I am thinking about switching from a sealed to vented enclosure for my D615D2's. The box I am currently using is 48" on the front baffle, 44" on the back, 17" tall, and 14" deep with each driver seperated with a center brace of MDF. (Almost 5ft^3 before driver displacement I believe) Diamond audio recommends a box which is 3ft^3 with a vent 4" in diameter and 11" inches long, per driver. When I put this in WinISD the rear port velocity was very high, like over 40 m/s! Won't this create crazy port noise???

Anyway.... my question is can I simply place a vent this size in each chamber of my current box to create a box tuned at or below 30Hz with apx 2.3ft^3 per driver, and compensate for the smaller volume with some polyfill?


Here is a link to the T/S parameters and the recommended enclosures:

http://www.diamondaudio.com/products/pdfs/D6%20Woofer%20Tech%20Sheet2.pdf

I put the #s thru WINIsd, and at that small a box size, you'll need to use 2 4" vents about 13.1" long. This will get your port velocity down to .06mach, which should be OK....

Another option, if it will fit in your vehicle, is that 6cuft tuned to 30hz box on the spec sheet. Using 3/4" MDF with outside dims of 44"W X 17"H X 18.25"D, with a single slot port 15.5H X 2"W X 7.5" D will tune it to 30hz....

Easy to build, and it should pound pretty good.....

__________________
BigRedGuy
Still bumpin' after all these years
Kenwood/AudioControl/Orion/JL Audio/Lightning Audio

Unfortunately that depth is too large or I would definately have done it! My current sealed box is just about as big as I could cram into the trunk; I had to put it in first before mounting the subs (god help me if i need the spare....)


Just to clarify you are saying that each side of the current enclosure requires a 4" X 13" circular vent, or that the enclosure need four total, two on each side? Do I have to worry too much about having a smaller volume than Diamond recommends?

Thanks for your help, I am pretty excited about venting the subs. They sound alright now, I can't wait to hear them ported!

A couple more questions...

What is the equivelant to .06 mach in m/s ? When I input a 1000W signal into WinISD (for the 2 drivers 5ft^3, with the two 4"X13.1" vents) I get over 40m/s, according to the totorial on sounddomain this is almost double what it should be for a trunk enclosure.

Is the varible subsonic filter (15Hz or 30Hz) on my Alpine MRD-M1005 sufficent to prevent unloading the driver with this enclosure?

Is it realisitic to expect a 3db gain from porting my subs as WinISD predicts?