Box Port confusion

[blacknirvash]

I ordered a MA HK15x2, and have taken a look at its specs, it needs 5.0CF airspace, two eight inch ports at 13 inches long, and tuned to 32Fhz. can the ports run up to an inch of the back of the box? or do they have to come to some specific point of the box? im trying to fit this in the trunk of a 91 honda accord sedan and am looking for any ideas. thanks in advance!

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[DukeNut 10+ year member]

i hear it is the diameter of port away, so for you it'd be 8 inches away from the wall

 

[hispls 5,000+ posts]

Pair of 8" ports will need to be around 4 feet deep to acheive 32hz tuning

 

[blacknirvash]

i have come up with a few box designs... none of them come close to having 4 feet of depth. this is mainly due to the space available in the trunk. here are the trunk measurements: 32In wide at back seat, 47in wide at trunk lips, 30in from back seat to trunk latch, from the floor to the ceiling of the trunk is 18in.. here are two ideas listed in outer dimensions: 17.5H*25.5W*24D; 17.5H*31.5W*19.5D. i will be using 3/4In MDF. also could i use 4 4Inch ports and achieve same tuning freq?

 

[Kangaroux 5,000+ posts]

Go with a single 8" port..2 of them is HUGE, even for spl

 

[blacknirvash]

Go with a single 8" port..2 of them is HUGE, even for spl

what would you suggest for this particular build? i listed some of the acceptable measurements for my trunk in an earlier post. do you think multiple 4in ports would work?

here are the trunk measurements: 32In wide at back seat, 47in wide at trunk lips, 51in wide at the floor. 30in from back seat to trunk latch, from the floor to the ceiling of the trunk is 18in.. here are two ideas listed in outer dimensions: 17.5H*25.5W*24D; 17.5H*31.5W*19.5D. i will be using 3/4In MDF. i know practically nothing about tuning to frequencies and would appreciate any knowledge that isnt strictly mathematical formulas so i can gain a better understanding of it all. also enclosed is the manufacturers jargon; Vented (Cu. Ft) 5,

Vented to (Hz) 32, 3dB down point (-3dB Hz) 29, Port Diameter (") 8, Port Length (") 13, Number of Ports 2. SQUARE PORT INFO; Port Area (Sq/In.) 80, Port Length ('') 13: PARAMETERS

HK15X2; Fo (Hz) 29.581, QMS 3.965, QES 0.517, QTS 0.457, VAS (Liters) 147.723, REVC (Ohms) 1 (parallel), SPL @ 1 watt / 1 meter (dB) 90.6, X-max Linear pk-pk (mm) 70, LEVC at 1k Hz (mH) 1.043

 

[RangerDangerV2 5,000+ posts]

go with a slot port design or external aeros.

 

[dirtyunclerandy 10+ year member]

slot port for simplicity

 

[blacknirvash]

i found this looking through moe lesters post. would this work? http://imageshack.us/photo/my-images/35/5cubes32hz62sqin6hk.png/

 

[dirtyunclerandy 10+ year member]

Link isn't working. If I was better with sketch up, I woud give you one.

 

[blacknirvash]

Thank you all for the input! I wound up sending a link of the box from moe lester to MA audio's Customer Service and it was a fit! once i get it all in ill post some pics. mind you my car is old and shows its age. will be fun to see what rattles loose //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif