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JBL GT150 15 " subs (Read 13625 times)
60ndown
Ex Member



Re: JBL GT150 15 " subs
Reply #30 - 12/04/05 at 16:32:31
 
[quote author=gexter  link=1133408581/15#28 date=1133678019]I have an I.B. in my wagon and it sounds awsome but it just does not get loud enough for the times a guy likes it loud.


[/quote]

my amp is class d and puts out about 6oo wrms (stock electrical)and the 12" sub takes 500wrms has an fs of 18....yes 18 and an x max of 24.2 mm. it gets loud and low Wink

http://www.soundsplinter.com/specs/rlp12_specs.htm
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« Last Edit: 12/04/05 at 16:33:14 by 60ndown »  
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J_Rock
Ex Member



Re: JBL GT150 15 " subs
Reply #31 - 12/04/05 at 16:41:55
 
you have an expedition right, you wanna slam 3 WOs with 15 in there, without the back seats I bet you can do it.

What I would do first is to measure how wide the back is at the narrowest points, so between the wheel-wells.  Whatever that measurement is, make the WOs that measurement, Y, YxY x 19 or so.  then take the 3 WOs and lay them at angles pointed towards the front or back, whichever is louder.

Otherwise, set the WOs up in a triangle, one on bottom and the other two tilted on top.  I don't know if you will have the heighth though.

I drew some crappy pictures, although my mastery of Paint is Increaseing ten-fold daily.



If you go the route of angleing them towards the fron or back, try to angle them as much as possible, or as close to flat.  This will give you more air path above them, although you might wanna try different angles cause that could effect performance.
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« Last Edit: 12/04/05 at 16:46:27 by j_rock777 »  
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J_Rock
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Re: JBL GT150 15 " subs
Reply #32 - 12/04/05 at 16:44:07
 
also, ported version for SPL:



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gexter
Ex Member



Re: JBL GT150 15 " subs
Reply #33 - 12/04/05 at 22:23:42
 
thanks  J_Rock
I never saw the pictures of the ported version. It was not what I thought it would be.
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60ndown
Ex Member



Re: JBL GT150 15 " subs
Reply #34 - 12/04/05 at 23:27:55
 
port schmort Lips Sealed
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db_audio
Ex Member



Re: JBL GT150 15 " subs
Reply #35 - 12/05/05 at 04:56:18
 
GEX...you know what me and my wife were thinkin about how to port it. we came up with very close to what the pics show...but...im like naw that couldnt work because of the phase difference...but now you show pics and i guess it does work...
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db_audio
Ex Member



Re: JBL GT150 15 " subs
Reply #36 - 12/05/05 at 05:12:58
 
i bought my wifey a new expedition last week and im keeping her old one! which has a ton of gear in it already! i had 9 of the 15's in it (LOUD) but took it out 'cause we WERE gonna trade it...we didnt! YEAH!

my point is i wanna make this thing just stupid loud...louder than the 9 i just took out. Im hoping that the Wo is the ticket!

if i remember correctly my 9 15 box is around
50W X 33H X 30L

I figured i could have them firing toward the roof, they might load off the roof pretty good...just thinking.

oh yeah, those drawings wernt TOO crappy! LOL!
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gexter
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Re: JBL GT150 15 " subs
Reply #37 - 12/05/05 at 05:13:04
 
from what I ahve read so far on the porting of the WO is it is good for SPL only.
And I agree on the phasing and 60's view of the whole thing.
but........ I think its possible to make it close to the SQ with enough trial and error ( mostly error )

Sometimes the science of it is not the whole story.
also lack of funds makes a person try the silliest things....

I just bought an plate Amp today for really cheap out of the box.  it even came complete with a sub and box. Cheap box, cheap DVC sub. decent 100 watt plate amp. cheaper buying the whole thing than just the plate amp.


strange how things work out sometimes
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gexter
Ex Member



Re: JBL GT150 15 " subs
Reply #38 - 12/05/05 at 05:23:04
 
If your thinking stupid loud and stupid good don't take the chance on modifications. you have the area and the power to make the WO put out.
If you do the J_Rock tilted sub idea I would fire them off the roof also, but tilt them toward the back on your first trial run.

Excess is fun but rarely practical. But what kinda fun is practical?
Hey!  that could be my new tag line

too bad I am getting to practical  :(  thats just no fun!!   Wink

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J_Rock
Ex Member



Re: JBL GT150 15 " subs
Reply #39 - 12/05/05 at 05:29:31
 
if you measure the distance from the drive to the port opening in the horn mouth you get 1/4 the wavelength of the highest freuency total wave addition occours at.

So you measure, then tune the box to that frequency.  Not only making the front and back waves add, but also oncreasing efficiency at the frequency at and around which they add.  If you were gonna go real big you could aim to tune the entire thing at your vehicles transfer fucntion frequency to get even more bass.

I would suggest just 3 WOs though for sure.  port them if you can figure out the math and what not otherwise just let them sealed.

My WO has increased my 2 drivers rated sensitivity by 19db at least.  (Drivers max power = 2^[X]; X x 3 = Driver's proposed SPL at max Wattage.  My wo puts out 19 db more than that SPL at half volume on the dial. No way to test further...)
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J_Rock
Ex Member



Re: JBL GT150 15 " subs
Reply #40 - 12/05/05 at 05:33:32
 
If you could give me the width of you epedition I could figure out the WO chamber's and the original designs's ported frequency.  and then design the 6th order BP with smae chambers and front port to create what would be the supposed correct port.
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db_audio
Ex Member



Re: JBL GT150 15 " subs
Reply #41 - 12/05/05 at 05:48:10
 
i have a tightly squeezed 50" (max width)
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gexter
Ex Member



Re: JBL GT150 15 " subs
Reply #42 - 12/05/05 at 05:50:19
 
(transfer fucntion frequency to get even more bass. )

I have not heard that term before, are you talking about wavelength, or what exactly so I don't have to guess.
even a link to where you got the terminology would be good.

I had to learn so much stuff over the last month or two I have holes in my knowledge. and my life keeps interrupting me on top of that.

thanks
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db_audio
Ex Member



Re: JBL GT150 15 " subs
Reply #43 - 12/05/05 at 05:57:10
 
ok but doesnt the port need to be tune approx 5-10hz highter so that they dont cancel...or would you have to have the ported camber 1/16 wavelength if you have 1/4 coming from the mouth? im just thinking of distance and the timing...i havnt done the math yet.
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J_Rock
Ex Member



Re: JBL GT150 15 " subs
Reply #44 - 12/05/05 at 12:30:48
 
hold the thought bout port frequency, I just remembered something. SO I gotta check something else.

Transfer function is kinda like your entire car's resonant frequency. The problem is that as power goes up the cars resonant frequency goes up too, hence you get a function of resonant frequency vs. power output.  Kinda like this:

With my subs barely playing say at 45 hz, my car rattles like all hell and there is a noticeable increase in output going from 35 to 50 at 45 hz.  My car resonantes there at 50 w or whatever.  If I crank my WO all of a sudden my car doesn't resonant at 45 as much, the noticeable uncrease is at 55hz.  

At least its something like that.  I normally say resonant frequency of the vehicle but I get slack from a different forum for saying that...
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