Hi guys, I will be building the pre cut enclosures I calculated under RE enclosure calculator but there are a few things I would like to verify. I would like to tune the box between 33-35Hz @ 1.8-2.0 cubic ft. However, I just read that the RE calculator is not accurate. So I searched and found this website Enclosure Volume Calculator (EVC) and made the following calculations:

Box Width 23 Inches

Box Height 15 Inches

Box Depth 15 Inches

Material Thickness 0.75 Inches

Number of Drivers 1 Total

Total Port Volume 258.188 Inches3 -----> see calculations below:

Port Width 13.5 Inches

Port Height 1.5 Inches

Port Depth 12.5 Inches

Driver Volume 0.168 Ft3 -----------> From Fi Q12 specs

Number of Drivers 1 Total

Total Net Volume 1.95 Ft3

I would like to verify with you enclosure experts, if this calculations are ok and will be enough for optimal output of the sub. The sub will be powered @ 1200 watts RMS.

Thanks

Hi guys, I will be building the pre cut enclosures I calculated under RE enclosure calculator but there are a few things I would like to verify. I would like to tune the box between 33-35Hz @ 1.8-2.0 cubic ft. However, I just read that the RE calculator is not accurate. So I searched and found this website Enclosure Volume Calculator (EVC) and made the following calculations:

Box Width 23 Inches

Box Height 15 Inches

Box Depth 15 Inches

Material Thickness 0.75 Inches

Number of Drivers 1 Total

Total Port Volume 258.188 Inches3 -----> see calculations below:

Port Width 13.5 Inches

Port Height 1.5 Inches

Port Depth 12.5 Inches

Driver Volume 0.168 Ft3 -----------> From Fi Q12 specs

Number of Drivers 1 Total

Total Net Volume 1.95 Ft3

I would like to verify with you enclosure experts, if this calculations are ok and will be enough for optimal output of the sub. The sub will be powered @ 1200 watts RMS.

Thanks

Are you sure your port is 1.5" high?

Yes, the port is 1.5" high. So by changing the port layout to slotted type instead of an "L" shape port, I can add an extra volume inside the box by reducing the length of the first port slot ? I noticed that when I increase the volume of the box, the program reduced the length of the first port slot but the frequency remains at 34 Hz.

Thanks

L shaped ports are only that way because the port is too long to fit into the box without doing so. There's absolutely no difference between that and a slot port or whatever you're saying.

The program keeps tuning the same because it's calculating port length based on your inputs of box volume, port area, and tuning frequency.

Those box dimensions give you 2.26 cubes gross. Minus sub displacement of about .17 cubes and your port displacement of .22 cubes and you have net volume of 1.87 (port is .22 because you have to add in the width of the interior port wall itself, so the dimensions would actually be 2.25 x 13.5 x 12.5). Plug those port dimensions and box volume into my winISD and it gives a tuning frequency of 42 hz. Very off.

If you want a 34 hz tune with a 1.87 cube box, lengthen your port to 21.5". You'll then have to add on .16 cubes to your net volume so that it's 2.42 cubes gross.

L shaped ports are only that way because the port is too long to fit into the box without doing so. There's absolutely no difference between that and a slot port or whatever you're saying.

The program keeps tuning the same because it's calculating port length based on your inputs of box volume, port area, and tuning frequency.

Those box dimensions give you 2.26 cubes gross. Minus sub displacement of about .17 cubes and your port displacement of .22 cubes and you have net volume of 1.87 (port is .22 because you have to add in the width of the interior port wall itself, so the dimensions would actually be 2.25 x 13.5 x 12.5). Plug those port dimensions and box volume into my winISD and it gives a tuning frequency of 42 hz. Very off.

If you want a 34 hz tune with a 1.87 cube box, lengthen your port to 21.5". You'll then have to add on .16 cubes to your net volume so that it's 2.42 cubes gross.

I've been trying different combinations on that WINISD software and I came up with this....

I would like to keep the 1.87 cube box volume so what I did is change:

VENT DIAMETER = 0.75" x 12" and my VENT LENGHT = 9" instead of doing the 21.5"

BOX = 1.87 cub ft.

TUNED = 33.55 HZ

NOTE: The 1.5" VENT is the SQUARE PORT WIDTH from RE calculator program then I reduced it to 0.75" on WINISD program.

Please let me know if this will work out alright. I would like to keep the box Volume as much as possible at minimum 1.8-2.0 cub ft. tuned to 33-35 HZ without losing interior box volume.

Thanks

A .75" x 12" port is not nearly enough port area for the sub. That's only 9 square inches. You need at LEAST 20 unless you do an aeroport. 25-30 would be even better.

Alright, I've decided to do aeroport. 4" hole x 11" lenght. Now, does it matter where the port is facing? I want the port to fire upwards and the woofer facing the rear trunk.

Thanks

there is not really a difference in the tuning but on the audible part yes if it is in a trunk it should be sub front port front the best sound there are others

That port displaces .08 cube, so now you have a 2 cube net box. winISD says that's tuned to 34.75 hz. Not bad.