subs in xjs

[Beej]

Wow, you guys need some audiophile information clean up in this thread...

srimes, you didn't build an infinite baffle, you just installed your speaker in a larger semi-sealed box. That's why you've noticed more low end.

An infinite baffle means that the speaker is exposed to the environment on both sides, and there is no "suspension" in the "cabinet" as there is inherently built into a sealed box. The huge risk here (which FI appears to have adequately dealt with) is superceding XMax of the driver.

For what its worth, for anyone else at home, don't build an infinite baffle setup with any old driver, you MUST match your box/enclosure to the T/S parameters of your driver or it will quickly toast when you put some watts through it. Just as a point of note, when it comes to bass applications, the superior tone comes from ported boxes, then sealed and then infinite baffle, in that order. Infinite baffle is excellent for high frequencies, like between 1kHz - 20kHz, for low frequencies, you will enormously increase your output by running a tuned port system, or a 4th order bypass box.

Also, "overstressing amps" will not "blow speakers", however feeding a set driver too much wattage when its not in a correctly oriented enclosure will.

Lastly, displacement per stroke is not related to SPL, and one 18" will undoubtedly not be as loud as 2 15"s...

 

[srimes]

Wow, you guys need some audiophile information clean up in this thread...

ok

srimes, you didn't build an infinite baffle, you just installed your speaker in a larger semi-sealed box.

No. What I effectivly did is cut a hole in my jeep and plugged it with the speaker. That's what an infinate baffle is. The back is open to outside, and you can make the argument that the jeep itself is a "larger semi-sealed box," but that box is greater than 10 times the drivers Vas (at least I'm assuming it is), so Qts=Qtc, which is how infinate baffle is effectivly defined.

An infinite baffle means that the speaker is exposed to the environment on both sides,

No, that is an "open baffle" or "dipole" speaker.

and there is no "suspension" in the "cabinet" as there is inherently built into a sealed box. The huge risk here (which FI appears to have adequately dealt with) is superceding XMax of the driver.

true, the only suspension is in the driver itself. That's why it's cleaner, because there are no box colorations.

Just as a point of note, when it comes to bass applications, the superior tone comes from ported boxes, then sealed and then infinite baffle, in that order. Infinite baffle is excellent for high frequencies, like between 1kHz - 20kHz, for low frequencies, you will enormously increase your output by running a tuned port system, or a 4th order bypass box.

no. The cleanest most accurate deep bass reprodution is with infinite baffle. Sealed and ported can both be very good and depend on design. And bandpass boxes are the worst. They are the most effecient and therefor loudest for similar drivers and power, but they produce distorted and colored bass.

Also, "overstressing amps" will not "blow speakers", however feeding a set driver too much wattage when its not in a correctly oriented enclosure will.

Overstressed and clipping amps can produce distortion and power spikes that can damage speakers.

And yes too much wattage will blow a speaker, and there are 2 different modes of overpowering a speaker. What is usually listed (1000 watt sub) is the thermal limits, or how much power the voice coil can handle. The other limit is Xmax, or travel, which depends on both power and frequency.

Lastly, displacement per stroke is not related to SPL, and one 18" will undoubtedly not be as loud as 2 15"s...

No and No. It all starts with displacement. How do sound waves work? It's all about moving air.

And as for 1 18 vs 2 15, it all depends on the specific driver, but 1 18 can be louder then 2 15s.

For those that are interested in infinite baffle subwoofers check out this FAQ: http://home.comcast.net/~infinitelybaffled/index.html

And check out the "cult of the infinitely baffled" board.

 

[MaxxXJ]

if you got the same brand model 18 compared to the same brand/model pair of 15's that 18 will likely not be louder... personal expierence... i have 2 JL W3 12's running off a diamond audio 600 watt amp right... well everyone swore that the image dynamics IDMAX 12 would be louder because it had twice the x max... well they were wrong, maybe if i ported it but thats changing the game. the w3's were in a sealed box and my idmax is in a sealed box. where the max might be really close in comparison the 2 w3 12's sound better hit harder and had more bass everywhere across the freq's im very disappointed in the switch even if i did gain 1.5 cubes in cargo space.

 

[MaxxXJ]

and the part i forgot... you have to throw twice the power at the single sub to get the same output as the pair.

IMO JL audios W3 subs are the best ive heard/ had for the money and power requirements

 

[Beej]

ok


No. What I effectivly did is cut a hole in my jeep and plugged it with the speaker. That's what an infinate baffle is. The back is open to outside, and you can make the argument that the jeep itself is a "larger semi-sealed box," but that box is greater than 10 times the drivers Vas (at least I'm assuming it is), so Qts=Qtc, which is how infinate baffle is effectivly defined.



No, that is an "open baffle" or "dipole" speaker.



true, the only suspension is in the driver itself. That's why it's cleaner, because there are no box colorations.



no. The cleanest most accurate deep bass reprodution is with infinite baffle. Sealed and ported can both be very good and depend on design. And bandpass boxes are the worst. They are the most effecient and therefor loudest for similar drivers and power, but they produce distorted and colored bass.



Overstressed and clipping amps can produce distortion and power spikes that can damage speakers.

And yes too much wattage will blow a speaker, and there are 2 different modes of overpowering a speaker. What is usually listed (1000 watt sub) is the thermal limits, or how much power the voice coil can handle. The other limit is Xmax, or travel, which depends on both power and frequency.



No and No. It all starts with displacement. How do sound waves work? It's all about moving air.

And as for 1 18 vs 2 15, it all depends on the specific driver, but 1 18 can be louder then 2 15s.

For those that are interested in infinite baffle subwoofers check out this FAQ: http://home.comcast.net/~infinitelybaffled/index.html

And check out the "cult of the infinitely baffled" board.

I'm not going to bother arguing my above points. Never mind the fact that I've built speaker enclosures and arrays for 25 years, many of which are still pounding in clubs and bars across the Canadian midwest. For the record though, the "cleanest and most accurate bass reproduction" is with a folded horn - period. For anyone interested in speaker design, function, limits, etc, the information is available on the web - but its most certainly not available on or via car audio and sub forums.

That infinitely baffled FAQ is the greatest repository of misinformation and partial understanding of acoustic engineering I've seen and can be summed up nicely right here.

Misc really important stuff.... ;^) ​

Why are we called the "Cult of the Infinitely Baffled''?

We are a cult because like all irrational institutions, we know our faith and beliefs represent the only true path to low frequency enlightenment (LFE). And because no amount of rational thought, scientific knowledge, law suits or political pressure, will change these beliefs. ​

 

[srimes]

I'm sure the systems you built for the clubs and bars are great, and for that environment IB doesn't make sense. An as for opinions on horn subs, that's highly debated by those with no interest in IB subs.

fwiw, that statement is tounge-in-cheek, lighten up. And it isn't a car audio sight, any discussion of car audio is banned.

 

[IslanderOffRoad]

Here's my new box, the subthump.com cubby box:

 

[JeepAddict85]

Nice job, looks good. Ive been thinking of retiring my 15's for use in my home, and going with a single 10w7 in a sealed enclosure. Who knows thou, I really like the deep pounding bass I get with the eclipses.

 

[FlexdXJ]

Fi Makes good stuff. I bought my Fi after reading tons of positive reviews.

Yeah they do my buddy has an 18" Fi Q(i think its a Q anyways)in his WJ. Just heard it a few days ago. Its hitting hard in a 7-ish cubic foot box!

 

[NCjeepgirl83]

Those XJ pods only hold an 8" sub. The stealthbox was made for 10" subs. It's a shame JL stopped making them.

Anyone know why JL stopped making them?

 

[JeepAddict85]

Lack of interest, not many people buy them. The truck stealth boxes are pretty popular though.

 

[urban yan]

Also, I think they were pretty expensive when they came out.
Some JL Audio stuff isn't exactly budget friendly.

 

[NCjeepgirl83]

Also, I think they were pretty expensive when they came out.
Some JL Audio stuff isn't exactly budget friendly.

Yeah, that's what I've found with any JL stealthbox I've come across...right now someone's selling one for a H3 and he's asking $300 so I've never seen them for under about $200...and having said that, I still have to install mine...

 

[XJCasper]

But if you have somthing custom built similar, it would probably cost about 300 plus the speaker

 

[urban yan]

They're hard to come-by, but I did see another stealthbox a few weeks ago on eBay (that makes 4 or so in the 6 years I've been on eBay). It went for $300, but at least it came with a 250/1 amp, and JL sub. I consider that a good deal. I bet the stealthbox, alone, went for more when for more than $300 from JL.

 

[bmrrwolfe]

Heres my setup 2 12" Pioneer Premier Champion Pro Series 3000 watts a piece. 2400 watt RF amp and 0 gauge wiring. put in two seperate boxes so when space is needed i can take one out! :yap:

 

[horsefighting]

so i found a site that has some good info on building sub boxes. http://www.termpro.com/articles/buildbox.html

and i finally got mine hooked up. not sure what size amp but its a 12in sub. got it from a friend for free. sounds really really good. now i just have to upgrade my speakers...

 

[MahnkenVille]

Sony 500watt amp driving two 10" JL subs in a carpeted box, just got it wired up today. I still have alot of storage room back there, but i'm thinking of having disconnects put in so i can move it to put my kayak in, or more gear. Will disconnects decrease sound quality?

 

[GrimmJeeper]

i wouldnt worry too much about sound quality with one of your center cones missing . the slight amount of noise you might get from having a disconnect inline will not be noticable with your current setup.

 

[MahnkenVille]

haha, it came like that when i bought the jeep. i figure i'll upgrade those, eventually. do they make specific disconnects for car audio or will any standard connector work?