zzzzzzz

why does any of that matter? like would any of that really help answering my question? here it goes....


what car what amp ?
2002 huyndai accent. pair of hifonics colossus amps

what box what is in the box(fill) ?
a wooden box. see attached pic

is it outside test is it sunny?
indoor

WHERE IS THE BOX ?
in the trunk

it the box ported?
yes

is the box fastend down?
no

 

It really depend on the box and vehicule. If 52hz is the best frequency to burp, then it's because there's more "gain" at that frequency than any other one in the neighboorhood. If you're wize, you will build a box that will produce as much SPL as it is possible at 52hz. If you combine the peak in response from the box, and the peak in gain from the box, Then you're likely to experiment quick losse by raising or lowering the burping frequency.

Another thing that come into play is the vented box phenomenom. A vented box can only peak at tuning frequency or higher. If you are tuned a few hertz lower than your burping frequency, you're likely to experiment a slower decrease in SPL because the cone may move less and work in a higher BL zone

 

u cant be seriouse with that comment.

this whole time i was confused i thought that if 52hz is my loudest note i would make a box NOT to produce max spl at that hz......thanks for the heads up.

 

it was sacrasatic of course.
I just see too many "rules of thumb" for SPL over the many forums that just can't be applied. one of those is the "5hz below burping frequency" wich could cause a situation like you stated with many woofers

 

oh my bad...

 

im not sure where the sarchasm starts or finishes. But i have a question of my own.

Prolifik......what mic are you using. term lab or ac? my best guess is that it is a term lab.......and i have a reason for that but ill keep it to myself cause i dont want to argue.

I would figure that you are seeing those scores because of the way the mic reads. If im wrong i apologize. but if im right then you should not see that sort of rapid change in spl with the ac meter.

Like i said i am hypothizising yet i am curious as to what meter you are using and if you can do these same tests and runs with the other meter than the one you have with you.

i only ask this becuase i have used both and can now predict what our car does at what freq and which meter.

 

TL dude. no access to AC

 

FYI TorqueGuy... Yuli is one of the loudest 'street' guys in Canada, so he definitely knows what he's doing.

I think he's just asking for everyone else's opinion on the situation.

 

I never tought about assuming he didn't know what he was doing, just like you said it, he asked for opinion, and I gave mine, and he's free of thinking what he want about it. One thing I know is that when dealing with high power and spl, you're dealing with a bunch of things car are almost unpredictable. Specific vehicule peaks shift with pressure, temperature, humidity, but specificly loudness. With a given woofers, amplifiers and box size, the best cabin peak to use will not necessary be the same than with smaller or largerbox, powerfuller or weaker amps. etc Put impedance fluctuation in the equation, and you could fine a frequency wich is easier to drive by the amp, drawing less current, and ending beign louder over the time the Termlab calculate the score. So in fact, there's not a single theory that can explain the situation, there's plenty theories. I'd say more, you don't even need to rely on theory, you just need to mesure and plot the in-car peak spl vs frequency, out-of-car max spl vs frequency, impendance and port air flow, and with that, you will be able to pinpoint the phenomenom.

 

transfer "function of the vehicle"
very well said... now start using what you know and start building!
this is not meant as sarcasm... I understand what you mean and agree with you... plus wavelength theory

oh... everyone else should read this over and over until they understand what is written here and use this information!