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Hell-Razor

Port Vs Power

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I have talked with rob and rusty from dc on everything to do with my upcoming design for summer 2012. I am going to go with 2 xl 12s on two SAZ-3500Ds, backed up with juicebox batteries and a 220amp excessive amperage alt.

The box will be a little smaller than recommended seeing as DCs love smaller boxes when they are overpowered. Now my question for everybody that I cant seem to get a hold of is port area, would I be better off giving it a little more (Kerf port btw) space (say 18-20sqin per cuft) or the "normal" range of 15-18sqiin per cuft? My goal is to get decent numbers in the low 30s. I do not have the depth either for aeroports. A 5" aero though would be 21 sqin per cuft which I think would be too big, and a 4" aero would be 14.5, which is too small.

I have been running my designs through bbp and using torres calculator to back up my designs. It seems the smaller ports are louder but more peaky than the larger ones. The larger ports seem to be able to play lower and more effecient but not as loud. And yes I do understand this is just a model and the cars frequency will change it, I will test and build and test and build some more but I want to see if I have a good handle on this before I start pumping out miltiple boxes on a termlab.

Anybody have suggestions as well on replacing boxes? I think im going to use just different size / length ports on different faceplates. I think I will try 3.25, 3, 2.75 and 2.5 inches wide and see what plays louder at lower hz.

I will be sealing off the trunk from the cab and firing both subs and port into the cab.

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Just remember, port area has nothing to do with box volume and everything to do with driver displacement.

If you are running designs and see an increase in output when you change port area (especially making it smaller) it is because you are manipulating something else unintentionaly.

When you make a box smaller you make it less efficient, 100% of the time. It isn't that the driver likes the smaller box better, it is that you have lowered system efficiency with the by product of increased mechanical power handling. It will never be as loud as a larger more efficent box with proportionaly less power due to thermal compression.

If you are modeling, shoot for lowest vent velocity possible while keeping you port a managable size, that really is all there is too it. It has nothing to do with the volume of your box...

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Large ports wam on the lows!!!!! Most of the time. And they are more efficient. And move a ton of air!

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