Sundown SA-12: less powerful than I tought?

[bkolfo4]

And you thinking a port sized based on box size is causing a sub to free air is much better. . .

Guess a port is just a big hole in the box to let pressure out. . .

I will stand by my comments and add if you don't understand what you are talking about, it is probably better to just refrain from trying to help.

I'll refrain from being a dick when you refrain from posting false info.

[Hellbilly429]

I was making a simple reference, not a literal one, I know it's not free airing, but that is one big port for a single 12.

But you go ahead dude, I'm done, tried to help and of course there is always someone like you who can't see that and just nicely explain why I'm wrong rather than just point out everyone's mistakes so that you can feel better about yourself.

So please, share your knowledge rather than run your mouth

And don't bother replying, cause I'm gonna walk away and not read it, cause I'm tired of people like you

[bkolfo4]

I know you will read it, so let me say I have posted a million times that the sqin per cuft is just an ESTIMATE. 38 sqin of port is no where near too much port for that 12" sub.

Larger ports don't have less "bandwidth", and they are not just for SPL.

I will apologize now if I came off as a dick. After seeing the same incorrect port info so many times, and explaining that it is wrong so many times, I probably just had one of those moments.

[TeamHT]

I honestly didn't think it was a dick response at all, some people just don't like admit they're wrong. We're all guys so sometimes it's hard to swallow our pride but bkolfo4 knows his shit and sometimes when I was wrong I've had to go and test for myself and the go hmm...lol.

He's not being a dick he's being straightforward. I've seen assholes post dick responses, trust me...this is nice.

[truthsayer]

if you don't have a dd-1 or a O-scope, just use a simple voltage meter.

[SojiaRaggs9000]

Id kinda like to know myself. Pretty sure my math was on point but you never know. I did have some M1 XL 12's in a 3cu ft box and it still got down but it was tuned to like 33 ish and I wasn't overpowering them. Well... I was but with box rise it worked out lol.....

[slowfkncar]

Well to be fair,smaller port vs larger port depends on (subwoofer VAS,Subwoofer Q,Vehicles ability to pressurize the cabin,power output after rise,enclosure size,vehicle resonance ect... Generally,a 3ft^ enclosure with 60sq.in port area will have the ability to play flatter then a 3ft^ enclosure with 90sq.in port area because the sub can still pressurize the port away from tuning frequency IF you do not exeed the amount of air the subwoofer can displace in your vehicle. 90sq.in of port area will allow the sub to move more air at the tuned frequency,to big of a port will reduce air velocity,an oversized port will render your subwoofer to not be able to move the air properly in the enclosure because it simply cannot move that much air because of limited xmech and/or cone area(remember this is a general statement,different subwoofer,vehicle,windows down vs up ,enclosure, ect... plays a big part) like everyone is saying,the best way to test is with a meter,every car every setup is different and even the small things play a part in tuning.

[bkolfo4]

99% of car sub enclosures have ports that are too small anyway. You are not going to get into a situation of too much port area in a car unless you are totally stupid with the design. The smaller box sizes do not allow it, the ports become way too long.

Minimum port area is based on maximum air velocity, which is based on the volume of air the cone can sweep and the frequency the port is tuned to.

What happens with the port when the volume is not at maximum, does the port just not do anything? Some of the logic on these forums indicates the driver would have to be moving near full excursion all the time for the port to work correctly. It is almost like saying low power blows speakers - does that mean you have to keep your volume up all the time to keep from blowing the speaker?

And I am not saying things don't change with port size, because they do (and that does not just apply to an enclosure in a car), but there is a lot of confusion on why the changes are occurring and what is required to make the port sized correctly.

I give up - this will be my last post on port area. If asked, I think I will start quoting the 12-16 sqin per cuft "rule"

[SojiaRaggs9000]

TBH his port "size" per squared feet isn't the issue its the length of the port. That and the overall size of the box.

[Golitan11]

Ok guys I get PLENTY of output now it is ridiculous, even maybe a bit too much LOL... I tried just for fun the gain at 2.5 o'clock, with the preouts at the maximum (+6) and the volume at 40 (I should have done it at 50, maybe it is getting way too much now, but it did not smell yet, dustcap only getting a bit warm, and I have port noise XD). With those settings (with a -3 dB @ 50 hz test tone) I was getting about 32V, which is like ~1000W, subsonic and lowpass filter off). Now I get voltage drop, it goes down to like ~12.5 now):

Before it was like this:

Here is a video (sorry for the bad microphone quality and the phone orientation):

http://www.dailymotion.com/video/x145qo1_sundown-sa-12-flux-pavillon-bass-cannon_auto

I know it is really hard to see but it almost get the same excursion as this:

http://www.youtube.com/watch?v=XI5VEetMxf4

Is it really too much LOL? Or it will just be ok if I only do this like a few seconds per day XD? Thanks!