# Unknown SPL box design



## kippo (Aug 31, 2008)

my local scene here do SPL competition but they call it 'external SPL' where the cars open their boot and see how can register the highest dB measured by AC or Term-lab mic.

now most of them start to have this unknown design in which they claimed that it increases the dB reading. I cannot see the technical superiority of this design except that it tries to mimic horn loading by having a narrowed exit.


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## aznboi3644 (Jan 25, 2009)

If you want external sound go with a tapped horn design. Thats not really horn loading its just a negative taper to try to aim the sound and focus it more in that direction.


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