Problems with Ported Enclosure for 12'' Fi X

[KU40 173]

Are you sure that you don't have a bass boost on in the head unit

[Kanaworm$ 292]

Are you sure that you don't have a bass boost on in the head unit

x2 or the "Loud" function turned on

Set your bass at 0 on the head unit or if you have a built in eq and can adjust it set it to flat and try going from there.

[imhungnurnot 9]

The higher freq sounds overdriven When I raise my LPF to 50 Hz with a 18DB slope. Then i turned down the gain and the high was fine but it lacked volume with the low freqs.

[jcarter1885 995]

The higher freq sounds overdriven When I raise my LPF to 50 Hz with a 18DB slope. Then i turned down the gain and the high was fine but it lacked volume with the low freqs.

Well if your trying to compare output from higher frequencies at the same volume to lower frequencies then it wont never be even. Regardless where you have the filter at, 500 watts @ 30 hz will sound lower and have less output then 500 watts @ 40, 50, 60 hz and so on.

[imhungnurnot 9]

The higher freq sounds overdriven When I raise my LPF to 50 Hz with a 18DB slope. Then i turned down the gain and the high was fine but it lacked volume with the low freqs.

Well if your trying to compare output from higher frequencies at the same volume to lower frequencies then it wont never be even. Regardless where you have the filter at, 500 watts @ 30 hz will sound lower and have less output then 500 watts @ 40, 50, 60 hz and so on.

less output in the higher frequencies.. which is what i was aiming for because i had enough volume with the high but not enough with the low.. so i cut the high to balance it out with the lows a little better..

[imhungnurnot 9]

We shifted topic with the crossover, but i'll try what you all told me later..

What i'm confused about is the port area..

I know 12-16 inches of port area PER cuft of net volume.

I built the box with 11.25 inches of port area per cuft.. its not that far off from 12.. and i figured it wouldn't be a big deal because of the weak suspension on the speaker.. Is it correct to think that way? because if the speaker has weak suspension, then a smaller port will increase the back pressure against the sub to keep it in control with the lower frequencies.. but if this is true.. will the smaller port constrict the speakers movement in the higher frequencies?

Maybe my theory is completely wrong.. But what do you all think?

[Notorious97200 339]

My enclosure has far less port area than it should : about a half !!! And my 15" Icon sounds so good with that.

You must keep on working on your system; something is still wrong.

[///M5 2,833]

The higher freq sounds overdriven When I raise my LPF to 50 Hz with a 18DB slope. Then i turned down the gain and the high was fine but it lacked volume with the low freqs.

Well if your trying to compare output from higher frequencies at the same volume to lower frequencies then it wont never be even. Regardless where you have the filter at, 500 watts @ 30 hz will sound lower and have less output then 500 watts @ 40, 50, 60 hz and so on.

Not in my truck, pretty flat across the whole band. Of course that is the box and not the driver...

[///M5 2,833]

11.25 isn't causing this issue.

[KU40 173]

12-16 sq. inches per cubic foot is definitely not an iron figure. Adequate port area actually just depends on the capability of the sub and just keeping the port size high enough to avoid port noise (chuffing) but low enough that it won't act like a hole in the box (this usually only happens once you get port size up near the Sd of the sub).

So forget about back pressure. That's not the issue.

[shizzzon 461]

well lets look at what you said-

you allow higher frequencies to play and it sounds "overdriven" so u turn the gain down and there is hardly any lows audibly...

Just by analyzing that and nothing else, common problems are-

Box not large enough, port tuned too high, crossover points arent set right(for your case- it should be somewhere around - SSF = 25hzLPF = 60-80hz)

Also, a bass boost engaged on the stereo, amp or amp's remote can also cause this.

[imhungnurnot 9]

well lets look at what you said-

you allow higher frequencies to play and it sounds "overdriven" so u turn the gain down and there is hardly any lows audibly...

Just by analyzing that and nothing else, common problems are-

Box not large enough, port tuned too high, crossover points arent set right(for your case- it should be somewhere around - SSF = 25hzLPF = 60-80hz)

Also, a bass boost engaged on the stereo, amp or amp's remote can also cause this.

I believe its the 1.6 cuft net volume.. 2.0 cuft would probably fix the problem..

i played with the crossover today.. and i moved the crossover from 40 Hz 12DB slope (it was set at 12 the whole time, not 18 like i stated earlier) to 50 Hz 12 DB slope and once again the high freqs were overdriven, so I left the Hz at 50 and changed the slope to 18 and it balanced the high and low output pretty well.. but the overall output is still weak.. again, i think increasing the enclosure to 2.0 cuft will increase the output.. correct?

when designing an enlcosure, will maximizing the port area increase the overall output?

[imhungnurnot 9]

anyone?

[imhungnurnot 9]

please help..

[shizzzon 461]

in SPL competition, increasing port area will produce more pressure than being tuned properly!

So, let's say your ear is most sensitive to 33hz...

You are tuned to 35hz with 20sqin of port...

If you lowered tuning to about 31hz then played 33, it would be louder... but

If you increased port area to around 35sqin and left tuning at 35hz, playing 33hz would more than likely be louder.

If you are gonna build a new box, i do not know the requirements for an optimal box for this sub but from a basic stand point, try this design-

2.2 cube NET, tuned to 32hz with 35sqin of port.

[Notorious97200 339]

Why don't you build a bigger box? A much bigger one.

Small box : boom boom !

Tune it around 35 Hz, or make a sealed box, it is easier

As they told you : ssf @ 25 Hz and LPF @ 80Hz.

Just my 2 cents. .