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idontknowwhatimdoing
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« on: November 11, 2005, 02:09:31 pm » |
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I have two of these T212D4 12" subs as of yet unused, and am struggling with an enclosure. I hate the standards that most manufacturers are recommending these days with the wicked bump @ 45hz. I am a picky listener and they should live through anything I am going to throw at it (within reason) Any suggestions on a box for these woofers or should I sell them?
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Forceaudio
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« on: November 11, 2005, 02:09:31 pm » |
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Robert
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« Reply #1 on: November 11, 2005, 10:26:54 pm » |
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Welcome to the forum. Who are these made by? Sounds like a Rockford product. Do you have any t/s specs? That might help a little :wink:  Edit: Alright, its not so bad looking stuff up since I dumped dial up. What excatly are you after? Stupied low bass, something just not so peaky, etc. I usually ten to recommend stupied low bass boxes because thats what I like :wink: :lol: |
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Robert
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« Reply #2 on: November 11, 2005, 10:55:33 pm » |
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If I was building a box for myself. Id do 2.5 cubes tuned to 27hz's. Looks flat out of car which adds a fairly nice bump in low end.
Heres the t/s specs for anyone wanting to recommend something.
Qts: .44
Vas: 26.3l
Qms: 4.72
Qes: .48
Spl: 85dB
Fs: 29Hz
Re: 6.4 ohm
Le: 5.6
Bl: 27
Xmax: 19mm
Sd: .043m^2
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Forceaudio
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« Reply #2 on: November 11, 2005, 10:55:33 pm » |
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idontknowwhatimdoing
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« Reply #3 on: November 12, 2005, 09:17:43 pm » |
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Fast bottom end, quick, roll-off around 35, high power handling, you know, everything in one...a miracle! I am looking at the SAME box...2.6 total net@ 26.5 hz
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idontknowwhatimdoing
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« Reply #4 on: November 21, 2005, 12:09:15 pm » |
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Built one this weekend...1.7 ft per driver ported to 38 hz.........fast fast fast....I thinkI am pretty happy.
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95Honda
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« Reply #5 on: November 21, 2005, 01:06:36 pm » |
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That alignment looks pretty peaky-
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95Honda
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« Reply #6 on: November 21, 2005, 01:14:32 pm » |
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Those subs make it pretty tough to design a nice ported box. Thier Vas is just too small, and combined with thier Q, if you make make a box big enough to get a decent size vent with a low tuning they start to get a lot of ripple. They were made to play in tiny sealed boxes, or peaky vented boxes. I'll bet they would get loud, but I would pass on them for anything but that....
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Forceaudio
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« Reply #6 on: November 21, 2005, 01:14:32 pm » |
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idontknowwhatimdoing
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« Reply #7 on: November 21, 2005, 01:34:59 pm » |
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I will fire up LMS this weekend and take a sweep........I bet it will surprise everyone....including me. So far no real peaks that stand out...the curve tells you nothing of the way it *actually* sounds
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95Honda
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« Reply #8 on: November 21, 2005, 01:48:01 pm » |
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It may be fine with the cabin gain of your car.... Or room.... You never know...
Peaky response though.
Sometimes I listen to my RE8s with the tune at 50Hz (10+ db peak) and it sounds OK as long as I keep it low levels....
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idontknowwhatimdoing
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« Reply #9 on: November 21, 2005, 01:54:12 pm » |
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I agree with the theory on the peaky box graph, but listening is the key for me...I am about as picky as it gets (I was heavily involved with the final tuning of the "Best Sound At The Show" winning room @ hi-fi '98) So I have pretty narrow standards.
Alos you might want to try using the T/S parameters but dividing Re by 4 for 1.6 ohms and Le by 2 for 2.8mH...this is what was the starting point...still peaky, but better. The T/S measured were drastically different from the specs too, I will try to post them when I get a chance.
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TalNLnky
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« Reply #10 on: November 22, 2005, 10:11:59 am » |
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That alignment looks pretty peaky- last week i tired modeling this up in BBP, and i came up with a very peaky response too... I wasn't sure if i had inputed the values incorrectly or made some other sort of error. So i was afraid to make any comment. Glad to know that I didn't lose it after all. |
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95Honda
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« Reply #11 on: November 22, 2005, 11:33:08 am » |
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That alignment looks pretty peaky- last week i tired modeling this up in BBP, and i came up with a very peaky response too... I wasn't sure if i had inputed the values incorrectly or made some other sort of error. So i was afraid to make any comment. Glad to know that I didn't lose it after all. No, your right on. It's tough to model a flat alignment with that sub with it's Qe and Vas.... It just wasn't designed to be put in a ported alignment that could model predicably flat. It is along the lines of many other car audio subs that will go into a tiny sealed box and get decently low with cabin gain or work in a smaller ported box at the expense of excess ripple. Alot of this can still be over come by tweaking the ported alignenments with the expense of overall efficency. The response curves predicted in our modeling programs will look nothing like the complete response curve you would have once you started adding in your crossover and filter circuits. And the gain of whatever type of environment you get in your particular application. There is just too many variables to consider. Still, a peaky response is still a peaky response, and will have more actaull ripple than a flat response most of the time. |
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Forceaudio
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