Why smaller enclosures have higher maximum SPL?

[thadman 10+ year member]

Why do smaller enclosures offer a higher sensitivity at higher frequencies and higher maximum SPL (at the higher frequencies) vs a perfect (assuming no phase cancellation) Infinite Baffle alignment? The only difference I see between the two is that the smaller enclosure will provide a higher acoustic low pass filter (why you're able to dump more power into them, without an electronic xo), higher non-linear distortion caused by waves dissipating inside the enclosure at a different rate than the waves outside the enclosure (improper pressure between sides), and maybe less thermal power handling since the heat from the voice coil would have less air to dissipate into it. In all of these scenarios the Infinite Baffle alignment is more desirable.

Why then, do small sealed enclosures (vs IB installations) have higher maximum SPL or efficiency in the higher frequencies? Are the enclosures releasing stored energy from the rear wave through the cone caused by the complex wave interactions inside the enclosure or what...im stumped.

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[onearmedbastard 10+ year member]

my guess is more air pressure is built up since its smaller. but thats just my guess

 

[thadman 10+ year member]

my guess is more air pressure is built up since its smaller. but thats just my guess

Displacement is directly linked to output, especially in sealed enclosures which do not rely on modulating the air within a port to increase sound pressure. Their linear excursion is directly correlated to sound pressure. Other than causing the linear excursion to be more non-linear (pressured differences, ie results in higher distortion), I fail to see how increasing the pressure behind the cone would increase the cones mechanical travel and thus achieve a higher sound pressure level.

 

[iagrdshaka 5,000+ posts]

http://audioforum.termpro.com/topic/3/6709.html

Reading that should help. There's better threads, but I don't feel like looking for them. //content.invisioncic.com/y282845/emoticons/tongue.gif.6130eb82179565f6db8d26d6001dcd24.gif

 

[thadman 10+ year member]

http://audioforum.termpro.com/topic/3/6709.html
Reading that should help. There's better threads, but I don't feel like looking for them. //content.invisioncic.com/y282845/emoticons/tongue.gif.6130eb82179565f6db8d26d6001dcd24.gif

Your link refers to ported enclosures. I specifically stated sealed enclosures. Ported enclosures are entirely different beasts altogether and are quite complex compared to the fundamental nature of sealed enclosures. Sealed enclosures rely upon only the volume displacement of the woofer, whereas ported enclosures make use of the rear wave by allowing it to modulate the air within the port.