DB drag question

[old dude]

i have done two db drags and one thing i have noticed is that when i hear other people do there runs it sounds like there systems pound realy hard for the first five seconds and then i dont hear anything for the rest of the run. i thought it was a score bassed on thirty seconds but i dont know. do i have to run the full thirty seconds all out or not?

[Neo_frog]

The trick is minimal voltage drop. If you are playing music, then that's not going to yield the highest possible numbers. You would have to know at which frequency the pressure peaks in your car, play that frequency only for a short burst, then be done. Playing any more than that is useless.

[matt402]

bass race = 30 second avg

db drag (burps) = 2-5 second test tones

[old dude]

The trick is minimal voltage drop. If you are playing music, then that's not going to yield the highest possible numbers. You would have to know at which frequency the pressure peaks in your car, play that frequency only for a short burst, then be done. Playing any more than that is useless.

ok i thought thats what i was seeing other people do. i have a metter and i have my boxes tuned to 39 but i have not checked out the resonant freguecny of the van yet so i may have to retune the box for that.

[Neo_frog]

Well remember that your box won't necessarily show the resonant frequency of the cabin. It will only show you where your cabin peaks based on the box response. Most of it is trial and error matching them up.

Some have other test methods, but I've found that port shaving is the best to match up the peaks. Especially since a box vs a wall could yield significant differences in the peak due to the lack/excess of air outside the enclosure.