Why?

[longlivetheZ]

I have the 88 300ZX in my sig. It's only a 2 seater and has very little interior volume. I have 2 12" subs in it pushing ~250 watts or something and it is LOUD AS HELL when you're in the car. It gets REALLY loud...my head's sub volume control goes up to 15 and I veeeeeeeeeeeeeery rarely ever go past 6.

What I was wondering is this:

How can it be so loud in the car but so quite outside the car. I used to hear cars all the time when I worked in the ghetto that were just fucking ludacris. Some HAD to have been running 4 15" subs at 10000 watts each or some crazy shit. Some were SO fucking loud that I can't believe the people in the car were ALIVE...let alone able to hear. One actually rattled shit on the wall as it drove by. That's just too much...

My car...nothin. I can have it up as loud as possible, get out of the car, shut the door, take 5 steps back and hear nothing. lol But as soon as I open the door...BOOM!

**Now don't get me wrong. It is in NO WAY my goal to be able to be heard outside the car. I don't WANT to be that annoying person. It's annoying to people, I'd get pulled over all the time, it's actually better when you keep the sound IN the car, etc...I was just wondering why my car is so quiet. Could it be cuz the molding on the rear windows is blown out? (Mostly from the subs...lol...told you they were fucking loud...) I'm tempted to tear apart my car to see if there's some dynamat hidden in there.

[corning_d3]

A lot of it has to do with the interior space inside your vehicle. I have a '96 monte carlo with the rear seat removed and 2 10" vented DVC's and 400 watts pushing both, and it's loud as hell inside and out..But in my buddies neon, it's quieter outside..

[dave92cherokee]

I doubt that there's any dynamat in your car what it probably is is that when your car was being manufactured at the time it was considered a sports car so just like today's sports car the regular insulating is alot better than say a Geo Metro that way it would cut down on the engine and road noise as you were driving. Same goes with a cadillac if you put some 12's or even a couple of 15's in the back seat area (which is the same as the trunk area in your car) and roll up all windows and turn it up so it's pounding inside then get out and close the doors you will hardly be able to hear anything above a hum outside of it. The reason that all these other people can be heard so loudly is because it's all in their trunk which doesn't have any noise insulation in it because frankly who cares about reducing road noise inside the trunk you're not riding in it.

[CBFryman]

You want loud outside? rub IB through the floor

[longlivetheZ]

Originally Posted by CBFryman

You want loud outside? rub IB through the floor

No, I don't, but what the hell is IB?

[Jet-Lee]

Infinite Baffle

What most call "Free-Air".

[longlivetheZ]

Ooooooooooh oh oh oh oh....got ya.

[ngsm13]

Originally Posted by Jet-Lee

Infinite Baffle

What most call "Free-Air".

Incorrect. Infinite Baffle and Free-Air are completely different.

There, I learned you something.

NG

[Jet-Lee]

http://forums.clubrsx.com/showthread...&threadid=7402

Originally Posted by post #13

Infinite Baffle: This is basically a free air mounting of the subwoofer. If is extrememly effecient, takes up very little space in some cases and can offer some very good sound if done correctly. Driver choice becomes a huge factor in IB setups. You will preferably want a reasonably high Qtc because the system Q will relect that number. .5 to .8 would be a good range to consider.

http://www.dictionary.com

Infinite Baffle - a flat surface that completely isolates the back wave of a driver from the front without a standard enclosure.

http://72.14.207.104/search?q=cache:...s&ct=clnk&cd=9

Free air mounting uses the trunk as a "box." Please note that rear hatch covers do not isolate very well and are not usually strong enough to support the weight of a subwoofer.
Advantages : Free air is easier, quicker, and cheaper. It can also fill up less trunk space.
Disadvantages : In most cars, the trunk leaks to the passenger compartment. Therefore, free air mounting will lose bass output compared to a boxed woofer. Since the woofer is not loaded by box air pressure, it handles less power.
Tips : Reinforce the factory rear deck and seat back, and caulk any remaining openings to the passenger compartment. Of course, this can be more work than making a proper enclosure!

http://www.caraudiohelp.com/custom_c...udio_boxes.htm

Infinite Baffle "Enclosure"
The simplest enclosure type is an infinite baffle or free air system. Note: Free-Air™ is a trademark of Stillwater Designs (Kicker) In this system the woofer has the front of its cone isolated from the back of its cone by mounting the woofer to the rear deck or on a board placed across the back of the rear seat.


Advantages of this design include simplicity, minimal occupation of space and lower cost due to not having to have a box type enclosure.

Disadvantages of this design are a larger power requirement, difficulty (sometimes extreme) in completely isolating the two sides of the cone from each other, and slightly less accurate sound reproduction.

http://www.polkaudio.com/forums/showthread.php?t=8306

Originally Posted by post #10

Now that we understand that, lets get back to the free-air misnomer. There is no such thing as Free-Air. It's properly referred to as "Infinite Baffle".

Wow. Mount the speaker in a single baffle to isolate the rear wave from the front wave.

Do you wish me to keep editing this with proof?

[longlivetheZ]

What I don't get though is I had a car just like the one I have now, but the other one was a 2+2...no big difference, when I was younger and I only had 1 12" in there and it would set off car alarms...I don't get it. My record was 3 alarms in one parking lot.

[Jet-Lee]

Different speakers, different cars, different characteristics.

[longlivetheZ]

Originally Posted by Jet-Lee

Different speakers, different cars, different characteristics.

Eh...it was the same car, same size speaker but only ONE of them. I dunno...

[Jet-Lee]

...

Originally Posted by longlivetheZ

...but the other one was a 2+2...

[longlivetheZ]

Z31 2+2 - Z31 2 seater = ...like...a foot...

...in other words, there is very little difference in the two size wise. The back seats were more like shelves than anything else...it was so small that no one could ride back there except for small kids or someone willing to lay across the back. Really not much bigger then the car I have now.

I just find it weird how 1 12" in that car (the slightly bigger one) would set off car alarms while 2 12"s in the smaller one is silent.

Ya know...I don't really know why I started this thread. I guess I was just kinda thinkin "out loud"...I dunno.

[alphalanos]

Isn't there something about the louder it is in the car, the quieter it is outside? My car is the same way. I have one 12 and it takes your breath away when your in the car, but outside, it's like "is the sub on?" lol