Onkyo TX-RV47 A/V receiver Review

Onkyo’s TX-RV47 combines a highly versatile audio and video control center with an amplifier rated to deliver 55 watts per channel continuous output into 8-ohm loads from 20 to 20,000 Hz with no more than 0.08 percent total harmonic distortion. It carries dynamic-power ratings (at 1,000 Hz) of 90 watts per channel into 4 ohms or 73 watts into 8 ohms. In addition to all the usual control features, it has sound-processing circuits that can simulate stereo from mono programs, expand the sonic image of a stereo program, and dynamically enhance the bass response. There is also a four-channel matrix system designed to extract “surround sound” from encoded stereo movie soundtracks as well as ordinary two-channel stereo programs.

The TX-RV47’s digital-synthesis AM/FM tuner has both automatic and manual tuning modes and sixteen station presets that can be assigned to either band. The preamplifier has inputs for a phono cartridge, a CD player, and two audio tape decks, with dubbing possible from Tape 1 to Tape 2. It can also control two VCR’s and a videodisc player (VDP), channeling their video outputs to an external TV receiver or monitor and their audio to the hi-fi system’s speakers. Videocassettes can be dubbed from either VCR to the other, and the sound portion of any video program can be replaced by a program from any of the audio inputs.

Except for three small horizontal sliders for bass, treble, and balance, all the receiver’s controls are soft-touch keys or pushbuttons, and most of their functions are duplicated on the supplied wireless remote control. Although preset stations cannot be randomly accessed from the remote control, it can step through the presets sequentially in either direction or else scan them automatically with a 5-second pause on each station. The display window on the front panel provides complete information on the receiver’s operating status.

In addition to the usual audio input and output phono jacks, the rear apron of the TX-RV47 contains jacks for the video inputs and outputs from the VDP and VCR’s. A slide switch for each VCR selects either mono or stereo audio output (stereo is usable only with a hi-fi VCR), and a third switch disables the audio “beep” that normally accompanies any operation of a tuning or input-selector button. There are insulated spring terminals for the two pairs of speaker outputs and four a.c. outlets (three of them switched). The binding-post antenna terminals for AM loop and 300-ohm FM antennas are supplemented by an F-type jack for use with 75-ohm coaxial inputs. Finally, there are two integral cables, terminated in DIN plugs, to connect a compatible Onkyo record player or cassette deck for control by the receiver’s remote unit.

The Onkyo TX-RV47 measures 17-1/8 inches wide, 15-3/8 inches deep, and 4-3/4 inches high, and it weighs 21 pounds. Price: $500.

Lab Tests

The Onkyo TX-RV47 is a relatively large and heavy receiver for its rated power, and as a result it became no more than moderately warm at any time during our tests, including the 1-hour preconditioning period at one-third rated power.

The audio amplifiers had no difficulty driving loads as low as 2 ohms at power levels considerably exceeding their 8-ohm ratings. The amplifier’s dynamic headroom (2.14 dB) was also excellent for a moderate-power receiver. The equalization accuracy of the phono preamplifier was so good that we had to plot its response on the expanded scale used for CD players in order to measure its departure from the ideal RIAA response. In all of our significant other measurements, the TX-RV47 either met or surpassed its rated specifications.

The loudness-compensation control boosted both low and high frequencies as the volume setting was reduced, although the effect was only slight until the volume was set at least 30 dB below its maximum. Below this point the response was fixed, with a maximum bass boost of 7 dB and a treble boost of 5 dB. The simulated stereo circuit is a comb filter that modifies the frequency response of each channel to create the illusion of a “true” stereo signal.

The stereo image expander appears to be a phase and amplitude modifier that spreads the sound-stage across a larger portion of the room (sometimes beyond the limits of the speaker positions). The dynamic bass expander is an unusual circuit that boosts the response below about 100 Hz when the program contains energy in that band, but only in proportion to the signal level. At low levels the response is not affected, and the bass is gradually boosted at higher program levels, to a maximum of about 6 dB.

The FM tuner section of the TX-RV47 was in some ways quite ordinary and in others outstanding. For example, its 44-dB image rejection is only marginally acceptable for a good-quality home receiver, though it still surpassed the manufacturer’s rating of 40 dB, and the alternate-channel selectivity of 51 dB fell slightly short of the rated 55 dB. In some other important respects, however, such as its capture ratio of 1 dB and AM rejection of 80 dB, the tuner far surpassed both its own ratings and the expected performance of a receiver in its price class.

Comments

Onkyo has created a highly versatile and attractive receiver in the TX-RV47. It does many things and virtually all of them very well. If you have, or plan to have, an integrated audio/video entertainment system, this receiver could meet your needs. The emphasis seems to be on the audio portion of its capabilities, in which it provides more genuinely useful control than most other receivers we have seen. Its video role is essentially one of signal switching, with no attempt to provide specialized video modification effects besides the option of substituting any audio program source for the recorded video soundtrack. But most users will probably find the audio and video dubbing capabilities more than adequate.

We used all of the TX-RV47’s audio control and signal-modification features in our listening tests, and they all worked well for their intended applications. The four-channel surround-sound matrix was especially interesting to us. Since there is no independent control of the rear speaker level, we wondered how effective the system would be. In a word, very! Apparently the results are quite satisfactory as long as both front and rear speakers are of moderate sensitivity (say, 85 to 90 dB), with an effect of enhanced spaciousness even though the rear speakers are rarely audible as distinct sound sources. The rear speakers carry only the difference signal (L—R) and are effectively silent during mono programs. A novel feature of the Onkyo matrix system is that the lower-bass frequencies, which usually have little or no separation, are injected full strength into the rear speakers at all times. The intent is to impart an enhanced bass response to the overall system (especially if the rear speakers have good low-end response) without losing the spatial enhancement of the speaker matrix. The circuit seemed to have the desired effect, as did the dynamic bass enhancer.

Everything about the Onkyo TX-RV47 worked as it was supposed to, leaving us with a very positive feeling about it. Although the receiver is certainly feature-laden, it is easy to use, and every control does something useful. If you are a purist, you don’t have to use all its features to enjoy its performance. Even though some of the super-power receivers on the market today might give you the impression that 55 watts per channel is a skimpy power reserve, the TX-RV47 is far from underpowered. Its amplifier section can deliver a lot more than 55 watts into almost any speaker load it is likely to face without getting hot or even tripping its protection circuits (they never operated during our tests, which tend to be rather abusive of an amplifier). This is a lot of receiver for the money.

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