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<blockquote data-quote="Lightninghoof" data-source="post: 2993418" data-attributes="member: 569919">Jon,I&#039;ll let you do most of the final math, but here&#039;s what I came up with.&nbsp; According to Dan Wiggins at Adire Audio, you want to try and limit peak air velocity to below 20 m/s at 20Hz.&nbsp; I feel this will depend on your tuning frequency however.You are currently calculating for 60 square inches of cross-sectional port area.&nbsp; Including the other specs that you listed, peak air velocity at 20Hz would be roughly 15 m/s.&nbsp; The highest peak air velocity occurs at about 27Hz, at roughly 19 m/s.&nbsp; That&#039;s completely acceptable IMO, and should not be audible by any means.I would say the minimum port area that should be used is 55 square inches.&nbsp; Optimum would be 60 square inches or higher.So it appears you are definitely on the right track.My advice though is to use a single port rather than multiple ports.&nbsp; Just a personal preference, but I find it easier to implement and tune.I didn&#039;t account for box fill.&nbsp; The fill will of course increase Vb by an estimated margin of 10% ~ 30%.&nbsp; This will in turn alter Fb accordingly.&nbsp; This is very difficult to precisely account for.</blockquote>

[QUOTE="Lightninghoof, post: 2993418, member: 569919"] Jon, I'll let you do most of the final math, but here's what I came up with. According to Dan Wiggins at Adire Audio, you want to try and limit peak air velocity to below 20 m/s at 20Hz. I feel this will depend on your tuning frequency however. You are currently calculating for 60 square inches of cross-sectional port area. Including the other specs that you listed, peak air velocity at 20Hz would be roughly 15 m/s. The highest peak air velocity occurs at about 27Hz, at roughly 19 m/s. That's completely acceptable IMO, and should not be audible by any means. I would say the minimum port area that should be used is 55 square inches. Optimum would be 60 square inches or higher. So it appears you are definitely on the right track. My advice though is to use a single port rather than multiple ports. Just a personal preference, but I find it easier to implement and tune. I didn't account for box fill. The fill will of course increase Vb by an estimated margin of 10% ~ 30%. This will in turn alter Fb accordingly. This is very difficult to precisely account for. [/QUOTE]

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