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dual 10w7 ported enclosure

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=133456
Printed Date: March 28, 2024 at 7:31 PM


Topic: dual 10w7 ported enclosure

Posted By: james.jaros
Subject: dual 10w7 ported enclosure
Date Posted: January 28, 2013 at 8:52 PM

Hello all, I just purchased a second 10W7 and need some help with the enclosure. I have built many enclosures in the past but every time I built for a single woofer so I want to make sure I am doing this right.

First question, I would like to build a vented enclosure, do I use seperate chambers or can I just make one large chamber?

Can anyone help me with dimensions so that I know the enclosure is the right size and is also tuned properly? I have a maximum width of 39.5 with a max height of 16 and would like to stay at a depth of 14.5 or less if possible.

According to JL the 10W7 optimal box conditions are:

Wall Thickness      0.75 in / 19 mm
Front Baffle Thickness      1.0 in / 25 mm
Volume (net int.)      1.5 cu ft / 42.5 L
External Width (W)      23.25 in / 591 mm
External Height (H)      13.5 in / 343 mm
External Depth (D)      14.5 in / 368 mm
Internal Slot Port Width (SW)      1.5 in / 38 mm
Internal Slot Port Height (SH)      12 in / 305 mm
Internal Slot Port Depth (SD)      22.5 in / 572 mm
Port Extension Length (EL)      7.25 in / 184 mm
Tune to      35.33 Hz
F3      32 Hz

If anyone can help I would greatly appreciate it. I am more than capable of building the enclosure (I have a small wood shop and have built several) but apparently I am not smart enough to calculate internal volume or port tuning and sizes. :)

Thanks again in advance.

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-under_lucky-



Replies:

Posted By: james.jaros
Date Posted: January 31, 2013 at 9:35 PM
So I used the RE calculator and this is what I have come up with. If one chamber is acceptable that is:

W = 39.75 (I re-measured and I can get 39.75 - I even cut a pc of plywood and shoved it in the trunk to make sure.
D = 14
H = 14.25
Port Width = 3
Port Length 1 = 10.25
Port Length 2 = 7

This is all calculated off of .75" wall thickness but I would like to do double front wall thickness, how much will this effect the enclosure if I was to add the second pc or layer to the outside of the enclosure so that the internal of the enclosure remained the same? How about bracing internally? If you wanted to put some bracing in the corners and something on the walls (since it is so wide to reduce flex) how would that have an effect?

Again, any help would be appreciated.

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-under_lucky-




Posted By: soundnsecurity
Date Posted: February 01, 2013 at 8:15 PM
adding layers to the outside wont affect the performance in a negative way, it will only add strength to the box. usually a brace is recommended on any wall bigger that about 24 inches but any bracing on smaller walls definitely doesnt hurt. the stronger you make the box, the better it usually sounds as long as it is designed right.

i dont know if there are any strict rules on port placement in relation to where the subs are placed. personally i like to keep an even space between each sub and the port, usually having the port in the middle between each sub is the most common design i see . i also like to build these boxed with the port along the whole top or bottom which keeps the subs spaced evenly relative to the port.

once again, i dont know if the exact placement is critical to performance. you may be able to have the port on the left or right hand side and the two subs next to the port with one sub being farther away from the port that the other sub. i honestly dont think it will make a big difference.

you have to be very careful when you are measuring a trunk to see how big of a box you can fit through the opening. you say you just cut a flat piece of plywood but that is totally different from trying to stuff a 3 dimensional box through the trunk opening. if that piece of wood barely fit then chances are that the box wont fit. its hard to explain but you have to make sure you have the clearance to fit the box as a whole instead of just the individual measurements.

a good example of this is a ford mustang, the trunk is big enough for a box for two 10's but good luck fitting even a modest sized box through the trunk opening. the only boxes that really fit through the hole of a mustangs trunk are bass tubes and very thin "truck boxes" that are designed to fit behind the seat of a regular cab truck.

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Posted By: james.jaros
Date Posted: February 02, 2013 at 12:33 AM
Hmm... I never though of that. So using a port on the bottom, these are the dimensions I came up with:

W = 39.5
H = 14.5
D = 14.25
port w = 1
p1 = 12.75
p2 = 8

I am confident this enclosure will fit because I measured multiple angles in the trunk. I can also put the enclosure in through the cab because both seats fold down. Do you think two subs in one enclosure is ok? I was thinking about adding .75" to each of the depth dim's for the cuts so that I could do a double front while maintaining the internal volume.

What do you think?

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-under_lucky-




Posted By: soundnsecurity
Date Posted: February 02, 2013 at 10:52 AM
can you explain your measurements for your port im confused, are you using a slot port or a circle port?

having 2 subs in the same box is just fine, my point was that i would design the box so that each sub was the same distance from the port. this is how i build all of my boxes. but, because i have never built a box where the subs were different distances from the port, i cant really tell you for sure if doing that will hurt the sound.

making the box as strong as possible is always a major goal for building any custom box, so if you want to double the baffle then be my guest, it cant hurt. those subs are pretty heavy so every bit of strength you can add to the front baffle will help your box last longer.

any panel that you double needs to to be treated as a single piece though when you put the box together. cut the two pieces of wood to the dimensions you want and glue and screw them together so that they will act as one single thick piece of wood. if you dont do this then you risk them separating over time from the vibrations of the sub. once the pieces separate you might as well throw that box away and start over.

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