Depending on how you look at it... either their argument is self defeating or it makes perfect sense...
If you really like exactly the way your main speakers sound...
Then you don't want to mess with it by adding things like filters...
But, if that's really true, then you're also "messing with how your speakers sound" by using a sub...
THIS IS THE ARGUMENT FOR SETTING YOUR MAIN SPEAKERS TO LARGE AND NOT USING A SUB WITH STEREO MUSIC.
(And, if you look at it that way, and your main speakers do everything you want, then that makes perfect sense.)
But then their argument goes on to say...
"Obviously you aren't satisfied with the bass your speakers are capable of making or you wouldn't need a sub..."
"Therefore obviously yo DO need a sub..."
"And we all agree that a high-pass filter will have at least some effect on frequencies above the cutoff frequency you configure it to..."
"But our sub can add the low bass you want WITHOUT IN THE LEAST AFFECTING THE WAY YOUR SPEAKERS SOUND."
(That last part is the one that seems to need a bit of a reality check...)
And it is indeed true that any high-pass filter will have some effect on frequencies above its cutoff frequency.
But, since the low-pass filter feeding the sub isn't perfect either, the sub itself is also going to have some effect at those frequencies.
And, by eliminating half of the active crossover filter, you are sacrificing the otherwise precise control you could have over the transition.
And you're substituting the uncontrolled low-frequency roll off of your speakers for the controlled low-frequency roll off of the high pass filter.
And, to be fair, with some skill, and a bit of luck, you can probably match the low-pass filter on the sub to that pretty well.
(And you're also sacrificing another benefit of that high-pass filter - limiting the low frequency power being sent to your main speakers and their amps.)
As for WHY REL takes this stand...
I personally think that's pretty obvious...
REL makes really great subs...
But they're trying to claim that they've discovered the "holy grail of subwoofers"....
adding the super low frequencies your otherwise great speakers just can't reproduce - without affecting how they sound even a tiny little bit...
And, from what I've heard, when luck is with you, their solution does in fact work pretty well...
(But, no, I like their subs a lot... but I'll stick to a real bass management crossover.)
I own REL subs but I don't agree with the logic in this article. I think it flys in the face of accepted practice of segmenting speakers in Home Theater to their respective low end capabilities (e.g. Small Speeker settings). I also have had good success by inserting a High Pass fitler in front of my Magnepan LRS speakers. The gist of the Rel argument is they don't want to stomp on the toes of the original speaker designer's intent? Not trying to bash REL, just curioius why they have taken this stand?
What is a High Pass Filter and Why Doesn’t REL use Them?
