need some port dimensions

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=105684
Printed Date: May 02, 2024 at 10:01 PM

Topic: need some port dimensions

Posted By: young-n-dumb
Subject: need some port dimensions
Date Posted: June 25, 2008 at 11:30 AM

well im getting a PA fubar 15 within the next few days and im going to try and build a ported box at about 3.4 cu.ft.......ive used like every port calculator and i cant get 2 answers even close so i need some help since i have no experience on the subject. Im going to use a round port(s) i just dont kno what length and diameter they should be for about 28Hz tuning. the calaculator on this site calls for a 4" port that is 9.7" long but other sites will b something totally different and i just dont kno which numbers to go by. plz help thnx

Replies:

Posted By: young-n-dumb
Date Posted: June 25, 2008 at 4:26 PM

change of plans now instead of a single 15 im getting 2 12s but i still need help with the ports. I should ba able 2 throw 2 12s in a 3.4 cu.ft. box right?

Posted By: DYohn
Date Posted: June 25, 2008 at 7:10 PM

What speakers?

Your port calculation for 28Hz in a 3.4 cuft enclosure is correct (4" X 9.8" long actually.)

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Posted By: young-n-dumb
Date Posted: June 25, 2008 at 8:09 PM

i just ordered 2 HFi hifonics cuz my dad wasnt wiling 2 dish out much money at the moment but they got good reviews and they were 85 for a pair

Posted By: DYohn
Date Posted: June 25, 2008 at 11:34 PM

Hifonics. OK, but which model? I'm trying to help you decide if 3.4 cuft is going to work for your speakers and if it is wise to port at 28 Hz.

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Posted By: young-n-dumb
Date Posted: June 26, 2008 at 5:21 AM

https://sonicelectrnix.com/item_9357_Hifonics+HFi+12D4.html

theyre hifonics lowest model but supposedly theyre alright especially 4 the price.......thnx 4 all the help by the way. ive looked at a bunch of other threads and seen some of your posts and u seem to be an expert with audio so i trust your judgement

Posted By: DYohn
Date Posted: June 26, 2008 at 9:52 AM

OK, several comments. First, those woofers will not reach down to 28Hz so if you port your enclosure that low you will damage them. With only 1.7 cuft per woofer you need to port up around 40Hz for those. Your speakers are DVC 4-ohms rated at 300 watts RMS so I recommend wiring for a net 4-ohm load and looking for an amplifier capable of 600 watts into 4-ohms to drive them. Wiring would look like this:

Your other option is to wire for one-ohm and get an amplifier capable of delivering 600 watts into a 1-ohm load.

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Posted By: young-n-dumb
Date Posted: June 26, 2008 at 6:12 PM

ok so ill just use the calculator on here so i dont trouble you anymore lol.. thanks for the help