Hello gentlemen and ladies. Here goes my first post...

I've been rolling with a 12" Polk SR DVC 4ohms 700RMS2.0cu ft. and had a baby she's just 7 months now, it's pain to carry that monster into the house every time we plan to go shopping with the stroller. Also feels unsafety with the huge box in the back of the hatch with baby on board.

Today I was so excited to pickup a SA-8 V2 from a guy locally for $80, when I got there it doesn't seem like the SA-8 V2, so I though it's a V1 so I grab it anyway, came home start building my box, and do my research while waiting for the glue to dry, finally find out that that sucker sold me a E8v2, which i'm planning to get a SA-8, but the cut out hole is different which it's small than the SA-8v2 which can be a easy fix later since the box is built to handle SA-8V2, so I'll just keep it and try it in the mean time since SA-8 are in back order.

here's some pix of the process. not sure what's the #cu on it but it's 11 1/8"x12.5"x16"

so happy i bough the 3/4" MDF just $5.99 at Home Depot they sold it ripped 11 1/8"x 96" so it made my project so easy by cutting to the length I need. I spent one day to find box plan and way to tune it, my head want to explode, so I just build this box like I always do to get the job done, if anyone is kind enough which are good at math that could tell me how many #.#cu ft box I have and it's freq. I'll provide more info on box... thanks

Also I had really bad day at Home Depot today, while holding the Woodglue walking around later i found out glue all over my casual dress jacket, jean and my new J Crew wallet in my jacket pocket is filled with glue, so I rushed in to the restroom, trying to wash my jacket and jean, wash my new wallet too, it's pure leather so I don't know if it's ruined after it's dry. BAD BAD BAD day ever, head back to work without a jacket plus a cold windy day ever....

Layout

calking after wood glue is dry.

2" Ported/Vent

I made a bigger circle for the SA-8v2 so I can easily jigsaw it later.

VS...

more pix and video of it vs the 12" Polk SR 700RMS coming soon...

Edited January 13, 201213 yr by sw07tc

baby box

Looks good though.

I been pushing my 12" Polk SR with my Old School Alpine MRV-T420 @ •340 watts RMS x 1@ 4ohms in bridged mode for about 4 years under power, but sounds pretty good but haven't got the money to affort a stronger amp, so now with the Sundown E8v2, I believe I'm a little over power it when I turn the volume little over 25, sounds pretty good at vol 20, as for the 12" i could have my vol up to 40, but comparison at the power level with a smaller sub and encloser I pretty much get the same bass as I always get with my 12" since I usually listen to my music at about vol30~34 where 20~25 just a little lower, but it's seem to be a beast for a 8", I'm a Sundown Fan from now on, and screw Polk SR, Kicker L7, JLW7 which I had before, I'll pre-order my SA-8v2, and I'm sure it will goes compete with those 12"...

here's a few more shot I took today on my way to work.

Edited January 13, 201213 yr by sw07tc

nice!!!

nice!!!

thanks, I took a few video clips with my DSLR but the built in mic on my camera doesn't like the bass so it sound grocery bag. probably I'm gonna try record it with my iPhone 4 see if it record the sound more realistic.

I guess I gotta wait a few more month till I get the SA-8v2 in order to carpet this tiny box

Edited January 13, 201213 yr by sw07tc

The mic on the DSLR is probably more realistic.... it's picking up pressure and sound... upload those bitches... lol

Interesting enclosure design tecnique - build enclosure first, figure out enclosure volume and tuning afterwards.

Predrill your screw holes so you wood does not split.

The mic on the DSLR is probably more realistic.... it's picking up pressure and sound... upload those bitches... lol

Maybe so, I think I gotta try again with my window down, and take some more clips of if vs my 12" and then spend sometime with Final Cut...

my rear view mirror shakes a bit

Wow that is a tiny box.

I did the math and came up with .89 cft gross. Not sure what your port size and displacement is to figure net.

What coils do you have?

Wow that is a tiny box.

I did the math and came up with .89 cft gross. Not sure what your port size and displacement is to figure net.

What coils do you have?

cool, I'll get the port length and size for you to find out freq for me, and what do you mean what coils i have?

Wow that is a tiny box.

I did the math and came up with .89 cft gross. Not sure what your port size and displacement is to figure net.

What coils do you have?

cool, I'll get the port length and size for you to find out freq for me, and what do you mean what coils i have?

here's all the measurement of the box hope you guys can find the exact cu ft and tune freq on it for me, and tell me if this box is built correctly, as I usually listen to hip & hop music looking for deep & warm bass. thanks

I came up with 0.90cu ft. minus the port vol I get 0.83 cu ft. just need to figure out the tune frequency, I'm guessing around 55hz freq, I don't quite get the port calculator...

Edited January 15, 201213 yr by sw07tc

Box Measurements

Here goes the final video I made compare with the 12" Polk SR

Also if anyone got any idea to modified my box to tune to around 33-37htz, really appreciate it. thanks

Edited January 15, 201213 yr by sw07tc

best I got it figured out to be is .6ft^3 @ ~69hz. There is nothing you can really do to modify the box, its either lengthen the port or reduce the port area. You need to build a whole new box and it will need to be bigger to accommodate the port area and length needed.

You could extend the interior port some but it would reduce the net cft a bit. Only other thing you could do is extend the port externally as well. It would definitely improve the sound. Tuned that high it would almost be better sealed.

You need to build a new box, no way around it.

You need to build a new box, no way around it.

is it because my port is too big? i'm thinking about remove the two piece and add two new piece to make the port smaller and longer it'll be reduce from 2" to 1 1/4" but I need to know how long to get to around 33-36htz

So, I've decided to build a new box so it'll be embed to my spare tire space. the new Outside dimensions is 8 3/4"x 22" x 11 1/4", 1 1/4" port 7 1/4" high, 20" long. I used the http://www.the12volt.com/caraudio/boxcalcs.asp#por calculator with the dimensions I have got 0.84cu ft, which is good!!! and with the port length I got it tune to 36hertz, I'm not sure if that's the tuning I need since I love deep/warm bass for mostly R&B and hip hop musics. As I see many people goes with 33hertz which I have to reduce my port size from 1 1/4" to 1" with 19" length.

here's two design that I need you guys help me decide which design is best for the sound. thanks

1.

2.

I'm not sure if the calculator from the12volt is correct or not, please help!!! really appreciates it...

Lots of mistakes, would definitely recommend doing it over. If you plan on keeping it, line the internal chamber and extend+stuff the port. This will increase the effective internal volume and lower the tuning frequency, plus it will help cover up some of the negative consequences of your errors.

Some tips for the future (some have already been mentioned):

- Calculate volume and tuning before buying the supplies

- Measure twice before cutting

- More caulking in the corners (Leaks are bad)

- Construct the port with as few turns as possible

- Round any edges of the port

- Carpet is your friend

- I personally would not have the sub pointing up, mostly due to theft concerns. If you're going to do it, at least tint the back windows. You're rocking an $80 sub in a homemade box back there, not a Ferrari engine.

- I personally would not have the sub pointing up, mostly due to theft concerns. If you're going to do it, at least tint the back windows. You're rocking an $80 sub in a homemade box back there, not a Ferrari engine.

ROFL thats awesome.

So, I've decided to build a new box so it'll be embed to my spare tire space. the new Outside dimensions is 8 3/4"x 22" x 11 1/4", 1 1/4" port 7 1/4" high, 20" long. I used the http://www.the12volt...oxcalcs.asp#por calculator with the dimensions I have got 0.84cu ft, which is good!!! and with the port length I got it tune to 36hertz, I'm not sure if that's the tuning I need since I love deep/warm bass for mostly R&B and hip hop musics. As I see many people goes with 33hertz which I have to reduce my port size from 1 1/4" to 1" with 19" length.

here's two design that I need you guys help me decide which design is best for the sound. thanks

1.

2.

I'm not sure if the calculator from the12volt is correct or not, please help!!! really appreciates it...

The first one but the port is crooked and the construction quality needs improvement (panels aren't flush with each other, gaps in the wood, etc.)

I put your measurements in the torres calculator and came up with .84cu ft gross. After port displacement it is .71 tuned to 38.57Hz and once you add woofer displacement tuning is going to end up over 40Hz

I put your measurements in the torres calculator and came up with .84cu ft gross. After port displacement it is .71 tuned to 38.57Hz and once you add woofer displacement tuning is going to end up over 40Hz

thanks, so I finally figure out how to use sketchup, and here's what I got done, getting it to tune to 32.6hz so with the SA-8v2 in I'll probably get around 34hz?

Edited January 17, 201213 yr by sw07tc

Lots of mistakes, would definitely recommend doing it over. If you plan on keeping it, line the internal chamber and extend+stuff the port. This will increase the effective internal volume and lower the tuning frequency, plus it will help cover up some of the negative consequences of your errors.

Some tips for the future (some have already been mentioned):

- Calculate volume and tuning before buying the supplies

- Measure twice before cutting

- More caulking in the corners (Leaks are bad)

- Construct the port with as few turns as possible

- Round any edges of the port

- Carpet is your friend

- I personally would not have the sub pointing up, mostly due to theft concerns. If you're going to do it, at least tint the back windows. You're rocking an $80 sub in a homemade box back there, not a Ferrari engine.

Thanks Jmac for taking your time to look closely at my pictures and point out all the errors and tips.

my rear windows is limo tinted in the rear, SA-8v2 probably $135 btw, I was able to learn carpeting my old sub, so that will be easy.

you can look at the upper final sketch up I made of how my box will be. but I think I will need to resketch it again to route the port to face up

The first one but the port is crooked and the construction quality needs improvement (panels aren't flush with each other, gaps in the wood, etc.)

that's b/c I'm trying to take a picture of how it going to look after cutting the pieces. it wasn't screw or glue yet.

Edited January 18, 201213 yr by sw07tc