[BrandonG]

Hey Guys,

I recently built a 2.0 cu.ft sealed box with an ACI AC12 Driver and a Keiga KG5150 amp (http://www.madisound.com/catalog/product_info.php?cPath=360&products_id=368), but I'm not completely satisfied with the response on it. I was thinking about rebuilding it using the same parts in a ported box, but I want to keep it as small as possible, and I'm not sure if it's worth doing. Here are the specs on the driver:

➢ Nominal Diameter: 12”, Impedance: 6 ohms, Range: 18-1kHz
➢ RMS Power: 150 watts, System Power: 250 watts
➢ Sensitivity: 89db
➢ Magnet mass: 1134 grams, BL: 14 Tm, Fs: 18 Hz
➢ Qms: 7.65, Qes: .32, Qts: .31
➢ Vas: 250 liters, Cms: 651, Mms: 121 grams, Mmd: 117 grams
➢ Xmax (linear one way): 7.68 mm, Voice Coil Diameter: 2”
➢ Voice Coil Height: 24.89 mm, Air Gap Height: 9.525 mm
➢ Voice Coil Inductance: 2.7 mh, Voice Coil Resistance: 4.7 ohms

Any help/recommendations would be awesome!

 

[Mike P.]

In 3.5 cu.ft. tuned to 22 hz you would gain 4 -5 db in the 20 - 30 hz range over the 2 cu.ft. sealed. The modeling assumes the amp has a high pass filter (rumble filter) at 18 hz. With the subs limited Xmax it would be easy to overdrive the sub, use some caution.

 

[BrandonG]

Do you think it's worth rebuilding? This was also on the spec sheet I was given,

Box Volume Box Res. QL Q/Ripple Port *1 F3 F10
1.5 cu.ft. Sealed 47Hz 7 .97 - 42 28
2.0 cu.ft. Sealed 42Hz 7 .72 - 40 25
3.0 cu.ft. Sealed 36Hz 7 .61 - 41 24
2.5 cu.ft. Vented 27Hz 7 +2db 4” X 15.7” 32 24
3.0 cu.ft. Vented 23 Hz 7 + .6db 4” X 18.5” 30 21
4.0 cu.ft Vented 21Hz 7 0db 4” X 16.4” 27 18

 

[Mike P.]

Do you think it's worth rebuilding?

You aren't happy with the response from the sealed, what are you looking for, more low end for a HT application?

 

[BrandonG]

Yeah I want to get more out of it as it gets down closer to 20/25hz, while still keeping the tightness so it will sound good with music as well.

 

[Mike P.]

3.5 cu.ft. tuned to 22 hz would be the most you can get with the ACI AC12. Upgrading the sub to a CSS SD12 using the same box and amp would make a big difference in low end extension and SPL.

Yellow - ACI AC12 sealed
Green - ACI AC12 ported
Pink - CSS SD12 ported

 

[BrandonG]

Another question, would it make a difference if I had a front-firing driver, but had the ports facing downwards running along the back of the box? Basically a front firing sub with vents on the bottom?

 

[Mike P.]

There's not much difference between a front or bottom ported sub, as long as there is enough clearance from the floor.