Subwoofer Choice

I am in the process of building out my system. I have the end goal in mind, and ticking off the equipment as I get them. I do need some advice in the subwoofer category.

I am currently driving Monitor Audio Silver 500s with a Michi X5 integrated amp (600w @ 4Ohms RMS). This is way overkill for these speakers. But my purchase (coming in August) will be the Focal Sopra No. 3s.

That being said, I am looking also to add a subwoofer and I’ve settled between two (2) REL T/9x’s or one (1) REL S/510. T/9X is $1,249 vs S/510 at $2,749.

There is a REL youtube video from their chief designer comparing (briefly) the two and actually stating that "just because one S/510 costs twice as much as 2 T/9x don’t think you can equate them with 2 vs 1". I paraphrased a bit.

But the below is only 3min long please watch and let me know!

What are your thoughts. Obviously 2 subs are better balanced than 1, I get that. But given the specs here am I better at buying up for the better 10"?

Listening room is carpet, 16’ x 24’. 384sqft. 8ft ceilings. What info did I leave out?




Great post, pinthrift. Looking forward to your impressions. I bet it’s going to be fantastic.




I put together a system for my daughter that has the Monitor Audio Gold 50 and Rel  Tx9.  They mated well together


it does not look like the Michi will support the CR-1 crossover. You would need an amp input. Does the michi have bass management built in? Looks like it has a sub out. 

Just guts feeling: size matters. Even if 2x xx diameter might have the same surface area (or moved air volume) than 1x yy (or to show my point, 20x 5 inch woofers same as (haven't done the math) 1x 18" woofer), I just don't think a bunch of 5" can naturally produce the 50 Hz and below (down to 20) that an 18" can. Therefor IMO, 1 big is better than 2 small.  

This is coming from years of listening to towers with sidefiring 10", plus 2 active 12". Then I got my first REAL SUB (in a humongous vented box, driven by an ICE sub amp), and the world changed. I ran the towers as 'small' speakers in my 5.1 system, and now the tiny (5x80W) receiver sounded SO much better. 

I am now using an 18" in a sealed 4.5ft3 enclosure, driven by the same B&O ICE design amp. Just LOVE it. Once you heard real SUB (the stuff "down there") there is no going back. My Nautilus 804 are said to have great lows. And they do. But so much better if aided by the 18 incher.