The ATC SCM20ASL Pro is at the lower end of ATC’s Studio Monitor range, in terms of price and physical size, but make no mistake it’s pedigree is crystal clear from the moment you turn them on. That is to say, they provide the clarity and detail like no other speaker manufacturer. These are not speakers for the faint of heart, brutal honesty is in their DNA.
The ATC SCM20ASL Pro is designed for near field monitoring applications positioned close to the console in any size control room, but they are equally at home in full Dolby Atmos systems where they would form a truly world class monitoring system. At 23.5 kg each, you will need to secure them very well on stands or wall/ceiling brackets capable of this weight level.
These studio monitors are not simply passive monitors, these are a complete monitoring system that includes amplifiers and crossovers; active not passive crossovers so they do their job with little of the phasing errors of crossovers found in passive speakers. The amplification is perfectly designed for, and suited to the task at hand, providing a 50 watt MOSFET class A/B amplifier for the tweeter, and 200 watt MOSFET class A/B amplifier for the mid/bass driver. So rest assured there is no lack of power available.
The ATC SCM20 has been around for many years, but the latest iteration, the ATC SCM20ASL Pro is a much improved speaker with performance that I doubt can be had at anywhere near this price point. So what has changed exactly? For one, the original featured a VIFA tweeter, but the ATC SCM20ASL Pro now features a proprietary ATC 25mm S-Spec tweeter (SH25-76S), which is a product of ATCs painstaking research and a worthy match to their incredible mid/bass drivers…and it is superb! The mid/bass driver has been elevated to an ATC designed 150mm Super-Linear driver.
New S-Spec Tweeter
ATC takes a unique approach to tweeter design that sets it apart in the market. By integrating a secondary suspension component, the moving assembly is naturally confined to travel solely in the axial direction. This results in a design that effectively minimises rocking modes, ensuring lower distortion levels. The added stability from this method eliminates the necessity for ferro-fluid, typically used for cooling and damping. Consequently, the magnetic gap can be reduced, enabling ATC tweeters to not only perform at their best for longer periods but also enhance power handling compared to traditional designs.
While this distinctive tweeter topology delivers superior performance, the increased moving mass and overall complexity require meticulous alignment of all components. This necessitates manufacturing and assembly processes that demand exceptional care and precision—a level of expertise at which ATC excels.
The standard SH25-76 and its advanced ‘S’ spec tweeter as seen in the ATC SCM20ASL tackle these engineering challenges differently yet with equal success. The standard tweeter features a unique, lighter moving mass bracing component, whereas the ‘S’ spec driver boasts an exceptionally powerful motor assembly. When combined with the optimally stiff and lightweight coil former, it produces remarkably low levels of odd harmonic distortion and maintains a well-controlled extended frequency response beyond the limits of human hearing.
Super-Linear Technology
Since the inception of the moving coil loudspeaker, designers have sought ways to enhance the sonic performance of speaker systems. No company has prioritised this pursuit more than ATC, and the introduction of the Super Linear Magnetic System marks a significant breakthrough in overcoming a long-standing obstacle. The adverse effects of magnetic hysteresis have been recognised for years, but it is the convergence of timing, the availability of the right materials, and ATC’s engineering prowess that brings this technology into the realm of loudspeakers.
The magnetic properties of the steel used in the magnet assembly of a loudspeaker are inherently non-linear due to magnetic hysteresis. This non-linearity results in distortion of the input signal, introducing audible coloration to the sound.
ATC’s innovation in the form of the Super Linear Magnetic System involves adding rings of the SLMM to the magnet assembly pole and front plate, positioned adjacent to and concentric with the loudspeaker voice coil. These rings effectively reduce 3rd harmonic distortion by an impressive 10-15dB between 100Hz and 3KHz. The incorporation of the SLMM brings about a substantial enhancement in sound quality, reducing distortion to such an extent that it unveils an additional layer of information for the listener. Ambient sounds and subtle effects, previously obscured, become distinctly audible, creating a heightened sense of realism. The resultant improvement in the reproduction of human voice and piano unequivocally attests to the success of this technology.
How good are they?
If you want the short answer, amazingly good. The more detailed answer is that these monitors are so brutally honest, and in this context brutal honesty means extremely detailed, but do not mistake ‘detailed‘ for overly bright, no not with ATC. They are very ‘open’ sounding, providing space around every instrument in the mix, and provide real width and height to the music playing through them.
I will admit, the bottom end is not going to reach to the depths of the larger ATCs, but what it does provide is so powerful, tight and again, detailed. Those 200 watt amplifiers can deliver copious amounts of very clean power, and that Super-Linear mid/bass driver never shows any sign of straining. If you look at the construction of this 150 mm mid/bass driver, you will see the magnet structure is actually larger in diameter then the cone itself, which goes someway toward explaining the driver’s ability.
The one thing that surprises me perhaps the most, is the midrange capabilities of this system. The higher end ATC speakers are famous for the ATC midrange driver, that delivers insanely good midrange performance. It is a driver that has been imitated by many other companies, but never matched or beaten. Yet somehow, this two way monitor is seemingly able to do away with that midrange driver and still deliver brilliant midrange performance, proving that these speakers are more than the sum of their parts.
Conclusion
There have been many new companies producing ‘studio monitors‘ over the last decade, and every week there is another flavour of the month monitor that everyone is talking about. Quietly in the background ATC have continued down their chosen path of producing deadly accurate monitors for studio monitoring duties, with no gimmicks or marketing hype. For that reason, many will simply never even attempt to audition ATC, instead seeking out the latest ‘flavour of the month‘ monitor so that they can then jump on some forum page to talk about their latest purchase, and be praised for their brave and wise choice.
But for those of us who favour being able to mix with the knowledge that you will get better mixes, and that what you mix will translate to ANY speaker system you care to play your mix on, then ATC studio monitors are what you want. I urge you to go and audition these monitors, they are extraordinary, and I think, a bargain at AUD$9,965. Don’t expect these to playback your favourite album that has been poorly mixed/produced and make it sound better, that is not what these are about, but they will show just how bad, or good the mix is and that is what a mix engineer should ultimately want.
I believe nothing gets even close to what these speakers can deliver and yes I have tried other monitors, many of them over the years including PMC, Neumann, Tannoy and these ATC’s are simply in another league. Make no mistake, you cannot simply play your music through these and expect it to sound good, they require you to mix better as they do not candy coat the sound in any way, as a sub-standard monitor will do, or a home stereo system will do. Simply put, if you want the best, to be the best, then buy these monitors. I make no apologies for the 100% score below, they easily deserve it!
