Ok...most people dont realize just how inefficient subs really are, so here is a lil Physics approch to show just how bad speakers actually are at producing sound.
You will need to know how loud your system is, and how much power your sub(s) are actually seeing.
First of...find your systems actual Intensity Io = 1.0*10^-12 I = Io * (10^(dB/10))
I do 149.8dB, so....
(1.0*10^-12)*(10^(149.8/10) = I
(1.0*10^-12)*(10^14.98) = 954.9 w/m^2 <----that is my actual Intensity
then... sqrt(954.9) = 30.9
When i did 149.8dB, i measured ~1700w from my amp after box rise....so,
(30.9/1700) * 100% = 1.818%
My install is only 1.818% efficient!!!
Just imagine if you could create a 5-6% efficient install....holy snit
yeah hey where do you get ur pvc pipe and do u use a torch or heat gun when making the flares. sorry for hijacking the thread, but if you want me to post my efficieny I need to make ports first so its all tied in really lol
hey Marshall - what was ur port area to cuft ratio again ?
i seen u post it a few times b4 but cant remember it offhand but u said 10-16sq inches / cuft ? which site did u see this or is this with ur experience ?
was this for SPL tuning only ?
i normally calculate it using T/S but i would still like to know a average port area thats good 4 SQL no matter what the sub is ....
I just wanted to post this because I just had an exam on this in Physics today. At least some of it...really just the intensity part, i took it alil farther than we actually studied.
I talked to the Prof. about this after the exam today...I showed him how I got the calculations and when i said, "ok, i do 149.8dB at 48hz w/ ~44vAC and 39A from my amp, roughly 1.15ohm impedence rise from .35ohm DC"...he stopped me and said, "WHAT?!?"
