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<blockquote data-quote="Buck" data-source="post: 8723576" data-attributes="member: 591582">no no.&nbsp; absolute maxiumum air speed is about 54 m/s or .16 mach.&nbsp; I have really good results with 30-35 m/s for daily.&nbsp; Expecially with 4th order.&nbsp; I don&#039;t like much under 20 m/s or so for ported boxes.&nbsp; But it depends on the woofer and basically how stiff the suspension is.&nbsp; People give WAAAAYYYY too much port area for 4th orders for some strange reason.&nbsp; I&#039;ve done a lot of 1000w-1500w per woofer 4th order bandpasses that use 12in^2 per cube, like the older 1250w sundown x 15&#039;s.You really have to keep in mind that t/s parameters + box designing programs =/ real world sound.&nbsp; Air speed can be way off, is what I&#039;m saying.&nbsp; If you ever get to design over 1000+ individual boxes, you can recognize when t/s parameters are doodoo.&nbsp; Subwoofer box programs also sometimes have issues with woofers with progressive suspensions.&nbsp; You can have a relatively high Vas, reltatively low Fs (mid 20&#039;s to low 30&#039;s), AND low Q factors with a progressive woofer, and I&#039;ve found that sometimes programs don&#039;t know wtf to think about that.&nbsp; My old Fi Bl 18&#039;s were like that.&nbsp; They modeled horribly.&nbsp; But they were stupid loud.&nbsp; So you gotta kind of see through the haze of some of this stuff.</blockquote>

[QUOTE="Buck, post: 8723576, member: 591582"] no no. absolute maxiumum air speed is about 54 m/s or .16 mach. I have really good results with 30-35 m/s for daily. Expecially with 4th order. I don't like much under 20 m/s or so for ported boxes. But it depends on the woofer and basically how stiff the suspension is. People give WAAAAYYYY too much port area for 4th orders for some strange reason. I've done a lot of 1000w-1500w per woofer 4th order bandpasses that use 12in^2 per cube, like the older 1250w sundown x 15's. You really have to keep in mind that t/s parameters + box designing programs =/ real world sound. Air speed can be way off, is what I'm saying. If you ever get to design over 1000+ individual boxes, you can recognize when t/s parameters are doodoo. Subwoofer box programs also sometimes have issues with woofers with progressive suspensions. You can have a relatively high Vas, reltatively low Fs (mid 20's to low 30's), AND low Q factors with a progressive woofer, and I've found that sometimes programs don't know wtf to think about that. My old Fi Bl 18's were like that. They modeled horribly. But they were stupid loud. So you gotta kind of see through the haze of some of this stuff. [/QUOTE]

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