so all the years of playing round blownin stuff and spending to much money is teaching me some thing???????????????? wow

 

^ maybe about boxes but not about resonant frequency

 

what do you mean
?

 

what do you mean
?

1130 is the speed of sound in ft per second .
my car is 7.2ft long from bottom of the windsheild to the bottom of the back glass so divid the speed of sound by the lenght of the car gives you the RF of the car..
1130/7.2=156.94hz.... and if you dont think that i am right then you can tell MECP that they are wrong cus it is in the silver level study book
like yes me and them understand that the speed of sound depends on how high you are above sea level but the avg is 1130ft/sec

this is also how you find out how long the "period" of a cycle is like a 20hz tone is 56.5 ft long for the waves to complete the full 360 of the wave form you can use that to time correct a system that does not use a digital time correction system

 

post edited

 

i just thought of some thing we are talking about 2 different things... the guy asked what to tune the box too and the best tuning for SPL is the fullest wave form that the car will play and the way i am using math is correct but i am wrong in saying that it is the rf of the car..

 

Wrong

That wave theory is so 3 years ago

 

yes but it works but dont take my word for it look it up in MECP

 

I would suggest you put down the MECP guide and get yourself, oh, even a grade 9 physics textbook.. You can develop a standing wave, hence a 'resonance', with a HALF cycle eh.. That would drop your RF to 78ish Hz. In some situations you can even develop a standing wave with a QUARTER cycle, but inside a closed up car is not one of them.

Now, to expand on this a bit - since you have made it all the way to the 'silver level' MECP guide I am sure you realize that the lowest RF of a vehicle (as there are many resonant frequencies) develops from the LONGEST dimension of the car? You sure that the middle of the base of your windshield and the middle of the base of your back window is the LONGEST dimension in the car? What if the surfaces that give the longest dimension are not parallel? What if things like seats are in the way?

You would be wise to listen a second to Xiphoid too - wave theory is flawed for SPL. Martin has dedicated years to SPL - he did not simply read a book.