Reply to thread

Message: <blockquote data-quote="T3mpest" data-source="post: 8278819" data-attributes="member: 560148">Couple things.. First off a 3x16 inch port is TOO SMALL for an 18inch subwoofer..  Go graph your airspeed in winisd, without a computer in front of me I can tell you your well above 20m/s at full tilt.. Second, the lower you tune a box, the lower airspeed you actually need to avoid port compression, winisd will NOT show you this, it'll just show lower airspeed with lower tuning which is great, but it NEEDS to be lower to be adequate. A port tuned at 20hz with 25m/s airspeed is too high a port tuned at 40hz with a 35m/s airspeed will actually suffer LESS compression effects.  The port airflow switches directions more often, which stops turbulence from forming.Your doing 2 bad by switching this design up..  First your lowering tuning, which means you need a bigger port and lower airspeed for your port to be effective.. Then to keep your keep your port length managable, your shrinking your port size way down so the port fits easily and doesn't eat up all your airspace.. However, all the airspace makes your woofer nice and effecient at driving that port. In this case driving it right into compression where it's not doing it's job.A large 5 or 6inch port tuned at 37hz will outperform a 3inch port when you start throwing 2kw at it, even below tuning.  A 3x16inch port is more a long the lines of  a high powered 12inch woofer or a mid level 15, not a high powered 18.  These subs use very stiff suspensions so going below tuning isn't a problem, but if you want the output in the mid 30's and up that your paying for, you need to use a nice big port.  Also when designing a port it is always preferred to use as few bends in the port is possible, air doesn't like to make turns lol.  You also want to keep at least a port widths distance away from the back wall of the enclosure for the same reason, if not it acts as a bottle neck.. If you look at your enclosure depth of 25 inches, a 17 or 18 inch port accomodates this VERY well, again, something a box program won't show you, that holds up in real life.Box programs like winisd won't show you everything although they DO have their place in making a good design.  Anyway if you can fit a 30hz tuning with an adequate sized port and proper airspace, go for it. However I think you'll find a 6inch 30hz tuned port is going to be a little to long to fit your design without at least 1 bend and will probably take away from your airspace quite a bit which lowers low end output regardless of tuning.</blockquote>

Verification

Top

What's new

Forum list