Subwoofer Enclosure (All suggestions and opinions appreciated)

[alextheonly]

I recently bought two Kenwood KFC W3013PS 12" subs, and I designed a box for it. The box specs are as follows:

- Dual 12" box, single chamber with port in the middle

- 4.5 cuft, 4.3 cuft after subwoofer displacement

- Tuned to 33 Hz roughly, port area is 54 sq.in, port length is roughly 26 in.

The box is simple; no kerfs and no 45s, just 90 degree bends all around.

I am using a Hifonics BRX1600 to power the subs. The amp is rated 1200wrms @ 2 ohms, but I i highly doubt I can achieve that. 1200w is too much anyways, the kenwoods are rated at 400wrms @ 4 ohms, so in parallel the two subs require 800wrms @ 2ohms. I'm aiming for 1000wrms @ 2 ohms so each sub is overpowered by 100w and nothing more.

Can anyone tell me what to expect from this enclosure with the given power fed to the subs? Will it be loud? Will it rattle everything in my vehicle (2011 RAV4) or will it just be loud (SPL)? Will it hit the low 30's and high 20's hard or will it hit at a higher range? I'm not concerned about SPL, but achieving numbers above 100 would be a good benefit from this box.

The reason why I'm asking all this is because after plugging in everything and playing with some numbers in WinISD, the graph tells me that I have an 8db peak at 47.8Hz, which I find to be really peaky :/ I mean, 8db? isn't that a lot?

Also, I would like some opinions on my box. I know its not the best because of the lack of 45s, but I can always add them in if its highly suggested.

All help is appreciated!

*edit* if needed, can someone explain how to upload images? I'll gladly upload an image of the box design, or if possible upload the Sketchup file. I'm new to this forum.

[bbeljefe]

Real world performance won't be what WInISD predicts because it doesn't account for the unique acoustics in a vehicle. That said, it will probably still peak at ~40Hz but not by 8dB. As for anything below 30Hz, don't plan on getting much from entry level subs.

If your box rolled off below 47Hz in WinISD you can probably expect -3dB to be in the low to mid 30s in the vehicle, which means you won't hear anything at all below 30. Also, those subs will probably unload below 30 in that much air space/port area.

If you're seriously interested in response below 30Hz I would recommend one good quality 12 or a couple of high quality 8s or 10s in a transmission line.

[alextheonly]

Real world performance won't be what WInISD predicts because it doesn't account for the unique acoustics in a vehicle. That said, it will probably still peak at ~40Hz but not by 8dB. As for anything below 30Hz, don't plan on getting much from entry level subs.

If your box rolled off below 47Hz in WinISD you can probably expect -3dB to be in the low to mid 30s in the vehicle, which means you won't hear anything at all below 30. Also, those subs will probably unload below 30 in that much air space/port area.

If you're seriously interested in response below 30Hz I would recommend one good quality 12 or a couple of high quality 8s or 10s in a transmission line.

Alright, what would happen if I tuned it down to maybe 25Hz? Would I see a gain in the low 30's? And what about a good quality 15 instead of a 12, so I could have more surface area?

[bbeljefe]

Real world performance won't be what WInISD predicts because it doesn't account for the unique acoustics in a vehicle. That said, it will probably still peak at ~40Hz but not by 8dB. As for anything below 30Hz, don't plan on getting much from entry level subs.

If your box rolled off below 47Hz in WinISD you can probably expect -3dB to be in the low to mid 30s in the vehicle, which means you won't hear anything at all below 30. Also, those subs will probably unload below 30 in that much air space/port area.

If you're seriously interested in response below 30Hz I would recommend one good quality 12 or a couple of high quality 8s or 10s in a transmission line.

Alright, what would happen if I tuned it down to maybe 25Hz? Would I see a gain in the low 30's? And what about a good quality 15 instead of a 12, so I could have more surface area?

Tuning that low with those subs in a car will get you some low end response but it will be at the expense of everything above 30Hz. A good 15 would do the lows better but it'll need about the same air space as the 12s you're looking at in just a ported box. A t-line for one would consume at least 8 cubes.