# Determining cabin gain



## 2500hd (Aug 22, 2009)

So I am under the impression that the transfer function relates to the old 1127/whatever hz= length, but I'm not sure how to determine the correct length of my vehicle. 

So my question is do I measure the longest length in the vehicle (chevy crewcab),i.e. the uppermost part of the drivers side windshield to the lowermost part behind the rear seat; the distance between the sub and the dash; or since it's a sealed enclosure, is it a question of volume?

I'm not going to be competing, I just want to maximize the efficency of two 8" subs that are ported....


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## thehitt (Aug 30, 2009)

hmmm


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## 2500hd (Aug 22, 2009)

I guess just get a mic and measure it, right guys? Dang I wanted an easy way to figure it out...


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## Oliver (Jun 25, 2007)

Measure it . . . or ask if anyone else has


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## greeyman (Sep 12, 2009)

i know i am really stupid and all that wrong forum to post and all that but i really have an important question that maybe one of you very smart audiophiles can awnswer. so here it goes.
I just got a memphis 15 inch woofer have no idea about it cant find anything about it searched high and low and came up with nothing.
it is a mclass dvc no idea about ohms. have two rolls of foam for the surround and has refrence series like m logo but smaller with chrome around it like diamond plate. says mclass around the maganet cover
any help on the specs of this sub would be very much appreciated.
thank you so much


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## 12vTools (Jan 15, 2009)

that an old mc154d 
dual 4 ohm
300 watts rms power handling
they like 2 -2.5 ft sealed
3 or above for vented'


need a box for it?>


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## greeyman (Sep 12, 2009)

thank you for your help. i have a sealed box i think its 2.5.
what kind of box do u have?
this will be going in to a 4 door truck so space is at a minimum


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## BassAddictJ (Oct 1, 2009)

keep the sub in a sealed box

measure the db with a cheap meter at the same volume at all the bass freqs from high to low

youll find the freq your cabin peaks at

then build a ported box tuned about 5hz lower than that measured freq and your box will likely peak at or close to the desired measured freq.


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