Tuning freq for my 12W7

[efm80 10+ year member]

what would you tune a 12W7 2 cu.ft ported enclosure to?? I have two of them and am having a box built for them with 2 cubes each and was thinking 33hz. I love the low bass and am more of an SQ guy so I am between 32hz-34hz. what you guys think??

eddie

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[Chatham540i 10+ year member]

http://mobile.jlaudio.com/products_subs_enclusure.php?series_id=9

 

[efm80 10+ year member]

http://mobile.jlaudio.com/products_subs_enclusure.php?series_id=9

looking for more of a personal answer and someone that has experience with the W7 to give me their opinion. I know JL says 36hz on their online manual and 32 hz in the booklet that came with it. Little contradictory. For my post above and my tastes I was hoping someone could chime in. Thanks though

eddie

 

[helotaxi 5,000+ posts]

Go lower than that. Flat response is from a low 20's tuning and in a considerably bigger box. If you're only giving each driver 2cf you're really better off keeping them sealed.

 

[Pioneer~Saturn 5,000+ posts]

I would aim for 31-32Hz IMO if you're looking to go low

 

[pjhabit 10+ year member]

Go sealed. You'll get better SQ out of your W7s & they'll still have plenty of output

 

[efm80 10+ year member]

well, I have had sealed boxes before and I just have had no luck with them. I think the bass sounds to mid and muddy and has no low extension. My last box was ported with 2 12" Infinity Perfects tuned at 33hz and it sounded great. Now I know the w7 is a different beast, but why not go ported and achieve more db's easier. And I know if I tune it low I have heard SQ with the W7 is maintained, but because of the ported enclosure I will hit deeper and louder. Jl recommends 1.75 cu so I am already giving them more than that.

1. Why is 2 cubes not enough??

2. Doesn't a bigger box just give you more SPL, but take away from SQ???

3. And with sealed isn't 750watts(JL HD750/1) to each kinda underpowering them. I know when they are sealed they need and can handle more power. And I know ported needs less power to produce the same output.

But I have not had the box built so I am open to ideas. Please chime in.

thanks

eddie

 

[helotaxi 5,000+ posts]

Have you had W7s before? They will get LOW in a sealed box and that 2 cubes is about perfect for them sealed. JL recommends a sealed box for the W7. They spec a ported one for people that want more SPL, but it is very much at the cost of SQ. By going with a small ported box you're going to lose efficiency and low end extension because they want a big box when ported (like 5+cubes each big). A larger sealed enclosure will help the efficiency (getting you more SPL, even though 750 w is plenty for one of those to really pound for a sane person) and will enhance the bottom end. If you are trying to get really loud, you bought the wrong subs. You have SQ subs that excel in the lowest octaves in a sealed box. Ported in a 2cf box tuned to 30hz you will have a really fat sounding setup because the output around 40hz will be pretty exaggerated.

 

[azimuth 5,000+ posts]

they can sound good ported, but it's impractical to tune the box to 20hz. just go sealed.

 

[efm80 10+ year member]

Have you had W7s before? They will get LOW in a sealed box and that 2 cubes is about perfect for them sealed. JL recommends a sealed box for the W7. They spec a ported one for people that want more SPL, but it is very much at the cost of SQ. By going with a small ported box you're going to lose efficiency and low end extension because they want a big box when ported (like 5+cubes each big). A larger sealed enclosure will help the efficiency (getting you more SPL, even though 750 w is plenty for one of those to really pound for a sane person) and will enhance the bottom end. If you are trying to get really loud, you bought the wrong subs. You have SQ subs that excel in the lowest octaves in a sealed box. Ported in a 2cf box tuned to 30hz you will have a really fat sounding setup because the output around 40hz will be pretty exaggerated.

thanks for another well thought out informative reply helotaxi. You are my go to guy on here!! of course some questions and insight.

1.) I have not had W7's before

2.) Why will you lose effeciency and low end with 2 cubes ported? Most people on here do from 2.2-3.5 cubes ported from my research. even some did the jl spec at 1.75cubes. 5 cubes each seems insane. I do realize 2 cubes is a little small, but I figured it was at least bigger than the 1.75 JL recommendation.

3.) How does a larger(2 cubes each) sealed box increase effeciency and enhance the bottom end?

4.) I will have 750 watts from each of my 2 HD750's going into its on 12W7. With that being said and if I went sealed would it rattle my brain, (for a lack of a better word //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif)

5.) What do you mean by "excel in the lowest octaves in a sealed box"

6.)Lastly I didn't get the last sentence, "Ported in a 2cf box tuned to 30hz you will have a really fat sounding setup because the output around 40hz will be pretty exaggerated." Fat=flat , And why would the output at 40hz be exaggerted and why is that bad??

I guess my main issuue is my experience with sealed boxes. I had recently my two 12"Infinity Perfects in a 1.2cu total enclosure sealed and they sounded so weak and horrible. Put them back in my old 3.4 ported box tuned at 33hz and sounded 10 times better!! Extremely louder, cleaner, and much deeper. Then unfortunately those blew last week, which brings me to my new purchase. I put my friends 2 Boston Pro 12" woofers in a 2.5 cubes total sealed enclosure for the time being. They really do not sound good. They do not hit nearly as hard as my Perfects ported and the bass sounds really high and not deep and low like before. Keep in mind with all the different setups I was using the same PPI PCX2200 800 watt amplifier so the power did not change. So I have had bad experience with sealed and great with ported which leaves me confused and really unsure to go sealed. PLEASE HELP...

and I know its a huge post with lots of questions, but thank you so much HELOTAXI and anyone else who would like to give some input. I really appreciate it!!

eddie

 

[pjhabit 10+ year member]

Some subs are just better ported & some are better sealed. IMHO the 12W7 is better sealed. It plays low & loud while you stand in disbelief that its coming from a sealed enclosure.

 

[joeyrocks 10+ year member]

where is that chart for a 10" w7??

I'm having trouble navigating their site..

 

[rc10mike 10+ year member]

1.2 total for two 12's is very small.

 

[helotaxi 5,000+ posts]

Those subs will not sound that good (my opinion) in a small ported box because there will be a response peak in the 40-50 hz region that coupled with the transfer function of the car will grossly exaggerate those frequencies. On the other hand a sealed box of the same size should couple nicely with the transfer function to play fairly flat all the way down into the single digit frequencies. Larger sealed boxes exercise less influence on the cone and thus the cone moves farther for the same amount of power and in a sealed box cone excursion is directly related to output. This becomes the most apparent at the lower frequencies where the cone must move the most for a given output level. The overall effect is that the larger sealed box is more efficient than a smaller sealed box at the lowest frequencies and thus the system response rolls off more slowly on the bottom end with a larger box. You would get some more output with the ported box but it won't blend with the rest of the system worth a **** and the W7 really are pretty freakin' loud sealed and just sound better set up that way in terms of transient response and tonality.

 

[CarAudioGuru 10+ year member]

I'm with Heliotaxi, sealed is typically what an "audiophile will want (a Qtc of .707)

Here is what it will "probably" do (using my Ouija board!) in a typical vehicle (with the transfer function Heliotaxi was talking about)

Both will work just fine, the vented will be a bit of a "slammer" to it versus the sealed.

I will say that the vented will play 6 dB louder for FREE, or will sound like you have a 4 X more power on it versus the sealed.

Or lets say you have 500 watts on the whole woofer setup, the vented will sound like it has 2,000 on it.

Totally different sounding enclosures. Only you can pick.

Short chick with great tits, tall chick with great ***....you pick.//content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif

And if you want to play with subwoofer designs (computer simulations) go here:

http://www.linearteam.com (get the Pro version)

Its FREE! And has JL specs already installed. Cool huh!!!

I've modified it a bit to add the transfer function.

PM me if you want to know how to do. Super easy.

Have fun. And remember that we are here to help.