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Audio and Video Talk
General Discussion
Misconceptions in the SA general public regarding Home Cinema
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<blockquote data-quote="Timber_MG" data-source="post: 1103" data-attributes="member: 18"><p>The rear volume doesn't waste the energy of the rear wave, it (in simplified terms) adds impedance and if the driver is severely underdamped the sensitivity drops but the efficiency (remember the impedance has just risen significantly around resonance and gotten more broadband) more than makes up for the difference (efficiency is at 1W electrical input). By heavily increasing motor strength (BL/sqrt(Re)) a sealed box can approach an efficiency of 20-25% in extreme cases (as mentioned with driver nto yet available with sufficient Xmax).</p><p></p><p>The distortion introduced by a sealed box is (save the radiation by the cab and higher order cone breakup) minimum-phase. The resonances in a port are not and are way more audible in the midrange than 2nd/3rd order harmonic distortion so the engineering trade-off is in bandwidth.</p><p></p><p>That a sealed box will require around 2 x more potential acoustic output from the same driver is the trade-off of the construction (meaning it is cheaper to build a ported subwoofer of same output and distortion than a sealed equivalent) but a sealed version is generally less resonant higher up. Takes your pick.</p></blockquote><p></p>
[QUOTE="Timber_MG, post: 1103, member: 18"] The rear volume doesn't waste the energy of the rear wave, it (in simplified terms) adds impedance and if the driver is severely underdamped the sensitivity drops but the efficiency (remember the impedance has just risen significantly around resonance and gotten more broadband) more than makes up for the difference (efficiency is at 1W electrical input). By heavily increasing motor strength (BL/sqrt(Re)) a sealed box can approach an efficiency of 20-25% in extreme cases (as mentioned with driver nto yet available with sufficient Xmax). The distortion introduced by a sealed box is (save the radiation by the cab and higher order cone breakup) minimum-phase. The resonances in a port are not and are way more audible in the midrange than 2nd/3rd order harmonic distortion so the engineering trade-off is in bandwidth. That a sealed box will require around 2 x more potential acoustic output from the same driver is the trade-off of the construction (meaning it is cheaper to build a ported subwoofer of same output and distortion than a sealed equivalent) but a sealed version is generally less resonant higher up. Takes your pick. [/QUOTE]
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Audio and Video Talk
General Discussion
Misconceptions in the SA general public regarding Home Cinema
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