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Ported enclosures & WinISD accuracy?

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Old 04-11-2005, 06:08 PM
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Post Ported enclosures & WinISD accuracy?

I'm currently running models of a ported enclosure for 2 8"s in my regular cab truck.

Internal volume of 1.7 cubic feet
Prefered tuning of 30hz

But since it's a regular cab truck I have very little depth to work with.

WinISD suggests a single 2" circular port 4" long OR 3" x 10.2", but with the larger size I can only install it in the side because the box is only 6" deep!

Do you think that the 2" x 4" port would sound alright?
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Old 04-11-2005, 06:38 PM
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You could put the 3" port in the front and just turn it at the back. Making it an 'L' shape.
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Old 04-11-2005, 06:51 PM
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you may have unacceptable port noise with either of those. I would try to go 4"x 19" on the side if possible. 3.5" x 14" should also be o.k. Also you could use a slot port that is 8" x 1.5" x 18.5" if that's a possibility. Remember if the port velocity is too high you may get( will get) port noise. Use the drop down menu and go to "rear port air velocity"to check if your port is too small and will induce port noise.
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Old 04-11-2005, 07:17 PM
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he's talking about 2 8", not 2 12" or 2 10" 1 3" port should be cool.
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Old 04-11-2005, 07:37 PM
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Yeah should be o.k, since I don't even know what drivers he is using and I assumed a power level of 150 watts. Anyway play with the program that's half the fun.
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Old 04-11-2005, 07:58 PM
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The subs are each mounted 9" from the sides of the enclosure, and are pratically the full depth of the box.

What is an acceptable level of port air velocity (ft/s)?

With a single 3" x 7.5" aero port I have 14.3 ft/s of air velocity at 31-34hz, will that be audible?
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Old 04-11-2005, 08:01 PM
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The drivers are discontinued Massive Audo RW 8" I can't get the tech specs anywhere so I am using RE8's for the model, Though the massive's are much bigger, in motor size, power handing and xmax, I'm sending them around 350rms for the pair.
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Old 04-13-2005, 01:32 PM
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remember to input the power you are going to use under the "signal" tab. I think you might have just looked at the graph and assumed it input that info for you. The default input power is only 1 watt, that is why you got such a low air velocity for that port size. You want to try and keep the port velocity below 17 m/s or approx. 56 ft/s within your listening frequency range. However, most people say they can't hear port noise that is a bit faster than that and also depending on where the sub is located. I used 2 massive audio's pw 8 specs and your box size of 1.7 ft^3 and your port size of 3"x 7.5" flared both ends and came up with a max port velocity of 50.5 m/s(166 ft/s)@ 28.3 hz at 350 watts. Obviously, that is much higher than the program wants, but you may not hear any noise depending on the type of music( lowest notes above 45 hz) and listening level(tend to keep volume well below max). Try the smallest one first, you can always make the port bigger.
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