Jlw7 help

[Massive spl]

Its supposted to be 1.5. And FYI if you don't understand dampening and how it affects frequency response I'll be glad to help.. The stiffness on those drivers really aren't ideal for vented alignments. Although they do have ways around it there just not ideal..

You have to have a certain stiffness to mass ratio for vented alignments to obtain critical damping. This causes a underdamped response. Making the enclosure smaller lowers it's compliance to compensate for the softer suspensions used.

The higher qe also means that it has a wider bandwidth electrically wherein the driver resonates and this naturally means easier low frequency reproduction visit great sensivity..

And I'm talking in the sub bandwidth we

Here in the human perception is ruffle 20hz to 100hz typically closed to 30-70hz cause most people know next to nothing about speakers

According to JL the woofer needs 1.75^3 ported and 1.4 sealed

12W7-3 - Car Audio - Subwoofer Drivers - W7 - JL Audio

 

[Papermaker85 5,000+ posts]

Your attitude is getting old around here. Your givin bad advice around the forum.. In another thread u said put a sp4 15" in 4.25cubes tuned to 40hz on 1000watts... Umm no that woofer is a big box low end woofer. More like 6cubes tuned to 30hz on 1000watts would hammer.
Same goes for these jl w7s just because it has a soft spider doesn't mean they need to go in 1.4cubes... That's small for these high excursion low distortions woofers. 2-2.5 ported is nice for these w7s each. The OP problem either lies in his tuning/settings or his port is off.

6 cubic feet for a 15? Kmsl no. It's not every really designed to be ported.. if you want a shifty sounding bottom heavy sub may.

I've been building woofers for a while now.

The reason. I told him tune higher was because he had **** for high frequency output. Tuning up shifts the efficiency up in the range he wanted more output in.

Go read on damping and how it affects output and transient response and then we will talk..

We is actually recommended for 1.75ft^2 not a.big box.. that's why the ops system is bottom heavy bloated and lack any topend.

BTW I build woofers. I know a thing or two..

 

[Papermaker85 5,000+ posts]

According to JL the woofer needs 1.75^3 ported and 1.4 sealed 12W7-3 - Car Audio - Subwoofer Drivers - W7 - JL Audio

duh. I know. But it's still high in group delay and still sounds muddy compared to a woofer designed to be ported.

 

[Papermaker85 5,000+ posts]

Plot the 1.5 tuned to 32 and look how much lower the group delay and phase as well as impedance shifts are.. you don't have to be a duck if you disagree. I started building boxes at 11 and competing at 14. I've built tons and tons of boxes for people all over. There is a lot of misconceptions..

The W7 is a sealed box woofer. A **** fine one. But it's one of those designs that do poorly in the typical vented alignment a give ported boxes a bad name/myth

 

[Papermaker85 5,000+ posts]

According to JL the woofer needs 1.75^3 ported and 1.4 sealed 12W7-3 - Car Audio - Subwoofer Drivers - W7 - JL Audio

i know i come off as a **** man but you have to remember that the parameters of a sub change based on there acoustic environment and they shift more so due to heat as far as the electrical side. typically FS even at half xmax(1/2 linear stroke)shifts 15-25% higher than small signal measurements QES often shifts up 20-30% as well.. 99.9% of the industry uses small signal parameters which aren't real world accurate its meant to be a base line for designing //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[LosIsATool 5,000+ posts]

I've worked with a few 12W7 builds.

JL spec 1.75 will be peaky in the mid 40hz range as well as sealed. That's why they say it's "tight"

Go a bit bigger and it brings out the bottom end and flattens the peak. Same for every spec mainstream box. It works since most people don't know what 30hz is.

It's the port. Sounds very typical

 

[Massive spl]

Honestly your a old school pencil pusher and I'm not even going to argue with you. I'm a get in the garage and build build build and find out what works and what doesn't. 2-2.5cubes tuned to 28-32hz is great for a w7.. If you want to suffocate a woofer and put it in a small box so all it has it punchy 70hz bass be my guess, if you want to slam 20hz-50hz like a sub stage should then bigger box with a lower tune for these high excursion low distortion woofers. I'm done in this thread because this is going no where. Peace

 

[Papermaker85 5,000+ posts]

I've worked with a few 12W7 builds. JL spec 1.75 will be peaky in the mid 40hz range as well as sealed. That's why they say it's "tight"

Go a bit bigger and it brings out the bottom end and flattens the peak. Same for every spec mainstream box. It works since most people don't know what 30hz is.

It's the port. Sounds very typical

i agree but to an extent. that sounds good in theory because it does lower the peak yess but you loose even more efficeny from the lack of damping. ive built about a dozen w7 boxes 1.75 is stil peaky and bottom heavy and still falls off fast above 60hz. instead you go slightly smaller to increase the efficiency above tuning(while a larger box increases efficiency at and below tuning) and you increase port are which also changes the damping(qt)s and lowers the acoustic resistance around and at tuning.. this does 3 things. lowers the group delay between the driver and the port, shifts the effective bandwidth OF the woofer higher and increasing port area decreases the QT of the port making the ports bandwidth more efficient and effective and have a narrower bandwidth at tuning so you get greater efficiency at tuning despite the smaller box while keeping group delay lower..

think about increasing port area like lowering your QES/QTS ad tuning the port like the subs compliance. its peakier ove a narrower bandwidth.

the smaller box also shifts the phase and impedance lower this is more affetive for high frequency output becasue that high above tuning the sub is doing above 80% the work where as in the port at tuning does all the work and the sub barley moves..

 

[Papermaker85 5,000+ posts]

Honestly your a old school pencil pusher and I'm not even going to argue with you. I'm a get in the garage and build build build and find out what works and what doesn't. 2-2.5cubes tuned to 28-32hz is great for a w7.. If you want to suffocate a woofer and put it in a small box so all it has it punchy 70hz bass be my guess, if you want to slam 20hz-50hz like a sub stage should then bigger box with a lower tune for these high excursion low distortion woofers. I'm done in this thread because this is going no where. Peace

the OP wanted more high frequency output. thats why i said go smaller with alot of port area. yes its going to hurt efficency but the driver isnt built for vented alignments so you have to sacrfice a-little low end and output for a flatter response.

 

[BoomTaco64]

god dam guys. papermaker and massivespl need to send each other pics of their junk to see whos is larger and quit the i'm better than you $hit. not helping while bickering. for fawks sake

 

[Massive spl]

god dam guys. papermaker and massivespl need to send each other pics of their junk to see whos is larger and quit the i'm better than you $hit. not helping while bickering. for fawks sake

And your comment is pointless ^. There is no I'm better then you going on.... We are trying to help the op get the sound he's looking for.

 

[Papermaker85 5,000+ posts]

I agree. Every one has experience here nobody is dumb.

I'm simply reinforcing my reasoning behind the recommendation. massive disagreed so I'm explaining the theory behind it.. nothing wrong with putting two heads together even if they bump sometimes.. I'm not mad.. lol. And the real point here is fixing the problem

 

[Jeffdachef 5,000+ posts]

4 cu ft seems a little small for 3 12's.
12W7-3 - Car Audio - Subwoofer Drivers - W7 - JL Audio

its two 12s not 3

Edit: sorry for bothering you in your corner lmao..

 

[Jeffdachef 5,000+ posts]

I got two jl 12w7 and two I'd 1x1000 jl jx. I will upgrade to the hd someday. First off. The subwoofers get incredibly low. Whole car shaking reiw view mirror fell off in a matter of seconds. So here is the deal. With low long bass lines it sounds great. Like three 6 mafia who run it sounds amazing. But a song with short burst bass like bow down by west side connection the sub distorts and does does not hit real hard. I quickly lowered the volume. The box is not double chambered and is about four cubic foot after port and displacement. It is tunned to 35 hrz. So need some advice. Is it the box or my settings? My crossover is set at 80 -12db. My gain is about a fourth of the way turned up along with the bass boost at 1. Any advice would be great. My past three subs have been sealed and I'm now thinking of going back to that

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[blazian87 10+ year member]

I got two jl 12w7 and two I'd 1x1000 jl jx. I will upgrade to the hd someday. First off. The subwoofers get incredibly low. Whole car shaking reiw view mirror fell off in a matter of seconds. So here is the deal. With low long bass lines it sounds great. Like three 6 mafia who run it sounds amazing. But a song with short burst bass like bow down by west side connection the sub distorts and does does not hit real hard. I quickly lowered the volume. The box is not double chambered and is about four cubic foot after port and displacement. It is tunned to 35 hrz. So need some advice. Is it the box or my settings? My crossover is set at 80 -12db.My gain is about a fourth of the way turned up along with the bass boost at 1. Any advice would be great. My past three subs have been sealed and I'm now thinking of going back to that

Is there any way to change the -12db crossover slope to -24db or something? That just seems way too shallow for a sub IMO. Everytime I've messed with 80 hz @ -12db, it always sounded muddy on high frequencies. It's playing too many frequencies at once. And definitely put your bass boost to 0. Those reasons could be why it don't sound good with a punchy song like bow down by westside connection.