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Old 27th January 2008, 13:31   #16
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The simulation softwares are good to play with. Help a lots of time but the results can be very weird when wrong parameters are used.

Any particular reason for a bandpass enclosure ? why not ported.
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Old 28th January 2008, 09:43   #17
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The addition of polyfill in the port side of the design helps in attenuating the vent, as the ported chamber is responsible for the upper F3 value. The downside is that port length should be increased compared to a no fill which may become a constrain when the ported chamber has a reduced volume.
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Old 28th January 2008, 14:14   #18
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Quote:
Originally Posted by low_bass_makker View Post
The simulation softwares are good to play with. Help a lots of time but the results can be very weird when wrong parameters are used.

Any particular reason for a bandpass enclosure ? why not ported.

I will try to justify my choice here
  1. Main reason being the Gt4-12 driver parameters are not great for a proted enclosure as per what i understand. It can either do well with a sealed or a single tuned bandpass.
  2. The driver noises would not be thrown out due to enclosure's upper f3 which, an active or passive LPF will not be able to deliver.
  3. The acoustic boom factor or in-car dynamics at 50 hz crossfades well with the rollout.
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Old 28th January 2008, 17:32   #19
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Quote:
Originally Posted by Xmax View Post
I will try to justify my choice here
  1. Main reason being the Gt4-12 driver parameters are not great for a proted enclosure as per what i understand. It can either do well with a sealed or a single tuned bandpass.
  2. The driver noises would not be thrown out due to enclosure's upper f3 which, an active or passive LPF will not be able to deliver.
  3. The acoustic boom factor or in-car dynamics at 50 hz crossfades well with the rollout.
The EBP of the sub is 53.8 so it is close to 50 but greater than 50. which means ported. Also the qts is .429 which is again at the margin point.

In which car are you going to use the sub. Hatch or sedan.

The best roll out is for the sealed enclosure. But then again there are compromise.
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Old 28th January 2008, 18:52   #20
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i am planning this for a sedan - lancer's boot to be precise.
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Old 28th January 2008, 20:58   #21
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i am planning this for a sedan - lancer's boot to be precise.
Xmax can we all have the pleasure of an intro?
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Old 28th January 2008, 22:22   #22
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Quote:
Originally Posted by JPL View Post
Xmax can we all have the pleasure of an intro?

JPL bhai, I tried one at the introduce yourself thread and finally had my share from our jkdas .

http://www.team-bhp.com/forum/introd...91-hi-all.html (Hi all,)
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Old 28th January 2008, 22:30   #23
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Quote:
Originally Posted by Xmax View Post
i am planning this for a sedan - lancer's boot to be precise.
Hate to say that the sub will get a bit low in the sedan when compared to a hatch.
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Old 29th January 2008, 00:27   #24
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Hi Vimal Paul! Welcome to the ICE section!

For someone not professionally into audio, you have a good hold on audio concepts. It will be great to have you around here, and read your contributions.
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Old 29th January 2008, 10:55   #25
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Quote:
Originally Posted by Xmax View Post
JPL bhai, I tried one at the introduce yourself thread and finally had my share from our jkdas .

http://www.team-bhp.com/forum/introd...91-hi-all.html (Hi all,)
Sorry for that man..thanks for the link though.

Quote:
Originally Posted by Bass&Trouble View Post
Hi Vimal Paul! Welcome to the ICE section!

For someone not professionally into audio, you have a good hold on audio concepts. It will be great to have you around here, and read your contributions.
I agree, welcome again.
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Old 29th January 2008, 14:05   #26
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Thanks B&T. Its the simplicity you gurus maintain in this forum, that makes newbies participate without hesitation. The ICE section especially has always been a great place for learning things in its best possible. Keep up the good work.
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Old 25th February 2008, 10:17   #27
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Quote:
Originally Posted by Xmax View Post
Hi Sam,

Thanks for the design. Just to clarify, do you really need it that big? Because I am able to achieve an f3 low at 30 and f3 high at around 90 (in theory) with a chamber lesser in size.

V rear 27.98 L
V front 24.5 L
Port 3.5 in
Length 8 in

Hey Gurus, What say? After alll that we have dicussed so far on this thread, Will it be worthwhile sticking to these for the enclosure parameters for my GT4-12 ?
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Old 26th February 2008, 01:27   #28
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you can try the ported box as suggested earlier. I will be easy to build when compared to the bandpass.
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Old 26th February 2008, 10:45   #29
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Quote:
Originally Posted by low_bass_makker View Post
Hate to say that the sub will get a bit low in the sedan when compared to a hatch.
the extra efficiency of a band pass box might help over come this.

Quote:
Originally Posted by hydrashok View Post
Is it intended more to reduce the velocity of the air exiting the port, and so to reduce port whistle?
not really it is to ensure that none of the midbass get out. a 6" dia port will not have much air noise (even if it is 10" long).

I dont have the T/S of the woofer but with a Qts or about 0.4 it is ok for band pass.

LBM, remember not to take the published T/S parameters as the gospel. There are often variations that are significant. With an EBP of 50 the woofer can swing both ways.
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Old 31st March 2008, 15:52   #30
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Quote:
Originally Posted by low_bass_makker View Post
you can try the ported box as suggested earlier. I will be easy to build when compared to the bandpass.
Thnx for reiterating the same.But LBM; what will be the specs for the Ported one...can't really figure that out!!
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