Port area. what does it affect?

[Kyblack76]

so if my dc resistance is .7

i wont fall below that right?

Yep.

Impedance consists of two parts, resistance and reactance. Resistance is your DCR which is always the same, well, at least its not directly affected by frequency. The reactance is the other part of impedance which basically represents the opposition to a change in voltage or current because of inductance or capacitance. In our case with speakers, its basically just the magnitude of inductance produced by the woofer's coil that affects our impedance. The magnitude of this inductance is a function of frequency. So, it is this reactance portion of the impedance that is responsible for what we call impedance rise or box rise in car audio.

i think you dont know i dont get this... lol....

[Kyblack76]

soooo

enough of dc vs applied

can we still speak of the vent ??

[Jessica]

i may just grab a sheet of MDF build a .65cuft box for one of my p3 8's and make a couple ports for it. on of them as big as will attach to the box and on near manufactures specs and tune them both at the same freq and see what it does.

[Triticum Agricolam]

i may just grab a sheet of MDF build a .65cuft box for one of my p3 8's and make a couple ports for it. on of them as big as will attach to the box and on near manufactures specs and tune them both at the same freq and see what it does.

Sounds like a cool experiment. Let us know what you find!

[Jessica]

here is my question though, If i go with a ton of port area i'm going to need a pretty long port to keep my tuning down but it has been said in here that i should keep the port short. So can i get some clarification on that?

I'm going to just tune to 40hz or 42hz since the p3 8 that i am using isnt going to be smashing the lows and i want a more upper freq response out of them anyway.

[Krakin]

Make the best of all evils.

[Triticum Agricolam]

here is my question though, If i go with a ton of port area i'm going to need a pretty long port to keep my tuning down but it has been said in here that i should keep the port short. So can i get some clarification on that?

I'm going to just tune to 40hz or 42hz since the p3 8 that i am using isnt going to be smashing the lows and i want a more upper freq response out of them anyway.

I try to keep ports under 50" or so, that puts your first port resonance at 135 Hz. Shorter would be better since most people recommend you keep your first port resonance at least an octave above where your sub is crossed over at, but its not the end of the world if you cross over less than an octave below that.

[Jessica]

i'll keep that in mind

[fecupe2001]

very nice topic! so bad i got here so late but i´m still gonna add a couple of things!!

I´m with my boy triticum here, aka huge , there´s no problem with the big ass port area other than having a long port, he says 50" long is the max he goes, i go WAY shorter than that, i´ve been competing and testing for spl and daily boxes many years, and i learned that i already that the longest aero you can go is about 20" , more than that, trust me that even with a lower tuning you would loose output on lows for example.

Krakin said there´s a math that gives you the same efficency on an slot port and aero, would love to know that, but on my own experience and testing, there´s a 29% difference between those ports, in other words, if a 6" aero is the best you found out for your application and want to use slot port now, you would need 36.5" SQ of slot port area and same goes with the lenght, if 20" is the longest i go for an aero, then slot port would be 26"; honestly speaking, the best way is to test test test and find out what works better for you, i´ve changed the port on my explorer 4 times already, once i add more power or even reinforce the cabin a little bit, output, power and impedance changes like hell.

you only need the time and effort to get loud, my explorer is already burping 158.6 dbs @ 44 hz with 5600 clamped watts!!!! how did i do that??? well, my wife was pregnant and i didn´t have the money too add more power or anything like that, so i´ve had to work my ass on that piece of crap car, funny thing is, i´m still using a single stetsom 11K wired at 1 ohm

[Kyblack76]

very nice topic! so bad i got here so late but i´m still gonna add a couple of things!!

I´m with my boy triticum here, aka huge , there´s no problem with the big ass port area other than having a long port, he says 50" long is the max he goes, i way WAY shorter than that, i´ve been competing and testing for spl and daily boxes so many years, that i already found out that the longest aero you can go is about 20" , more than that, trust me that even with a lower tuning you would loose output on lows for exampler.

Krakin said there´s a math that gives you the same efficency on an slot port and aero, would love to know that, but on my own experience and testing, there´s a 29% difference between those ports, in other words, if a 6" aero is the best you found out for your application and want to use slot port now, you would need 36.5" SQ of slot port area and same goes with the lenght, if 20" is the longest i go for an aero, then slot port would be 26"; honestly speaking, best way is to test test test and find out what works better for you, i´ve changed the port on my explorer 4 times already, once i add more power or even reinforce the cabin a little bit, output, power and impedance changes like hell, you only need the time and effort to get loud, my explorer is already burping 158.6 dbs @ 44 hz with 5600 clamped watts!!!! how did i do that??? well, my wife was pregnant and i didn´t have the money too add more power or anything like that, so i´ve had to work my ass on that piece of crap car, funny thing is, i´m still using a single stetsom 11K wired at 1 ohm

I was looking for you to comment in every page man.....