An odd aerport question?

[Mitch86 5,000+ posts]

Let us know the length x width x height of your enclosure and maybe someone can determine if 8"ers are an option. According to my calculations 8"ers will displace around double the airspace as the 6"ers. (Given the same lengths)

 

[95Prober 10+ year member]

Im running two HDC3 15s aluminum coils

Box is 34"x32"x16" external dimension with 3/4" mdf

would like a tune of around 32-34hz

Precision says the 6" ports are 6"x17" including the flares. I dont know what the port volume is for one full lenth 6" aeroport

Thanks again!

 

[THATpurpleKUSH 5,000+ posts]

2 8inchers with 3.5 cubes each would need 29.688 inches of length for a tune of 33hz

 

[95Prober 10+ year member]

Thx Kushy thats a long port haha

would 35hz be a few inches shorter?

Also why do the ports need to be 17" long for 6" aeroports tuned around 33hz

but 8" ports cover more port space but need to be longer?

 

[CHEMMINS 10+ year member]

You've been on this site and in car audio since 2004 and don't know the basics?

 

[winkychevelle 10+ year member]

Thx Kushy thats a long port hahawould 35hz be a few inches shorter?

Also why do the ports need to be 17" long for 6" aeroports tuned around 33hz

but 8" ports cover more port space but need to be longer?

its all about resistance the bigger the port opening the less resistance thus you would need a longer length to achieve the same resistance of the smaller opening but in turn you will be moving more air which can do a number of things. sometimes to much port i a bad thing and your box will turn into a one note wonder. this is especailly true with smaller boxes. yours is average size but if you added enough port to drop internal space to 3cubes it could have an adverse effect on what you are trying to achieve. my last 15 design was for 4 15s. it was 16cubes with 4 4inch aeros 8inches long. it was plenty of port area for the ab tnt 15s we had on two 1250s. they destroyed the lows and still got loud.

 

[95Prober 10+ year member]

Thx for the info

If i tuned a little higher around 35hz how much shorter could I cut them?

As kushy mentioned at 33hz its almost 30in. long

 

[THATpurpleKUSH 5,000+ posts]

25.74inches for 35hz with 2 8s and 7cubes.

When using more than 1 port, you divide the airspace by the number of ports you want to use, then use that # as the volume and calculate as if you were using one. So if you go on the 12v, you take 7 cubes / 2 ports = 3.5 then plug in the numbers. Some calcs like the one on psp's site give you the option of using multiple ports but its always good to know how to do it when that option isnt available, like with the 12v.

Subwoofer Enclosure Calculators, Fraction to Decimal, Parallel, Series, Port Length and Volume Calculators

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[95Prober 10+ year member]

Thx kushy!! Much appreciated!!

 

[95Prober 10+ year member]

25.74inches for 35hz with 2 8s and 7cubes.
When using more than 1 port, you divide the airspace by the number of ports you want to use, then use that # as the volume and calculate as if you were using one. So if you go on the 12v, you take 7 cubes / 2 ports = 3.5 then plug in the numbers. Some calcs like the one on psp's site give you the option of using multiple ports but its always good to know how to do it when that option isnt available, like with the 12v.

Subwoofer Enclosure Calculators, Fraction to Decimal, Parallel, Series, Port Length and Volume Calculators

Products Menu

Also, is it feasable to criss-cross ports or have them both face the same side?

The reason I ask is because if the ports gotta be that long with the ports facing the rear and

the subs firing up, the subs wont clear the ports because of the magnets.

If I placed the subs up near the front of the box firing upwards and had the ports near the rear

of the box but sideways together Or criss-cross, would that be alright?

 

[mlstrass 5,000+ posts]

can ports be partially outside the box?

 

[95Prober 10+ year member]

can ports be partially outside the box?

Sadly no

Couldnt i fire one port sideways to each side instead of the rear?

 

[mlstrass 5,000+ posts]

why tuning so low? I never go below 35hz with HDC's, but I don't play below 29Hz either...

 

[95Prober 10+ year member]

Well I think even at 35hz the ports would be too long and they wont clear the subs.

I dont compete in SPL and I want the bass as deep and hard hitting as possible.

Would tuning higher make me lose what Im trying to gain?

 

[THATpurpleKUSH 5,000+ posts]

Don't criss cross the ports, If you can't fit 2 8s, your next best option is a single 10.