REL Subwoofer to match monitor speakers similar to Raidho X-1s?

Thanks @b_limo.  The good news is that I did hear back from REL finally.  Regarding matching with my speakers, part of the problem is I really cannot get any info on the Eben X-Streames in terms of their specs.  I just know they are like the Raidhos.  

I’m dubious about the need or benefit of multiple woofers, unless you need the floor to bounce, and like banging your head. I had a friend who’s method of evaluating a speaker was to turn the bass up to 11, and the volume up to twice that. He drove me to 11 when he pulled it on my setup.

I have an SVS SB-3000, now ain my multi-media room, and the REL, mentioned above, very recently acquired. SVS advises keeping the settings such that you can’t spatially locate the sub with your ears. I like that advice. Still, head-jarring volumes are possible if it’s your thing. The REL to my ears has a very desirable, more subtle quality about its bass by nature. I haven’t been able to replicate the "boom" with the REL. I’m ok with that.

You’ll have to experience both yourself, I’m not too sorry to say. Have fun, and Best Wishes.

The need for a full range speaker is simply not true. I have a pair of T/9x’s paired with Harbeth 30.2 XDs, stand mounts, rated at 50Hz – 20kHz. They work great! The difference in cost between the 7’s and 9’s isn’t that much, BUT I strongly recommend a stereo pair of RELs. EDIT: Assuming you are mostly interested in stereo audio. 1 is fine if surround sound is the primary application.

You can dial in the crossover to integrate with the main speakers frequency range, whatever that is. The X1’s are rated at 80 Hz – 50 KHz so maybe yours are close?