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<blockquote data-quote="jimmyjames1700" data-source="post: 912745" data-attributes="member: 558886">Follow the link below and check out the tuning freq of their own recommended 32Hz tuned box with.&nbsp; Mathematically it is designed to be tuned at around 38Hz.<a href="http://www.jlaudio.com/subwoofers/pdfs/12W7_MAN.pdf" target="_blank">http://www.jlaudio.com/subwoofers/pdfs/12W7_MAN.pdf</a>In fact all W7&#039;s, or other supersubs for that matter, need to be designed with box tuning that much higher (6-7Hz).When we first started designing and building custom vented boxes for the W7&#039;s we wondered why the tuning always ended up way lower than predicted.&nbsp; In fact, the first 32Hz vented box we designed and built for a customers 12W7 ended being tuned at 26 Hz!&nbsp; It definitely perked my curiousity.So a after a quick call to Hector at JL we learned that simple port formulas or programs like BassBox Pro cannot accurately predict what a sub/box combination will do once current starts flowing through a subs Voice Coil.&nbsp; Thats why the big shot&#039;s use programs like Leap which take into account many other factors.&nbsp; Basically T/S parameters and box calculators just get you into the ball park.I&#039;ve seen it first hand.&nbsp; All vented sub enclosures designed with port formulas our say BassBox Pro will tune lower than predicted.&nbsp; Most will tune about 10%-15% lower than predicted, with the supersubs usually being significantly more.</blockquote>

[QUOTE="jimmyjames1700, post: 912745, member: 558886"] Follow the link below and check out the tuning freq of their own recommended 32Hz tuned box with. Mathematically it is designed to be tuned at around 38Hz. [URL="http://www.jlaudio.com/subwoofers/pdfs/12W7_MAN.pdf"]http://www.jlaudio.com/subwoofers/pdfs/12W7_MAN.pdf[/URL] In fact all W7's, or other supersubs for that matter, need to be designed with box tuning that much higher (6-7Hz). When we first started designing and building custom vented boxes for the W7's we wondered why the tuning always ended up way lower than predicted. In fact, the first 32Hz vented box we designed and built for a customers 12W7 ended being tuned at 26 Hz! It definitely perked my curiousity. So a after a quick call to Hector at JL we learned that simple port formulas or programs like BassBox Pro cannot accurately predict what a sub/box combination will do once current starts flowing through a subs Voice Coil. Thats why the big shot's use programs like Leap which take into account many other factors. Basically T/S parameters and box calculators just get you into the ball park. I've seen it first hand. All vented sub enclosures designed with port formulas our say BassBox Pro will tune lower than predicted. Most will tune about 10%-15% lower than predicted, with the supersubs usually being significantly more. [/QUOTE]

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