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View Full Version : 12" L7 in a single cab truck



Criostior
05-14-2010, 09:43 PM
I've designed a 3ft^3 box for an L712 that will fit in a single cab 98 Chevy. I was hoping that ya'll would let me know If you see anything that would cause any major issues.

The open section around the sub in the pictures is going to be fiber glassed in.

http://i2.photobucket.com/albums/y50/overclockersannonymous/console/L7ConsolewamprackFinalFront.jpg

http://i2.photobucket.com/albums/y50/overclockersannonymous/console/L7ConsolewamprackFinalDriverside.jpg

http://i2.photobucket.com/albums/y50/overclockersannonymous/console/L7ConsolewamprackFinalPassside.jpg

http://i2.photobucket.com/albums/y50/overclockersannonymous/console/L7ConsolewamprackFinalback.jpg

http://i2.photobucket.com/albums/y50/overclockersannonymous/console/L7ConsolewamprackFinalbackopen.jpg

PrestigeSounds
05-15-2010, 04:32 AM
how big is that port supposed to be? what are dimensions of the actual enclosure?

Criostior
05-15-2010, 11:48 AM
how big is that port supposed to be? what are dimensions of the actual enclosure?

According to: Subwoofer Enclosure Calculators, Fraction to Decimal, Parallel, Series, Port Length and Volume Calculators (http://www.the12volt.com/caraudio/boxcalcs.asp#porsq) , the port tuned to 30hz is 10"x1"x7".

Sorry about the dimensions. I thought I uploaded this pic. All measurements are inside.

http://i2.photobucket.com/albums/y50/overclockersannonymous/console/L7Consolewamprackfinaldimensions.jpg

PrestigeSounds
05-15-2010, 12:39 PM
how long it take you to draw up these prints? and what program you use? port length seems to be okay.....could be slightly longer to hit the 30hz nail on the head but no biggie

Criostior
05-15-2010, 12:49 PM
how long it take you to draw up these prints? and what program you use? port length seems to be okay.....could be slightly longer to hit the 30hz nail on the head but no biggie

In using Google sketchup. Total in the plans I have about a week of off and on work, but I have gone through a ton of different iterations trying to maximize what i can fit in the space, and swapping box volumes from the sub I was originally designing it for.

Bobby322
05-15-2010, 12:54 PM
Nice looking build, but why put all that effort just to stick an l7 in there?

davidt487
05-15-2010, 01:13 PM
where in tx are you??
your going to want more port area which means more port length and more port displacement
what is you gross volume after displacments
ive seen this design work with 2 12 w3 on a 1000.1 so i if you can get the box specs were they need to be for that l7 then you will be good

PrestigeSounds
05-15-2010, 01:26 PM
i was going to recommend a bigger port too but this will work okay and i figured maybe he was going for tighter bass or something....

davidt487
05-15-2010, 01:59 PM
kicker recommends between 33 and 40 sq in 1.75 cu ft and 3.25 cu ft

Criostior
05-15-2010, 06:20 PM
Nice looking build, but why put all that effort just to stick an l7 in there?

Was planning for a w6 at first but came across a screaming deal on a L7 and a zx1500. Plus i like a challenge and was already have my interior stripped for a full custom treatment.


where in tx are you??
your going to want more port area which means more port length and more port displacement
what is you gross volume after displacments
ive seen this design work with 2 12 w3 on a 1000.1 so i if you can get the box specs were they need to be for that l7 then you will be good

Currently in Midland, but oddly enough am originally from the WF area. Volume after port and woofer displacements is ~2.98 cu.ft. if Ive done my math right. Its hard to nail it perfect with the plan for the top to be glassed with the sub being "pushed" out. Kicker specs ask for 1.75 - 3.25 cu.ft. As far as port length/displacement I was just going by what the12v.com's calculator said.


i was going to recommend a bigger port too but this will work okay and i figured maybe he was going for tighter bass or something....

The reason for the low tuning is Im looking for an SQ box with some SPL potential. I like the nice tight bass that Ive gotten from other low ported boxes in other vehicles.

Criostior
05-15-2010, 07:37 PM
i was going to recommend a bigger port too but this will work okay and i figured maybe he was going for tighter bass or something....

If I enlarge the port to be 13.5"X1" using the box bottom and sides for 3 of the port walls this would increase my port to 10.5" in length. but would lower box volume to ~2.95 cu.ft. Would this be preferable and why? Ive always built sealed boxes so I'm not totally sure on what makes a certain port better than others.

sulin's baby
05-15-2010, 09:29 PM
Thats a nice build...but like stated before why an l7 even if it was cheap the SQ ***** on those...no offence bro! Well with the volume being lower your lower bass wont hit as hard but with the longer port your tuned freq. will hit better...anybody correct if im wrong please but I believe im right lol

Criostior
05-15-2010, 11:45 PM
Thats a nice build...but like stated before why an l7 even if it was cheap the SQ ***** on those...no offence bro! Well with the volume being lower your lower bass wont hit as hard but with the longer port your tuned freq. will hit better...anybody correct if im wrong please but I believe im right lol

If a longer port is just for a better boost at the tuned freq I think Ill probably stick with the shorter port. A flat response is ok for this box. This is actually phase one of the build for this truck. Phase 2 is gonna be awhile as I will be turning it into a uni-body and doing a bed box. Thats when i plan on a full SPL oriented box.

I've built a ton of sealed boxes but this is just my first shot at building a ported box and figured Id go for a more balanced box to start with. I know a lot of work for "practice" but Ive had several people ask me about building boxes for them. I want to practice ported before I do one for someone and just slap my name on it.

joe98chevy
05-16-2010, 12:30 AM
i wish i had bucket seats :(

Criostior
05-16-2010, 12:38 AM
i wish i had bucket seats :(

I hear ya. Mine didn't originally but I plundered a 95 suburban for a pair at a local wrecking yard.

davidt487
05-16-2010, 12:54 AM
im not telling you to tune lower keep your tuning frequency but add port area
25 to 30 sq in would be my min for a box that size but to keep your current tuning freq you will have to lengthen your port

joe98chevy
05-16-2010, 12:58 AM
I hear ya. Mine didn't originally but I plundered a 95 suburban for a pair at a local wrecking yard.
i was thinking of doing the same months ago but now i just want to sell the truck and get a tahoe. i need room for some 15z lol :)

Criostior
05-16-2010, 02:22 PM
im not telling you to tune lower keep your tuning frequency but add port area
25 to 30 sq in would be my min for a box that size but to keep your current tuning freq you will have to lengthen your port

Im not sure Im following you. At 10*1*8 the port is covering 80 sq in. are you talking about the side (1in height part) needing to cover the 25 mark, and not the bottom (8 in wide part)?

PrestigeSounds
05-17-2010, 12:16 AM
bring it up to 2...

SubNit
05-17-2010, 12:22 AM
I see standing waves in your future with that design.

I hope you know what kind of sound you'll achieve with that space/port combination. After working with L7's myself I can tell you they usually sound like **** with small ports

davidt487
05-17-2010, 12:50 AM
you dont multiply all 3 measurements in calculating port area just the 10X1 which means you have 10 sq inches of port
if you make the port 10X3 you would have 30 sq in but you port is going to be a lot longer taking up a lot of you vol the sub will be using

davidt487
05-17-2010, 12:55 AM
right now if you have a box vol of 3 cu ft with that 10X1X8 port would give you an tuning freq of 29 to 30 hz
to keep that tuning you with a port 10X2.5 the length would be 22 inches.

Criostior
05-17-2010, 01:46 AM
I see standing waves in your future with that design.

would you care to elaborate on where you see the problem coming from?


you dont multiply all 3 measurements in calculating port area just the 10X1 which means you have 10 sq inches of port
if you make the port 10X3 you would have 30 sq in but you port is going to be a lot longer taking up a lot of you vol the sub will be using

I follow you now. I'm learning ported boxes as I go here. =)

So after some playing around with numbers I can get 27 sq in port by going to a 13.5" (box width) X 2" port (comes out to 25.5 in long) and keep myself at 2.7 cu. ft. Well within Kicker specs, and from the consensus here a much better choice for sound.

mxer657
05-17-2010, 02:06 AM
You should do this design for a real sub :fyi:

I really like your design just hate to see it go to waste on that sub :/

Criostior
05-17-2010, 02:25 AM
You should do this design for a real sub :fyi:

I really like your design just hate to see it go to waste on that sub :/

What is so wrong with the L7?

davidt487
05-17-2010, 03:31 PM
i think you port is going to diplace more volume than .2 cu ft just the port will displace .4 plus the wood that makes the port.
have you modeled the l7 in win isd to see what kind of box you should be using??

Slo_Ride
05-17-2010, 05:57 PM
Ive heard plenty of L7s that sound fairly decent. Hell I've heard Solo X's with decent sq. I hate when people say a certain sub will sound like crap, ANY sub can sound like ****. Work on your port, make sure its not to small (height need to be more than 1"), and you will be impressed with a 12' L7 in a single cab truck.

Criostior
05-17-2010, 06:08 PM
Your correct on the larger displacement (its actually closer to .5 including the mdf). I was able to do a more precise volume calculation by having a friend of mine import my model into cad and have it calculate for me. The actual displacement of the box is 3.2 before port but including driver. That is how I got the 2.7 number.

As far as the winisd I cant find all the parameters it wants for the driver. This is what I came up with with the info in the manual.

Driver : L7
Vas : 2.2
Qts : 0.51
Fs : 34.00
SPL : 0.00
--
Project by : Criostior
Project for : you
--
Number of drivers : 1
Box type : Vented
Box size : 76.5 l
Tuning frequency : 30.00 Hz
Vent : 1 vent(s)
0.602 m length for each
0.343 x 0.051 m rectangle


Relative
Freq Gain SPL
[Hz] [dB] [dB]
20.00 -13.64 -13.64
25.00 -2.40 -2.40
30.00 9.00 9.00
35.00 4.96 4.96
40.00 2.40 2.40
45.00 1.28 1.28
50.00 0.72 0.72
55.00 0.42 0.42
60.00 0.24 0.24
65.00 0.13 0.13
70.00 0.07 0.07
75.00 0.03 0.03
80.00 0.00 0.00
85.00 -0.02 -0.02
90.00 -0.03 -0.03
95.00 -0.03 -0.03
100.00 -0.04 -0.04

davidt487
05-18-2010, 12:38 AM
if im reading that right you have a 9 db peak at 30 hz then at 25 it drops to -2 that is gonna sound boomy. factor in cabin gain and its gonna make it worse but who knows try it if you dont like it scrap it and start over
ps if you just used a bunch of random numbers in winisd then you my not see these results anyway
try the online version of isd with those number and see what it looks like