I have my passive SCM40s some 80cm from the back wall and about 60cm from the side wall (Or bookshelf, as it is). I find it works well. I started out with them a bit closer to the back wall, but the placement looks more right now, and I can’t say either sounds better or worse. Both worked well.
regards
TBH I don’t think the 40’s need a Sub , they sound great with movies here . When I was considering 40 or 50 I spoke to ATC who said its always best to get the model that suits your room , as ever . I have space so it was a toss up that the 40’s won , the price difference did come into account as I bought them after major renovations that went over budget … Very happy with my choice as they fit in perfectly but I do cast an admiring glance at the 50 from time to time .
Thanks Porphyr I’ll be around the same distance I had to be careful when home demoing them loading the room too much. Compared to the spendor D7.2 which were extremely good they loaded the room way too much. The Atc were just right Proac were too bass heavy atc scm 19 again superb staging and clarity but slight lack of bass extension
Totally agree, unless your a real bass head sub not required, 50 are so tempting I have the budget but not the house….
How big is your space? I wouldn’t say that 50’s are that much more difficult to position in room than 40’s. Both of them wake up room modes if that’s the case (at least actives).
Btw. I had PMC 20.23 also before I got 40’s back in 2014. PMC clearly lost that battle.
Cool apartments in Netflix bordertown though, if you’ve seen it😀
It’s a garage conversion with vaulted ceilings so long and narrow irregular shaped and extreme insulation, hence no bass boom, my dealer felt scm50 might overdrive, I think they may be a tight fit, but hey it’s my man cave 
I’ve demoed ndx2 282 hicap, recently which shows how much more more is possible, but I struggle to make my mind up on these kind of things, I’m not a go for it person……
PS love Scandinavia, I worked for Ericsson in UK and was fortunate to get contract to work in Stockholm (1989/90) we did visit Finland, well to the extent we took the booze cruise to Turku, Scandinavianapartmentments knock uk into touch, In December -23c we could wear shorts and t shirts in Stockholm no way we could do that in uk😀
It sounds like 50’s wouldn’t be a bad fit at all. If the space sucks bass (sorry if I misunderstood the part about the insulation), then there shouldn’t be a problem at all. 50’s don’t play bass any louder than 40’s, they just go 10hz lower and sound bigger. Even the bigger models like 100 or 150 aren’t ”bass monsters”.
Haha the booze cruise, that’s a thing in Finland. I’ve done dozens 
Yes you’re correct the garage conversion sucks excess bass.
Ps
Yes a few of the Finns we met in Stockholm city centre on the weekend tended to be very happy very expensive to be “merry” in Stockholm though"……
Hi Patu,
I’m pretty much in that situation at the moment, and looking at a HiCap DR (As a first step towards a NAC282 and a suitable poweramp). How would you describe the HiCap influence on the SN2 with SCM40s?
I take it that the SN2 won’t get more power per se, but the HiCap somewhat offloads the poweramp part in the SN2, as it feeds the preamp part. But does that really mean more power ready for the poweramp section and the SCM40s? (I also miss the information from Naim about transient power in VA for the SN2, where as a NAP250 has stated 400VA of transient power.)
regards
I actually always used SN2 with HCDR, I had the extra power already with SN1. When SN2 was released and I upgraded to it, I just plugged HCDR in straight away. One time my dealer told me he sometimes preferred SN2 without HCDR so I decided to try this at home with 40’s and it didn’t go well. I had listened the combo with HCDR for years, now after I removed it from the mix, sound got loose and lost much focus and grip. I can imagine this could work with sensitive speakers which might have slightly sharper signature sound but definitely not with 40’s. HCDR really is a significant upgrade for SN2 and probably 3 also.
I moved straight to the actives when I changed my system a couple of years ago, but I did audition the passives at my dealer’s. I tried them with my then 250 DR and felt this was the minimum I would want to use, at least as a long term setup. The thing about ATC speakers is that they are not especially inefficient and are designed to be pretty easy to drive, but they are extremely revealing. It’s what I love about them, although it puts others off. So any investment in source, preamp or power amp will be well rewarded. There is at least one poster and equipment reviewer here who runs them with 282/250DR and seems very happy with what they are delivering.
Roger
Btw. New Naim Uniti Atom Headphone Edition would be tempting to try out as a dac-preamp to active speakers. Uncommon to Naim gear, it has balanced xlr-output which makes connecting it to active speakers easy. I read some review where they mentioned that the preamp section of Atom HE is very competitive.
There was a post from someone from Naim on one of the Atom HE threads (sorry forgotten which) who tried the Atom with active SCM 50s and reported back very positively. I think there is hope from some forum members that a higher level version might appear soon, possibly with the option to add a PS.
Roger
I recently demoed them with that combination plus ndx2 as a potential upgrade to nac 272 very impressive, I think it is JonathanG who has that system and is/was a hifi journalist
Thanks. Yes, it feels like these are speakers that readily will follow a fair bit up the “ladder”. I’m happy with the setup at the moment, so I don’t feel I have to rush it. Might even go for a better streamer/DAC as the first step.
regards
Thanks! I can feel that HiCap DR is going to be in my system in a not too distant future. 
Very interesting comments on Active v Passive ATC 40s - has an SN3 got ‘enough’ to drive the passive version? In this particular space I think passive will be more than enough, but I have run into problems with under-driven speakers before.
I can’t really say if a SN2 or 3 is enough. I did not try the SCM40s with more powerful amplifiers.
What I hear is clearly better than my former speakers. (Audiovector K3 signature) which were more sensitive and easy to drive, so for me the SN2 with the SCM40s is an improvement anyway.
What would be the more obvious signs of speakers being underdriven?
Helpful, thanks.
A marked lack of bass at low volume was my key experience using a Nait 3 with my current speakers. On certain tracks, higher volume was unpleasant, as the amp was close to its limit. Chatting with a few dealers recently has confirmed my suspicions that my B&Ws should never have been paired with such a small amp.