Originally Posted by Sickofthehype
I don't care for ported designs they usually have higher distortion than a good sealed design like a Velodyne DD series or a Martin Logan Descent or Depth. I think all ported designs will produce port noise at a certain volume level, some more than others. Can you point me to a white paper or controlled test that proves downward ports reduce noise ? If so great and forgive my ignorance. If not then it is just marketing hype.
This issue comes up almost every day. The difference is that sealed designs will roll off more gradually at the lowest frequencies, while a ported design will have a much sharper roll of below its tuning frequency.
As far as distortion, the Velo DD series has the servo mechanism that will hold both distortion and output down as the subs limits are approached.
Some ported subs have been designed with limiters to hold distortion down.
It's interesting to note that in the test by Tom Nousaine, the $15,000 sealed Velodyne DD-1812 put out only 0.1 db more output from 25-62Hz than the $1,600 Epik Conquest. Even more interesting the Conquest just murdered the $15,000 Velo DD-1812 from 25Hz down to 12.5 Hz. The Conquest put out 112.3 db at 25Hz vs. 107.6 db for the DD-1812, 109.3 db for the Conquest at 20Hz vs. 103.9 db for the DD-1812.
And for people who like pipe organ or the deepest effects on DVDs, the Conquest did 104.7 db @ 16Hz vs. 101.9 db for the DD-1812.
Last but not least, at 12.5 Hz the Conquest put out 103.9 db with only 3.4% distortion.
The Velodyne DD-18 could not reproduce 12.5 Hz at any level without exceeding 10% distortion.