Ok I had a 12 in a sealed box and it came appart. I sent it back in and they are redesigning the subs so it will be a long wait for another 12...but they will upgrade me for free to a 15 and they have the new styles now and can ship now. My question is does any one have a pic of a single 15 in a CL. I would love a bigger sub but I just dont know how it will fit in there. I was going to do ported on the 12 when I got it back so now I am thinking maybe ported on the 15. The 2 boxes on the 15 would be sealed 21 x 18 x 10 1/2 and the ported is 26 3/4 x 17 1/2 and I dont know front to back.

So what would the sound difference be if I went from a 12 to a 15 in a sealed box with the same power...I know ported is louder than sealed but I dont know if a ported 15 would fit well in the cl.

Need to know asap
Thanks

 

Sounds overkill to me. You would also need a higher power amp to run a 15". Say goodbye to your trunk space.

 

They told be the amp I have will run it fine...they dont need tons of power. My trunk would go buy by but heck....I can always pull it out when I need my trunk. I am sure its overkill because the 12 sounded good...but I am a bass head and would always be ok with more

 

It's about SQ not SPL.... stick with the 12. The 15 will drown out the sweet sounds from those CDTs.

 

well a 15 doesnt reproduce the low midbass freq as well as a 12 and with a ported set up you lose a lot of accuracy. if you listen to a lot of rap this wont be too bad, but if you want the bass to sound tight and snappy id either seal the 15 (which would require more power) or see if they can get you 2 10's

 

Well I do listen to mostly rap but I do listen to everything else. I am thinking more and more about it and I dont know if I would do the 15 ported...thats just a big fuken box in the CL trunk. I think I would do the 15 sealed and I have a hard time thinking the 15 will drown out the CDTs...that are very loud to I dont want 2 10's because I like low bass and the 12 does better than the 10's and the 15 would be that much better. Also the guy told me the 15 will do good with the same power as the 12. Same parts (magnet spider and so on) just a bigger cone so they say with the same power in the same kind of box it will be a little lower and a little louder. The lack of mid bass from going to the 12 to the 15 is something I have not thought about...will there be that much lacking??

Arrgh why did they even have to mention this to me

 

no you will not loose any mid bass going from the 15 to the 12... the mid bass should be taken care of by the front and rear stage not the sub woofer... personally i would stick with the 12 simply because it takes up less room but if you like bass by all means get the 15...


Hobo... i would have to say you are wrong about the who ported box not being as accurate as the sealed.... a properly tuned ported box can be just as accurate or even more so than a sealed box...

 

This is my old sub......

 

Yeah I think a good ported box is accuret as well...I went with the 12. I will just have to wait for them to replce it because they are not shipping yet. I am going to port the 12 and the guy said the 12 ported should be neck and neck with the 15 sealed as far as volum with the same amp. So 12 ported for me Ill take some pics for yall when I get it done.

 

Straight from the JL website...

Sealed Boxes are....

The sealed (aka: air-suspension, acoustic-suspension) enclosure is a classic box design. Patented in 1949 by Harry Olson and popularized in the 1950's by Acoustic Research, this design has stood the test of time and has been adopted by many home and car audio companies.

In a sealed enclosure, the woofer is tightly controlled by a trapped volume of air in the enclosure which acts as a spring (hence the name "air-suspension.") The woofer must literally pull the air with it as it moves outward thus decreasing the air pressure inside the box and compress the air inside the box when it moves inward, which increases the air pressure inside the box. Since the air pressure inside the box seeks to equal the barometric pressure of the atmosphere, it acts as a controlling force over the motion of the speaker. The more the speaker moves inward or outward, the greater the pressure exerted by the air-spring of the sealed enclosure in the opposite direction.

The relationship between the parameters of the speaker being used and the volume of air inside the enclosure dictates the performance of the sealed subwoofer system. By making the box larger, the air spring limits cone motion less and allows the system to play lower and with flatter overall response (lower Qtc) at the expense of power handling. If you go too large, however, you begin to lose efficiency in order to gain the additional low frequency extension. By making the box smaller, the air spring exerts more control and limits cone motion at low frequencies which increases power handling but does not let the system play as low and produces a more peaked response (higher Qtc.)

For any speaker competently designed for sealed box applications there is a range of enclosure volumes that will produce good high-fidelity sound. Changing the enclosure volume within that range can fine-tune the response to suit the tastes of the listener and/or the acoustic properties of the vehicle.


Ported Boxes are....


Ported enclosures (aka: Bass-Reflex, Vented) have actually been around longer than sealed designs. The ported enclosure was patented in 1932 by A.C. Thuras. Further development since then has defined the behavior of ported systems much more precisely. A.N. Thiele and Richard Small are generally credited with having done the most definitive work in this area, which is why enclosure/speaker parameters are commonly referred to as Thiele-Small parameters.

The coupling of a port or duct to the air inside the enclosure allows the subwoofer system to take advantage of the work being done by the rear of the woofer cone to reinforce the low-frequency response. The resonant characteristics of the column of air in a port, when installed in a given box, are adjusted by altering its resistance to motion, which is accomplished by changing the dimensions of the port. In some designs, instead of a port, a speaker cone with no motor assembly or a flat diaphragm is used to achieve the same effect. This is known as a passive radiator. The resonance of a passive radiator system can be adjusted by altering the radiator's surface area, mass and compliance (stiffness of suspension.)

In a ported enclosure, there is a delicate relationship between the volume of air in the box, the resonant effect of the port, and the parameters of the speaker being used. When these three factors are correctly integrated, the rear output wave of the speaker is delayed just enough so that when it comes out of the port, it is in relative phase with the wave being produced by the front of the speaker. The result is constructive output from the port limited to a desired low- frequency range. This low-frequency reinforcement is one of the big advantages of a well-designed ported system. Using the work of the rear of the cone in a constructive manner means that a gain in efficiency of about 3dB over a broad band in the sub-bass range can be achieved as compared to a sealed enclosure using the same woofer. The other big advantage is that the interaction of the port, the enclosure and the speaker's resonant characteristics also reduces cone motion and, therefore, distortion at higher volume levels in the frequency range controlled by the port. The down side is that at frequencies below the tuning of the port, the speaker gradually begins to act as if it were not enclosed at all (more on this later.)

The increased output combined with reduced distortion in the "meat" of the bass range (35-60Hz) is a big reason why many home speakers and high-power sound-reinforcement systems use ported enclosures for low-frequency reproduction. The vast majority of recording studios also use ported enclosures as monitors for the same reasons.


The rules governing the behavior and proper design of ported speaker systems are considerably more complex than those for sealed enclosures. For this reason, it is a good practice to follow the advice of the speaker manufacturer or an experienced enclosure designer when it comes to designing a ported system. It is very easy to screw up a ported box if you just guess at the size and length of the port or the tuning frequency for the box. Not only will a poorly designed box sound bad, but it can easily damage the speaker if it is played hard.



And the Real Proof.


It is generally accepted that an optimized sealed enclosure exhibits the best transient response characteristics. The control provided by the air-spring in a good sealed system contribute to generally outstanding transient behavior (at very high power levels, the increased distortion can overshadow this advantage, however.)

A ported enclosure can also achieve good transient behavior but never as good as an optimized sealed enclosure. It is possible, however, for a well-designed ported enclosure to have better transient response characteristics than sealed enclosures with higher Qtc's (above 1.0.) The specific alignment of the sealed and ported enclosures plays a huge role in determining the transient characteristics of each individual subwoofer system.


[My rant]
Nearly everyr audio manufacturer worth a damn has faq's or tech help that will revel a similar opinion about sealed vs. ported enclosures.

Ported Boxes are great for really pumping up low frequencies, and are great boxes if made correctly, but they will never be as tight as a sealed box. Not to mention that building an airtight box is easier than tuning a port to specific music choices, enviornment, etc.
[/rant]

 

Yep I agree that seald has an edge but with a good ported box I do think you can still get close to seald SQ. Who knows I have never had ported in my car but my home subs are and they sound great. I will do the ported they suggest on the website and I will let yall know what I think because I have a sealed box as well I just want a little more boom because I do listen to mostly rap when I am alone in the car and I can actualy turn it up (Wife dont like the boom boom haha)

 

jl w7 12" all a thats all i can add

 

"It is GENERALLY ACCEPTED that an optimized sealed enclosure exhibits the best transient response characteristics." humm does this mean that it has not been proven.. I bet that given the same speaker, the same amp in the same car with one box being ported and tuned to say 40-45hz and one box being sealed you whould have a hard time guessing which is sealed and which is ported..

 

Well I will have the same sub same amp and same car and I already have a seald box and I will be doing ported next so I can let ya know what I think. But the box on the website I believe is tuned to 28hz...so it might not be the same testing you are talking about.

 

i listed one example...

i have heard the same set of 15's and 12's in sealed and ported enclosures and they do sond different... the ported sounds boomy and if not tuned properly, the port can fart at some frequencies. i like the sound of sealed better, but justy mho



whoever brought up home audio that is a different topic, the acoustics of a car and a house are different and so are the magnet sizes and power levels, many more varibles, also home audio speakers are nearly all ported, including the midbass and high frequency woofers. Most of the installs ive seen on here people dont worry about enclosing their door speakers in a mfg. size box, im wondering why everyone is so opinionated about sub boxes, i provided an industyy leader's opinion, one which is repeated by nearly every comapny in teh business in writing.

anyways... we are so far off topic now

 

oh btw.. it is generally accepted that racism is bad.. but that again is mho

 

I said something about my home subs being ported but was not compairing them. I know its way different than a car. I was just saying that because I said I have never had a ported sub...except for home.

 

wasnt raggin on you but i just thought i should point out the differences...