping the midrange frequencies-where most of the music is-as clear as possible.

If you have to have higher distortion in some range as compensation, make it the bass range. That is what the double chamber design does.

Of course, it would be a good idea for me to listen to one to verify this theory. But if I had to speculate, that would be my guess.

Are those yellow coned drivers Focals? And what brand of ribbon tweeter are you using?

[mikee12345]

If you have to have higher distortion in some range as compensation, make it the bass range. that is what the double chamber design does

yes

if you model the port to be large area,it wont puff and have lower compression <17m/s

Personaly i think all too often we hear boomy bandpass boxes
-car audio has to answer for that

a box designed to notboom- will surely sound better..there was an article in EA that has a bandpass box so an optimized one with ideal woofer should be fine

il stick to my sealed or ported boxes :-D

1% distortion isnt so bad in the bass range-its hard to find exact numbers.also IM distortion sounds more disgusting than normal harmonic related distortion


1% distortion in the midrange would be awful