sub confused

[Atvstevo1337]

Alright im looking to put a 12" sub in my 240, and i have not been able to decide what to get as I really want that sharp punch that you can feel at your heart. For the sub i was looking at the JL 12"W6. Would i be best suited to get a ported or sealed box, I was hopeing to get a custom made one. And would my kenwood KAC-81030 amp do the trick? I'de rather not have to buy another amp so i could spend more on the sub/box

[coolhand]

Question:

Is the w6 single voice coil or dual coil?

Dual voice coil subs allow you to wired them like you have two subs and will allow you change the ohm rating your amp sees. This link will helphttp://mobile.jlaudio.com/supp...d=161

It should sound nice with what you have. I like the MTX thunder series (8500 series will work nicely)

[EW]

12W6v2 ported will pound on 400W RMS. Are you sure about the amp model number? I could not find it.

[coolhand]

KAC-8103D

[Atvstevo1337]

yea thats the number i mistook the D for an 0, My amp is only a 300w. thats what i was hopeing to hear but im not sure if i want a ported or sealed box yet?

[coolhand]

That is at 4 ohms. You can get 500w at 2 ohms with that amp safely.

[Broadfield]

Sealed to ported is going to come down to several things. Sealed will play tighter and lower than a ported. It will be a smaller enclosure than a ported. It might also cost a little less to build. The sealed is best for all around music listening. The ported box can gain you up to 6db or so of output in a particular frequency range depending on port design. So if you have a little amount of power, the ported box can still have a good amount of output. A common misconception is that the sealed box can handle more power, but actually the ported/vented does as long as you do not play tones below the tuning frequency.

I usually prefer sealed, but that's just personal taste.

[Atvstevo1337]

From what I can see I think I'll go with a sealed box, now my only problem is that the sub I was looking at from JL is a little high in the price range I was hopeing to spend somewhere around 300$~ any suggestions?

[EW]

13W3v3 $299Boston G5 $349There are many subs in that price range that are good.

Broadfield:Any tech docs to back up the "ported allows woofers to handle more power" theory?I saw this on JL's tutorials http://mobile.jlaudio.com/supp...d=147but not really referencing power.Quote »At higher power levels things change considerably. The dual-reflex bandpass, due to the fact that its ports control cone motion over a wider range of frequencies, produces the least distortion and exhibits the best power-handling characteristics. The ported enclosure and the single-reflex bandpass also do a very good job producing high-levels of undistorted bass output, again due to reduced cone motion in this frequency range. Bringing up the rear in this category is the sealed enclosure, which produces higher levels of distortion at high power levels. There is a common misconception that ported designs produce more distortion than sealed boxes. As you can see this is not entirely accurate; it depends on the frequency and the power level.[/quote]I prefer a ported enclosure but for customers it does take up more space and it does cost more to design/build the enclosure.

Modified by EW at 2:21 PM 2/28/2008
Modified by EW at 2:22 PM 2/28/2008

[Broadfield]

Sorry EW, I didn't type what I meant to say. I meant that the ported doesn't automatically handle "less" power just because it is ported compared to sealed. The way I said it made it sound like a ported can handle "more" than a sealed. I'll rephrase by saying a ported can handle "as much" as a sealed while not being played below it's tuning freq.

Thanks for pointing that out!

[the converted]

I thought it was that you could go an octave below before the box would "unload"?

[EW]

So if you tune to 40Hz you're going to set the infrasonic at 20Hz? Not me.

[the converted]

I personally have my box tuned to 27 hz with a 15hz subsonic so I guess i'm barely good.

[PoorManQ45]

I'd recommend a Exodus Shiva X 12

It will hit harder then a 12w6(more excursion), and it will be as clean as the W6 as it has the motor strength to control the extreme excursion.

Note: The Shiva X has an Xmax of 27mm one way whereas the W6 has an Xmax of 16.5mm.

Shiva X = $165. W6 = $300~$500.

Use the saved money for either a better amp or more mods for your car

[Broadfield]

Well, the problem with the Shiva is that it needs a box twice as big as the W6. That's very important to some people. The vas value on that thing is enormous!

[PoorManQ45]

Yep

But for the price you could purchase two of them and have enough saved money to purchase a more robust amp.

Put the two shivas in an isobaric alignment to half the airspace requirement. This would require twice the power, but thats where the better amp comes in.

The advantages would be, flatter frequency output, lower output, superior control/reactions then pretty much any single driver, not much extra space required(just to accomadate the 2nd driver).

Cons, half the power is "wasted"

[Looneybomber]

Sealed will play tighter and lower than a ported.

Uh oh, you started a sealed vs. ported debate. Anyway, that statement is not true. Two-three years ago I might have agreed with it, but now I wont. Sealed is fairly constant whether your box has a Q of .8 or .6. It's still basically a 12db/oct drop off at the fb which will likely be as high as 60-70hz with a sealed car oriented sub. That sealed will only play lower after the tuning freq of the ported. If it's fairly large and tuned to say 25hz, then the sealed will start beating the ported (in SPL) around 15-18hz. Is that useful? However, from 70-20hz, the ported will play louder. From 23-40hz it will be considerably louder. Possibly as much as 12db, which would require 16x the amount of power in the sealed enclosure to equal the ported.

As for being tighter, that's all about the transient response and group delay in the upper bass frequencies. All things being equal, you can build a ported box to have even less group delay than a sealed in those upper freq's by building large and tuning low. So, in that case the ported would actually be "tighter".

The sealed is best for all around music listening.

Your oppinion my differ from others. Incase you're wondering, I like horn loaded.

Broadfield:Any tech docs to back up the "ported allows woofers to handle more power" theory?

Above the tuning freq, it performs nearly the same as a sealed box. At the tuning freq, mechanically, it will easily handle 3-4 times what a sealed will at that same freq if the coil can even disipate that much heat.

I thought it was that you could go an octave below before the box would "unload"?

It starts to progressively unload immediately under the tuning freq. Depending on your excursion capabilities and power, you can get away with an octave, but usually you put a SSF in place just a couple hz under the tune freq.

[Broadfield]

Plain and simple fact is you can build a box to get it to do just about whatever you want. However, you are sacrificing size, cost etc. I am speaking from dealing with the average customer 20, 30, 40 thousand times. Most customers want a simple box that doesn't take up very much space and will have a fairly flat response to it. It's all about figuring out what your customer wants, not what you want them to have. Although I do try to push my needs on them once in a while

[Looneybomber]

Very true, however all encompassing things like "sealed is tighter" or "sealed plays deeper" are wrong, and are only correct with an improperly designed ported box.

I hope I'm not coming off as rude, but they're just stereotypical comments.
Modified by Looneybomber at 6:15 PM 3/2/2008

[PoorManQ45]

I want a 20ft^3 box for a single 18" driver that's ported to 12hz

[Looneybomber]

I want a 20ft^3 box for a single 18" driver that's ported to 12hz

You must be talking about the Rl-p18

If you really want one, buy one (or two) pretty soon. With TC-Sounds/Audio Pulse shutting down again, who know's what's going to happen to Sound splinter

[EW]

Above the tuning freq, it performs nearly the same as a sealed box. At the tuning freq, mechanically, it will easily handle 3-4 times what a sealed will at that same freq if the coil can even disipate that much heat.

So above the tuning freq power handling is the same and below the tuning freq the driver is unloaded, but AT the tuning freq it can theoretically handle 3-4 times more power than the sealed driver?

[Looneybomber]

So above the tuning freq power handling is the same and below the tuning freq the driver is unloaded, but AT the tuning freq it can theoretically handle 3-4 times more power than the sealed driver?

Yes, above the freq. a ported enclosures power handling is similar to a sealed box.

It's all because of the helmholtz resonator (port). Above the tuning freq. the driver is air mass loaded. As it gets closer and closer to the tuning freq. the loading becomes more and more powerful, thus the driver moves less and less. At the tuning freq. it loads the driver like crazy, thus reducing it's movement a lot. Why? because nearly all the sound that is produced is by the port and not the driver. Below the tuning freq. it can no longer load the driver and that's why it becomes unloaded.

I will post some graphs as soon as I can get back to my house and play with my software. A picture is worth a thousand words.

[krimsonviper]

I am officially confused at how you people come up with these conclusions. Honestly i think all you guys said was "stick a banana in a giraffes *** and you'll get its neck extended by 5 inches because its surprised you didnt use a coconut" how'd you all figure these things out and where can i learn this? this is all mathematics right?

[PoorManQ45]

LOL, visit http://www.the12volt.com

read everything you can on google about audio

sound&vision forum. AVSForum. read everything you can.

Anyways, back on topic guys.

I won't recommend a W6, it's way too overpriced.

Check out Audio Pulse. They make some awesome products.

looney: You're correct. Also, I was referring to the Rl-p18. They are just plain sick. My only other choice would be a quad to eight pack of Mach5 Audio 18s in an IB setup

[Looneybomber]

Here's an example of sealed vs. ported using the driver I currently own. The CSS SDX-15

Sealed = red linePorted = white line

This first graph is the Transfer Function Magnitude. It tells you how the subpeforms in relation to 0db. You can see just how much the sealedenclosure drops off and just how soon. So the notion, "sealed playsdeeper" is only true well below the tuning freq. of the ported enclosure.

This graph is of the cone excursion with 1400watts delivered to each driver. As you can see from 35-100hz, the ported will actually handle more powerand as you saw above, since it's also more efficient below 70hz, will alsoproduce more SPLs. Now look at the white line. See how it dips like crazybelow 20hz? That's because it's tuned to 18hz. At which point the cone isonly moving 13mm as opposed to the sealed moving 32mm. (above the redline is bad as the driver runs out of xmax and becomes non linear. The driver is also mechanically limited to 40mm, so anything above that will cause damage to the driver. That is why a subsonic filter is needed.)

This graph is about group delay, which tells you how long it takes the subto produce the sound it's presented in it's signal (less is better). In a sense, it tells you how "tight" the sound is. As you can see, the ported isactually quicker from 35hz+. So in this case, during normal music, this sub will sound "quicker"

However, as you can see, below 35hz it all goes downhill. Which is acceptable because low bass is less critical since our ears are less efficient at hearing those frequencies.

*edit* most of the things I point our are very close to the point where it'snegligable, for example cone excursion and group delay above 35hz. It's measureable, but your ears wont be able to tell the difference. Also
Modified by Looneybomber at 10:59 AM 3/4/2008

[schmiddr2]

The middle graph, if I read it correctly, the sealed plays on into the sub 18hz frequencies at high excursion while the ported, being tuned for 18hz dies off. Advantage to the ported, better use of power and no need to produce le2s than 18hz IMO.

To me the last graph appears to show the sealed to be more steady. So when does a subwoofer become better suited as midrange woofer?

My ultimate question is: Assuming same sub, same power, and the 2 box options. Are there any differences in the sound being produced when they're played at the same hz? Or at any other hz?

BTW: Ya'll are way smarter than I was doing this in 94'. Good information was an experiment away.

[EW]

W6v2 is a great driver and not overpriced. Made in USA by a company with MANY speaker engineers on staff using in house developed design/testing software. They have won all kinds of patents and are always reviewed well. Great sound and a two year warranty plus all the tech info you could ever want. JL Audio has won many dealer surveys and People's choice award for best car audio manufacturer by visitors of cardomain.com. Great product at a good value with some of the best R&D on the planet.

[Looneybomber]

Those graphs only represent that exact driver in those exact boxes. Different drivers in the same box will perform different. The same driver in different boxes performs different (as you can see in the graphs). It's a package deal and you can manipulate your ported box to reach certain goals. If I used the same size box, but tuned it for 50hz instead of 18, there would be a HUGE spike upwards of 8-10db above the baseline of 0db.

The middle graph, if I read it correctly, the sealed plays on into the sub 18hz frequencies at high excursion while the ported, being tuned for 18hz dies off. Advantage to the ported, better use of power and no need to produce le2s than 18hz IMO.

To me the last graph appears to show the sealed to be more steady. So when does a subwoofer become better suited as midrange woofer?

My ultimate question is: Assuming same sub, same power, and the 2 box options. Are there any differences in the sound being produced when they're played at the same hz? Or at any other hz?

The first graph is how much sound will be produced by the sub. As you can see, at 10hz (if the subwoofer did not run out of excursion) it would still play louder than the sealed because it's more efficient.

The second graph shows how far the sub's cone has to move in order to produce that level of sound. At 18hz, while the ported is producing ~10db MORE sound than the sealed, its moving less than half the distance. The graph just shows how the port effects the movement of the woofer.

Sealed is definately more steady and easier to manage, which is why people love them so much. They're so simple.

Something you mentioned was there's no need for sound reproduction below 18hz. In the home audio world, guys are trying to get large amount of output in the single digits. I, however, believe 15hz is plenty low and will also be the frequency I will choice to tune my enclosures to.

As for subs playing into the midrange, I don't advise it, but it's certainly possible for 15" drivers to play up to 2-3k (on axis) and cross it over to a tweeter. It's not common because it takes a hell of a driver to pull it off and creates another problem called "beaming" and can introduce something called intermodulation distortion at higher volumes.

[PoorManQ45]

I have visited the JL Audio facility in Pembrook Pines. It was a surprising change from the normal run of the mill factory setups.

Yes their quality control is outrageous.

They check each assembly at each `~5 steps. Like the motor assembly, spider & VC get electrically tested by themselves.

EVERY unit is checked. 100%. It's not just a few out of the batch. It's 100% of them.

This is great. But do you reaqlize that their parts are actually made in China and india. All their rubber comes from these countries. Their VCs and spider assemblies are made their too. I think only their patented "W" cone assembly is made in house.

Everything else is simply assembled inhouse.

Note: When they get batches of VCs in they only check 3~5 randomly out of each batch of 100. This isn't that bad though because 100% of the drivers are tested and if they're too far out of spec they'll be rejected.

Note: if there is a problem with one of the units the whole assembly line for that driver is shut down until they figure out the problem and correct it in all subsequent parts.

Also, something cool. Every single part has a serial number on it that can actually be traced backed to the individual person that tested it!

But, don't go thinking that JL is all high and mighty by using USA made parts. Their products are only assembled here!

Also note: Their Home audio line uses scanspeak drivers. Not JL drivers

Also, please don't ever use consumer awards as a strong point of a product. If we went off of consumer awards then that must mean that Bose is the best audio company in the world. And we all know for a fact that that isn't true.