Free Air JL Audio Sub

[nbovelle]

JL Audio Free Air Sub

Ok, here is a real sub woofer question.
I have a JL Audio Free Air Sub (JL Audio calls it an infinite baffle sub). I think that the model number is 8IB4. It is currently discontinued. I bought it a few years ago to replace a damaged free air sub in my Lexus SC400 but never put it in.

I am wondering if that sub might work in the location of the stock sub without a sealed enclosure. (I know that I cannot use the stock system to power it. I am planning to replace the Bose speakers and amp, but keep the stock head unit.)

I know that "tighter" bass can be obtained from a sub in an enclosed box, but am wondering if this one might work and what it might sound like.

Its free air resonance is 37.5 Hz, Efficiency (1W/1m) is 87.4dB.
Impedance is 8 ohms and its continuous power handling is 75 watts.
The mounting depth is 3.875 inches

Any thoughts?

Thanks,

Nate in DC

 

[Veleno]

Re: JL Audio Free Air Sub

A free air sub uses the area where it's mounted as an enclosure, like the trunk, doors, under the rear deck. I'm guessing that if you mount it down where the oem "sub" is at the sound quality will not be great at all, and the sub will not be used to it's full potential. JMO.

 

[Malibu Rapper]

Yeah it will not sound good. The problem is going to be backwave because the sound from the back of the speaker needs to be blocked otherwise you have cancellation. If you block the sound coming from the back of the speaker, you might as well just make an enclosure and get a regular sub. I suppose it can be done if you cut out the floor from behind the sub and let all the sound escape outside.

 

[nbovelle]

Thanks.

I was hoping that I could use it because I already have it. However, it does not seem that a free air sub would be a great choice for this application. If I have to build an enclosure, I might as well get a sub that is made for one.

I am awaiting Ken's speaker templates and will keep you all informed of my progress. I will probably gather all the needed parts during the winter and start my install in the spring. I am still researching which 6.5" door speakers to get and it looks like I will now have to start looking at a new sub and enclosure too.

Thanks for your responses!
Nate in DC

 

[john@johnhudakracing]

Re: JL Audio Free Air Sub

Ok, here is a real sub woofer question.
I have a JL Audio Free Air Sub (JL Audio calls it an infinite baffle sub). I think that the model number is 8IB4. It is currently discontinued. I bought it a few years ago to replace a damaged free air sub in my Lexus SC400 but never put it in.

I am wondering if that sub might work in the location of the stock sub without a sealed enclosure. (I know that I cannot use the stock system to power it. I am planning to replace the Bose speakers and amp, but keep the stock head unit.)

I know that "tighter" bass can be obtained from a sub in an enclosed box, but am wondering if this one might work and what it might sound like.

Its free air resonance is 37.5 Hz, Efficiency (1W/1m) is 87.4dB.
Impedance is 8 ohms and its continuous power handling is 75 watts.
The mounting depth is 3.875 inches

Any thoughts?

Thanks,

Nate in DC

The IB sub you mentioned has thiele/small parameters that lend itself to working well in either a free air or aperiodic application. Acoustic suspension designs when coupled with that model would not perform well, however, with the correct tools an aperiodic installation can actually be theoretically ideal. In general practice easier to start a-new given a replacement's low cost.