The first time I heard a REL sub it was paired with the Magnepan 3.7 speaker. The combination was seamless. The REL sub was the now discontinued Gibraltar G2, I immediately knew I had to have one. Besides being super fast the Gibraltar has a remote and a digital display. Since recordings have bass levels all over the place the remote was very handy. The double bass on some early jazz recordings is almost invisible but a few adjustments of the crossover and volume while remaining seated can make the ensemble whole again without adding bloated bass. The levels can easily and quickly be returned to your defaults using the digital display. Modern pop and electronica has the opposite problem with unnaturally loud bass with is easily tamed with the remote.
The REL with the Maggies crossover was usually set to 40Hz and it disappeared. My REL Gibraltar G2 crossover is set at between 28Hz - 32Hz depending on my mood, the Salk HT2-TL go down to 34HZ and most of the time I can't tell the sub is on unless the recording has deep bass. A good sub will also add space and depth to the recording, it's not always about bass.
I also use the sub for home theater so it is important for me to have a sub with a LFE input.
As you research subs make sure they go low enough with full power. A sub that only goes down to 30 Hz would be very hard to integrate.
I have never heard a SVS sub but in reviews they come out 2nd when compared to REL. A couple of friends have dual Rythmik subs and they are very good, I still like my REL better. It could be the room.
