ATC active vs. passive

Another variable to consider is in the active option, is it using DSP or using analog xovers?  You can have active but without DSP.

If using DSP, I am assuming the speakers take the digital signal directly from the cd player, perform DSP, then using an internal DAC to convert it back to analog before feeding it to the internal amp.  

For example, if you have a 3way speakers, you will need 6 DAC, three for each channel, which won't be cheap.

I bought ATC scm40 and powering them with luxman 595, MASTERSOUND 845 and Grandinote Shainai integrated amp. 
I like the tonality and happy with low end. However, the tweeter is inferior to my Triangle Magellans. I’m still interested in ATC 50 and 150, hoping the tweeter is a big upgrade from the 40. 
if I get the 150, I probably won’t have enough to upgrade my amp for a while. Hopefully luxman 595 is enough. 

OP,

Your thoughts on the larger ATCs are justified. I can still recollect the boogie factor on the large ATCs. They were playing Daft Punk’s Loose Yourself to Dance. It was late evening and I was tired. But still felt like dancing! Stayed back in the room till the song finished. Go for it, if you can. You can get a powerful amp later. I believe they were using some Audionet amplifiers, if I am not mistaken. But a memorable experience.

@ei001h 

Do your SCM 40s have tweeters that sat "ATC" engaged right in the metal flange around them?  If it doesn't, these are the older SEAS tweeters used in the SCM40 Mk1's , while the newer SCM 40 Mk2's use the ATC hand made tweeter introduced in 2017-2018 or so. Now ATC is using only their own tweeter in everything

Brad.       

I have the scm40 MK2 version. Still lacking to my ears compared to Triangle Magellan. I know ATC SCM50 and above have a superior tweeter just not sure how much of an upgrade it will be.