I'm inFInitely Baffled.

[mrogowski 5,000+ posts]

Many would argue that allowing air to escape would be beneficial since it brings the alignment closer to a "true" infinite baffle setup rather than just a very large sealed box. I do believe Scott Buwalda (or someone of the sort) went so far as to cut a hole in the bottom of their trunk and covered it with gortex to intentially allow air to pass to the outside of the vehicle. And most who go IB are fond of trunk vents for this reason aswell.

That's a good option to do.

There's a general rule for IB config's - if you can achieve a rear volume equivalent to 10x VAS of the driver or greater, you are in IB territory.

Best,

Mark

 

[UndercoverPunk 5,000+ posts]

Hmmm.... if I build a lexan wall behind my front seats I could IB an 18.

just kidding.

 

[James Bang 5,000+ posts]

Many would argue that allowing air to escape would be beneficial since it brings the alignment closer to a "true" infinite baffle setup rather than just a very large sealed box. I do believe Scott Buwalda (or someone of the sort) went so far as to cut a hole in the bottom of their trunk and covered it with gortex to intentially allow air to pass to the outside of the vehicle. And most who go IB are fond of trunk vents for this reason aswell.

...shoot. I guess i sealed off any leaks to the exterior because of my fear of the sub unloading. But still I am very satisfied w/ the sound even though it's not a "true" infinite baffle. I guess that the term trunk baffle comes into play here.

I just finished listening to some tracks off the 2005 iasca test cd, and wow, I am amazed on how ridiculous the lows are.

good stuff james... wouldnt mind seeing it in person //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

That's grounds for ANOTHER meet. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif which I am always down for

 

[azbass 5,000+ posts]

gah stuff like this makes me wish I had a car with a trunk, instead of an open hatch.

 

[Immacomputer 10+ year member]

...shoot. I guess i sealed off any leaks to the exterior because of my fear of the sub unloading.

The idea of true infinite baffle means the sub is playing with nothing to dampen cone movement except for the driver's suspension. That way, your Qtc is equal to Qts and the Fc is equal to the Fs of the driver. So those vents are theoretically great as long as they're big enough to allow ease of passage.

 

[cj232 10+ year member]

Good stuff, should sound real good.

 

[squeak9798 5,000+ posts]

The idea of true infinite baffle means the sub is playing with nothing to dampen cone movement except for the driver's suspension. That way, your Qtc is equal to Qts and the Fc is equal to the Fs of the driver. So those vents are theoretically great as long as they're big enough to allow ease of passage.

//content.invisioncic.com/y282845/emoticons/word.gif.64b12e39f936af3b4fff38a1c0bd0244.gif

The entire idea behind IB is that the subwoofer isn't "loaded" or damped at all by an enclosure.

So unloading the woofer should be a concern.....in fact it should be your goal.

 

[James Bang 5,000+ posts]

how big of a difference do you guys think the vents will make in my situation. Should I try and create vents to the exterior? Now i'm contemplating that I should 'cause I sure would like a "true" infinite baffle.

 

[mrogowski 5,000+ posts]

Calculate your VAS vs rear volume first. You may not have to do anything..

 

[MTXThunder9500 10+ year member]

My trunk had a vent that I sealed up just in case. maybe someone else can give you a better reply on that question.

What kinda vent was it and what did you do to seal it off? i have a vent in my trunk that leaks but it leaks a bit of water and thats something id rather not have by the stereo you know

 

[James Bang 5,000+ posts]

Calculate your VAS vs rear volume first. You may not have to do anything..

I think I might just leave it how it is...

What kinda vent was it and what did you do to seal it off? i have a vent in my trunk that leaks but it leaks a bit of water and thats something id rather not have by the stereo you know

The vent was an air vent. When i had my ported box in the trunk you can hear the vent flapping due to the pressure. It had a rubber layer to allow air to escape but not enter the trunk

 

[squeak9798 5,000+ posts]

I honestly wouldn't worry about it.

Just with a quick modeling in WinISD there isn't a big enough difference between a 20cuft enclosure (estimate of a standard sealed trunk) and a 60cuft enclosure (10x Vas) to really matter much.

 

[Immacomputer 10+ year member]

I honestly wouldn't worry about it.
Just with a quick modeling in WinISD there isn't a big enough difference between a 20cuft enclosure (estimate of a standard sealed trunk) and a 60cuft enclosure (10x Vas) to really matter much.

Haha, I just did the same thing. There was like a very small change in Fc (~2hz) going from about 20 cubes to 50 cubes.

 

[James Bang 5,000+ posts]

I honestly wouldn't worry about it.
Just with a quick modeling in WinISD there isn't a big enough difference between a 20cuft enclosure (estimate of a standard sealed trunk) and a 60cuft enclosure (10x Vas) to really matter much.

Cool. I was hoping to get a response like that. I really appreciate your input. I've always admired how you provide a lot of knowledge and help to this board.

edit: you, too, immacomputer //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[mrogowski 5,000+ posts]

Haha, I just did the same thing. There was like a very small change in Fc (~2hz) going from about 20 cubes to 50 cubes.

Interesting. What frequencies are we dealing with here? It may mean absolutely nothing if they are below the audio spectrum...