Building sub enclosure. Volume on Adire plans not matching up (1 Viewer)

[Darren_T]

Hi,

I have been reverse engineering the cabinet volume for the Adire Alignment Tempest plans. I calculated the volume before removing the volume of the internal braces, ports, and driver which was 13448.0 cubic inches or 220.4L. Then I took 220.4L - 214L and ended up with 6.4L or 390.55 cubic inches. This is fine until I figured the volume of the internal braces which came to 577.34 cubic inches or 9.46L. Subtracting this volume alone takes us below the 214L. The plans say it is a net 214L but my figures come significantly under that after taking the braces, ports and driver into account.

Am I missing a step? Are my calculations wrong?

Thanks.

Darren

 

[Dustin B]

Damn Darren, emailed me, so I had to actually do the calculations, or maybe I didn't, oh well did them anyways :p)

Here is my email reply to Darren for those lurkers who might want to read it:

Well I punched the numbers through. I came up with 13448"^3 for the gross. And 1080"^3 for the driver, ports and braces. Which gives a net of 12368"^3. Which is 202.8L.

The plans also call for 64 ounces of polyfill. When you add polyfill or a similar material to an enclosure, its' appearant volume increases. So in reality the enclosure will be seen as effectively 214L to the driver and ports (Adire likely measured the tune from a finished sub, and figured out how much the polyfill increased the appearant volume and quoted that for the enclosure).

The other thing to remember is at this size, being up or down 10L doesn't really affect anything. The tune may go up 1/2 a hz or down 1/2hz. But with two enclosures side by side that differed like this you couldn't tell the difference.

My sub is 260L and tuned to somewhere between 15.75 and 16.75hz with a 6" port. What the appearant volume is from the little bit of insulation and polyfill in my sub is I don't know. Doesn't really matter to me either, sounds great.

 

[Darren_T]

He he...yup. I was stuck and needed to see if I was overlooking something. Looks like the polyfill is what I overlooked in figuring the volume.
Here are a few pics...
Pic 1
Pic 2
Pic 3
Pic 4
Thanks again.
Darren