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MikeyMan
New Member
USA
59 Posts |
 Posted - 06/11/2009 : 8:57:10 PM
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| this weekend I'm building a custom slot ported enclosure tuned to just a tad below 30 hz. I know its necessary to use a sub sonic flter to keep the woofer from bottoming out since below the tuning frequency does not support the cone correctly. However, the fs for the sub (t112d4) is 33 hz and i am tuning below that. Will the natural rolloff of the sub be enough to keep lower frequencies from doing damage to my sub? If not, does anybody know where to get an active subsonic? I do not want an fmod, because I have read too much bad things about them. Unfortunately, my T1 does not have a frequency response curve like my p3 did, so I cannot be too sure where the f3 begins. thanks for the help!! |
09 scion xb
Pioneer f90bt
1 t112d4 running at 2 ohms
MTX Thunder Elite 600w @ 2 ohms
6.5" Polk Momo Components run from a Rockford p300.2
2 farad tsunami digital cap
All Tusnami 2g wiring |
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EmperorJJ1
Advanced Member
USA
4116 Posts |
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MikeyMan
New Member
USA
59 Posts |
Posted - 06/12/2009 : 06:43:56 AM
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| That's a negative, one of the only ones that doesnt. you'd think a thunder ELITE would, but it doesnt. I'm eventually upgrading to a t10001, but till then, I am stuck with this |
09 scion xb
Pioneer f90bt
1 t112d4 running at 2 ohms
MTX Thunder Elite 600w @ 2 ohms
6.5" Polk Momo Components run from a Rockford p300.2
2 farad tsunami digital cap
All Tusnami 2g wiring |
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EmperorJJ1
Advanced Member
USA
4116 Posts |
Posted - 06/12/2009 : 8:38:31 PM
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eventually? google my name and T10001bd and see what shows up
that's actually pretty sad of mtx thou |
http://www.cardomain.com/ride/2604492
FIRST DUAL ALTERNATOR COBALT SS/SC
Second 360.2 installed 2/6/09 |
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Admin
Forum Admin
USA
2753 Posts |
Posted - 06/13/2009 : 08:36:58 AM
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You didn't specify the box volume, nor the power applied which is mandatory when determining a theoretical excursion plot. Also, it's not advisable to tune below the Fs of the speaker. I took some liberties and modeled this enclosure system:
Vented Box Size: 0.75 cu.ft. each
Tuning Frequency: 33Hz
Power Applied: 600W
With the above system parameters, you'll have good Mechanical Power Handling down to 24Hz, at which that frequency you'll most likely tear the surround or spider. So it's safe to say use an infrasonic at 25Hz. |
Eric Russell
Rockford WebWizard |
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MikeyMan
New Member
USA
59 Posts |
Posted - 06/13/2009 : 12:10:09 PM
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| thank you for the help, im glad this happened before I cut my wood for the box. i will have to change my plans. The vb of my box is 2.25 minus the port and displacement and whatnot, liek RF recommends. I will change the tuning to 33 as recommended, and I will be getting a t1001bd running at around 700 - 800 watts with the subsonic at 27hz. I've been running my t1 a little over half gain on my 600 te601d watt amp, and it wants more power less gain, so I Wam hoping the power boost will help my output and having less gain will improve my quality of sound. What way is there to improve power handling from the box? Making it bigger or smaller? |
09 scion xb
Pioneer f90bt
1 t112d4 running at 2 ohms
MTX Thunder Elite 600w @ 2 ohms
6.5" Polk Momo Components run from a Rockford p300.2
2 farad tsunami digital cap
All Tusnami 2g wiring |
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Admin
Forum Admin
USA
2753 Posts |
Posted - 06/14/2009 : 2:53:31 PM
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I was confused if you already subtracted the displacements out and you had 2.25 NET left or if that was the GROSS and you still needed to subtract the displacements. I assumed it was NET so I re-ran the box with these params:
Vented Box Size: 1.25 cu.ft. each
Tuning Frequency: 33Hz
Power Applied: 800W
Basically, the F3 is lowered from 40Hz (.75) to 32Hz (1.125), but the excursion limit increased from 24Hz to 26Hz (actually more like 27Hz).
Better power handling comes from smaller enclosures, but at the expense of low end performance ... this is why it's a delicate balancing act. |
Eric Russell
Rockford WebWizard |
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jeff_macon
Starting Member
46 Posts |
Posted - 11/03/2009 : 7:22:15 PM
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| hey admin..i'll call you god if you can tell me what program you used to get those specs..i really need to build a serious box for my 15's..the boxwizard doesn't support old school power dvc's..thanks! |
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Admin
Forum Admin
USA
2753 Posts |
Posted - 11/03/2009 : 10:32:33 PM
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| Here at RF, an engineer and I wrote the BoxAdvisor - pictured above - I just slammed some older specs in there. I gotta go back and backload a complete catalog of older models, but we've been pretty busy preparing for CES at the office.... you may want to call into RFTECH and have them run the box designs I created for that manual and they can tell you what mods you can make. |
Eric Russell
Rockford WebWizard |
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EmperorJJ1
Advanced Member
USA
4116 Posts |
Posted - 11/04/2009 : 9:15:26 PM
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| i know huh jeff. Eric is seriously badass making stuff like this. invaluable if you ask me really |
http://www.cardomain.com/ride/2604492
FIRST DUAL ALTERNATOR COBALT SS/SC
Second 360.2 installed 2/6/09 |
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Discussion Forum
Subsonic necessary?!?!?
