Kenwood KR-X1000 AV-receiver
After a spate of A/V receivers suffering from significant faults - such as non-flat frequency response, noisy surround outputs, and poorly planned subwoofer circuits - it comes as an immense pleasure to find one that can be recommended essentially without reservation. Such a seemingly rare animal is Kenwood's KR-X1000, which incorporates digital signal processing (DSP) circuitry that provides both Dolby Pro Logic surround-sound decoding and Home THX enhancements for more theater like performance when playing soundtracks.
To carry Lucasfilm's THX logo, the KR-X1000 must meet strict requirements in several areas, many of which benefit normal stereo music reproduction in addition to soundtracks. Very important to me are the THX criteria for maximum noise levels. Appearing more sexy on data sheets are the requirements for an amplifier section's output power, which the KR-X1000 easily meets as it is rated to deliver, in surround-sound mode, 135 watts per front channel and 80 watts per surround channel into 6-ohm loads (both at 1 kHz). Lucasfilm also requires a well thought-out system of bass management that properly shunts low frequencies into the amplifier's subwoofer output, removing them from the three front channels. Additional THX circuitry provides high-frequency equalization for soundtracks (THX re-equalization), equalization to reduce the difference in perceived frequency response between the front speakers and side-placed dipole surrounds (timbre matching), and equalization to remove the mono quality of the decoded Dolby Pro Logic surround signal so as to increase the perceived diffuseness of the surround output (decorrelation).
Aside from those THX circuits, the KR-X1000 is a rather simple A/V receiver, without a profusion of features, which makes it easy to use. For example, there are only four surround-sound modes: Home THX Cinema, Dolby Pro Logic, 3 Stereo (for soundtrack playback over three front speakers only), and DSP Logic, an enhancement mode for surround-encoded music programs. There's a forty-preset AM/FM tuner as well as audio-only connections and switching for a CD player, two audio recorders (or one recorder and one equalizer), one auxiliary input, and a phonograph cartridge (moving-magnet). The A/V connections include both composite-video and S-video jacks for two VCR's and three play-only A/V sources, one of which has connections on the front panel for temporary hookup of a camcorder or video game.
Most of these connections are made on the receiver's rear panel, which also has connections for the speakers (multiway binding posts that take single but not dual banana plugs), a complete set of preamp-out/main-in jacks (three front channels, two surround, all normally connected by jumpers), a subwoofer-output on/off switch, two switched AC convenience outlets, and connectors for an AM antenna and an FM antenna (an F-connector). The rear panel also has a vent for the receiver's cooling fan, which turns on whenever high outputs are continuously delivered for periods of several minutes or more.
Front-panel facilities are unusually complete: No operation of even moderate importance is relegated to the remote control only. The most prominent front controls are two large knobs. The one at the far right is the volume control, and next to it is the input selector; both rotate continuously. It would be nice if the input selector served double duty as a tuning knob, but that function is controlled by conventional up and down tuning buttons. You can also tune in stations by entering their frequencies directly, a nice feature and a rather uncommon one.
Other front-panel controls select the surround mode, adjust the DSP Logic surround mode, enable surround-sound speaker balancing, and activate the tone controls. The large fluorescent display has useful indicators showing the status of surround operation, the tone controls, and radio tuning. A fifteen-character alphanumeric section shows the tuned frequency, the radio band, the preset selection, the surround mode, and the volume setting in decibels referred to THX 0 dB (that setting will produce close to theatrical levels when the receiver is used with a typical laserdisc player and a THX loudspeaker system).
Activating the KR-X1000's basic functions - input selection, volume control, surround-mode selection - with the supplied infrared remote is unusually easy thanks to the superb differentiation in size, shape, and feel of its buttons. Beyond the basics the remote's operation becomes a little more difficult since it comes preloaded with the command codes for many different brands of VCR's, laserdisc players, and TV/cable boxes. Several of the buttons take on multiple functions when these external-component commands are activated. You have to remember which button does what depending on which input is selected. Confusion is somewhat reduced by the back-lit LCD readout, which shows the selected source.
In the lab the KR-X1000 did very well. Overall the performance of the tuner section was average. Nowadays that means very good - except for the AM frequency response, which was abysmal, although typical of contemporary AM-section performance. Do not be misled by the too-good stereo sensitivity measurement; the receiver was no better than average at pulling in distant stations.
In stereo mode, the amplifier delivered large amounts of power into 8-ohm loads and almost twice as much into 4-ohm loads, indicating that it operates very much like a true "voltage source" and is relatively immune to the load placed on it. Note that Kenwood's higher power ratings are for 6-ohm loads. Calculations from our measurements show that the KR-X1000 should deliver its rated power or slightly more into such loads.
Even the center and surround channels in Dolby Pro Logic operation behaved like voltage sources, which is very unusual for surround outputs. Other unusually good performance results are due to the high-quality DSP used to perform Dolby Pro Logic decoding: Specifically, noise was outstandingly low and channel separations unusually high. Measurements of THX-circuit performance showed negligible deviations from THX specifications. The only anomalous surround measurement was of left/right distortion. This is a distortion plus noise measurement, and in this case the higher distortion in the left and right front channels, compared with the center and surround channels, was caused by some additional - but inaudible - low-frequency noise when the subwoofer output was activated. Filtering out frequencies above 400 Hz in this measurement produced an excellent reading of 0.028 percent.
The receiver can be set to attenuate the selected input signal before it hits the DSP circuitry, so as not to overload it. The front-panel overload light comes on at about 0.8 dB below a standard CD-player or laserdisc output of 2 volts, which is a conservative indication since DSP clipping doesn't actually occur until just above a 2-volt input. You can ignore the clipping indicator unless your player has a maximum output greater than 2 volts (as in some "high-end" CD/laserdisc players and outboard digital-to-analog converters). These considerations don't apply to conventional stereo operation, which doesn't involve the DSP circuitry.
Hookup and adjustment of the KR-X1000 was thoroughly straightforward, aided by such details as consistent orientation of the speaker terminals and an unusually well-conceived, well-executed, and well-written setup manual. Once I got everything connected, including a full THX speaker system, I was immediately impressed by how clean the KR-X1000's Dolby Pro Logic and THX modes were. Lately we've been finding receivers whose sur-round-channel noise was not only some 10 very audible decibels worse than the KR-X1000's but was also unaffected by the setting of the volume control and remained high even in two-channel stereo operation. What a pleasant change to find surround-channel noise levels that were low enough not to be audible at our prime listening position unless the volume control was set very high (above -10 dB), as well as no audible noise at all when plain stereo playback was selected. The receiver's Pro Logic decoding was as accurate in image placement as its noise level was low.
The THX enhancements to Dolby Pro Logic playback did their usual wonders for many soundtracks, reducing harshness via the re-equalization and creating more seamless side and rear sound fields via the timbre matching and decorrelation. Although the decorrelation process used in the KR-X1000 was not totally free of the "tunneling" sound character that can disturb the tuning of such instruments as pianos, it had far less of this trait than most other THX devices we've tested.
When used with an adequate speaker system - a full THX speaker system qualifies automatically, but others must at least have a subwoofer that crosses over to the main speakers correctly - the KR-X1000 had an effortless sound quality stemming from its low noise and distortion and quite substantial power capabilities. Even at very high levels (THX 0 dB), I never sensed that the receiver was running out of power (and oscilloscope traces showed it didn't) with the most violent of soundtracks, the loudest of symphonic or pipe-organ music, or the most raucous rock.
The only sonically disappointing aspect of the KR-X1000 was its DSP Logic surround-enhancement mode. The manual says it can be used for surround-encoded audio CD's when you want to change their perceived ambience. To this end, the outputs of the Pro Logic decoder are fed into a digital ambient-reflection generator. The generator has controls for Room Size (controlling the temporal spacing of the reflections) as well as Effect and Wall (which control the reflections' levels in different ways). DSP Logic does what it is supposed to do with surround-encoded CD's, though it seems to me that the one reason to sur-round-encode a CD is to convey the particular ambience selected by the producer. With normal music CD's, the presence of the Dolby Pro Logic decoder in the signal pathway disturbed the front imaging and was at times revealed by signal-pumping effects. DSP Logic would have been far more useful as a general-purpose ambience-enhancement mode if the surround decoder were removed from its processing and if it didn't have an excessive, nonsensical, and very audible high-frequency rolloff (-3 dB at 6.6 kHz, -5 dB at 10 kHz) in the front channels. Thank goodness the receiver's Dolby Pro Logic and THX performance were superb.
I had some ergonomic difficulties with the KR-X1000, although far fewer and less serious than I normally find in A/V receivers. Surround-mode selection on the remote is a round-robin affair: You have to cycle through as many as four modes to get to the one you want, making A/B comparisons between Dolby Pro Logic and THX operation impossible. Similarly annoying is that switching to stereo-only operation via the remote's handy stereo button also resets the surround mode to Home THX. Despite the neatness of the easy-to-turn front-panel in-put-selector knob, it has such light detents that it is very easy to turn past the input you want, as happened often to me. Finally, although THX components are almost unique in handling subwoofers correctly, the Kenwood has the same drawback I have found with most THX subwoofer outputs: The low-pass crossover is fixed in frequency (80 Hz) and cannot be defeated. That is ideal for THX-certified subwoofers, for which the outputs are designed, but if your subwoofer and main speakers require operation at a substantially different crossover frequency (above 100 Hz or below 60 Hz), you're going to have to turn the receiver's subwoofer output off, feed your subwoofer's crossover from the rear-panel left/right-front main-out jacks instead, and set the center-channel mode to "normal." It makes more sense to have a subwoofer crossover that can be switched out.
That is an amazingly short list of criticisms, all of them truly minor, of something as complex as a THX receiver. Used in stereo mode with music or in Dolby Pro Logic or, better, THX mode with movies, the KR-X1000 left little to be desired. It's a rare receiver that does so much so right and so well.