Some of you may know that I was going to get Sundown X 12s and then decided to get 2 10s because I couldn't fit 2 12s properly since they require a much bigger box and I'm kinda limited on room. I decided to have subs/port facing rear and have my battery and amps up closer to the front and build an amp rack there. I have a box design for the 10s here it is: Sundown recommends a much larger box (1.5-2.0 cubes per 10) to utilize the new surround and suspension. It will get much more excursion then. Also minimum required port area for these 2 10s is 75in2. Well I've been thinking since I have a height of 17 and a width of 34 I could fit 2 15s on the face. However, the box would be sealed. With those dimesions I can have a sealed box around 5.75 - 6 ft3. I'm not sure how big the X 15s need for a sealed box though; I'm calling sundown to ask tomorrow. I doubt it's more than 3 cubes. Now I'm pretty sure that the 15s would get louder due to the big increase in cone area. I'm just not sure if they would get as low. I love the lows and have not had a sealed box since my first setup 2 years ago when it was 2 orion cobalt 12 in a very small sealed box. I'm not sure how sealed boxes actually play and where they peak since there's no port, but I like to listen to low songs like on my level, white girl, and no hands. Songs that have low bass like that. I'm really not concerned with the loudness as I know the 10s would be plenty loud. I'm more concerned with the 15s being in a sealed box and not being able to play lows as well as the 10s in the ported box will. Can someone tell me how well sealed boxes play low? I know bigger the sealed box, the lower it will play? Wait, right? haha Thanks in advance.