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Box Port help for 2 18" RE SX-18


Trill

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I have posted on a few different forums without much help. If someone could help me figure out a port for this box I would be very thankful.

Hey everyone I'm hoping to get some help designing and tuning a box for 2 18" RE audio SX18's
What I really need is the correct type of port and size and location of it. I'm ok with subs up with port up but also subs up and port forward between the seats.

It will be going into my 2007 dodge ram 1500 quad cab.
Plan on using a single Hifonics BRX 2400.1 @ 1ohm unless I decide on a more powerful woofer and will use 1 for each woofer.

I have made this in sketchup as it will be close to my max size I want to fit in the back of my truck.

Max OD W=60" H=24" D=26-27"
Material Thickness will be dual layer 3/4" so 1.5"
Looking to tune it to 34hz
Will be playing mostly music but want it to be loud and low

Woofer = If you can recommend a better woofer in this price range let me know!
RE Audio SX18D2 (SX18-D2) 18" Dual 2 ohm Car Subwoofer
SX 18" T/S Parameters:
Electrical Q Value (Qes): 0.53
Mechanical Q Value (Qms): 6.1
Total Speaker Q Value (Qts): 0.48
Free Air Resonance (Fs): 33.2 Hz
Equivalent Compliance (Vas): 159 liters
One-Way, Linear Excursion (Xmax): 22 mm
Efficiency (SPL 1W/1m): 92.7 dB SPL
Effective Piston Area (Sd): 1210 cm2
DC Resistance (Re): 1.9 ohm
Nominal Impedance (Znom): Dual 2 ohm
Thermal Power Handling (Pe): 1000 W
Force Factor (Bl): 21

This box will have a 3" baffle to get my 24" height but could change it to 1.5" if it improves performance with more volume by increasing Height.

ID H=19.5"-21"(21" if 1.5" baffle) W=57" D=23"-24" (24" makes me scoot my seat up an inch :))
DualRE18NoBaffle_zpsb12a2be0.png

And thanks in advance for anyone bored enough to help me design my port for this box!

Minnesota! Y U NO GET WARM!

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@Trill-I had the same measurements as you 24x58x24 with a box comin in a lil over 16cuft.

Joe helped me with a box and made it 10cuft. Dropping my box size to 21x58x19. Now I can recline my seat with out the worry. I'm hopin the box produces well though. He also designed a L port for it. Ill be pushing (2) 15" Fi BLs -2k rms each

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Hey thanks for the input. I'm having a hard time with this design and was hoping you could help me out a little bit more. You said subs up/ port up on the drivers side. Does that mean just a slotted port with 3 common walls on the driver side of the vehicle? Is there some rule of thumb to use such as lenght of port should be x" away from rear wall as width of port?

Like if my port is 6" wide should the port end be 6" away from the back wall of the box?

Also should I do an L port?

If you could give me a quick drawing of what you are explaining I could model it up in sketchup and show you what I come up with. Right now I have a new drawing of a port 23" long x 6.25" and like 16" Deep into the box but I'm struggling to get 10 cubic inches per cubic foot in the port this way.

Sorry for being such a noob at this but this is the first time I have built a ported box.

Minnesota! Y U NO GET WARM!

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You could make port wider and longer to get more in^3 per ft^3

Chick took 3 shots of Jager, and then, pissed in my mouth.. oh.. wait.. naw.. that wasnt weird..

He probably tearin dat ass up every night. Reason for "insomnia" Ain't sleeping cause he's like a horny hamster on coke.

2000 grand prix gtp: SOLD My Home Theater Build (working progress) 2002 accord coupe

subs: 2 soundqubed hds300 12s 4'1" towers tuned to 29hz sub: AQ hdc3 12

Amp: pioneer gm9061 amp: poineer gm9601

headunit: kenwood kdc 255u mids: SQ pro mids

midbass: polk db 8s highs: stock

mids/highs: shitty off brand

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I may be able to go wider by a little bit but height is max at 23" In sketchup I have the sub cutouts dead center of each half. I guess I could move them apart a little bit more to allow a wider port.

Minnesota! Y U NO GET WARM!

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Not taller I mean deeper when you widen the port it makes the tuning go up so u have to make the port longer/deeper to compensate then u will get more port area in both fields(in^3 per ft^3 and port area) but less cu ft net

Chick took 3 shots of Jager, and then, pissed in my mouth.. oh.. wait.. naw.. that wasnt weird..

He probably tearin dat ass up every night. Reason for "insomnia" Ain't sleeping cause he's like a horny hamster on coke.

2000 grand prix gtp: SOLD My Home Theater Build (working progress) 2002 accord coupe

subs: 2 soundqubed hds300 12s 4'1" towers tuned to 29hz sub: AQ hdc3 12

Amp: pioneer gm9061 amp: poineer gm9601

headunit: kenwood kdc 255u mids: SQ pro mids

midbass: polk db 8s highs: stock

mids/highs: shitty off brand

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Port per cube means nothing. A driver needs to have X amount of port based on a couple a parameters along with the desired tuned frequency. Net volume does not affect the amount needed.

For your question about how far away from the back of the wall the port should be, it should be as far from the back as the opening is wide.

So let's say that the port is 12.5" x 6". The port would need to be 6" away from the back of the wall.

b_350_20_692108_381007_FFFFFF_000000.png

Krakin's Home Dipole Project

http://www.stevemeadedesigns.com/board/topic/186153-krakins-dipole-project-new-reciever-in-rockford-science/#entry2772370

Krakin, are you some sort of mad scientist?

I would have replied earlier, but I was measuring the output of my amp with a yardstick . . .

What you hear is not the air pressure variation in itself

but what has drawn your attention

in the two streams of superimposed air pressure variations at your eardrums

An acoustic event has dimensions of Time, Tone, Loudness and Space

Everyone learns to render the 3-dimensional localization of sound based on the individual shape of their ears,

thus no formula can achieve a definite effect for every listener.

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