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Positive Feedback ISSUE43
as reviewed by Ryan Colemen
Count me in the group of audiophiles who state that they'd rather listen to good gear in a great room rather than state-of-the-art gear in an acoustically challenged room. A visit some time ago to a dealer's showroom only confirmed it; while my reference system has a MSRP north of $60k, my careful attention to room acoustics gave me sound that outclassed the dealer's reference system with a MSRP north of $300k. My audio friends who were along for the visit agreed; a great collection of gear in a sorry, untreated room is a recipe for unfulfilled promises.
I wasn't a late convert; my experiences as an audiophile necessitated a focus on room acoustics as my systems have evolved in one small room after another. My current dedicated digs are 11' by 15' by 8', and I'm sure I'm not the only audiophile who turned a spare bedroom into an audio den. A dedicated room gives license to treating acoustics as the sound warrants. The preferred solution is always passive treatments: ideally, a dedicated room, but if that's not in the cards, tube traps, wall panels, reflectors and diffusors are tools that should be in every audiophile's toolbox (just like different flavors of tubes and isolation devices. Recreating the recorded performance in the home is like making a meal—you need all the ingredients in your pantry even if you aren't going use them every night.)
But having the luxury of a dedicated room is not always a given amongst audiophiles. For those whose systems reside in shared family rooms, the thought of filling corners with tube traps and taking down artwork to hang diffusors is not likely to pass muster with the rest of the household's inhabitants. Formerly, they would simply have to accept the performance within the limits of the room's acoustics. For these poor constrained souls, there is an alternative to the untreated room: the Rives Audio PARC.
The Rives Audio PARC is a purely analog (no digital conversions) 3 band / channel parametric equalizer that is inserted between preamp and amp (or, in the tape loop), but it really should be thought of less as an equalizer and more as an attenuator. In Rives Audio's research, its room nulls that are less insidious than room modes; whereas the former give rise to leanness at a specific frequency, the nulls don't necessarily compromise the rest of the frequency band. Furthermore, trying to boost nulls is not a good idea. It overloads amplifiers, damages speakers, and guess what? The null still exists no matter how much you boost that frequency. However, room modes screw things up all over the place, obscuring low-level details in the midrange and cause the oft-troublesome BOOM that muddies mid-to-low bass information into a one-note mess. As such, the PARC only removes nodes between 18Hz and 350Hz (the bass region), and does not try to correct nulls.
As mentioned previously, there are 3 bands per channel that can be attenuated (and the PARC gives the ability to store 3 different collections of settings, such as one would have for "audio," "home theatre," and "unchanged"). Settings are made along 3 parameters: the amount of attenuation in dB, the frequency band to be addressed, and the width around the band that's relevant for attenuation (a parameter known as "Q factor", expressed as "Center of frequency / Width of frequency". Wider Qs are obviously worse as they affect a wider range.).
Now, that might read like a simple set of adjustments to make once you know where the bass nodes are, but I was terribly afraid that programming the PARC would be Chinese-algebra hard. Instead, it took me all of 5 minutes to figure out how to make and change parameters for each channel, and how to cook up new parameters in a comparison of "audio" vs. "home theatre" vs. "unchanged" versions to demonstrate the PARC's effectiveness. I cannot compliment the engineers at Rives Audio enough. While this device could've been as difficult to configure as a wireless network, it was far closer in difficulty to that found in connecting a DVD player. But first things first; one needs to know what settings to make!
As a reviewer, I received service that is normally reserved to those who buy a PARC from an authorized reseller—namely, an acoustic readout of my room which identifies problematic room modes that the PARC could be configured to attenuate. As an audiophile, I cannot stress the value I found in having a dealer trained in room acoustics to come into my listening room and give a professional acoustical snapshot. I must take a moment to compliment the work from Doug Smith at Architectural Electronics in Houston (713-465-6333; www.aetexas.com ). Rives Audio instructs its dealers to use a microphone, a PC loaded with Rives' own proprietary BARE software, and necessary cabling to hook the PC audio output into the customer's stereo; the PC will generate test signals and the mike will capture quasi real-time frequency responses at the listening position, which are then generated as frequency graphs on the PC (thus allowing identification of room modes). If you've ever seen those graphs of speaker frequency response in Stereophile, that's what the PARC reseller does for your room. Hell, even if you don't buy a PARC, every audiophile should splurge for this information. On a dollar for dollar basis, this might be the best money audiophiles spend on their systems! Wouldn't you want to know what you're really listening to before you decide to spend one cent on new speakers or subwoofers? Measure, then adapt accordingly. Just like Darwin would want: good science.
From the moment Doug at Architectural Electronics arrived, it took 2.5 hours to measure the room, identify modes, install the PARC and make all the settings as the software recommend, along with some modified settings (i.e. the "home theatre" and "unchanged" settings); again, what could have been a nightmare in complexity was dumbed down enough for rapid installation and ease of use by even the least savvy audiophile.
Doug Smith did warn me that I was not apt to like the initial configuration as recommended by the BARE software, and that proved to be true; it was as if my system went from being floorstanders to mini-monitors, so accustomed I was to the un-PARC'd room. The simple solution he recommended (which, incidentally, has been confirmed by the Richard Bird as being unanimously preferred amongst his clients) was to just reduce the amount of attenuation applied on each frequency range by 25-50% (and given how easy it was to configure the PARC, it invited experimentation).
After cutting the attenuation 25% across the board, I sat down to reevaluate and found the PARC to positively influence three aspects of my system's performance: bass articulation, low level detail retrieval, and PRAT (pace, rhythm and timing). More importantly, it did not have any downsides as a result of its insertion (more on this later).
The PARC was designed to attenuate only the frequencies between 18Hz and 350Hz, as room modes occur in this range. Just about every room has them, and it's their removal via a device such as the PARC that allows the listener to get increased accuracy in the mid- to deep-bass region. Walking bass lines from an acoustic bass and ultra-deep bass, as found in orchestral works, both had far greater inter-note articulation without the blurring that only becomes obvious after experiencing its absence. Acoustical venue cues are better defined, allowing stage depth and hall corners to be clearly ascertained. While the removal of select modes was psychologically akin to reducing some ‘punch,' it was a welcome removal as the mode removal was simply a distortion to the signal's intent.
While increased articulation and low-level detail was expected in the bass region (where the attenuation occurs), what I found surprising was the improvement in low-level information and detail retrieval that occurred all the way up to the upper midrange. Allow me to offer an analogy: have you ever intentionally set a subwoofer's crossover or volume control too high? In both instances, attentive listeners will also perceive a loss of low-level information in the midrange as the overpowering bass now obscures micro-detail. This is the exact same effect I found with the PARC in the circuit. Minor details that we audiophiles sweat over (like the sound of Sinatra breathing, Armstrong's lips as he puckers before blowing, or the decay of the orchestra as it dies away) became evident without strained focused listening on my part. More detail is always a good thing as it only enhances the sense of realism; the PARC paid big dividends here when none were initially expected.
Another area that was positively impacted by the PARC was my system's pace, rhythm, and timing (PRAT). Running with the improperly-set subwoofer analogy from above, PRAT suffers mightily when the bass is overpowering. Music loses its leading edge, slows down, and muddles through a thoroughly bloated and unsatisfying performance. Room modes have the same effect; it's simply a question as to their degree and significance. By addressing room modes, that muddying effect is taken out of the equation allowing transient snaps and rhythmic drive to speed along without having the parking brake engaged.
Most audiophiles like me are naturally reticent of putting anything into the signal path that's not supposed to be there—adding complexity usually adds artifacts, and this can only reduce the truthfulness to the signal. If I had a dollar for every time I've been told or read that some active electronic signal processor is "sonically transparent" I'd have cab fare for a drive from NYC to LA. I must admit that when I plugged the brand-spanking-new PARC into my system and compared the "unchanged" settings vs. the bypass mode (which disengages all active circuitry); it was anything but sonically transparent by having a notable etch and whitening in the upper registers. Let me be blunt—it was obnoxious in what it did, and I feared this product was going to be a "good only in select circumstances" type of endorsement. But this isn't my first rodeo and I've been through lots of electronics that require significant run in before sounding their best; the PARC is no different. It needed a solid month before the obnoxious artifacts I heard on initial installation disappeared, but disappear they did As my test scenarios included "unchanged" vs "bypass" and also both of those vs. removing the unit from the signal path altogether (and plugging the two balanced interconnects which went into the PARC together), I could hear no negative impact from the unit's insertion after a complete burn-in.
There's a famous audio quip that goes something along the lines of "you don't listen to your stereo; you listen to the room your stereo is installed in." Every room is different and it is a worthwhile investment for an audiophile to invest the time and money to optimize their space as much as possible. As I said at the start of the review passively treating the room is always the first preferred method of building a proper listening venue. However, some audiophiles simply don't have the space or the acceptance for the myriad bass traps that would be required to turn a boom room into an acceptable listening space. For these fellow brethren, the PARC would be a better investment than spending another four-to-five figures on upgraded electronics.
If you haven't had your room measured by an acoustician, I assure you that you will not regret it. All Rives Audio dealers have the equipment and are trained to take these measurements. If you have unaddressed (or unknown) room nodes and an inability to passively treat them, the Rives Audio PARC should be tops on your list for your next audio purchase. Ryan Colemen