March 2007

The Nearfield
Little Boxes and Big Wires

Article By Steven Stone
Click here to e-mail reviewer

ATC SCM7 Passive Speakers
The ATC speaker company are know for their active powered monitors, but they also make speakers sans electronics. The SCM7 is just such a passive desktop monitor. At $1200 a pair it's ATC's least expensive speaker, but it is certainly not cheap. Regardless of its price, for desktop nearfield use it may be all the speaker that anyone, regardless of their audiophile expectations or pocketbook, will ever need.

ATC made an earlier version of the SCM7 that sported a larger, boxier enclosure. Forget that. This new SCM7 speaker has been totally redesigned. It has a neodymium magnet soft-dome tweeter with a precision wave-guide enclosure, 125mm mid/bass driver with a soft-dome cap, a hand-wound flat-wire coil, 3 Kg optimized motor assembly, and a newly designed crossover that has a flat "easy-to-drive" impedance curve that produces a nominal impedance of 8 ohms. But with a sensitivity of only 84 dB at 1 watt the SCM7 still needs an amplifier with some backbone to drive it to its rock and roll maximum level of 103dB. The SCM7's 300mm by 160mm by 230mm sealed enclosure delivers a measured bass extension of 60Hz (down a whopping -6dB), so using a subwoofer is recommended and de rigueur.

Although the ATC speakers have shielded drivers, if you own a CRT monitor you will have to spend a lot of time and effort placing the speakers so they don't affect its color purity. I found that canting the drivers, even when they were 12' away from the monitor's outer edges, had a negative effect on the color rendition. I recently switched over to a 19" NEC 1970NX LCD monitor and was able to move the speakers closer and cant them with no effects on the color whatsoever.

Although the ATC SCM7 speakers are a sealed box speaker, they don't have a boxy look. This is due in large part to their curved-edge front baffle. This black baffle makes the SCM7s appear to be smaller than they actually are since it protrudes from the rest of the cabinet and minimizes the impact of the speaker's actual dimensions.

Here's my quick and dirty sonic description of the SCM7 speaker; it combines the dynamic agility of the Thiel PCM monitor with the harmonic suavity of the Aerial Acoustics model 5. That doesn't mean that the SCM7 is sonically similar to either speaker, merely that it shares many of their best attributes.

The ATC SCM7 has a different harmonic balance than the Aerial model 5, with more upper midrange and lower treble emphasis due to its greater dynamic contrast in this region. While the SCM7's dynamic agility doesn't go so far as to give the ATCs a tipped-up harmonic balance, it does render the ATCs less laid back than the Aerials. This makes the ATCs less tolerant of marginally recorded material. In-your-face mixes are more likely to pin back your ears. The Tanya Donelly track "Pretty Deep," which comes already installed on most i-Tunes players, was recorded at 160kps (which is almost the lowest resolution possible via i-Tunes.) It sounds especially rude through the SCM7's. Conversely Dave Alvin's "Every Night About This Time" from the King of California CD, which I recorded into i-Tunes at 320kps, sounds very rich and harmonically complete through the ATCs.

The ATC SCM7 also has less bass extension than the Aerial model 5, which makes it leaner than the Aerial model 5 in the mid-bass region. Again this doesn't necessarily translate into a thinner harmonic palette, merely one that has less mid-bass warmth. When the ATC speakers are mated with a good subwoofer such as the EarthQuake Supernova Mark IV you can achieve a very smooth transition from sub to satellites that minimizes differences in bass presentation between the SCM7 and model 5. Still, depending on your tastes, the SCM7 speaker may sound a trifle lean or the model 5 a shade fat.

At higher SPLs the ATC SCM7 shines. It reminds me of the Thiel PCM speaker in that both of these transducers beg to be turned up loud. At low and moderate volume levels the ATC sounds like it is merely idling and warming up for some real work. While it might be possible to stress the SCM7 speakers in a large room, in a nearfield environment your ears will cry uncle long before the speakers begin to exhibit any signs of audible distress. If you prefer to listen at lower volume levels, however, you may be less enamored by the SCM7 speakers compared with the Aerial model 5's because the Aerials sound more complete and at ease at lower levels. Both speakers dredge up oodles of low-level information and detail; its just a matter of what volume level you prefer.

Due to their smaller cabinet size and closer distance between the tweeter and midrange/woofer, the SCM7s image slightly better than the Aerial 5s. They also create a somewhat larger listening window and aurally disappear more convincingly. A much smaller footprint speaker such as the Role Kayak vanishes even more completely, but for its size the ATC SCM7 does a very credible job of throwing up a cohesive three-dimensional soundfield. On phase-coherent recordings such as my own live concert CDs of the Boulder Philharmonic orchestra the ATC speakers deliver a remarkably accurate picture of the entire orchestra on stage to the point where I can even discern the different seating heights between the woodwinds and horns.

After a month of using the ATC speakers in my desktop system it will be hard to let them go. They are among the most dynamically satisfying small-footprint desktop monitors I've ever heard. In terms of fit, finish, and overall performance they keep up with speakers that are nearly twice their price. But the SCM7's are not merely high-value speakers. They are so good that even folks who could pay far more for a desktop speaker will discover that $1200 will purchase speakers that are all they could ever want.

Meridian 518 Digital Audio Processor

Bob Stuart, Meridian's chief designer, is an archetypically understated Englishman. When he writes that an audio component sounds "good," in American-speak he means it sounds fantastic, and when he writes that something sounds "incredibly good," as he does on page 8 of the Meridian 518 user manual, he means, "freaking wicked-pisser two hits of pure psilocybin I-just-saw-God-and-he-said-hello awesome." In what context does the Meridian 518 achieve such Olympian audiophile heights? When it's employed as a digital preamp/volume control in a two-channel system. The 518 allows you to connect a DAC directly to a power amp, thereby eliminating any need for analog preamp in the signal chain.

Ever since I first managed to cobble together a hot-rodded system without a preamp or gain control I've been a firm believer that the best pre-amp is no preamp. Even with the most transparent parts, switches, cables, and connectors, every bit of electronics degrades the signal slightly and gets you further away from optimum fidelity. The problem is unless you only listen to one piece of software so you don't need to adjust the volume once it's been set; a sound system requires some way to adjust its output levels. If your signal sources are digital, the logical place to adjust the output level is in the digital domain. That's exactly what the Meridian 518 does.

Unfortunately, Meridian hasn't made the 518 digital audio processor since 2002 when they discontinued their 500 series of components. I bought a used sample on EBay. I tracked the supply and discovered you can usually find a 518 for $350 to $550 depending on their condition and the bidding intensity. I paid $385, including shipping, for my sample (it came without a remote.)

My current signal chain consists of an EAD 8000 Pro player/transport for CDs and DVDs, Pioneer MJ-D707 for mini-disks, and a MacPro 2.66 for i-Tunes. The computer USB output goes into a Trends Audio USB DAC UD-10, which transforms USB to a Toslink output, which then goes into the Meridian. The EAD coax and Pioneer Toslink digital outputs go into a Monarchy Audio DIP, which I use as a digital selection switch. It puts out a Coax signal for the Meridian. Once in the Meridian 518 the signals go to the April Audio Stello DA100 D/A and then to a Bel Canto S300 amplifier and Stax SRM-006tII output driver unit. I use a pair of Monster solid Y-connectors to split the signal from the Stello, which only has one set of line-level outputs. The subwoofer feed comes from the high-level speaker outputs of the Bel Canto. I used both the Aerial Acoustics model 5 and ATC SCM-7 passive speakers for most of my listening.

While this set-up acts much like a conventional system, it does require some care to keep it from making rude noises. First the amplifier MUST be turned off before the Stello DA100; otherwise a very loud pop will result. Also the volume MUST be turned down when switching sources through the 518; otherwise the system will emit a loud click. Most of the time my listening levels on the Meridian's 0-99 volume scale (87 is unity gain) sat between 60 and 80.

How much better does the 518 digital control system sound than the best analog preamp I've had in my desktop system? Pervasively better. In addition to far less stress at high volume levels, there's also less dynamic compression. With every source music had better pace and more extreme micro contrast. I also noticed a dramatic improvement in soundstage characteristics - the soundstage was wider, deeper, and lateral imaging is more precise. The front of the soundstage also moved back so the whole image was less attached to the front plane of the speakers. The soundstage has greater stability and the listening window was larger with both speaker systems I used - more room for side-to-side chair dancing. Low-level details were easier to hear through the 518. You don't have to work as hard to listen deeply into the mix. Employing the old cliché about panes of glass between you and the musical event, using the 518 is as if the neighborhood window washer took a hammer to your triple pane window. The glass was not merely cleaner, but gone! Installing the Meridian 518 in my desktop system was easily the biggest sonic improvement from changing a single component that I've experienced in the last couple of years.

If you can find a Meridian 518, or you're lucky enough to have one collecting dust in your equipment closet, put it to work in your desktop system. In the words of Bob Stuart, it does indeed sound "incredibly good."

The Next Nearfield

I've got some wild stuff in store for you including two one-box desktop systems and two integrated amps. The one-box systems are quite inexpensive and the integrated amps are not. See ya.