Keith, you must first understand what mixing entails. Currently you think it is the same as listening to speakers in a lounge room for fun.

I already understand what you are saying. I have a pretty expensive and enjoyable hifi system.

But, how much does off axis response impact things in an acoustically treated room sitting 75cm away from my monitors in super nearfield arrangement?

At that distance the distance between transducers (to create a point source), the phase response and the transient response are more important in my experience than off axis frequency response.

Seeing as ATC is still a custom speaker maker, you can still order anything you want if you talk to them and they think it's possible. Only problem with this idea is they don't make an SL woofer of the right size.

When I was looking at the 25 and wanted a vertical oriented speaker, I talked to them about possibilities. And there were custom possibilities. Very few companies in this market will do client requests like this but they've always done it. (I saw the other day a bipole/dipole ATC 20SL for sale that was obviously a custom order for someone -- still trying to figure out how only 1 was for sale; imagined it was part of a larger order for a theater setting)

I was puzzling over that listing the other day as well.

I've seen a custom center channel in an Atmos room. It was basically a long horizontal version of the 110 similar to the 45's but a bit longer and thinner. Pretty cool

That one isn't actually custom. That's the C6C (from the consumer line.) They've made that one for a long time.
https://atc.audio/hi-fi/loudspeakers/centers/c6c/

Nice. Yeah looks like the same one minus the wood. The one I saw was built into a Northwood room so it built into glass

Have been using atc20 asl for almost three months now, i'm still learning the the sound curve on them.

I used to work on 8040a,after i changed to the 20asl ,i found my mixing is larger and cleaner then ever,i think this is due to the reason that i have more accurate mix decision.

But on the other hand ,i found my mixing is sometimes did not trans well in the car speaker on the low end (when i turn the low boost all the way up),this does not happen when i mixed on the 8040,and sometimes i found my mixing also sound a little bit too bright .

Any one who has the same experience?

Yeah I can relate to that. The low end in particular. I’m fairly confident it’s exacerbated by my temporary (small) room. Everything else has been so much better that doing some additional checks on the low end feels like a small price to pay. Once I’m in my main room again I will assess whether I want subs or not. I remember the low end down there being much more prominent with the 20’s.

i have a very treated room,i am considering if i can add a sub to solve this ~

Does the SCM45a have the same tweeter as the SCM20ASL, or does the 45a have the same as the 25a?

Edit: Read specs on the ATC site and I see it’s the same as SCM20ASL.

AFAIK the 25 has an OEM tweeter, as opposed to 20, 45, 50, 100, 110 and 150 which have their own in house tweeter. We A/Bd the 25 and 150. The tweeter on the 150 had a bit more definition but the 25 was no slouch IMO. The family resemblance between the two was remarkable. I've become a shameless ATC fan boy...

Has anyone used ATC HTS On Wall series for Atmos mixing? It looks like ATC shows them as Hi Fi, where PMC considers the Ci series professional reference monitors, but the footprint for both brands are similar. I use ATC SCM45a monitors for stereo today and I love and prefer ATC. I like the flexibility of a thinner monitor that can be wall and ceiling mounted with a low profile for 7.1.4 or greater. Especially helpful if the room size is close to the Dolby spec for Atmos. If HTS are not a good choice for Atmos mixing I may consider PMC.

Re ATC HTS:
Whenever you boundary mount a speaker you get a significant boost in the bass, which damatically changes the acoustic footprint of the speaker. What was flat before suddenly sounds very different. It is very difficult to integrate such a bass boosted speaker with a properly stand mounted speaker that is built to be as flat. This is true regardless of brand, its just physics.

So ATC built HTS for home audio dealers, where this could be the only speaker used, such as a home theater. I have them myself in a home theater application. In this application, an all HTS system would have a unified footprint and the bass boost could be compensated for using EQ. This is an aceptable solution for home, as all the speakers would have a similar boost due to boundary mounting.

In a pro application, mixing HTS speakers as surround or ATMOS channels with 25s/45s/50s etc, does NOT work the same way. You have a relatively flat speaker (25s etc) being mixed with boundary boosted speakers; this would not be the recommended ATC way. You are mixing radically different footprints together making a unified sonic footprint almost impossible. If you are a room correction fan, even that cannot compensate for multiple different speaker/room response curves on these different channels.

So the answer is ATC does NOT recommend mixing HTS with pro speakers for ATMOS or any other multichannel application.

ATC does make a SCM 12i, an installable speaker (with steel a steel reinforced cabinet and even drivers wire tied to that steel) to mount safely to a surface, ceiling or wall. We have been using this sucessfully on several ATMOS rigs, such as Ryans Ulyate's [Tom Petty] 7.1.4 system using 7x50A's on the floor, 4xSCM 12i's driven by 2xP1's overhead. This has a smooth integrated sonic footprint that sounds very unified. Now the mix decisions you make are not influenced by very different channel [speaker] sonic footprints. ATC also makles flyable versions of many monitors, these have pull tested mounting points so they are safe providing the way you fly them is safe. Typcially a flyable speaker would be integrated into a room using a rigging expert to make sure its properly installed, properly secured. Why flyable, there are always at least 3 flypoints, sides and then tieback.

There is more installable speakers coming, but ATC is obsessed with safety, making sure that anything mounted overhead can be secured and will not fall under any number of conditions (ie. earthquakes are a legit concern in LA ). I've seen improperly mounted speakers fall and trust me, you dont want that. I've seen installers use MI speakers with particle flakeboard cabinets mounted overhead using giant screw eye bolts. So dangerous!

Im glad you asked that question as it does come up from time to time.

Brad

Hi Brad, thanks for your input. I understand your point about HTS. I may not have been clear as I was not planning to mix HTS and SCM45a. But rather use the SCM45a for stereo only, and separate from that, consider HTS + Sub for only Atmos mixing. Still may not be the right approach, but though it would be good to clarify anyway. Ideally I am trying to budget to expand my SCM45a setup and use SCM20ASL for center, sides, rear, and SCM 12i for ceiling. Again, thanks for all of your knowledge and input!

I can imagine the ATC offices when Blackbird C decided to hang a bunch of SCM100's from 20 feet up

I believe those were specially reinforced. (I also think ATC's Ben Lilly came for that setup/event too)
A friend here in LA had a studio built where all the ATC 45A top speakers were structurally reinforced for hanging (ATMOS room) at the factory.

I believe British Grove's rear surrounds are also specially built (300ASL and 150ASL) for the rotation track mounting they are attached to.

Been thinking about this a lot and I prefer the SCM20 to the SCM45 (similar speaker to the SCM25).

The SL mid/bass driver in the 20s is crystal clear and super tight in the low-mid range, while also providing plenty of detail in the mids. I feel like the SL driver is preferable to the soft mid dome if you can only choose one.

SCM20 was also a lot easier to integrate into my spaces. I think I would try SCM20 with multiple subwoofers in the future.

Keep in mind the above are observations made it project studios - not high-end acoustician designed studio spaces.

SCM25a is in its own category and does not use the same tweeter as the SCM45a, 50ASL, etc..

I own a pair of SCM45a and SCM20ASL. Both are incredible. The 20ASL paired with the new ATC SCS70 12" is my new favorite near field setup.

Ah, so you own the new SCS70 already? Would you mind giving a comparison of the two setups?

I have the 12is as Atmos height speakers. They are heavy – 15kg each (heavier than the regular SCM12) – and they definitely need to be installed by someone who knows what they're doing. I needed to remove one yesterday to send for repair and it was not trivial.

If I was doing it again, for my size room, I would think about the hi-fi SCM7s as heights, presuming they could be adapted to ceiling mounting. They are smaller and less obtrusive and you can get them in white But, obviously, the ideal is identical speakers all around equidistant from your ears.

The SCM7 and SCM12 can be very hard to tell apart sonically when I’ve done comparisons.

Scm7 s are hi if speakers and are not installable. What makes the 12i a proper install speaker is the steel reinforced box to protect the people who sit below it. Having worked for manufacturers building live sound boxes, a heavy speaker improperly installed can be a dangerous thing. Brad

Mmmmmm just saw the new ATC SCS70... they do a flush mounted version too.

Wow those SCM 70 are so cheap... I guess in 6 years I could have the money

Inexpensive compared to the mains. These are not domestic appliances more like scientific instruments. Even the SCM20A is £4k+ in UK.

yes it took many years to get a pair of my ATC SCM20 ASL and sold all my other monitors to afford them...

I wished the stock market would rise up again and maybe I can afford the subwoofer some day. Because under 100 Hz there is not so much information: I always use my Headphones for the bass territory. It is not a big issue but having a better presentation of the kick would be very nice.

I picked up a pair of Rythmik 15" sealed subs. So far, so good! The pair are half of the price of the SCS70.

No doubt the ATC sub is better, but in my limited use the Rythmiks are hard to fault. They integrate fairly seamlessly with my 45s, are fast, and go LOW/LOUD.

I keep going back and forth between dual cheaper alternatives and something like a single ATC SCS70. I know for monitors, the upgrade to the high end was well worth it. For some reason I'm less clear on how much of a difference more $$ makes when it comes to subwoofers. Like, are subwoofer pros better than the equivalently sized Rhythmiks? And are the ATC's so much better than the subwoofer pros? Seems like most people make a commitment and the search ends there, whereas with mains people tend to try a lot of speakers so there are more anecdotal comparisons out there.

Anyone ever go through a bunch of different subs and hear the differences for themselves?

Scm7s are what I plan to hang in my setup.
I plan on adding a steel plate inside to prevent the enclosure from bending and possibly breaking but a 7kg it’s not extremely heavy.
If anyone has experience and tips in doing this i am all ears, i plan on foing this in 2 weeks.

I will have 5 scm12 pros and a pair of scm11s on the floor.

Regarding subs i have the dynaudio 18s that works superbly with the scm12s for stereo. I will put something bigger for the atmos.

Are you using a single SCS70 with the pair of SCM20asl, or two of them? How much am I sacrificing going with a 2.1 over a 2.2 setup in this case?