View Full Version : resonance frequency for grand am 01

06-28-2007, 01:00 AM
Im trying to get the TEST SPL tuning for a box in a 01 Grand Am, 2 door. The box is going to be 4 cu ft for a SSA Icon . I'm trying to design a SPL box for a competition coming up on July 8th so any info anyone can help me with would be awesome.
I was told that the best SPL tuning would be 5 hz below the resonance frequency of the vehicle, not sure how to spell resonance, but hopefully nooe gets too confused.

06-28-2007, 03:19 PM

06-28-2007, 03:22 PM
its different for every car, no matter if they are the same year, make, and model

06-28-2007, 03:24 PM
how are you able to find out what it is, like test it and everything?

06-29-2007, 01:59 AM
yup just keep testing different boxes but it would be easier if i had a termlab

06-29-2007, 01:42 PM
speed of sound/ 2D (d=distance between windshield and trunk) that should give you a rough estimate of the resonant frequency

speed of sound = 1130 fps

06-29-2007, 01:46 PM
also, do it from side to side and top to bottom, if the #s you get are multiples of each other then your car was designed badly from an acoustic standpoint, but you'll have one tone that will be insane for your car (i think the honda element and scion xB would be good examples of cars with bad acoustics)

06-29-2007, 02:32 PM
the way i did mine...

i had a sealed box with a 10" in it. played tones inside the car and recorded the spl for each. recorded tones outside the car (the same tones at the same volume) and recorded the spl for each. you will see a peak in each test. the average on the two peaks is you resonant freq.

when you make you comp. box, you want it to peak at this freq. generally tuning 5-10 hz below will get you there, but it depends on the box, sub and car. a computer program will get you a visual curve and be more accurate.

06-30-2007, 03:55 PM
thanks guys

09-08-2007, 04:14 PM
find me at the next benchmark comp, I'll be the guy with the team digital devastation shirt on with the termlab out, most likely somewhere near the saturn.