Chris,

Here's a quick simulation I did in WinISD comparing the Dayton 15" DVC and the Tempest. They model very similarly. The Tempest plays a little lower, but requires a bigger box to do so. As you can see, the vented box needs to be roughly twice the size of the sealed box.


http://diy2001.8m.com/cabinets/DVCvsTempest.jpg

In your room, you may be better off going with a sealed box. You'll start to get room gain as high as 175Hz. Although the sealed box may look less desirable on paper, it may actually sound "flatter" or more accurate in your room. Room gain is an interesting effect that is generated when a sound wave hits a wall or intersection. You will typically see a 12dB/octave increase (i.e. the SPL will increase 12dB each time the frequency is cut in half). I believe room gain starts kicking in at the half wavelength of the longest wall in the room. That would mean that at around 175Hz you will already be seeing a little gain. Sealed boxes roll off on the lower end at a 12dB/octave rate, so the room gain could potentially give you a flat response down to 20 Hz or lower. A vented box in that room might sound boomy or overkill. You'll also probably get a little tighter sound from the sealed box.

Also, in this room, you definitely wouldn't need to go any bigger than a 15". In fact, that may already be coming close to being overkill. With the 500 watt amp, you should be able to get 115dB fairly easily, which is definitely enough to cause nausea if endured for more than a few seconds!

Good luck
Jason



[This message has been edited by JasonA (edited March 11, 2002).]