Music in the Round #10 Page 2
SOS: Getting to the bottom
But for all the RealTraps' blandishments, I simply could not use enough of them to deal effectively with that 70Hz mode. Certainly, the ASC SubTrap could do that job—but then I found a much smaller and nearly ideal solution.
In the past, I have had the pleasure of using and reviewing both the TacT RCS (digital) and Rives PARC (analog) room-correction systems. Both of these are quite flexible, offering multiband equalization to correct for room modes, but neither can fully take the place of physical acoustical treatments of the midrange and treble. Eventually, I hope to try their multichannel equivalents, the TacT TCS and the Rives PARC+. But because I'd already whittled the problem down to a single peak at 70Hz, I though I might just build a little bandpass notch filter and be done with it.
Instead, I obtained the ready-to-wear ACEI Subwoofer Optimizing System, or SOS ($269), a single-band, self-calibrating parametric EQ. It operates between 20 and 80Hz with adjustable gain and Q, and works with any powered subwoofer that lacks an active crossover (or has one that can be bypassed).
The SOS comes in a small extruded-frame box with switches on one side and connectors on the other. Installation and setup are quite simple: 1) Connect the output RCA jack directly to your subwoofer with the provided cable or one of your choice. 2) Connect the provided microphone and place it at the listening position. (I taped it to the top of a photographer's tripod.) 3) Make sure the switches are set to Operate, Filter, and Normal. 4) Power up the SOS by plugging in the provided wall-wart power supply. 5) Flip the switch from Operate to Calibrate. 6) Stand back!
The unit will sweep through several series of test tones; if calibration is successful, the green Cal'd LED will illuminate. Switch over to Operate-Filter-Normal and you're good to go. Until recalibrated, the SOS will remember the filter parameters, even if you unplug it. There is a Bypass option, as well as the ability to inject test tones, if you want to assess the SOS effectiveness by ear or instrument. That's all there is to it.
Before I regale you with a description of how great this little gadget is, let me remind you that it is not the equivalent of a multiband equalizer such as the Rives PARC, and that, unlike the TacT, it does nothing in the time domain. On the other hand, subwoofers are rarely used over much more than a two-octave range (20–80Hz), and, depending on your room, there may not be more than one offending mode in that range. That was the case in my room; the SOS suited it to a T.
The most significant improvement was that my Paradigm Servo-15 subwoofer simply disappeared as a localizable source when used solely as an LFE speaker, or with bass management set to 80Hz. Normally, I subject only the rear channels (Paradigm Studio/20s or Magnepan MGMC1s) to bass management, as I run the front three Studio/60s full-range. However, with the SOS controlling the Servo-15, the entire system became tighter in the bass, as well as much more solid and powerful. I no longer had to pay the usual price of bass management: more mid- to low bass in the sub's vicinity.
The best demonstration of the effect was with the RCA Living Stereo SACD of the Saint-Saéns "Organ Symphony" (BMG Classics 8287-66139-2). This is not a surround recording—all three channels are up front. Running the three Reference Studio/60s full-range was very satisfying, but there was a lack of ultimate power and extension. Switching in the SOS and the sub with an 80Hz crossover strengthened the extreme bottom end, especially in the second movement, but it still came exclusively from the front. In addition, whatever the Studios were contributing to the 70Hz mode was somewhat attenuated, but this time by the rolloff of the Outlaw ICBM.
The SOS was just perfect within its limited capabilities, and is worth a try if your room doesn't saddle you with multiple peaks and nulls in need of correction. Full-range speakers will, of course, still energize the low-frequency room modes; the SOS can't help them. It should work fine for those with smaller main speakers using bass management in all channels. But even if the SOS can cure only the major problem, that may be all you need.
Linar Model 10: rethinking the multichannel amplifier
Until the audio industry gets its act together and offers us a truly universal digital interface, we're going to be using preamplifiers and power amplifiers with analog inputs. Why not put them in one box? After all, there are many integrated stereo amps. Well, the Linar Model 10 ($4200) is just that: a 5.1-channel preamp with a five-channel power amplifier in the same chassis ().
This 60-lb block, a high-end amp from designer Victor Sima, sports two 750VA toroidal transformers, Teflon-insulated machined RCA connectors, and a circuit free of signal-path capacitors and global feedback. It has five stereo inputs and one six-channel input (designated Aux 1), and five power amps rated at 120W each into 8 ohms. The dual line-level subwoofer outputs carry full-bandwidth mono signals when a stereo source is selected.
The Linar 10's front panel looks like a power amp with a small green LCD display and five pushbuttons: Input, Power, Tape Monitor, and Power Up/Down. The LCD indicates input selection and volume level in each of the modes, but was generally too small to read from my listening position. The rear panel has five pairs of binding posts across the top (L/C/R/LS/RS), and RCA jacks across the middle for its line-level inputs and outputs.
But after I'd hooked up the inputs and outputs, I never laid a hand on the Linar 10 again, preferring the very capable remote control. This little beauty has direct-access buttons for each input: CD, Tuner, Aux 1 (multichannel), Aux 2, Aux 3, Mute, Volume Up/Down, Tape Monitor (On/Off), Display (On/Off), and, of course, Power On/Off. In addition, there's a button to duplicate the stereo L/R signals at the LS/RS outputs for stereo in four channels, and another, labeled Rear Volume, that toggles the volume buttons from controlling all channels to setting levels independently for the subwoofer or rear channels. Note that, in the Stereo in 4 Channels mode, the Model 10 could also be used for biamping stereo speakers or for powering a stereo pair in another room. Strangely, there is no simple facility for left/right balance adjustment in multichannel, and the workaround for stereo is kludgy. Not a big problem.
I used the Linar 10 as an integrated amplifier, as it was designed to be, but also as a power amp, with the McCormack MAP-1 handling selection and levels. In either role, the sound was always ample and smooth, but just a little smoother with the Linar on its own. Background noise was inaudible at any level setting, and there was plenty of power for the Paradigms. All functions worked smoothly and silently from the get-go, except for a fairly quiet burp on power-up.
I might characterize the Linar's sound as warm, not because of any rolloff in the extreme treble but because the high frequencies are gently softer and the midbass generous. Compared with, say, the MAP-1 or the Bryston 9B-ST, the Linar 10 had a little more of a velvet glove covering the steel fist that was notably present. Overall, it resembled the Bel Canto digital amps harmonically, but without their granitic bass. If that suggests Goldilocks' choice of not too hard and not too soft, you get the idea. The Linar 10 was clean with every music and film selection, its rendition of soundstage depth and width excellent, its dynamics impressive. The Linar did well with the Paradigm Studio/60s, but it was a particularly felicitous match with the Magnepan MGMC1s, which sang as sweetly as they do with much more expensive amps.
As a single-box solution, the Linar 10 is pretty much without direct competition, so I can compare it only to separate preamps and amps. Having done that, I think it competitive in sound quality with any that has passed through my multichannel system, and all of the combinations of those separates cost much more than the Linar on its own. With a universal player and stereo sources, the Linar 10 provides an audiophile's transition from stereo to multichannel. Those who've made that transition can feed the outputs from a multichannel processor or receiver into the Linar 10's multichannel input and still enjoy all-analog stereo from the other inputs.
The only issue is whether this clean, hefty all-in-one suits your needs. I had to add the Zektor MAS3 that I reviewed in December to accommodate multiple multichannel inputs, but for most folks, the Linar Model 10 and a decent universal player would make a great audio system. And think of what you'd save in interconnects!
Next time: The promised discussion of cables and power treatment, an upscale universal player, and more Recordings in the Round.