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View Full Version : Smaller port volume than reccomended?



pdtran
02-13-2007, 03:00 AM
What are the consequences of having less port area than suggested? My AQ SD2.512 has a reccomended 15-16 cu. in. of port for every cu. ft., but i am giving it like 11 or 12 cu. in. of port right now.

This is because I bought a box from someone online, found out it was tuned to ~30hz using WinISD, and cut one of the port walls down to bring it to the recommended 35-40hz range, still don't know EXACTLY what it is tuned at. I'm using http://www.reaudio.com/speaker_box/LPort_Box_Calc.html (and getting around 37) but that doesn't account for sub displacement.

Box is like 2.5 cu. ft.

Pimpdaddyq
02-13-2007, 03:03 AM
less port area then suggested, is going to obviously set off your port frequency. If you are tryin to get 35hz out of your enclosure, and you don't follow the port recommendations, you are NOT going to get what you want. I say follow your recommendations, and deal with it.

Andrew

pdtran
02-13-2007, 03:06 AM
**** it.

Trixter
02-13-2007, 06:31 AM
port area does not effect tuning freq. tuning freq. is determined by the length of the port. too little port area can cause port noise due to too much turbulance. in your case it probably won't make that much of a difference. becareful with port calculators. you need to know if they account for the port displacement as well.

Duke
02-13-2007, 06:35 AM
Usually a good rule of thumb for average enclosures that I follow is just to go with 1/3 SD for port area. Has never let me down yet.