RESONANT FREQUENCY anyone?

[ayjay]

well i'm going to be building the box for my sub soon, and i was just wondering what the resonant frequency of the cabin in the 240sx HB is? my buddy's integra is 55hz, so i'm thinkin mine's around that, but i wanna make sure...

i want to know this before building my box cause i wanna tune it slightly lower than the resonant frequency of the car so i can get max SPL outta my sub/box config...

[SmithSR]

Do you have Car Toys in B.C. ?? They're all over Washington state. Call em up, if you get ahold of somebody smart, I'm sure they could tell ya, or at least get you in touch with somebody who does. Good luck!

[ayjay]

ya, don't think we have car toys, but have a few good car audio shops really close by... maybe they could do some testing...

but surely someone knows, cause anyone that wants to build a proper box (for spl anyways) should have built their box according to the resonant frequency...

[ayjay]

well found a link on how to create a dope box:

http://momentum.soundillusions.net/octo ... t2001.html

here it talks about resonant frequency:

"Step 5 - Resonant frequency

Install your speakers and take measurements to find your resonant frequency. Now that the vehicle has been adapted for SPL and most major changes have been made, we can accurately measure the resonance. Keep in mind that we still do not have enclosures behind the wall. This is to our advantage because we have a large sealed enclosure with no significant resonance, allowing us to measure only the resonance of the vehicle. Place an SPL meter in the exact position used during competition, sweep the lower frequency range and find the one frequency that is the loudest. This is your vehicle resonance. Here is where a CD with test tones can really be useful. Using previous test discs you could find a frequency with an accuracy of 1Hz."

so in other words, does anyone know the frequency that hits the loudest in a 240sx hb... and this is from an eclosure behind the rear seats, NOT A WALL...

thanks in advance to anyone who can help me out...

[diamondj30]

rta and test tones .

[ayjay]

rta and test tones .

sorry dunno what RTA is, but i do know that in order to listen to test tones and find out the resonant frequency, you need to have already created a box, and then you have to modify the box after you get the results back...

i just want to know the resonant frequency without having to build a test box to begin with...

once i find out what the resonant frequency is, i can build the proper size slot port for my sub which will be targeted at that frequency...

thanks for the advice though, if i can figure out what RTA is then i'm sure i'll be able to build the proper box

[diamondj30]

real time anylizer.spelling off.radio shack db meter.there not perfect but it should help.mine is 40hz in my car.

[Simmsled]

Remember that if you decide to put dynamat in your car that your resonant frequency will be lower than before the install.

[ayjay]

i decided that i'm just going to build my box, and take it into a local car audio place to do testing and seal off the spot for the slot port. this way the box will be taking up the exact same amount of cabin space and i'll be able to create the port according to the resonant frequency that i find with the box being sealed.

and my buddy found 8 rolls of sound deadening material on the side of the road, each roll being about 50feet long and 8 inches wide, and adhesive coating on both sides. so i'm gonna use 3 rolls of that for my car (approx 50 pounds worth) and hopefully that will be good enough i'll take my car in for testing after sound deadening and all panels are in place.

thanks for all the help guys, should all be installed within the next few weeks, and i'll post numbers with the box sealed, and with the slot port installed... hoping for around 140db

[Simmsled]

Quote »and my buddy found 8 rolls of sound deadening material on the side of the road, each roll being about 50feet long and 8 inches wide, and adhesive coating on both sides. so i'm gonna use 3 rolls of that for my car (approx 50 pounds worth) and hopefully that will be good enough i'll take my car in for testing after sound deadening and all panels are in place. [/quote]

HOLY ****, and double ****

[ayjay]

haha ya... he told the story of how he found them to his girlfriend.. she wasn't nearly as impressed as i was such a good find!