i am currently looking at changing my set up and was considering to build with 10" xcons. I am looking at aero port for my box build curious what type of port area I need to be looking for? or is some one can let me know how to calculate this. Thanks.

12-16" per cu. ft alos depends on power and tuning.

12-16" per cu. ft alos depends on power and tuning.

 

there will be 3 subs on a saz 3500

final nominal impedance?

I haven't ordered subs so not sure. But they could be wired at .67, 1.5 if I get d1 subs and if I get d2 then 1.34. Can you tell me why this pertains to my question so I can understand?

Max box size is 15 high x 37 wide x 34 deep.

It doesn't, nor does the 12-16". No such thing as a generic rule. You need to model your enclosure, with your drivers & power and determine if the port velocity will bug you.

http://www.bitpusher.in/?p=portarea

I have been using the bit pusher. Trying to understand the velocity. Aka vent Mach but any information is useful to help me. But please speak in lemans I am by no means well versed in audio terminology.

http://www.bitpusher.in/?p=portarea

Or better yet: http://bitpusher.in/?p=portgraph&driver=6&xdrivers=3&rms=3000&tuning=30#bottom Also I believe the newer edition of WinISD can graph port speed and port area.

Another thing to note, when you calculate for port speed you should take impedance into consideration so you use a more appropriate power value than the amp's rating at XYZ ohms.

In simple terms: amp XYZ rated for 3500watts at 1ohm, you're "wired" to 1ohm, but in reality the integration or average of the impedance plot between your crossover points is more than likely above 1ohm.

So if you calculate port speed with 3500watts when in reality it's closer to 2000watts then it's going to appear much higher than the real value. Someone please correct me if I'm wrong, but I believe it's probably safe to say you could use 3/4 of your amp's power rating that you're "wiring to" and would still be playing it safe if you didn't want to do further modeling.

As to what port speed is acceptable, that's going to vary from application to application, and it's one of the harder things to get advice on considering most people on the forum haven't actually tested various port speeds and the resulting effects. There's a few white papers on the matter if you'd like to do some more extensive reading--I can try and dig some up if you want?

If it was me I'd aim for 25 m/s or lower, but that's just my opinion, so feel free to wait until someone else with more knowledge chimes in.

Edited January 7, 201411 yr by ssh

blah blah blah, im still looking at these sexy graphs.

Yes, the amplifier will produce different levels depending on the impedance it is driving, this is due to the "impedance curve" of the overall alignment.  It isn't impedance "rise" as it goes up and down, there is no such thing as just "rise".

 

When you model, look at the impedance.  At it's lowest point, that is where you get maximum power out of the amplifier.  If that lowest point is anywhere near the peak in your vent velocity, then you need to model for the max power of your amplifier.  Most of the time your vent has maximum airflow at resonance, it also happens that this is also the lowest impedance point, or close to it...