Couple decent questions...

[Utopia]

I'm completely new to this board and I hope this post is appropriate and in the correct forum- if it is not, I apologize. I have a sort of general car audio engineering quandry.

I'm currently running a single JL 12W3V2 in a sealed box in the trunk of a 2003 Subaru Impreza. I'm not a DIY type of guy. This is the sub configuration that my installer matched to the Focal 165Ws that I have in the front doors. I have a PG Tantrum 600.4 and 2 of its channels are bridged to drive the sub. (300W RMS)

Long story short - I've been through 2 installers and I'm possibly going to be looking for a third. I'm starting to think that none of these installers have a clue.

I'm not happy with the bass......its very tight and "hits" pretty well, but the sub is just firing into the trunk. The sub fires rearward. At louder volumes, it sounds to me like the box is just vibrating the snot out of my car. I don't feel any air being pushed around - obviously becuase there is no way for air to get into the cabin of the vehicle.

I have done a good bit of reading about sealed vs ported vs bandpass and what I want is to have the sub "hit", but also to have booming bass and to feel air being pushed around.

I'm willing to upgrade the sub and even have the box redone if necessary. I also want to add a second set of components (Focal 165W3) as I really enjoy saturated midrange/midbass, but will certainly need more bass to match another set of components.

Is it possible to have a "port" cut into the rear deck of my car so that the box and the trunk together form a sort of bandpass enclosure - so that air can then be pushed into the cabin rather than to have all of this vibration? Is this even advisable? If this works, I could potentally keep the box I have and just upgrade the sub to a W6V2 and get a second amp....or could I?

I'm thinking the best thing to do is to upgrade to a 12W6V2 because it can use a small enclosure (I'd like some trunk space) and have the box redone so its a bandpass enclosure (both boom and punch), have it ported into the cabin through the rear deck and just get a second amp to drive only the sub.....that also leaves two extra channels on my 600.4 for the other components.

How does this sound to you guys?

My budget for all of this (new sub/box/amp/components) is not to exceed $3k.

Any comments or suggestions would be greatly appreciated.

Thanks

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[holycrap 10+ year member]

he took all my answers //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif

 

[geolemon 10+ year member]

These are definitely on the mark, I just wanted to add to them...

My first impression was definitely "how do you know the enclosure is the problem [with the 'can't feel the bass' problem]?" myself... //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

I'd try sound damping material in the trunk, first (also called sound deadening material). Dynamat is overpriced, so I'd look into something that's almost as good but cheaper. There are tons of options out there (Second Skin, eDead, Brown Bread, etc.) That should stop the rattles and increase output from your subwoofer.

That's good for vibrating metal.. with a good install...But there's other things potentially that rattle, that might just need a good tightening up, a little careful squeeze of expanding foam, or a good liberal blob of silicone.

License plates are great with a little rectangle of carpeting behind them.

The next thing I would consider would be porting the enclosure according to JL's specs (if JL's enclosure can't fit into your cabin, I or another member of this forum can help you customize one, but then you'd probably need someone near you to build you one, too, as you're not a DIY person).

That's really only if you think the enclosure is off..How is it, tonally, anyway? Pick up a test CD, see how it is.

Critically listen with good music... stuff that's a priority to you, the stuff you want to sound good, or slam hard, or whatever. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

IF the enclosure is off, that's one thing to address.

But you don't want to change too many variables at once, or you'll never be able to say what fixed what issue...

That's one problem with paying someone to do work, also... //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

Besides the obvious one, that the system is a creation of someone else, something that someone else out there is proud of (or worse, doesn't give a crap about!), instead of you.... //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif

Third, I'd remove any speakers currently in the rear deck to allow more bass to enter the cabin.

There are way more reasons than this to remove your rear speakers...

But this sure is a good one.

Right now, it's analogous to setting up a stereo in your home, and sticking the subwoofer in a locked closet.

Removing your rear speakers will allow the airspace of your cabin and the airspace of your trunk to literally be one, the flow of energy, the air pressure fluctuations will be direct.

Like taking the door right off the closet. //content.invisioncic.com/y282845/emoticons/smokin.gif.f1dc8d2acb1809e863ebd6a47eaa0d45.gif

Not to mention, with all those strong pressure fluctuations going on in the trunk, they would absolutely wreak havoc on rear speakers, causing them to distort and bottom out... even if they weren't receiving a signal, or were disconnected! //content.invisioncic.com/y282845/emoticons/crazy.gif.c13912c32de98515d3142759a824dae7.gif

Like I said, there are way more reasons, you might appreciate them:

http://www.betteraudio.com/geolemon/Phasing/Phasing.htm

Lastly, I'd buy a new amplifier (500-800 RMS @ 2 ohms) for the 12W6v2

Or you could build a larger enclosure to compensate for less power.

Smaller amounts of power aren't always bad, and they don't always mean "less output", by any means.

It takes a 4x increase in power to effect a 2x increase in theoretical output.

In reality, it's even less, due to power compression and other inefficiencies in the sub.

300 watts should be plenty to drive the sub, unless you do want to squeeze it into a tiny enclosure.

The enclosure really drives the efficiency of the sub, so you do want to consider what your priorities are...

"getting away" with 300 watts - which will potentially even extend the life of your sub, but require a larger enclosure to reach full output levels...

or:

"brute forcing" the sub with 600 or more watts - which will be more taxing on the sub, but you'll be able to reach full output levels in a smaller enclosure.

Try doing a search on the "Iron law" of loudspeaker design, for more on that. //content.invisioncic.com/y282845/emoticons/cool.gif.3bcaf8f141236c00f8044d07150e34f7.gif

You could do all of these changes, but you'll never know which one really helped out, and that would cost you the most money...

Something I'm sure you are painfully aware of, if you're shelling cash out to yahoos to do this work for you... I'm sure you don't want to spend more than you need to. //content.invisioncic.com/y282845/emoticons/titanic.gif.8089b7552c370bcc138aa121756d0c0b.gif

 

[flyasspimp 10+ year member]

uhh what does DIY mean

 

[geolemon 10+ year member]

Do It Yourself!

 

[marleyskater420 5,000+ posts]

Do It Yourself!

i think he is the smartest man alive^^^^^ oh and check ur pm's bub!

 

[geolemon 10+ year member]

oh, oops.. we have PM's here! lol...

I'm used to CAF, where it actually notifies you...

Can you get it to do that here?

 

[namster44 10+ year member]

this guy has some money to spend, so I say get a new alternator, buy a TRU amp, and get a couple of 18 XXX's and let me know how much the air "moves".

Nah just messin around. But a new sub would help you out for sure. I bet if you dampin the trunk and drop in a new sub, you would be really happy.....

 

[Utopia]

Guys: Thanks much for all of the input. The rear deck has 2 holes in the metal for speakers that are not currently installed. However, the rear deck cover has no holes. I'll need to correct that I suppose. Also, I think I was unclear in my first post.....just to clarify, I'm currently running a JL 12W3V2 and thinking of upgrading to a 12W6V2. I think I can use the same box as the W6 requires only a small box.

I am going to meet with another installer in my area who is highly recommended. I'll see how that goes and come back to this thread is necessary. Thanks again to all of you for taking the time to post some info/input/opinions.

 

[marleyskater420 5,000+ posts]

oh, oops.. we have PM's here! lol...I'm used to CAF, where it actually notifies you...

Can you get it to do that here?

go to ur personal profile thingy.it notifys me when i gte pm's.