Jl 13 w7

 

New member
Username: 01gsxr

Post Number: 63
Registered: 01-2004
Jl stats that w7 in a ported box will hit 3 to 5 db more then if in a seald box, wat does that mean? wats the dif from spl and db?. does more db give you greater spl and if so how much
 

New member
Username: Glasswolf

Post Number: 728
Registered: 12-2003
dB is short for Decibel, which is a measure of volume.
SPL is sound pressure level, which translates to volume.
1 dB is defined as the smallest measureable change in volume to the human ear.
volume measured in dB is not a linear scale. it's a log scale, so the following holds true:
+10dB is an audible doubling in volume.
+10dB takes 10 times the power to produce.
double the power is +3dB in volume
the same power, and going from 1 sub to 2 subs is also +3dB.
a ported box is +3dB louder at the tuned frequency than a sealed box, so using a ported box is effectively the same as using twice the amplifier power, or doubling the efficiency at the tuned port frequency (usually 35Hz to 45Hz)

here is some more information on power and volume:
http://users.chariot.net.au/~gmarts/amppower.htm

(excuse me if I have typos here of make little sense. I seem to have the flu this weekend, and it sucks.)
 

New member
Username: 01gsxr

Post Number: 67
Registered: 01-2004
so if I was hitting 150 spl with a seald box I would be hiting 153 spl with ported box?
 

New member
Username: Glasswolf

Post Number: 740
Registered: 12-2003
that's an approximation, but yes, that should be right if nothing else changes.
same subs, same amps, etc.

you can gain more if the box is larger, positioned differently, etc as well..
up to maybe +5dB
 

New member
Username: 01gsxr

Post Number: 73
Registered: 01-2004
That sucks, so some one with 1 13w7 in a ported box will hit just as hard as my 2 in a seald box. Wolf you think I have room in the back of the suv to fit a ported box for them?
 

New member
Username: Glasswolf

Post Number: 752
Registered: 12-2003
you'll need around 4cu ft instead of about 3cu ft.
should be able to fit them.. hell I fit a 4.38cu ft box in the trunk of a festiva for two twelves.
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