free air sub...advantages?

alright audio gurus...what do I gain from mounting a sub w/o a box right to the deck lid like the stock jbl sub (minus the enclosure). I know that the power handling will essentially be cut in half, so im asking what kind of gains (or losses) can i expect from this type of setup? Is the bass punchier or weaker? I am going to buy an infinity kappa perfect which can be used in a free air/infinite baffle situation so im curious as to why this may be a good idea. Thanks.
/jeremy

I personally dont think you get as much bass from a free air sub.

1 advantage is that it doesnt need a box.

my friend bought his car with the sub like that.. IIRC its a 10'' 400w sub..
but it does "hit", but not nearly as hard as it does when it is in a box...
i dont think that his sub is an open air sub though, so it may be different.
but yea.. it will hit to a point... but not nearly as hard as with a box....

I previously had 4 free-airs in an old Oldsmobile project I had going. Was NOT impressed with the sound. Two reasons: 1) Not as clear of a hit (slusshy) 2) For 4 subs in one car, it just wasn't hitting near as hard for the amp/setup I had.

Would suggest that you use a little trunk space (plus this will not create a huge hole on your rear deck.

Subs work off of air, so its essential that it has trapped air for it to create the the sound levels that it produce.

A free air sub will sound almost like a blown sub. There is no air devoted to the sub therefore it has no air to use, the result is very little to no bass.

It has to have air somehow.

Yes. The only free air subs that are worth getting are EV's, cerwin vegas etc. Speakers that are used mainly for for high pass. You will have no low pass at all with free air. The bass has to go somewhere! Your best bet is a ported box. It will take up your trunk space, but it will hit hard, and you speaker(s) will breath nicely. Dont let anyone talk you into a sealed box whatever you do BTW dont expect to have some bass if (any at all) with a free air sub. They are used for high pass only. They do scream though. (Too ghetto for me)

I sub is put into a box because when the woofer throws, it creates a sound wave when going forward and the exact (so close, we will call it the same) reverse sound wave when returning to its original position. When the sub is in a box, the box absorbs the reverse sound wave so that you only hear the outside sound wave.

Now, when you go to a free air sub. The reverse sound waves travels around the sub and nearly cancels out the front sound wave, thus making no sound.

When you go to ported, there are certain specifications for every sub on port length and diameter. This length and diameter aide in a "time delay" of a few micro seconds so that when the reversed wave from inside the box exits the ports, just enough time has elasped that it has now reversed and now matches the front sound wave coming from the front (outside) of the subwoofer.

Think of ocean waves, if 2 exact waves traveling towards each other collide, they cancel each other out. If one is absorbed (in a box), the other continues and travels. If the 2nd wave was "turned around" (send back through a pre-determined port size) it may turn out to be bigger wave.

Maybe that helped shed some light...

Could you translate that in English please?

whats wrong with sealed boxes?

I've liked all the ones i've heard...ofcourse, they were being powered by monster amps

There is nothing wrong with sealed boxes...I have used them and still would use them. In my opinion, this is the best way to go for someone who doesnt know all there is to know about subs and wants some good bass.

I was just trying to explain why free-air subs are not your best bet for hard hitting bass. I was also saying that if the sub can handle a ported box, and you have the box built correctly, that it can/may be better than sealed.

jonny cash said:

Could you translate that in English please?

I tried to explain is general terms so people would understand...but if I didnt explain exactly, you know someone would be jumping on me.

Study up soldier!

You cannot push the same kind of power with a sealed box. The air has nowhere to go, and you could blow speakers left and right if you dont know what you doung. Plus, ported subs sound 10 times better.

NiNeTy Fo SHO said:

I tried to explain is general terms so people would understand...but if I didnt explain exactly, you know someone would be jumping on me.

Study up soldier!

Unfortunatly Im stupid and Im just jealous of your knowledge.

jonny cash said:

You cannot push the same kind of power with a sealed box. The air has nowhere to go, and you could blow speakers left and right if you dont know what you doung. Plus, ported subs sound 10 times better.

Umm...what do you mean you cannot push the same kind of power with a sealed box? The whole point of a sealed and that the air goes no where...and aids tremendously in keeping the woofer from throwing to far too fast.

Take a sub, power it without a box, and you will hear it popping when the cone starts to throw to far. Place that sub in a box (sealed or not) and notice how you can push more power (watts) through it without the sub having any problems...popping or blowing.

All subs can sound good, if you mount them correctly and power then correctly. (sealed, ported, or free air) Its all in what kind of "good" you like to listen to.

jonny cash said:

Unfortunatly Im stupid and Im just jealous of your knowledge.

No need to get offended. I definitely am not the end all be all of woofer knowledge...but I did take a class on it in college.