Having a very hard time getting help. PROS ONLY!

[mmouse57 10+ year member]

massive port man you could have done 2x12 and got the same results with port noise

 

[mendon mafia 10+ year member]

massive port man you could have done 2x12 and got the same results with port noise

yes but with less spl.

 

[PV Audio 5,000+ posts]

Post up the T/S for the speaker. It might be that with your given enclosure size, your system Q increases significantly at higher frequencies thus causing the sub to become undamped in its box. I've had it happen before when using high Qts cones in ported boxes.

 

[mendon mafia 10+ year member]

Name= Alpha12d2

Note= paper cone.mag180c25x2

Model= TSL

Domain= FreeAir

Shape= Round

Profile= Cone

Fmd= 3.0000 KA

Qmd= 1.0000

Flp= 8.0000 KA

Qlp= 2.0000

Znom= 1.8000 Ohm

Revc= 3.6000 Ohm

Sd= 55.0000E-3 M²

Mmd= 198.0000E-3 Kg

Pmax= 2.0000E3 W

Rtvc= 125.0000E-3 °C/W

Xgap= 20.0000 M

Xcoil= 54.0000 M

Xmax= 17.0000 M

Krm= 11.5600E-3 Ohm

Erm= 858.0000E-3

Kxm= 136.0000E-3 H

Exm= 560.0000E-3

Rms= 9.2457 N·S/M

Mms= 205.4126E-3 Kg

Cms= 121.1818E-6 M/N

Vas= 52.3579E-3 M³

Fs= 31.5998 Hz

Qms= 4.4530

Qes= 0.3506

Qts= 0.3250

BL= 20.5610 T·M

Levc= 2.8996E-3 H

SPLo= 88.8905 dB

No= 464.7595E-3 %

LOL just realized its a sticky on caco.

 

[mendon mafia 10+ year member]

The problem is most likely with your enclosure. Your box design should reflect the excursion and power handling abilities of your sub.
Download WinISD Alpha (not beta) and correctly enter the parameters of your sub. There is a tab that allows you to see the excursion of the sub at any given frequency with any given amount of power. Adjust your box design according to that and build a new one.

Remember, cabin gain exaggerates low frequencies. You could be expecting too much of your sub at higher ones. At a tuning of 37, you're going to have a huge peak around those two lower frequencies.

downloaded the program and if i tune to 44hz is the only way i dont over extend the sub past x max above tuning. port area for some reason has no effect.

 

[Lakota 5,000+ posts]

Box programs, meh. Everything changes once the box is put into a vehicle.

The box may be very peaky, causing it to have trouble controlling the sub if you're playing out of its optimum bandwidth.

 

[mendon mafia 10+ year member]

Box programs, meh. Everything changes once the box is put into a vehicle.
The box may be very peaky, causing it to have trouble controlling the sub if you're playing out of its optimum bandwidth.

i was just saying the box program is confirming what is happening in my enclosure. but according to the program all boxes tuned to 38hz should have the same problem.

 

[zierbox 10+ year member]

I agree with the option of; way to much port

The sub is not seeing the box (the air is simply rushing out the port)

You have to make up your mind, do you want an SPL box that plays limited frequencies loud or a box that play a wide range of music loud and in control

With that much air space I would also lower the tuning frequency

 

[mendon mafia 10+ year member]

I agree with the option of; way to much port
The sub is not seeing the box (the air is simply rushing out the port)

You have to make up your mind, do you want an SPL box that plays limited frequencies loud or a box that play a wide range of music loud and in control

With that much air space I would also lower the tuning frequency

im going to modify the boxes i have my cutting out the bend so that the port open up into the other corner. If that sounds shitty ill re build wither using 32" of area or a 6" aero port.

Most likely going to build a few different boxes of different sizes since i doubt my modification will work but i need a 30" long port if i use a 6" aero so it probably wont happen due to cost.

 

[patotay 10+ year member]

not a pro..try cutting some port.nice amp

 

[mendon mafia 10+ year member]

gonna add 45;s since it will only take a sec to do. is it even worth trying?

 

[PV Audio 5,000+ posts]

gonna add 45;s since it will only take a sec to do. is it even worth trying?

If it's a port issue, it's because the box is acting like a truncated transmission line. Basically what's happening is that instead of acting like a resonator which a ported box does, it's acting as a phase inverter like a transmission line. Problem is that the line isn't long enough to have the backwave shift phase by 180 degrees, and all you're getting is terrible mechanical damping.

 

[mendon mafia 10+ year member]

If it's a port issue, it's because the box is acting like a truncated transmission line. Basically what's happening is that instead of acting like a resonator which a ported box does, it's acting as a phase inverter like a transmission line. Problem is that the line isn't long enough to have the backwave shift phase by 180 degrees, and all you're getting is terrible mechanical damping.

yea that sounds exactly like my problem. because it sounds like its canceling out or somthing. that would explain why it moves move in the box than out if it. Dont transmission lines require the same port area as cone area though?

 

[PV Audio 5,000+ posts]

yea that sounds exactly like my problem. because it sounds like its canceling out or somthing. that would explain why it moves move in the box than out if it. Dont transmission lines require the same port area as cone area though?

Yes, but your box isn't acting like a true transmission line. By not giving the speaker airspace to pressurize, all that's happening is that you're shooting the air down a tube. A transmission line does the same thing, except it actually exits the tube as something useful.

 

[mendon mafia 10+ year member]

so should i not waste the time with 45's then?

I was also gonna try cutting port wall back a bit to raise tuning but also to get the port opening farther from the corner, or is this not worth doing either.

If none of that helps i was going to completely remove the port bend piece and then line the inner port wall until it reduces the port area to a point where its better. cutting back the port length if necessary.

if this all sounds like a waste of time please let me know as i dont have much time to do my builds but i want to be sure i get good results this time as i paid a lot for these woofers.

might sound difficult but im very good with a demo saw //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif at this point im just experimenting so i dont waste any more wood lol. ill build new boxes after i find a suitable port area.

probably do a common chamber next time and do ported on the driver side. or 2 6" aeros in the middle with 90bends.