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<blockquote data-quote="mcsoul" data-source="post: 5246825" data-attributes="member: 588440">[quote name=Juha HartikainenDesigning your Box, help file from winISD]If your mach rating is too high, the only way to lower it is to either increase the number of or the diameter of the ports.&nbsp; Of course, here comes that dreaded &quot;trade-off&quot; word again!&nbsp;&nbsp; If you make your port(s) bigger in diameter, they will be able to pass more air with less effort.&nbsp; However, in doing this, you have lowered the &quot;loading&quot; of the speaker(s) in the box.&nbsp; This, of course, changes the -3dB point of the box.&nbsp; The only way to get back to your desired -3dB point is to &quot;load&quot; the speaker(s) again.&nbsp; How?&nbsp; Well, you gotta make the new, larger port(s) longer!&nbsp; This forces the speaker(s) in the box to work harder to move the air into and out of the box, and brings your -3dB back to where it should be. THE END OF YOUR PORT(S) MUST BE AT LEAST 3 INCHES AWAY FROM ANY INTERIOR WALL OF YOUR ENCLOSURE.OP, keep in mind the a the depth of the port gets longer for the same tuning whenthe port area (port length x width) are increased. The depth needed will also increase for every port when you add additional ports.</blockquote>

[QUOTE="mcsoul, post: 5246825, member: 588440"] [quote name=Juha Hartikainen Designing your Box, help file from winISD] If your mach rating is too high, the only way to lower it is to either increase the number of or the diameter of the ports. Of course, here comes that dreaded "trade-off" word again! If you make your port(s) bigger in diameter, they will be able to pass more air with less effort. However, in doing this, you have lowered the "loading" of the speaker(s) in the box. This, of course, changes the -3dB point of the box. The only way to get back to your desired -3dB point is to "load" the speaker(s) again. How? Well, you gotta make the new, larger port(s) longer! This forces the speaker(s) in the box to work harder to move the air into and out of the box, and brings your -3dB back to where it should be. THE END OF YOUR PORT(S) MUST BE AT LEAST 3 INCHES AWAY FROM ANY INTERIOR WALL OF YOUR ENCLOSURE. OP, keep in mind the a the depth of the port gets longer for the same tuning when the port area (port length x width) are increased. The depth needed will also increase for every port when you add additional ports. [/QUOTE]

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