Posted January 22, 201015 yr Hello,At the moment, I have 2 Kenwood 12's (4 Ohms, 400rms) in separate ported enclosures that I built. It was my first time building a sub enclosure, and I don't think I did it right. I have an alpine MRP-M500 amp running at 300wrms at 4ohms. I listen to rap, and when I play a song that goes really low (Put on- jeezy for example) the lowest note is really quiet. I'm assuming its a combination of the wrong box specs and them being underpowered?I'm planning on getting a new system in a couple months, but until then, I'd like to fix my current one and in the process, I'd be getting another box build under my belt to practice for my next one. My goal is to make it louder, and enable it to hit the lower notes better. My idea is to build a new single sub enclosure, and just not use the other sub so I can run the other one with more power and in a bigger box. The amp is 500 watts at 2ohms, but the sub is 4 ohms. would it be possible to wire the sub to 4 ohms to increase the power going to it?I looked up the sub on kenwood's website and they list these specs for a ported box:• Volume: 1.5cu.ft• Width: 19-15/16”• Height: 14-3/16”• Depth: 12-5/8”• Mounting Hole: 11-1/8”• Slot Width: 1-3/8”• Slot Height: 12-11/16”• Slot Length: 18-7/8”• Displacement: 0.157 cu.ftAre these specs good, or would you recommend something else?
January 22, 201015 yr I'd recommend going with something else. Those box specs look horrible. 1ft^3 @ 43.5hz
January 22, 201015 yr Author I'd recommend going with something else. Those box specs look horrible. 1ft^3 @ 43.5hz lol it figures that I can't trust the manufacturer to give specs for a decent box How do you calculate the tuning? And do you have any suggestions for what size box I should be looking at?
January 24, 201015 yr Id get different drivers.The box port can be calculated with a simple formula. Box volume in cubic feet X 16 (the amount of port area in square inches per cubic feet of box volume). For example, 3.4 cuft X 16 sqin= 54.5 square inches of port area. Try to stay within 10% of this number.The port length should be 16 inches deep. This tunes the boxes to about 40 Hz.Some port lengths do not allow for 16-inch port depths without some sort of modification. The rule of thumb is not to let the end of the port get any closer to the back wall than the width of the port. So back to our example, we have an internal box depth of 12.5 inches. We need a 16-inch deep port. We will have to bend the port along the back wall to get the full port length. To calculate where to make the bend, subtract the port width from the inside box depth. 12.5 – 3.75=8.75. We must bend the port at 8.75 inches, then continue the port parallel to the back wall for an additional 7.25 (8.75+7.25=16).You now have an L shaped port totaling 16 inches in depth.Audioque.com
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