12w6v2 enclosure

hello, i am about to install a 12w6v2, the JL audio webpage says that the recomended cubic feet for that subwoofer is 1.5 (slot ported)

If I build a 2.00 cubic feet enclosure (slot ported also) will it work just fine anyway?.... 

any comment please let me know.

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Ricardo Daniel Meza Cavazos

if you are building it, why not build it to spec? This is an amazing woofer, I wouldnt short-change it.
I would go by the recommended enclosure volumes for sure. It wont hurt you to put it in a 2.0 cuft box, but I dont know what port length to suggest. Save the headache and build it to spec. Ported boxes are tricky enough already

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Well, the reason is because I am dealing with a very small trunk and if I build the 1.5 cuft, I would need to extend a port length of 29 inches which is very complicated. (a few days ago I built an enclosure with 2 chamber of 1.5 cuft each and I suffered to make the port, you can watch it at: www.fotolog.com/infinitekaudio )

Well then, in my little experience I know that a ported enclosure of 2.00 cuft must has a 18 inches port length.

I just wanted to know if an enclosure like that wouldn't hurt my subwoofer and if i could obtaing great sound quality.

It's just that this is a work for myself. for my car, you know.

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Ricardo Daniel Meza Cavazos

mezzaricardo wrote:

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Well then, in my little experience I know that a ported enclosure of 2.00 cuft must has a 18 inches port length.

I just wanted to know if an enclosure like that wouldn't hurt my subwoofer and if i could obtaing great sound quality.

It's just that this is a work for myself. for my car, you know.

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A 2cubic foot enclosure can have a port length of 3 inches...Its all relevant to your port area and desired tuning frequency.

This box would work perfect:
https://subwoofertools.com/forum/ported-box.asp?Ew=30&Eh=15&Dia=6&Xmax=16&Vd=.12&NumW=1&Vb=2&Fb=35&Qts=&Vas=&Fs=&CE=0

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'89 Mercedes-Benz 300E
Pioneer DEH-5900UB
(2)RE Audio SX 10"s
(1)US Amps MD3D
3ft^3 @ 37Hz

Blowing up in a car accident doesnt worry me, as long as I'm putting out some major dB's when I die...

CLOAK 559 Wrote

A 2cubic foot enclosure can have a port length of 3 inches...Its all relevant to your port area and desired tuning frequency.

This box would work perfect:
https://subwoofertools.com/forum/ported-box.asp?Ew=30&Eh=15&Dia=6&Xmax=16&Vd=.12&NumW=1&Vb=2&Fb=35&Qts=&Vas=&Fs=&CE=0
A 2cubic foot enclosure can have a port length of 3 inches...Its all relevant to your port area and desired tuning frequency.

can you explain me the difference between a very long port length and a small port length?

and the difference between a small slot port and a bigger slot port?.. in this case you recommend it as 2.25?..

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Ricardo Daniel Meza Cavazos

mezzaricardo wrote:

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]can you explain me the difference between a very long port length and a small port length?

and the difference between a small slot port and a bigger slot port?.. in this case you recommend it as 2.25?..
]

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There is quite a bit of math involved in designing and building a ported enclosure...

The three things you need to determine are:

-cubic footage after port and woofer displacment
-Port Area (Height x Width of port opening)
-Port Length

Cubic Footage:

Cubic footage is determined either by manufacturer specs or by calculating a woofers thiele small parameters to find optimal airspace for that driver...You have chosen to do 2 cubic feet for your enclosure.

Port Area:

Port area is determined by the woofers total linear displacement. This can get very complicated so its best to use this rule of thumb-you should have around 12-15 sqaure inches of port area per cubic foot of your box...Meaning that for a 2 cubic foot box you should have roughly 24-30sq.in. of port area.

Having not enough port area can result in port noise, which is created by air turbulance rushing through the port. its like driving at 25mph and cracking your window. If you just crack it, you will hgave the wind noise, but if you roll all of your windows down, it will be a lot quieter...Too much port area can result in your woofers not having enough negative pressure. This can lead to a loss in bass and woofer damage caused by your speakers excurting too far.

Port Length:

The length of your port determines the frequency in which your box is tuned to. At tuning frequency your speakers do not move very much, and the port resonates air to make bass. This is why you can accomplish a much louder and lower sound with ported boxes. Most daily bass boxes are tuned anywhere from 28hz to 40hz. For yours I would tune to around 35Hz...This will give you nice lows for rap music bat also give you the higher range for rock or country...there is a formula to determine length, but for you the online calculators will work fine. THIS is a good one...With 30 sq, inches of port you should have a port that is about 27.5 inches long...

So overall you should have a 2 cubic foot box with 30sq. inches of port that is 27.5" long tuned to 35Hz....



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'89 Mercedes-Benz 300E
Pioneer DEH-5900UB
(2)RE Audio SX 10"s
(1)US Amps MD3D
3ft^3 @ 37Hz

Blowing up in a car accident doesnt worry me, as long as I'm putting out some major dB's when I die...

coppellstereo wrote:

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if you are building it, why not build it to spec? This is an amazing woofer, I wouldnt short-change it.

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Hmm.  Never talked to coppellstereo before, but I've used these woofers and they like a *big* box.  Not a standard 12 I can assure you of that.  You should have absolutly no problem with 2cft ported enclosure..  furthermore building ported boxes is *very* easy.  I'll design one for you in WinISD so you won't have any doubt.

Okay, here is a text representation of the response of that woofer for a 2cft box with a 30hz tune.  I modeled a 35 hz tune as the cloak559 suggested, but I think this frequency produces a much better response curve.

Driver            : JL Audio 12w6v2
Project by        : sedate

Project for       : mezzaricardo

--
Number of drivers : 1
Box type          : Vented
Box size          : 2.000 ft^3
Tuning frequency  : 30.00 Hz
Vent              : 2 vent(s)
                    7.76 in length for each
                    2.00 in round
                                                           
                                                           
             Relative                                      
Freq         Gain         SPL                              
[Hz]         [dB]         [dB]                             
20.00        -12.38       73.52                            
25.00        -6.19        79.71                            
30.00        -1.90        84.00                            
35.00        0.73         86.63                            
40.00        1.94         87.84                            
45.00        2.27         88.17                            
50.00        2.20         88.10                            
55.00        2.01         87.91                            
60.00        1.78         87.68                            
65.00        1.58         87.48                            
70.00        1.39         87.29                            
75.00        1.23         87.13                            
80.00        1.10         87.00  

See that?  Beautiful!  From 30 - 80hz this box will be +/-3db! Virtually flat!

Also, notice the port calculation?  Get a 2" PVC pipe from Home Depot and cut it to 2 8 inche lengths and, viola! you have your ports.  You can put one on each side of the woofer so it'll look nice.  And no, the 2 ports will not produce any port noise. 

Any questions?

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"I'm finished!" - Daniel Plainview

Oh.  I reread ur post and you want a slot port? 

I can't stand all the carpentry involved there, but for the exact same tune in the same box, you're slot port would be 1"x12" and 13" long.  And no, that one won't produce port noise either.

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"I'm finished!" - Daniel Plainview

sedate wrote:

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Oh.  I reread ur post and you want a slot port? 

I can't stand all the carpentry involved there, but for the exact same tune in the same box, you're slot port would be 1"x12" and 13" long.  And no, that one won't produce port noise either.

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12 sqaure inches of port in a 2 cubic foot enclosure WILL produce port noise, I garentee it...

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'89 Mercedes-Benz 300E
Pioneer DEH-5900UB
(2)RE Audio SX 10"s
(1)US Amps MD3D
3ft^3 @ 37Hz

Blowing up in a car accident doesnt worry me, as long as I'm putting out some major dB's when I die...

Wow, very nice, man...

the only problem is that I am coming from my workplace (I´ve made the enclosure)

let me tell you what I did.

I considered the suggestions from cloak559 (I think he gave me one of the best explanations ever about slot port enclosure, I mean, without any complications).... he said that taking into account the port area I could obtain the port length (or I understood that), then my port height is 13.5 inches and the port width is 2 inches which = to 27sq. inches... And if he said that 30sq. inches = to 27.5 inches port length, then I made a three step operation and I deducted that my port length should be 25 inches.  (MEXICO; you gotta love it !!!, hahah )

My enclosure is e a little bit more than 2.00 cubic feet, because I had to consider the slot port and the used space of the subwoofer.

Is a Wedge box, well, I introduced the subwoofer and it sounds really great, amazing. I think JL audio is one of the best subwoofers ever. and it is just 400 watts rms.

Not like other brands that indicates thousands of watts.

I'll try to take some pictures tomorrow so you can see my work.

Anyway, I am going to consider that valious help you just provided me.

Can you tell me your method to calculate the slot port?.... or is the same method from cloak559.

this is my msn mezzaricardo@hotmail.com

just in case you prefer to chat.

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Ricardo Daniel Meza Cavazos

I think that using a 2 cubic feet

the subwoofer works with more freedom,  I mean, like if the subwoofer could use more properly the air to push and suction itself.

First I tried the 1.5 cubic feet, it worked really fine.

I Liked more this just recently made of 2 cubic feet considering your instructions, so thank you.

I really had troubles to envolve the slot port, I dont like just to paint it... i like to envolve the port with the fabric or anyway its called in english.

As i said before, i'll try to show you a picture of the installation by tomorrow or so.

thanks, and I hope i can keep in touch,.

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Ricardo Daniel Meza Cavazos

cloak559 wrote:

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12 sqaure inches of port in a 2 cubic foot enclosure WILL produce port noise, I garentee it...

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cloak the size of the enclosure has absolutely nothing to do with it.  The amount of air being forced through the port does.  The airspace in the enclosure does not impact this... the size of the woofer and the amount of power the woofer is getting do.

Now, if we had a *pair* of 12's in that same box, it would whistle like starving coyote.

Admittedly, I'm actually not sure of the relationship between the t/s parameters, but I modeled the box in WinISD and the box I described will have a vent mach of .1 .... whatever that is its like half again less than the audible range of port noise. 

mezzaricardo, both you and cloak need to start modeling this stuff on a computer and your understanding here will leap 100x over.  I designed that enclosure with WinISD in about 20 seconds and it takes care of all that aggrevating math with port calculations and what-not.  Read stevdarts sticky on the top of this forum and give it a try.

https://www.linearteam.dk/default.aspx?pageid=winisd

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"I'm finished!" - Daniel Plainview

mezzaricardo wrote:

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I think that using a 2 cubic feet

the subwoofer works with more freedom,  I mean, like if the subwoofer could use more properly the air to push and suction itself.

---

This is actually what happens.. but the woofer loses some cone control when it loses a tight air suspension behind it...

You also must be *VERY* careful about how much power you are running to that sub in a box that big.  You can get away with it, but like you said, the subwoofer works with more MECHANICAL freedom, which brings its effective power handling down.  You should assume your 12w6 is probably only going to handle ~300watts or so.. be very careful with your gain and back off of it considerably if you hear any distortion coming from that box.  You can kill that sub very quickly in a box that large.

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"I'm finished!" - Daniel Plainview

Well, don't blame me man, I said "freedom" because my mother tongue is spanish, I wasn't sure about the right word.

Ok, I am using an autotek super sport amplifier of 450 watts RMS at 2ohms, should I put the gain between the highest volme and the half volume?... I mean 75 percent or something?

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Ricardo Daniel Meza Cavazos

mezzaricardo wrote:

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Well, don't blame me man, I said "freedom" because my mother tongue is spanish, I wasn't sure about the right word.

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Huh?  blame? What?  Freedom is a perfectly fine word to use there.  You are actually doing a better job of communicating on this board than half of our new posters.

Tu englias es muy bein?

I dunno my spanish is awful.  I just don' t want you to hurt that beautiful woofer.

mezzaricardo wrote:

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should I put the gain between the highest volme and the half volume?... I mean 75 percent or something?

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Hmm.  Read the 'setting your gain' sticky on the top of the forum.  This is a really important point..

I can't answer that question. It depends on you deck's preamp voltage as well as your paticular amplifier.  75% is probably a bit high, but I really have no way of quantifying that for you.

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"I'm finished!" - Daniel Plainview

Well there is no gain setting sticky.

Okay look dude I really can't in good concious tell you to do it by ear.  You're gonna have to do a little research here.  Start with the search function on this forum if you want.  People go over this stuff all the time.
I'm sorry, I'm really wayyy to tired to even try to explain this. 

I always set my gains by ear and that's really kinda careless *especially* if your running that sub in a box that large.  That requires great care okay?

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"I'm finished!" - Daniel Plainview

okay, I will take care, believe me... I don't wanna kill that sub..... I paid too much to a Numptee Seller for it.

Well, I misunderstood the deal about that word. You know, sometimes there are words in spanish that if you translate them LITERALLY means nothing in english.

thanks for your valuable time and attention.

I'll search a lil' bit more about the gain stuff.

But in the beginning I remember you said there was no problem about using that subwoofer on that cubic footage., Although I guess that would be because of the slot ported design, in this case, of course.

As a comment let me tell you that  A friend of mine is running 2 alpine subwoofers SVC type E on a slot ported box with a V12 mono amplifier 600 Watts RMS, gain to TOP on an enclosure of two chambers of 3.5 cubic feet EACH).... that's being a murderer subs

Question:... Does WinISD or some webpage the calculus of slot ports?...

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Ricardo Daniel Meza Cavazos

mezzaricardo wrote:

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I remember you said there was no problem about using that subwoofer on that cubic footage

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Well not in theory and it shouldn't affect the sound quality of the sub.  Still, you have to set your gain properly.  It really wouldn't matter what sort of box you put the sub in you still don't want to overrun the thing.

mezzaricardo wrote:

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A friend of mine is running 2 alpine subwoofers SVC type E on a slot ported box with a V12 mono amplifier 600 Watts RMS, gain to TOP on an enclosure of two chambers of 3.5 cubic feet EACH).... that's being a murderer subs

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Yea I have abosolutely no idea how his subs are even working.  I couldn't imagine speakers that would last very long being treated like that.  I wonder how long his amp will last.

mezzaricardo wrote:

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Although I guess that would be because of the slot ported design, in this case, of course.

---

 

Like I was trying to explain, large ported boxes do not have the 'air spring' that a sealed enclosure provides.  Any ported enclosure is going to make the sub more sensitive to power (because the air isn't providing resistance to the woofer cones' movement) and thus more prone to mechanical overexcursion at higher power levels. 

This is why you have to carefully set your gain. 

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"I'm finished!" - Daniel Plainview

That's clear

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Ricardo Daniel Meza Cavazos

mezzaricardo wrote:

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Question:... Does WinISD or some webpage the calculus of slot ports?...

---

You can convert easily to slotted using WinISD but you have to learn the program well enough first to enter your driver's parameters into into it and get it up and running.  It doesn't have a quick and easy app that will just do a conversion for you.  But the following is an answer I wrote about this and saved in my docs folder:

pi r^2 to find the area of a circle

pi is 3.14
r is radius, or half the diameter of a circle
^2 is squared, or the number times itself
pi r^2 is 3.14 X the result of radius squared
pi r^2 gives you the square inches of a circle

You want to change the shape of the opening but keep it the same square inches.  The length of the port is not a factor and you will leave it exactly the length it already is.

Find the square inches of your circle using pi r^2 (ex. a 6 inch diameter circle yields 28.26 square inches)
Decide on the longest side you want your square or slotted port opening to be
Divide the total square inches of the circle by that long side, in inches (ex. 28.26 / 11.5 = 2.46)
The result is the measurement of the shorter side of the port opening

In the example, the 6" round port equals a slotted port 11.5 X 2.46 inches.  Round measurements to the nearest Imperial or metric value.  2.46 would be  2 7/16 to 2 1/2.

You should keep the ratio of length to width of the slotted opening at no greater than 8:1.

Use this math to convert your round port to a slotted port.  Square is best, while long and very skinny is worst, although both can comprise exactly the same square inches.  That is what I mean by keeping it less than 8:1 ratio.

Also, here is a list of web help and calcuators.  You might want to save the list to refer to.

Information links, calculators, and other online help:

https://www.bcae1.com/
https://www.the12volt.com/installbay/forum_posts.asp?tid=74558&PN=1
https://www.the12volt.com/caraudio/boxcalcs.asp
https://www.sound.westhost.com/tsp.htm
https://sound.westhost.com/site-map.htm

https://sound.westhost.com/articles/cscaling.htm
https://www.diysubwoofers.org/faq.htm
https://home20.inet.tele.dk/kou/ubmodel.html
https://www.soundandvisionmag.com/idealbb/view.asp?topicID=47166
https://www.vikash.info/audio/diy_audio_search/index.asp

https://www.thielesmall.com/database.asp
https://www.linkwitzlab.com/
https://www.linkwitzlab.com/design_of_loudspeakers.htm
https://www.pvconsultants.com/audio/frdgroup.htm
https://scienceworld.wolfram.com/physics/HelmholtzResonator.html

https://www./help2/Articles.cfm
https://www.partsexpress.com/resources/crossover/xoverhelp.html
https://www.users.bigpond.com/bcolliso/port-flares.htm
https://www.hometheaterhifi.com/volume_1_1/v1n1spk.html
https://www.realtraps.com/test-cd.htm

https://www.soundandvisionmag.com/idealbb/view.asp?topicID=37023
https://www.clubknowledge.com/Car_Audio_FAQ/?t29
https://diyaudiocorner.tripod.com/formula.htm
https://www.linearteam.dk/default.aspx?pageid=winisdpro
https://www.crownaudio.com/apps_htm/designtools/elect-pwr-req.htm

https://www.avsforum.com/avs-vb/printthread.php?t=759083&p=9024043
https://www.users.bigpond.com/bcolliso/freesoft.htm
https://www.mhsoft.nl/conv1.htm
https://www.apicsllc.com/apics/Misc/filter2.html#fourth
https://www.users.bigpond.com/bcolliso/driver-conversions.htm

https://www.users.bigpond.com/bcolliso/flare-it.htm
https://www.subwoofertools.com/forum/ported-box.asp
https://www.mkprofessional.com/freq.htm
https://www.gomath.com/geometrycal.html
https://www.falstad.com/mathphysics.html

https://www.opamplabs.com/cfl.htm
https://www.opamplabs.com/rfc.htm
https://www.subwoofertools.com/forum/portlength.htm
https://www./help2/Articles.cfm?id=31
https://www.1728.com/pythgorn.htm

https://www.hometheatershack.com/roomeq/
https://www.subwoofertools.com/forum/sag.htm
https://www.users.bigpond.com/bcolliso/sonosub.htm
https://www.mhsoft.nl/spk_calc.asp
https://www.mhsoft.nl/spk_calc.asp#top

https://www.cvs1.uklinux.net/calculators/
https://www.linearteam.dk/default.aspx?pageid=unitconverter
https://ourworld.compuserve.com/homepages/Bill_Bowden/r2.htm
https://www.danmarx.org/audioinnovation/theories.html
https://www.audioholics.com/techtips/setup/loudspeakers/subwooferplacementguide.php
https://www.ht-audio.com/audio.htm#Driver%20Manufacturers

 

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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

Thanks a lot man....

I will dedicate time to review the information you just provided me.

Regards.

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Ricardo Daniel Meza Cavazos

man, maybe that list should be stickied

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