Dynaudio c1 vs dynaudio c4

I have a dynaudio c1 confidence the c4 is better?, my room hace 3,5 x 6 mts, mcintosh 601 amplifiers and ayon cd5s cdplayer
Yes the C4 is a much better speaker in my opinion. That being said your room will make or break how well they will sound. I too have C1's and considered upgrading to C2's. My room is 3m X 8m. Unfortunately I can only have the speakers on the 8m wall. I had an in-home demo and the C2's sounded really good but because of the nearfield listening I heard a 'wall' of sound coming at me even with the C2's against the wall. Soundstage was great but the imaging suffered compared to the C1's. Your room in my opinion is boarder line depending how far your listening position is. Hopefully A'Gon member Stricken will chime in. He is a Dynaudio expert.

By the way the new MKII is the way to go. As with all the Confidence line the more you turn up the volume the better they sound. With the MKII/Signature they sound great at all volumes. I did upgrade from the original C1 to the Mocha Signatures.
C4 needs large listening area ,otherwise you can hear messy bass and punch from rear wall or listen at very low low volume in order to avoid it
3,5x6 m, well.... to small for c4.
I recently upgraded from the C2's to the C4's and can say although they are certainly a step up from the C2's, the C2's have an openness and sweetness that i have only heard from the c4's on occasions. I’m hoping that the c4's just need a few more hours on them and I’m working on some room treatments to help. They do need to be well away from the back wall so I would tend to agree with jkuc, 3.5x6m is way too small for C4's.
My C-4 signatures sounded awful till they ran in awhile, and I do mean strange and awful. Beaming midrange and just plain weird. Not so after many, many hours. It seem high-end drivers just aren't themselves till you run them in awhile. I'd wait awhile before I decided the speaker sound like "this" or "that".

My room is pretty large; 39 feet long, 13 feet wide and with a 9 foot ceiling. The C4's sit in the "long section" of an L-shaped room. The left speaker is open to the "L", the right speaker is to a wall. I set the speakers 4 feet from the back wall, and three feet from the right side wall. The left speaker is, as I said, open to the "L".

These speakers have crazy good detail and debth of the imaging field between, and behind, the speakers. Sonic placement is pint-point stable and open with the right pre-amp. The XP-10 I use is very good at detail. My RLD-1 platinum gives away some of that open and deep presentation for a super smooth almost tube-like presentation. The sound stage is more forward, the imaging is larger but with less detail and a shallower front to back debth. Still, the sound is addictive. For a SS unit, the RDL-1 is a very nice and smooth sounding pre-amp.

That the C4's can sound so different on each preamp says in-home listening will be required to select the right speakers / electronics at this level.

I have two modestly capable pre-amps and amazingly good ODYSSEY KISMET mono amps. So, I'm in a listen and decide mode on my final amp and pre-amp.