Another porting help thread!!!!

[andrewtexas123 10+ year member]

Ok so I have this sub.. http://www.caraudioclassifieds.org/f...ad.php?t=30899

In 8 cubes, and the current port is 3" wide, 22" High, 15" Deep.. I want to re tune it to 30hz. Can any one figure out how much port I need? Whats the easyist way to retune a box?

Click to read more...

 

[RAM_Designs 5,000+ posts]

Your link doesn't work. Just build a new box.

 

[andrewtexas123 10+ year member]

If you pay for it I will..

Product Description:

Its an all black, CF Capped, MONSTER 18" subwoofer. It will do very well in ported applications from 4ft up to 8ft with a mild tuning (somewhere between 28 and 35) for daily ground pounding.

It has a very healthy 3.2" p-p of excursion, a fairly low Fs, and will drop low when asked to!

Will withstand roughly 2000-3,000w rms depending on the user and the application.

Brand New Konaki Motor Assembly w/ Blank Magnet Boot

8 Layer D2 ohm Aluminum Flatwound Voice Coil

Dual 9" Linear Spiders

Dual Sewn Leadwire

18" Heavy Duty Cone Assembly

7" Carbon Fiber Dome Dustcap (LAST ONE )

8ga Direct Connect Wiring

Wrap Around Rubber Gasket

NOW HERE'S THE COOL PART:

The black 18" 6 spoke basket has 1.5" holes milled into it to allow for direct access to the bolts holding the basket to the motor. These bolts can be easily removed with a 10mm wrench (ratchet wrench is MUCH easier), allowing the entire top assembly to be removed and swapped to another motor, or to allow for a different top assembly to be mounted to the motor.

The removal of the basket isn't something that I would call "quick", but it's definitely do-able. I've taken it off and on quite a few times now.

I've tallied up the total cost for this subwoofer, pricing each individual option, and the value of the subwoofer would come out to be right at $500.

The Konaki motor is arguably as good or better than most large sub motors out there now. It has a large enough gap to allow for an 8 layer coil, large 220mm magnets, and tons of cooling vents in the motor. Its just as strong as most, and cools better! It's a VERY proper choice for a high output daily subwoofer like this. I could have used a Nightshade or RE MT motor for this woofer, but the Konaki is a better choice IMO. It took it off a built, but brand new 1207A.

If someone is interested in just the top assembly, I would consider selling it without the motor! The top would work with lots of different motors! It would be just great on RE MT's, Sundown Nightshade, Fi BTL's, etc etc etc... basically anything with a large enough gap, a standard bolt pattern and a top plate within 2mm of 25mm in height!

These are ALL BRAND NEW parts. This is a BRAND NEW subwoofer. It's got tons of add-on's and upgrades above most anything available right now. If you need a badass 18" that will drop LOW, this is it!

It has a PSI logo on the bottom of the motor, and a blank cap. I can put any of my logos on the cap, or leave it blank. I can also add a custom logo per your design for $30!

T/S Parameters are as follows:

Sd: 1230.00 cm^2

Vas: 126.00 l

Mms: 443.08 g

Rms: 12.52 Ns/m

Fs: 31.0 Hz

Bl: 26.76 N/A

Re: 3.90 ohm

Qms: 6.89

Qes: 0.47

Qts: 0.44

Spl: 90.9db 1w/1m

 

[RAM_Designs 5,000+ posts]

If 8ft^3 is after all displacements, you're already tuned to 31hz. I take it that you're not happy with the low-end response that you have right now?

 

[andrewtexas123 10+ year member]

Its already tuned to 31hz? How did you figure that out? Yea it doesnt hit the lows very well could it be cause of an amp underpowering it?

Thanks!

 

[Jh8909 10+ year member]

what amp do you have on it man? is it still that quantaum audio?

 

[RAM_Designs 5,000+ posts]

Its already tuned to 31hz? How did you figure that out? Yea it doesnt hit the lows very well could it be cause of an amp underpowering it?
Thanks!

If 8ft^3 is after port and sub displacement, then a 22"x3" port that's 15" long gives you a 31hz tuning. Now is 8ft^3 is before displacement, then you're looking at something like 7ft^3 tuned to 33hz...no reason why that sub shouldn't be hitting the lows pretty well. Lack of power could be an issue, what amp are you running to it? You'll need a good 2kw on tap.

If it's still fairly new, give it some time to break in and have the fs drop a little bit.

 

[Jh8909 10+ year member]

If 8ft^3 is after port and sub displacement, then a 22"x3" port that's 15" long gives you a 31hz tuning. Now is 8ft^3 is before displacement, then you're looking at something like 7ft^3 tuned to 33hz...no reason why that sub shouldn't be hitting the lows pretty well. Lack of power could be an issue, what amp are you running to it? You'll need a good 2kw on tap.
If it's still fairly new, give it some time to break in and have the fs drop a little bit.

as well as a decent electrical to back it up

 

[andrewtexas123 10+ year member]

If 8ft^3 is after port and sub displacement, then a 22"x3" port that's 15" long gives you a 31hz tuning. Now is 8ft^3 is before displacement, then you're looking at something like 7ft^3 tuned to 33hz...no reason why that sub shouldn't be hitting the lows pretty well. Lack of power could be an issue, what amp are you running to it? You'll need a good 2kw on tap.
If it's still fairly new, give it some time to break in and have the fs drop a little bit.

Lets see the sub is Brand new only been in a couple of days that could be part of the problem. Whats the best way to break it in?

As far as displacement goes the 8cubes is out side the port and does not have the sub are removed a beter way of saying this is the out side demintions are 38W x 22D x 19H. that might help. The amp is a Quantum audio QCA3000d does about 1300-1500.1 so I am trying to sell it to get a bigger amp!

Thanks for the help I appreciate it!

what amp do you have on it man? is it still that quantaum audio?

Yep still the quantum I am trying to sell it to get something bigger right now I know a guy with a Planet Audio BB2400.1 I here its a half decent amp and does rated. I will be doing the electrical probibly in july! I am short on money mainly because I am trying to get my car painted so most of my money is going to that.

 

[RAM_Designs 5,000+ posts]

Lets see the sub is Brand new only been in a couple of days that could be part of the problem. Whats the best way to break it in?
As far as displacement goes the 8cubes is out side the port and does not have the sub are removed a beter way of saying this is the out side demintions are 38W x 22D x 19H. that might help. The amp is a Quantum audio QCA3000d does about 1300-1500.1 so I am trying to sell it to get a bigger amp!

Thanks for the help I appreciate it!

How is your port 22"x3" if the box is only 19" tall?

On a side note, the box is 7.58ft^3 before any displacement. In the end you'll be around 6.6ft^3 tuned to 34hz. But I'd go for more port area and a slightly lower tuning if I were you.

 

[andrewtexas123 10+ year member]

I have the box on its side so the hieght is now the depth.. Some thing doesnt sound quite right I think the box is bigger like 39.5W x 23.5D x 19H when it is light in the morning I will have another look at it. With that extra space the tuning would be lower correct?

Thanks agian

 

[RAM_Designs 5,000+ posts]

That makes sense now, the 23.5" side will have a 22" port height.

 

[andrewtexas123 10+ year member]

So with those demintions what would be the tuneing of the box?