# JBL car sub driver, in old DIY cabinet...



## SRR (May 4, 2008)

Driver GT122D (scroll down):

http://manuals.harman.com/JBL/CAR/Owner's Manual/GT122,GT122D om.pdf

Amp NAD 3020 intergrated 25-30 years old.

Cabinet, DIY by my dad 10 years ago, 2.5-3 cubic feet or there abouts, port is plugged.

1124P 5 filters

Response:











This is just a temporary set up till my Epik comes. But I thought I would share.


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## Blaser (Aug 28, 2006)

Hi there!

Looks pretty flat down to 13 Hz...What's the tune? Can you post a graph with 10-200 Hz scale for the X-axis, and 45-105 Shack standard scale for the Y-axis?


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## SRR (May 4, 2008)

I have no idea of the tune, as the box was built for a 8" driver that I blew up long ago. The T/S parameters are on the .PDF of the JBL driver link above. If someone more knowledgeable about such things could tell me what the box is tuned to since I sealed it up I would be great full (Its got to be somewhere around 3 cubic feet). Btw I sort of went for a house curve I even boosted a little at 24Hz~ like 1-2dB I forget what I did, but I think for a box that my Dad built a long time ago, with a JBL car audio driver with just a 40oz. magnet, can do that, I am impressed. This FR, is with one main speaker, it was a quick Audyssey, three spots all in the first of my three rows. Oh the mic I used for REW, is a DBX RTA-M, mic preamp ART PRO MPA (black face edition). Room 19'x12'x8'~.


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## SRR (May 4, 2008)

Oh I have two more 6"x2'x4' traps going into the room this weekend if I get around to it.


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## Blaser (Aug 28, 2006)

Sorry...Since you plugged the port there is no tune anymore. It is sealed now. Great response, but I think you would benefit from a BFD. Great news about the bass traps:T


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## SRR (May 4, 2008)

SRR said:


> Driver GT122D (scroll down):
> 
> http://manuals.harman.com/JBL/CAR/Owner's Manual/GT122,GT122D om.pdf
> 
> ...


That is with a BFD....:whistling::whistling::whistling::yay::yay::yay:


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## SRR (May 4, 2008)

Blaser said:


> Sorry...Since you plugged the port there is no tune anymore. It is sealed now. Great response, but I think you would benefit from a BFD. Great news about the bass traps:T


Don't sealed subs still have a tune? I know sort of how tunning works with ports, and I only plugged it cause I had way to much energy at 60Hz, so I said **** lets see what I can get with sealed. The box isn't even MDF or Birch PLY, or any Plywood for that matter, It is 3/4 think Pine with a thin laminate of some sorts, I think....Bracing is 2"x2" in all directions of corners. Stuffed with poly and fiberglass.


One more thing, right now I have two 6" traps, two 4" traps, two 2" traps, and some 2" Auralex 4' x 3' foam at the first reflection points on the side walls. Then like I said two more 6" traps going in this week/weekend.


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## SRR (May 4, 2008)

Woooops, that second jpg isn't logarithmic, why? I donnna know, here is the log scale, to show ya a better representation of what it truly is:










Oh and I added a calibration for my sound card, -1.5dB at 10Hz, and something like -.7 at 20Hz, I forget, anyways it is corrected now. But even doing that doesn't calibrate the mic preamp. Which is probably far more off then a good sound card, good meaning M-Audio Audiophile or better. My sound card is a M-Audio 1010LT cause I do recording with this PC. Would like better mic pre's but all good things come after waiting....years in my case.


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## Blaser (Aug 28, 2006)

Yeah, I was about to ask you to change to a logarithmic scale... Now, apply a crossover, it will even look better.

Sealed boxes do not have a tune. They have a -3 db/-6 db point if you want. Tune is only applicable for ported boxes.


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## SRR (May 4, 2008)

I have a better curve now using 4 filters, need to grab it off my other computer this weekend some time, in the between time, I have six 2" rockboard 60 panels I need to turn into two 6" bass traps and the redo two others I stole from my studio. And I have to do it with out getting my fingers glued together. :gah:


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