Ive had my Avalanche in a sealed enclosure in my car for a few months now. One day I decided to build a home theater subwoofer so I bought the AA Atlas and decided I want to use my sealed box from my car in my house temporarily. Luckily I had a ported box laying around that I built in the summer for a PG Titanium. So I decided that this would be a good test to see what the differences in sound and output would be in my Escort.
The sealed box is made of 3/4" MDF with a double layer of wood on the front baffle and some bracing on the inside to get a total of about 1.35 cu ft after driver displacement. The box is perfectly sealed with no leaks.
The ported box is made the same except with only a single sheet of MDF on the front with a volume of around 2.0 cu ft tuned to 30-35 hz.
High pass crossover was set at 80hz on amp and head unit.
Amps and speakers are in my sig.
I switched the boxes out and finally turned on the stereo to very low volume and adjust the gain on my amp and head unit. For a normal blend of bass in my music I had to turn the gain down just a little bit to where its exactly half way now. On the deck I went from +9 down to +3. After this it sounded to be about the same output from the vented enclosure compared the the sealed one.
The first song I turned on was Around The World by The Red Hot Chili Peppers. This is one of my favorite songs of all time and have listened to it many times. I thought it would be a good track to test the differences in sound. I turned the volume up pretty loud and let it play. My first impression was wow, this is so much louder. The bass was deafening. I heard it more than felt it compared to the sealed box. I then quickly put the Lateralus album by Tool and turned on the first track. I wanted hear how this sub performed with much harder bass notes. When the track was finished my first thought or impression was how "loose" the bass sounded. The sub seemed to hit the notes harder than my sealed box but with a higher pitch, as if someone turned up the crossover frequency on my amp. This is probably what most people would call a "boomy" sound. Also it seemed like I could hear the sub go back into resting position after it hit a bass note. I then proceaded to play some Korn tracks that had some long deep bass notes. I quickly noticed that the lower frequencies(around 30hz were much quiter than the higher ones(around 50hz), but still very defined and audible. What I also noticed was that my highs were drowned out a lot more in this box.
Overall I really liked the sound of this ported box. I thought it would be much worse. The biggest difference is the overall tone the subwoofer puts out. I also loved how my sealed box would shake my car harder than the ported box at lower volumes. Once the volume is turned up though the output advantage of this box is crazy. Everything shakes even harder and my eyes would go a bit blurry on the deep notes.
In the end I do plan to go back to a sealed box. Its just more of a satisfying, equalized sound to me. The Avanlanche is a very warm and pleasing sounding woofer. Its very accurate and reproduces the double kick drums very well. I do agree though that ported boxes are much much louder with good sound quality as well depending on the tuning.
Here are some pics of the boxes and both the Avalance and Atlas: