ATC scm 19 vs ATC scm 20SL?

What is the differences of these monitors?
Wich is better...
Almost the entire line of ATC products has the same signature sound. As you move into the line, you get better integrated bass, better dynamics and transients, and better build in the cones and cabinets. But unlike most brands, these have a very similar sonic footprint around being very precise and uncolored, and truly, there are subtle improvements through the line. They are both inefficient speakers and require heavy duty amps to drive them. Tubes are not a consideration. The 19s are different than the 20s in that they appear to break in faster. The 20s take at least 800 to 1000 solid hours to burn in; the 19s about 500. Both throw a wide soundstage and play a wide variety of genres well. If space or room dimensions are limited, I would go down a level and look at the 16As.
One of the major difference b/t the 19 and the 20 is the tweeter. The older 20s uses a vifa tweeter and the newer 20s uses a seas tweeter. Both EXTREMELY revealing and very smooth, with the seas having a bit more detail (very hard to hear a difference, but better specs are better specs)...same goes for the non-SL vs the SL spec-ed 20s. I can't hear a difference really...but that is probably because I never hear it in the same room, and I always ask to demo them on tube-preamps.

The 19 uses ATC inhouse tweeter and are more meant towards home usage. ATC tame down the speaker so that the average recording sound a bit easier on the ear...although they are still very unforgiving.

The SCM20 and SCM20SL to the SCM50, SCM100 were meant for pro use. The ATC SCM40, SCM35, SCM19, SCM11, and SCM7 are meant for home use. Although they both carry the signature sound, they are quite different. If you are used to the "pro" sound you may think that the Entry Series may lack something. I tried going to the Entry series, but the sound is not as detailed nor is the speaker as transparent to source change. This does not mean the Entry series is not as good. Both series are like intensive X-Ray machines, its just that the Pro will do the full X-ray and has a zoom-in feature if you know what I mean.

But those are still very minor critiques. Both Pro and Entry level are great speakers. The entry level will trump most speaker if you are looking for the most uncolor speaker you can find.

Just remember to power them correctly if not, the ATC will be the most ugly sounding speaker ever. You will hate them. Also take into account that most of your recordings are will be unbearable to listen to, even with great electronics. They will spit out what is fed. If you look at my system, I used 2 huge monoblock class A amps to power them. However, I opted for a tube preamp because 75% of my music collection are not perfect recordings.

If you want the most extreme of the extreme, you can always opt for an all byston setup with the ATC. Then you have a system that is so precise it can surgically remove the music bit by bit.

whew..hope that wasn't too much info.
I think BongoB and Kinn got most of it covered. The 19 uses the same SL woofer/midrange driver so apart from a slight difference from the better tweeter extension (2.8Khz and up) they should sound pretty much the same. I have not opened a 19 up so I am not sure if they use the same good quality supersound polyproplene caps and air core inductors in their older models but I expect they do.

Judging by looks of the cabinet it has been engineered/designed to be mass produced at lower labor cost compared to the intricate work on the SCM 20SL. The 19 can be used without grills due to the rounded edges. The standard domestic 20SL needs grills installed to help reduce edge diffraction.

Since the SCM19 is cheaper i'd say it is better value but apart from that you are talking about substantially the same speaker.
Any comments on the sound of the SCM16A with a good tube preamp (say one using PX4 & 6NS7 tubes? Thanks!
There are revealing speakers and there are revealing speakers. I find ATC to belong to the second category, wherein they not only reveal the weaknesses of a system or recording but also equally honestly reveal the strengths/goodness of the whole chain + recording. Hence to me it sounds like a very straightforward honest guy who is always willing to entertain with the right mixture of good and evil. If a tube preamp is required in a chain it is simply because

1. The tube preamp is adding more honesty to the system than the SS preamp in contention.

2. The rest of the chain is not honest enough in bringing out the beauty of the music hence needs help.

3. The system might be great but the room may not be good so instead of treating the room one opts for a softer sounding preamp.

Since a truly neutral system will do justice to all kinds of recording I would rather believe most SS preamps are on the drier side of the neutral.
Will reflect the sonic signature, so it will color your music with a warm tubey glow. I can recommend their pre-amp or a Benchmark DAC1.
OK, thanks. What about the sonics of the SCM16A in general (especially vocals)? I am thinking of moving (up?) from a pair of Quad 12L actives.

I have seen no info in the forums on these here in Audiogon or some other popular sites. (I'm kind of surprised at that.)

There are few choices in high-end small/medium active speakers it seems to me.

The Quads are nice and listenable, but they don't really have a sense of palpable images that I usually look for in high end speakers (thought they are new & not really run in yet...)

Thank you.
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I've never heard an ATC (but would love to someday).

Bob it is true that diminishing returns are reached quickly in small active monitors (much quicker than passives). Veneer and good looks do add significantly to the cost and these are real cost factors not markup - although they do nothing to improve the sound. Provided one accepts a near field position and does not demand realistic live SPL then the choices multiply.

The big ATC's are kind of mind blowing but they also suffer from diminishing returns because the SCM20 is already very good (even the passive version). It is a matter of degree - the smaller speakers simply cannot do large orchestra or big band with quote the same aplomb - so they are not quite "you are there" - the dynamics from percussion is not quite what you get from a real drum set. The larger ATC speakers get you all the way there (a point where you simply cannot imagine better other than a live band or just a slightly different but equally good presentation) - but the extra cost is almost certainly into diminishing returns.
All ATCs sound excellent on vocals. In fact in a blind test based just on vocals, it can be extremely difficult to differentiate between two ATCs. I have heard even their smallest SCM7 and even those had a very similar lifelike palpable vocal like my SCM40. Unlike many other brands all ATC speakers sound very similar with similar strengths and (weaknesses ?).
Agree with the last two postings. ATC speakers are somewhat unique in that they are very neutral and unforgiving, qualities that professional sound engineers value. I have owned many versions of this speaker, all the way up to the 150s. I presently own the 16as at work and for the money, I think they outperform most speakers in the price range, and along with the 11s and 19s, represent the best consumer oriented speakers. I buy mine from their pro distributor in Las Vegas. They are bombproof in build quality. They are made for audio bays/worker cubes, and remember, most tracks are mixed down around the vocals. To Pani's point, you can easily distinguish them in a honest fashion, and from a engineer POV, where they are fusing together different takes to make a holistic song.
The only other speaker I have heard that match the ATCs are the new Sony speakers that grace the cover of the new Stereophile Magazine. Heard them at the T.H.E.Show in Newport two weeks ago and they were jaw-dropping beautiful, driven by Nelson Pass electronics. They are 27 thousand, a little bit shy of the price of 50s and 150s, but a beautifully smooth cross-over and very dynamic.
Another thread (on the SCM19) I read called ATC ruthlessly revealing, but some larger ones I heard some years back did not sound that way (just musical but clear and even silky but with impact).
So are they revealing with piercing highs or (as a former Wilson WP owner) Wilson scratchy vocals, with "accuracy" in the ear-bleeding sense?

Again, I am looking at the smaller active ones, like the scm16a or similar.

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IMHO, it is the the extended bass (down to 40 Hz) that you get with the bigger models. A large woofer will pressure up the room. It may be something we not only hear but feel. In any case you can definitely achieve similar results with a sub and smaller monitors. And yes a subwoofer has a ridiculously difficult task. Finding a sub that is powerful enough to play as low as 25 Hz with 115 db SPL and very little distortion or heavy compression is as rare as a needle in a haystack (ATC make one but it costs nearly 10 grand). Nearly all subs start to distort/compress at about 105 db SPL at 20 Hz (yes - I am even referring to the big big expensive ones)
Hi Folks
Just to add to this thread, I have recently purchased the ATC SCM19's after about 5 weeks of research as there was no dealer in my city up here in the Great White North. I can assure you that they do indeed have the SL(Super Linear) driver assembly and they are built like cinder blocks!!. I am running my particular pair through a Wyred4Sound ST500 Amplifier (250w rms @ 8 ohms) with great results. The bass from these speakers is really something else. I had a pair of totem hawks before I purchased the SCM19's and quite frankly the Hawks fall short in both performance and bass compared to these ATC SCM19's. Awesome speakers for the price,true sound with a great sound stage. Any other questions people may have before purchasing these let me know I will try and answer as much as possible,Thanks.
With ATC its a simple to understand their line up. There are passive 2 ways and three ways; there are active versions of some of the 2 ways and all of the three ways.

The three ways add ATC's proprietary mid dome, now copied by a lot of others, dropping midrange distortion by a LOT. This is what makes them so popular in recording studios. With the three ways, you choose how loud you want them to play and how low you want them to go (woofer size). Other the bottom end, all the three ways sound very very similar to each other, enough so that you can use larger ones in front and smaller ones in back in the typical multichannel 5.1 or more rig. Pink Floyd Dark Side 5.1 was mixed like this by James Guthrie, with 150s in front (15 inch 3 way) and 50's on rear (9 inch three way).

I own an ATC SCM20 SL since 1992. It is the oldest piece in my chain. I had a love-hate relationship, but I am glad I kept them. While they provide a rather dark, mid-hall sound, they brutally reveal any weakness in the chain. They are especially sensitive to any sibilance and "digitits".
I modded them heavily, with all Duelund crossover components, ring radiator tweeter and C37 lacquer. They are unique in combining intimacy with force. The Quad ESL63 had a similar "intimacy", while seriously lacking force.
I am happy now, driving them with Nuforce 9V3 SE, Metrum Octave dac, Audiophilleo2 and ASI liveline cables.
My dream amps would be Spectrals though...
How can you do a driver swap without destroying how they were originally voiced? I don't want to sound too critical as I have done this very same thing with 1985 vintage ProAc's. The tweeter replacement was from the Response series (i.e. one silk dome for another).
@ Linkster
The two tweeters (Vifa D27TG and Scan Speak D2905/9700) share the heritage, and the impedance curves are almost the same. So it was a drop-in, besides adjusting for the slightly different sensitivity. This was also confirmed by a professional who designes Xovers for loudspeakers. I was never very impressed by the sound of the original, cheap Vifa tweeter, and I never regretted the exchange. ATC seems to have recognized the weakness of the original Vifa tweeter as well, as newer models use a much better Seas tweeter.