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Dissapointed with w7

 

Bronze Member
Username: Souleraser

Post Number: 40
Registered: Feb-10
I recently bought a 12w7 and a JL Slash 1000/1 amp. I also ordered a custom made box for the 12w7. The specs of the box according to the builder are: 1.9 cu. ft. after all displacement and tuned to 30 hz. I hooked everything up and was very dissapointed. It hit pretty hard, but the bass didnt go as low as I though it would. I'm comparing this setup with my previous one which consisted of a 600 watt sony Xplod amp and a Rockford Fosgate P312 in a 1.79 cu. ft box(I think that was the volume) which I know hit lower than this and produced better quality sound.

Is 1.9 cu. ft. too big for a 12w7? JL recommends 1.7 cu. ft.

Should it have been tuned to 32 hz instead of 30 hz as JL recommends?

I told the box builder I wanted 1.9cu.ft. tuned @ 30 hz for my box because I wanted the low lows. Amp settings are correct, Im not a newbie on this, but this is the first box I have gotten built.

I've spent over $1000 on this setup.

Please help.
 

Gold Member
Username: Southernrebel

Monroe, Louisiana Team Audible...

Post Number: 8026
Registered: Mar-04
Get measurements. Port size and length, box external dimensions.

Also, any way you can get some pics of the box?
 

Gold Member
Username: Dustin3

Box Designer & Builder...Dustin

Post Number: 5556
Registered: Oct-05
x2 ^^^
 

Bronze Member
Username: Souleraser

Post Number: 41
Registered: Feb-10
I'll get the measurements and post some pictures by tomorrow.
 

Platinum Member
Username: Glasswolf

Lexington, SC USA

Post Number: 13369
Registered: Dec-03
http://www.glasswolf.net/papers/hoffman.html
 

Silver Member
Username: Skdooley

Roanoke, VA Usa

Post Number: 657
Registered: Oct-09
The box mine is in is 2 cubic feet after all displacements and it gets plenty low. Mine is only seeing half that power and it gets extremely loud and low no problem. What kind of car/truck is this in?
 

Silver Member
Username: Skdooley

Roanoke, VA Usa

Post Number: 658
Registered: Oct-09
If extreme SQL was what you were shooting for, you could have went with a SSA Xcon and a Sundown amp. It would get louder and cost you less money over all.
 

Platinum Member
Username: Glasswolf

Lexington, SC USA

Post Number: 13372
Registered: Dec-03
"SQL" isn't a good term to use. It's a made-up term, and really, it's not accurate. There's SPL (raw volume metered at a competition) or there's SQ (flat C-weighted curve response on an RTA). If you want loud, and clean, it's just a daily driver high-output sub.

Anyway I was lying in bed and couldn't sleep because I kept thinking about this, then it occured to me, Joe. When you made the box 1.9cu ft, was that straight LxWxD measurements, or did you add the driver's displacement and the port displacement volume to the measurement to achieve a volume of 1.9 cubic feet?
If 1.9 ft^3 is just the volume of the raw LxWxD measurements, then that's your problem, dead to rights. Your box will have ended up being too small.
 

Platinum Member
Username: Nyyfan13

Northern VA

Post Number: 11884
Registered: Jul-06
Did you really lose sleep over that Glass? Lol
 

Platinum Member
Username: Glasswolf

Lexington, SC USA

Post Number: 13379
Registered: Dec-03
When I get to thinking about something, it keeps me from being able to sleep. For some reason, that particular one was stuck in my head.

I'm really thinking his 1.9ft^3 was raw LxWxD dimensions, without accounting for sub and port displacement.
This would make the box much too small, and cause his issues with performance.
 

Platinum Member
Username: Nyyfan13

Northern VA

Post Number: 11886
Registered: Jul-06
Lol. Fair enough. That's dedication right there.

But I agree. It could easily explain the lack of performance in the lower end. It's either the box is too small or his expectations were too high lol.
 

Platinum Member
Username: Rovin

1 15 = 152.5 DBs ...Trinidad & T...

Post Number: 16242
Registered: Jul-05
nobody as yet asked about his hu & amp settings ...
 

Gold Member
Username: Kyle_lowe

Post Number: 1053
Registered: Apr-06
i can understand that he would have high expectations going from his old setup to his new one

i hope he gets this figured out
 

Platinum Member
Username: Nyyfan13

Northern VA

Post Number: 11887
Registered: Jul-06
That was going to be the next thing I asked Rovin but sadly enough, I went off the assumption that he played with them/have them all set correctly already. Bad assumption to make probably but I'm still very curious about the box.
 

Platinum Member
Username: Glasswolf

Lexington, SC USA

Post Number: 13383
Registered: Dec-03
I keep forgetting that you can buy JL on-line now. Good point, Rovin, thank you. I'm still used to JL requiring that a 1000/1 be purchased from an authorized brick and mortar shop, and installed by such to honor the warranty, which would imply the amp was tuned properly by the professional installer. I do doubt he expected more than a JL W7 can deliver, though. It is one very capable sub, and with a 1000/1 on a 13W7, it should knock his socks off.

What are your amplifier settings, OP?
 

Platinum Member
Username: Glasswolf

Lexington, SC USA

Post Number: 13384
Registered: Dec-03
oops, 12W7 but still.. (he is overpowering a single 12W7 by JL recommended specs. He should be using a 500/1 for that single 12 but even at that it shouldn't harm the sub since the 1000 watt rating is determined with a sine wave tone on a resistive anechoic load.)
 

Silver Member
Username: Skdooley

Roanoke, VA Usa

Post Number: 659
Registered: Oct-09
JL is doing a register to win shooping spree on their site. Check it out and sign up.
 

Bronze Member
Username: Souleraser

Post Number: 42
Registered: Feb-10
Ok guys, i'm back.

To Glasswolf: I specifically told the builder that I wanted 1.9 cubes after all displacement( sub, port, Mdf thickness and the support bracket inside the box).
I hope he didn't do it wrong.

And yeah, the amp setting are all fine.

Before I go any further, though, I bought this sub used for 200 bucks from a friend and just noticed that its making some weird noise, maybe there's something wrong with the voice coil. That could be the problem.

Nevertheless I still want to know if you guys can tell me if this box is really 1.9 cu. ft. and if the port is tuned to 30 hz.

Here are the measurements I got using a measuring tape (WxHxD):

22.5" x 16.2" x 15.6"

And here are the measurements for the port:

Length: 23.5"
Width: 1.8"
Height: 13.9"

I tried posting some pics but they were too large and I didn't have the time to shrink them today. I'll put them up tomorrow.
 

Silver Member
Username: Skdooley

Roanoke, VA Usa

Post Number: 661
Registered: Oct-09
What kind of noise(s) is the sub making?
 

Gold Member
Username: Southernrebel

Monroe, Louisiana Team Audible...

Post Number: 8028
Registered: Mar-04
I am guessing that your box is actually 22.5x16.25x15.5.

And port is 2"x14" and 32.5" long.

That would be ~1.9cuft tuned to ~36-37hz.

Even if the port was infact 1.8x13.9, it would still be tuned to 34-35hz.

My guess is, either your measurements are wrong or the box builder messed up. Still works out to ~1.9-1.95cuft net though, just tuning is higher that you wanted.


what vehicle do you have?
What direction do the port and sub face?
 

Platinum Member
Username: Glasswolf

Lexington, SC USA

Post Number: 13393
Registered: Dec-03
and what is your zodialogical sign
 

Bronze Member
Username: Souleraser

Post Number: 43
Registered: Feb-10
This box fits nicely in the trunk of my 02 Nissan Sentra and there is still plenty of space in there for cargo.

I measured the width and height of the port from the inside area, so it does not include the MDF thickness.

I measured the length of the port by running the measuring tape from the beginning of the port(outside) to the back wall of the box, then I added the rest of the port ( the part that goes 90 degrees towards the center of the box) those two combined gave me 23.5".

Maybe I should have let Bassman build my box .

Anyways, the subwoofer has a problem and it makes a strange noise thats hard to describe but Im certain that its the voicecoil. For some reason, though, when I push the surround on the left side of the woofer towards the center, it stops making that noise. My guess is that the voicecoil is touching one of the sides of the chamber and thats causing the noise. When I push on the surround, the cone is also pushed just a tiny bit, so I think that it re-aligns the voice coil and stops the noise.

I wonder if any of that made sense to you guys.

Well, I got the woofer to work fine for a while and it went very low, but i'm still not happy with the quality of sound i'm getting out of it. The bass hits very hard, but the quality is just not there.

Here are some pics:


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Silver Member
Username: Skdooley

Roanoke, VA Usa

Post Number: 662
Registered: Oct-09
That looks like a good box. Even if the box was a little small, it isnt THAT much smaller than it should be. Plus on 1000 rms the sub should be slamming reguardless. I think there may be something wrong with the sub itself..
 

Silver Member
Username: Skdooley

Roanoke, VA Usa

Post Number: 663
Registered: Oct-09
Here's a pic of my box. It may be a little larger, but it doesn't look much bigger.

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Bronze Member
Username: Lms

Post Number: 68
Registered: May-08
Jl bumped up power handling on the w7's by 250-500watts, so i guess that creates the idea of a v1 and v2.

Yours should be the v2, so your sub should do fine with the 1000/1.

Try playing the sub free air on low volume and listen for the noise.

Also, pushing on the surround or cone while the speaker is playing may cause mis-alignment of the voice coil. I would avoid doing that.
 

Bronze Member
Username: Souleraser

Post Number: 44
Registered: Feb-10
This is my previous install, I liked it more than my current. The W7 is really loud, but in my opinion the P3 had better quality or perhaps its because the box was tuned a bit higher, which blended the sub bass much better to the midbass.

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Platinum Member
Username: Glasswolf

Lexington, SC USA

Post Number: 13402
Registered: Dec-03
check the amp settings.

set phase to "normal" nd listen to a track on a CD.
then set phase to "reversed" (if I recall, your sub faces rearward?) and listen to the same track on a CD again. See which is better (yeah like your optometrist, right?)

set infrasonic filter to ON and set it to the frequency of your port tuning.
set Bass EQ to OFF
Ignore the "Q" "Center Freq" and "Boost" settings since Bass EQ is disabled for now
set Amp LP Filter to 24dB, and the dial to 50Hz
Make sure input voltage is set to LOW and gain is set properly.
 

Gold Member
Username: Van_man

Boston South, MA

Post Number: 5293
Registered: Mar-06
throw a dmm on the subs coils..If one of the coils is shot, all the tuning in the world wont help.
 

Silver Member
Username: 420pimp2

Baltimore Atlantic Ci..., MD, NJ

Post Number: 914
Registered: Jan-06
Lower volume and 2 more hz(32) will meet your desires.
 

Bronze Member
Username: Souleraser

Post Number: 45
Registered: Feb-10
Is there any way that I can change the tuning of the port of my box? Or will I have to have someone build me a new one? I really dont want to spend more money.

How can I change the internal volume of the box without modifying it? I hear some people say that you can add sand, but I woulnd't want it to go inside the voice coil. Someone else said you can use MDF but I dont know how to go about it.
 

Platinum Member
Username: Glasswolf

Lexington, SC USA

Post Number: 13432
Registered: Dec-03
tuning is altered by changing the length of the port.

to decrease the box volume you add sand IN A BAG or cut a sheet of MDF you can drop into the box with a panel removed that would match the interior dimensions of the floor of the box so you'd basically be raising the floor of the box to decrease volume by width by depth by 5/8" or 3/4" or whatever thickness of MDF you use. You can do this to the back of the box instead, as well, or even one side of both. you secure the MDF to the panel interior of the box with clamps and wood glue, or screws if you're in a hurry, once you're sure you like it that way.
 

Platinum Member
Username: Glasswolf

Lexington, SC USA

Post Number: 13433
Registered: Dec-03
oh, and if the box was built with an in-set removable side panel, you just remove the stops inside the box and set them farther inside the box so the side panel sets into the side of the box more deeply, thus reducing box volume.
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