tuning a Type R
Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=31043
Printed Date: May 03, 2024 at 7:54 AM
Topic: tuning a Type R
Posted By: alex75
Subject: tuning a Type R
Date Posted: April 26, 2004 at 8:57 AM
I'm going to build a ported box for my Alpine Type R 12, what should it be tuned to? The manual says nothing nor does the Alpine site. I know it needs about 2 CUFT. of space. I had 2 Audiobahns in a ported box tuned to 36Hz, it really pounds. How does going up or down in Hz effect SQ and SPL? I want the bass to hurt! I'll probably be using 3" PVC cuz I have a ton of it. Thanks-Alex
Replies:
Posted By: 94bonny
Date Posted: April 26, 2004 at 10:59 AM
i think that 2.0 cubic feet for a single 12" type r, i believe around 1.2 or 1.0 cubic feet would do you justice for this sub
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Alpine cda 9813
jl 500/1
eclipse aluminum 15"
Posted By: 94bonny
Date Posted: April 26, 2004 at 11:01 AM
haha forget my post i misread your post, the dimensions i mentioned are for a sealed box, forgive me
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Alpine cda 9813
jl 500/1
eclipse aluminum 15"
Posted By: alex75
Date Posted: April 26, 2004 at 3:34 PM
Thanks, I allready know the dimensions of the box, I'm asking about tuning the box via it's port length using 3" port tubing.
Posted By: framedragger
Date Posted: April 26, 2004 at 3:38 PM
im not expert but i wouldnt use round ports, use a slot port
Posted By: alex75
Date Posted: April 26, 2004 at 3:48 PM
Yeah-the factory Alpine box for these subs has a slot port bass-reflex design-talk about SPL! I'm hesitant to attempt to build a slot-port box myself unless I knew exact dimensions so it it properly tuned. Slot ports are supposed to produce better SQ than a round ports, that is if they are built right 
Posted By: Ravendarat
Date Posted: April 26, 2004 at 4:07 PM
Id make the port about 10.75inches loong if the interior diameter of the port is 3 inches. That should give you a tunning frequency of about 29hz if my math is right. I always tune my boxes that low and have always had good luck with them. Id also invest in a subsonic filter if you are gonna do a ported box
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double-secret reverse-osmosis speaker-cone-induced high-level interference distortion, Its a killer
Posted By: customsuburb
Date Posted: April 26, 2004 at 5:07 PM
The vented box size for these subs is from 1 to 1.75 cu/ft. I would use a 1.25 cubic foot enclosure with a 4 by 13 inch port.
Posted By: Ravendarat
Date Posted: April 26, 2004 at 5:11 PM
I guess the port I gave you would be 27.125 herz. I really like to tune low though so I guess its kinda a personal preference thing.
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double-secret reverse-osmosis speaker-cone-induced high-level interference distortion, Its a killer
Posted By: alex75
Date Posted: April 26, 2004 at 5:29 PM
What's the differance to your ears in tuning low, like your 27HZ, as compared to tuning to higher Hz-like 35-40HZ? I want this sub to hit hard and low while remaining somewhat musical. BTW, what does a subsonic filter do?
Posted By: customsuburb
Date Posted: April 26, 2004 at 8:45 PM
Below the frequency you tuned your box to the frequency response of your sub will start to roll-off (the damping factor decreases below the tuning frequency). This is why you use a subsonic filter set to around your tuning frequency, to keep your sub from playing those frequencys that are going to be rolled off (and since there is a decreased damping factor below the tuning frequency, the subs power handling drecreases so you can blow your sub if it trys to plays the frequencys below the tuning frequency). Whoaa, thats a long sentence.
Posted By: Pola_Trucos
Date Posted: April 26, 2004 at 9:09 PM
A subsonic filter will block all the frequencies that go below the tuning of your port. So if you have a box tuned to 27 hertz the filter will bloq all the frequencies below 27 hertz so the sub don't waste energy triying to play all the lower notes.
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Dont use ten words when 5 will do fine.
Posted By: alex75
Date Posted: April 27, 2004 at 8:47 AM
Gotcha, thanks. Still curious about the differance in sound between a box tuned to 27hz and something higher like 36 hz? What hits lower?
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