Spatial M3 Sapphire or Klipsch Forte 4

It’s mostly the amp. I too have OBs, in my case Emerald Physics 3.4s (concentric 1" polyester in a 12" woofer) and my room is ~ 35 x 20 x 12’ peak in an open beam ceiling. Front wall is ~ 80% glass and rear wall is 100% glass. A tough room to get thumped in. I tried using 2 SVS barrel powered subs, which I bought new 10+ years ago. In those days they were focused on HT, and these sucked for 2 channel. I sold them about 2 months ago, and my musical enjoyment is the better for it, but, no deep bass, and missing a bit of the muscular musical scale. By far the 2 biggest changes I made were replacing my EVS 1200 class D 600/1200 wpc dual mono amp with a LSA Voyager 350 GaN amp. And although the V has ~ half the EVS’ power it is actually a lot more room filling. The other addition, which significantly improved low end (as well as the rest of the spectrum), was replacing a Marantz HD CD-1 that I used as a transport with a dedicated transport- Audiolab CDT 6000.

I still want what good subs can bring, but the cost to do it right is elusive to my retired SS budget. HTH

I own the M3 Sapphires and use them in a 13X20X6.5’ dedicated basement listening room. I used to use two subs with my previous speakers (towers, bookshelf, Maggies) but moved them out when I got the Spatials. I use a 30W Class A amp (Pass Labs XA30.5) and I’ve never seen it leave Class A. I listen at 80 db avg. with 85db peaks (A Weighted). Lots of good comments on pairing the Spatials with LTA tube amps.

I love the dynamics of the Spatials and don’t feel they are missing any slam, nor do they overload the room! Honestly, they are amazingly refined speakers. The detail and texture in the bass is extraordinary. I have no Klipsch experience but I suspect they are VERY different in their presentation.

If you want efficiency, then Klipsch is at the top of the list. You can't go wrong with around 100db Cornwall's with a tube amp. They play low volume full bodied music or blow your roof off rock & roll with ease. Forte's and Heresy are basically mini-me Cornwall's and do the job just as well.

BUT

Spatial Audio Sapphire M3 open baffle is the reason you buy a two channel Macintosh integrated amp at 100wpc (AKA MA5200/MA5300) or the top contender according to you, hook up the speakers, and end your quest for the holy grail of audio sound so you can finally think about other things you want to do in life!.

Do you own the Spatial M 3 sapphires ?

I have owned Cornwall 2 and forte 3 before. Cornwall’s are too big. The forte’s I liked, but thought they could have been more refined. I haven’t heard the Spatials, but could buy either used, and re-sell if they don’t work. If the Spatials can work with 8 watts, I should be OK. I also have a music reference em 200 that pushes 100 watts. 

i owned m3 sapphires for a time, i would say they will not work properly with 8 wpc tube amps... the 4x 15 in passive woofers need pretty decent amp damping factor to control the bass output - i tried my cary 300b se-i on them and i felt the bass lost most of the tone and definition that can be heard when driven by, say, a good solid state amp like a hegel or exposure amp

that said, the treble and upper midrange can be somewhat biting on the sapphires, i can see how many would opt for tubes to improve the musicality in those frequency bands... as always, all speakers make and impose certain tradeoffs, up to the owner to choose the flavor they can live with best