Product Review - Russound CA 6.4 Multi-Zone Controller/Amplifier - October, 1999

Colin Miller


Russound CA 6.4 Multi-Zone Controller/Amplifier

Rated 20 Watts/Channel @ 8 Ohms, 12 Channels Driven

MFR: 20 Hz - 20 kHz 1dB  THD: < 0.1%

Size: 3 1/8" H x 9 3/8” W x 7" D

MSRP: Controller- $1,995 USA (Includes 6 Keypads and 4 IR Emitters), CA6.4 KP (Basic Keypad) $95 USA, CA 6.4 LRN (IR Learning Keypad) $275 USA

Russound Corporation,  E-Mail [email protected]; Web Telephone (800) 638-8055

What should one ask for in a multi-room music system?  They can become quite elaborate, and even very good, as well as expensive.  However, in most situations where mediocre drivers and crossovers meet far from ideal enclosures (the space between sheet rock and wall studs), and in questionable locations (behind books or draperies, opposite sides of the room, ceilings, etc.), where does a really high-end multi-room system’s ability to convey subtle nuance add any real value?  In most applications of this kind, it doesn’t. So long as the audio system keeps noise and distortion below grossly noticeable levels, allows satisfactory functionality, provides required output volume, and doesn’t break, anything more is gravy.  After all, as a peer in the industry once pointed out, “How much distortion is acceptable for a rock speaker stuck behind a shrub?” 

Like most audiophiles, I consider myself picky, even with multi-room applications.  What I consider gross levels of distortion, unacceptable frequency response deviations, or obnoxious amounts of noise, would probably pass unnoticed by those who just want music playing somewhere, anywhere. However, when it comes to background music, I too ease up my requirements by a large margin.  If I want to listen to something seriously, i.e., pay attention, I will stop my present task and sit down in the optimal spot of my acoustically optimized room and do just that.  If I’m doing something that requires standing and moving around, I probably don’t have either the time or inclination to become very critical.  So long as the sound quality doesn’t call special attention to itself as particularly bad, I can leave it be. Consumers can put just about anything in the wall and it will meet those requirements. For all others, particularly those who want a little class in the system, Russound has the answer.

The Russound Controller/Amplifier is a new product for custom installation, or you can do it yourself and just tell everyone it was custom built. It certainly has that kind of appearance.  Essentially, the entire system serves as six integrated stereo amplifiers (the unit has six "audio zones") that can share up to four sources. The sources are labeled "Tuner," "CD," "Tape," and "Aux," though one could hook up anything with a standard line-level output to any of these inputs.  It doesn't allow more than four sources, but to expand to more zones, the user need only split the output of the sources to multiple controllers.  (Splitting audio to more than two controllers may require additional distribution amplifiers to buffer the outputs.)

The tasteful front panel has no controls save a main power switch.  Six LEDs glow red when the zone they represent is inactive, and green when the zone turns on.  Connections in the back are as simple as possible.  Up to four sources plug in by standard RCA connections, speaker wire hooks up via space-saving Phoenix style connectors, IR emitters plug in via 1/8" mini-plug jacks, and keypad control wires go into their own little removable receptacles.  AND, for all of you  tweaks, the power cord is removable, so that you can insert any of your own IEC favorites.

Keypads control each of the six zones locally by plugging directly into the controller via eight conductor wire (CAT-5 is specified, readily available, and cheap.)  The setup requires running both speaker wire and control wire to each zone.  The basic CA 6.4 KP in-wall keypads, that mount into a single-gang box with a Decora style cut-out (see photo at left), allow volume control by a twist, toggling through sources by pushing the volume knob, and an infrared receiver that transmits local IR to the controller which then passes the information to source components either by IR emitters or directly into IR inputs.  This allows operation of source components from remote locations by hand-held remote control units.  That’s fine if each zone has its own learning remote, but if that isn't enough, there's an easy fix.

For those who want a bit more control at the keypad itself, Russound offers the CA 6.4 LRN, an extra add-on box that can share the second half of a double-gang box (photo at right), and piggy backs onto the same run of control wire as the basic keypad.  It’s essentially a smart learning remote.  It learns IR codes for each source, storing the commands on the “layer” of the selected component, and subsequently executing different commands as a function of the source selected by the basic keypad.  For example, the play button will execute one command when one component is selected, another command while another component is selected, and so on.  Pretty neat.  It can’t display the entire list of a 300 disc changer and then offer direct selection, let alone interface with an Escient system, but for a basic, headache-free system, I think it’s terrific.  Simply put, there isn’t much that can break.

Rated at 20 watts per channel at 8 Ohms, discouraging use with 4 Ohm loads, it isn’t exactly a back breaker by government standards.  To be sure, there is a positive aspect to this.  The CA 6.4 is also small.  I really like that- easy to install, easy to service, easy to pick up and move.  It fit nicely on top of my computer at work, under the desk, completely out of the way. It is actually designed so that you can tuck it away somewhere rather than being out in showcase form. The idea here is that it is "Custom Built-In", remember? Lastly, 20 watts per channel is plenty for multi-room audio, especially when you consider that this product offers a total of 240 watts divided over 12 channels. 400 watts per channel is a little distracting at dinner parties and candle light.

Fed by a Sonic Frontiers SFCD-1, the Russound did its job nicely.  Granted, at the time, the power supply for six zones only had to feed one pair of speakers at a modest volume, but still, it played as loud as I wanted to listen sitting four feet away.  For the purpose of background music one can talk above, I consider the output quantity and quality more than adequate.  I don't see any problem with having the unit on, running speakers in several rooms at once for parties. Incidentally, one pair of the M&K satellites (s-80s) presented a marginally difficult 4 Ohm load, and the amplifier worked fine.  With three or more pairs of 4 Ohm speakers running simultaneously, a problem with heat or excessive distortion would arise, so keeping to speakers with an 8 Ohm nominal load would be wise if you plan to fill the entire house with sound.

Even with a single pair of 8 Ohm speakers, the output capability won’t meet the demands of real concert levels, or that of a teenager's birthday party. But, it is not designed for that. Teenagers want a rack of components along with as many remote controls as possible, each with its own supply of sticky thumb prints on it. The majority of my own listening probably doesn’t require more than 20 watts.  Just be reasonable with expectations.  If the amp distorts, you can always turn it down.

Overall, given similar products on the market, I’d suggest that this offers a good value on the price/performance curve.  There are systems slightly easier to use that cost a bit more, but offer less actual control.  There are much more expensive systems that can do anything you ask, so long as you fork over the cash to do so.  And, yes, there are far less expensive systems that will do the job of distributing sound, but their quality and functionality suffer seriously for it.  Excuse me while I take the soap box on this subject, because I have had to install a few of the cheapo items:

Specifically, I’m referring to speaker-level switches in conjunction with transformer-based volume controls, either in an outboard box, or in the wall.  The switch is relatively harmless, but the step-down transformers, while more ideal than a resistor network, are awful things to put between an amplifier and a speaker.  Keep in mind that good tube amplifiers are expensive in part because a good step-down transformer must be large and therefore heavy so as to have enough inductance to pass low frequencies while minimizing distortion caused by saturation.  They must also be carefully constructed to minimize inductance leakage in order to pass high frequencies.  This costs a lot of money and takes up space.  The transformers used for multi-room speaker-level attenuation, either installed in the wall or inside a box near components, are designed to be small and cheap.  They may be suitable for situations where any sound at all is acceptable, such as outdoors, but in such cases, forget any pretense of fidelity, however marginal it might have been to begin with. While they are cheap, they’re often used to add a zone as an afterthought.  That professional system designers spec these into jobs from the beginning, let alone at all, blows my mind. What I am saying is that if you do some "custom" installation through an installer, make sure you know what you are buying. The Russound is built the way custom products should be.

Summed up, the CA 6.4 system sounds good, offers a simple, easy to operate interface, has useful control features, and compared to the competition, is priced nicely.  Conclusion?  When I get my own set of walls to pull sheetrock off of, the CA 6.4 will be on the A list.  If you’re looking for the heart of an all-around easy to live with multi-room audio system, you should consider the Russound product line.

 - Colin Miller -

Components used during this review:

Sonic Frontiers SFCD-1 CD Player
M&K S-80 Satellite Speakers
B&W In-Wall Speakers
M&K V-75 mkII Powered Subwoofer 

Copyright 1999 Secrets of Home Theater & High Fidelity
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