can subs run open air?.. how does it sound?

[babowc]

question just that..i was wondering how subs that run free/open air sounds?

i have a s13 coupe and i was thinking of running it through the opening in the rear seat/trunk.. but maybe a box would be better?

lmk what you guys think.i took everything factory off, so i'm speaker-less for my entire car.

[qsiguy]

Depends on the sub. Some are designed for free air operation. I have installed some with excellent results some with just ok results. Also depends on your needs. Obviously, you will save huge amounts of space and weight going free air. You aren't likely to get the SPL (sound pressure level) levels with free air that you will with a box but if you aren't looking for huge amounts of bass and just nice sound quality you could be very content with free air.

[babowc]

thank you!^im not looking for bone jarring base.. just a little thump(?)

how could i tell which are designed for free air operation?

thanks again!

[nvrplzd240]

the website you buy them from will 95% of the time tell you, and if not, then the manufacturer will.

heres an example:

Subwoofer Specifications

* Size: 10 inch * Rec. Sealed Box Dims: .3 - 1 cu.ft. * Rec. Ported Box Dims: 1.25 - 2.5 cu.ft * Free Air Usage: yes * Sensitivity: 87 dB * Frequency Response: 25-400 Hz * Recommended RMS Power: 400W * Peak Power Handling: 1600W * Impedance: 4 ohms subwoofer wiring options

[babowc]

ooh.. i see, thank you

[qsiguy]

Yes, most manuf. will have a few models that will work in free air. I've even done some that weren't really designed for it with decent results.

We will sometimes have people bringing in whatever garage sale crap woofers they have and want it installed on their beater car. Made a few baffle boards for them, cut a woofer hole, mount up against the rear seat or under the rear deck and thump away. Occationally been amazed at what you can get out of cheap stuff.

Main thing is to make sure front of the woofer is sealed off from the rear. Just like a normal box, just that the entire trunk is the box. You still need to make sure you properly mount the woofer and seal the rear wave.

One nice thing is that it's not nearly as much work to redo if you aren't happy with the results.

[babowc]

ooh i see now.basically, dont let any holes past where ever the sub is at, correct?i.e : sub in the rear seat opening on a s13 coupe, seal that off with an entire board and make hole(s) for only subwoofer to be placed in.and maybe mat the trunk?

[PoorManQ45]

Just a few notes about running a sub free air(even if it's designed for it):

Do not even attempt to put more then 60% of the power that the manufacture claims the driver can handle in it. Otherwise damage WILL occur.

ALWAYS put a high pass filter(sub sonic) at or above the resonant frequency or else damage WILL occur if any information is played at that frequency. This is due to the fact that there is absolutely NO air spring to prevent the suspension from over extending like there is in a sealed an ported(to an extent) enclosure.

Be sure that the front is sealed off from the back. Do do this just make your baffle(mount). Then go through and seal any holes that go from the trunk to the cabin.