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What effects would a larger port area have apart from reduced port noise and increase port length provided that the box volume and tuning frequency remains constant? Would the sub be louder or lower? How much port area is too much for a sub? Is there a minimum or max or an average per sub?
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If you kept the box volume AFTER displacement the same, you would see a gain in SPL. It can be good to about 2-3 dB if you arelucky and experiment enough.
------------------ Scott CMD AUDIO Hello, My name is scott, and I am addicted to Atomic Thunder. Owner of CMD Audio
Posts: 626 | From: Rochester, NY | Registered: Jan 2000
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posted
Man what seems like alot of people get this missed up.you will loose db and beat up your woffers if you have to much port.to much....over kill.Its o.k though people will learn.
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Alot of people will dis-agree on this subject. You can really only know by experimentation. A bigger port will have less port noise and produce more pressure. But there is a point were a port will be to large. Normally its when the speaker can't displace enough air in the box for the port to function. The goal is to have a low port velocity. Well I had two tens in a 8 cubic foot box, with 176 square inches of vent. With 500 watts I was pulling right at 146.9db. The sub were in control, so the port was producing all of the pressure. But I still had a very high port velocity. I think that you could have over 200 square inches of port on two tens and it will work great.
Right now I'm going to have right at 500 square inches on two tens. But this will be in a bandpass design, it works a little different. Personally I think that you can have about two times the moving area of a speaker, for a port!!
I think that a large port can also make up for having less power. Within reason!! I think that HUGE ports need to have alot of power to function. Cause the sub has to move a lot to displace the air. For ex; Don't expect to put 4 15s in a 32 cubic foot box, with 600 square inches of vent. And run 1000 watts to them and expect a high number. Those 15s will need a lot of power to move that big blocks of air. But when you start to add power it will gain a great amount!! But if your running a little bit of equip, like my old install, a larger port will work well. I don't know, somethings are just weird. Like I said at the top, experiment, you never know it might work. Or it might not.
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