VR-8070 THX Select Audio/Video Receiver
Kenwood USA has recently introduced their new VR-8070 A/V receiver that earned the THX® Select badging from LucasFilm. Available in both black and silver, the VR-8070 is the industry's first 7.1 THX® Select receiver to be priced with an amazingly low MSRP of $600. Features on the VR-8070 include THX Surround EX, Dolby Digital EX, DTS-ES® (Discrete, Matrix, Neo:6) and Dolby Pro Logic IIx. Seven channels of amplification (100-watt RMS each) are provided by Kenwood's innovative K-STAT™ (Kenwood – Self Tracking Audio Transistor) Discrete Audio Amplifier technology.
Powered by Analog Devices' 32-bit SHARC DSP (Digital Signal Processor), the VR-8070 is capable of powerful audio processing in a relatively low-priced receiver. Full 96kHz/24-bit audio DACs and ADCs resolve subtle detail with impressive dynamic range. THX® Timbre-Matching and Re-equalization for the front channels as well as THX® adaptive decorrelation for the rear channels are only part of this receiver's capabilities. Full Digital Bass Management with THX Crossovers and THX Bass Peak Level Manager maximizes the performance of your subwoofer. A variety of surround modes envelope the user, whether listening to music or watching movies. The DSP Mode simulates five listening environments that include Arena, Theater, Jazz club, Stadium and Disco. These modes create a larger acoustical space by adding reverberation and spatial cues found in larger listening environments. The Active EQ tailors the equalization for Music, Cinema or TV. The dual-zone design provides both audio and video in two separate locations.
The front panel features an easy to read Fluorescent Display that includes the current speaker configuration being used. This is especially helpful with the multi-channel digital formats that can vary from source to source. The front panel is uncluttered with eight buttons located on the left for choosing the input. The Listen Mode knob selects the listening mode. The setup button is used to configure the setting within the VR-8070 and utilizes the Multi Control knob and Up/Down buttons. A set of front panel A/V Aux inputs include two-channel audio, composite and s-video for use with a camcorder or other A/V component. The A/V Aux button activates this input.
The rear panel of the VR-8070 looks like most of today's A/V receivers with a wide assortment of audio and video connections. Five sets of A/V inputs each accommodate stereo line-level audio signals, a composite video and an s-video input. Composite inputs are automatically upconverted to s-video to simplify the cabling to the display. In many instances this would be recommended. However, there are some displays that have excellent 3-D motion-adaptive Y/C separators that would do a better job upconverting the composite signal to s-video. In those cases, the user should try both configurations to determine the best video performance. There is also a phono input along with a 5.1 audio input commonly used for multi-channel SACD or DVD-Audio sources. Line-level preouts are available for the 7.1 channels as well as a pair of stereo outputs for a second room (Room B).
Also included is a high-bandwidth 3-to-1 component video switcher that is capable of passing HDTV video signals with bandwidths as high as 50 MHz. Four digital inputs (two optical and two coaxial) and a single optical digital output is provided. The built-in AM/FM tuner has antenna connections that includes a 75 ohm coaxial F-connector and a balanced input for the AM antenna provided with the unit. IR sensor and IR repeater interfaces extend the range of the IR signals allowing the receiver to be placed behind closed doors. Two switched outlets provide 120 VAC power to connected components.
Seven pairs of binding posts are provided for the speaker outputs and are compatible with banana jacks as well as stripped wire. We used a set of pre-terminated Ethereal speaker cables that worked very nicely with the Kenwood binding posts. The connections were excellent and clean looking especially on this crowded I/O panel. In fact, we would recommend using preterminated speaker cables for this reason alone. Each of the seven sets of outputs have a color name associated with the channel to make it easier during installation, assuming the user or installer has color coded speaker wires. Each of the speaker outputs specify 8-16 ohm speaker impedance to prevent overloading of the output stage. A second set of front speaker outputs use the cheaper "push and lock" type connections and is intended for a second room installation if so desired. Not all installations would require this interface nor would they likely be high quality speakers, so Kenwood didn't use the same type of binding posts here.
The power supply in the VR-8070 is a linear design that uses a large power transformer and hefty 20,000 micro-Farad (10,000 per voltage rail) capacitors for storing large power reserves for the output devices. These large capacitors serve as a power reservoirs for short term high power needs.
At the heart of the VR-8070 lies the highly regarded Analog Devices ADSP-21266 SHARC Digital Signal Processor (DSP). This high performance 32-bit floating-point processor is optimized for audio processing. The DSP handles all of the popular audio decoding algorithms (THX Surround EX™, PCM 96kHz, DTS-ES, DTS 96/24, DTS Neo:6, Dolby Digital, Dolby Digital EX, Dolby Pro Logic II and Dolby Pro Logic IIx) and interfaces seamlessly with the AKM data converters to produce excellent audio fidelity.
The VR-8070 uses an AKM AK4628 Multi-channel audio CODEC for processing two-channel analog inputs with its 24-bit/96 kHz A/D converter with 64-times oversampling. The same chip also has eight 24-bit/96 kHz DACs used for the 7.1 audio outputs. The VR-8070 has two optical and two coaxial digital inputs and one optical output that are all handled by an AKM AK4114 Digital Audio Interface Tranceiver.
The component video switching circuitry has its own dedicated circuit board, which helps reduce video noise on these signals. HDTV requires a minimum bandwidth of 38 MHz, but can actually benefit from a higher bandwidth to avoid picture degradation. We tested the video switching using a Sencore VP403 HDTV video generator with our Optoma H77 high-definition DLP projector cabled with Tributaries component video cables. The results were surprisingly good with 720p high definition video making it's way through the receiver without significantly degrading the signal to the projector. DVD (interlaced or progressive) should have no problem passing its signal through this receiver.
THX® Adaptive Decorrelation™ is a newer version of the original THX® Decorrelation™ circuit developed by Lucasfilm that alters the phase or pitch relationship between the left and right surround speakers to produce a more enveloping surround sound field when the surround channels are receiving a mono signal. The "Adaptive" part of the Decorrelation circuit smoothly transitions to stereo when a stereo rear channel signal is detected. This prevents a perceived "jump" in the rear surround channels when moving from a mono signal to a stereo signal and back again. At least this is what the original developer of THX (Tomlinson Holman) told me many years ago. The process seems to work well to create an impressive sounding surround environment with stereo or mono source material in the rear channels. The THX® Front-Channel Re-Equalization™ circuitry applies an X-curve to the front channels that attenuates the high-frequency response, compensating for film soundtracks that can sound overly-bright when played in most rooms with reflective surfaces. If you notice most of the local theaters have sound absorbing walls that deaden the room reflections. More lively rooms such as those found in most typical homes will benefit from this processing. THX® Timbre-Matching™ further improves the sound by equalizing the response of the surround channels, which results in a smoother and seamless sound between the front and rear channels.
Also included in the VR-8070 is the THX® Bass Peak-Level Manager, which is designed to prevent overload to the subwoofer or full-range main channels by allowing the user to set the maximum LFE-channel output level for their system based on the performance capabilities of their speakers. This is especially important when watching high-impact movies where levels can be quite high during action scenes. THX® Loudspeaker Position Time Synchronization™ is important feature that is designed to compensate for the different distances between the listening position and each speaker in the home theater setup. Time delay compensation and level matching results in a more cohesive and realistic surround sound experience.
Something unique to the VR-8070 is the new Dolby Pro Logic IIx processing that extends the popular Pro Logic II capabilities by creating a 6.1 or 7.1 surround fields from a stereo or 5.1 source. Both movie and music modes are available allowing users to adjust parameters for a variety of listening experiences.
The VR-8070 offers a Midnight Mode that is used with Dolby Digital and DTS content to compress the dynamic range when watching movies late at night when others may be sleeping. One of the problems often encountered by users is the difficulty in listening to dialogue during a movie because the volume is too low. Raising the volume solves the dialogue problem, but causes loud scenes to become noisy resulting is the constant adjusting of volume during the course of a movie. The Midnight Mode solves this problem by making quiet sounds louder and vice versa.
Multi-channel SACD and DVD-Audio came from our Sony DVP-NS900V DVD/SACD player and Kenwood DV-5900M DVD-Audio player. Both units had their 5.1 outputs run through a Zektor MAS3 passive audio switcher for convenience. The 5.1 channel audio was connected to the analog inputs on the Kenwood VR-8070 receiver.The digital audio output of the Sony DVP-NS900V was also connected to the VR-8070 to test both Dolby Digital and DTS content.
Next, it was time to use the home theater features and particularly the THX processing that almost every home theater will benefit from. We started with Master and Commander and X-Men2 on the D-VHS D-Theater format that offers viewers with full DTS 5.1 Digital Surround at the 1509 kb/s bitrate. Using our Marantz MV8300 VCR, we were able to extract the DTS bitstream carried on these new releases from 20th Century Fox. The DTS audio quality is superb and creates an amazing theatrical experience with pristine video. Bass was tight and the midrange enveloped us with an unfatiguing presentation.
It should be noted that for high definition content we did not use the VR-8070 for analog video switching since our setup ran the video digitally from the tape to the projector. We were a bit skeptical about the VR-8070's ability to pass high definition content through the component video connections, so we ran a quick test using our Sencore VP403 HDTV video generator and our Optoma H77 high definition DLP projector. Sure enough, the VR-8070 was able to pass the highest frequency of alternating black and while vertical bars from the pattern generator which was about 38MHz. However, we almost always recommend avoiding built-in video switchers when possible.
- Kevin Nakano
Projector: Optoma H77 High-Definition HD2+
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