Harman Kardon AVR 25 A/V receiver Review

Holding the second slot among Harman Kardon’s A/V receivers, the AVR25 is rated at 75 watts per channel in stereo mode, 65 watts for each of the three front speakers and 25 watts for the surrounds in surround mode. In addition to standard Dolby Pro Logic decoding, it offers two surround modes, Theater and Stadium, both designed for ambience enhancement of conventional two-channel music recordings.

The receiver provides two sets of A/V connections for VCR’s (one play-only), one A/V input for a laserdisc player, two sets of connections for audio tape decks (both record/play), and one input each for a CD player, a phonograph cartridge, and another line-level auxiliary audio source. The rear-panel VCR2 play-only A/V connections have front-panel duplicates that can be selected by a front-panel pushbutton, effectively giving the receiver yet another A/V input, though one that cannot be switched from the remote control.

All the video connections are phono jacks for standard composite video, as are the two rear-panel video-monitor outputs. All the back-panel input jacks are arrayed horizontally, easing “blind” hookup by feel from in front of the receiver, and the various video connectors are directly above their corresponding audio jacks. In that respect, as in ease of use generally, the AVR25 represents an improvement over the top-of-the-line AVR30. The AVR25 also boasts about 1 dB more power in each channel. The AVR30 retains the advantage in versatility, however, with more inputs and seven mu-sic-enhancement modes.

A line-level preamp-out/main-in loop is provided for the front left and right channels, and there are also preamp outputs for the center and surround channels, enabling you to replace any of the receiver’s internal power amplifiers with more powerful external ones and facilitating connection of a powered subwoofer or two-channel equalizer. (The manual’s page 11 mistakenly shows a hookup driving an external front-speaker amplifier from the Main-In jacks rather than the Pre-Out connections, however. Also, the manual calls the front panel’s FM Mode button the FM Mono button, which is what it really is.) Connectors for main left and right and remote speakers are multiway binding posts that take single or dual banana plugs and wire ends, but not spade lugs.

Connectors for the center and two surround speakers are spring clips. An F-connector and a pair of binding posts are provided for an FM antenna and the supplied AM loop antenna, respectively, as are one unswitched and two switched AC outlets. I liked how the manual cautions against plugging high-current devices into the latter, devices like “irons or toasters.”

Miscellaneous convenience features include thirty memory presets for the tuner, a display-intensity control (bright, dim, off), and a sleep timer. The latter two features are operable only from the remote handset, which can also control selected Harman Kardon CD players and cassette decks. The remote is nicely done, with clusters of related controls differentiated variously by spacing, shape, and color.

Lab measurements showed the AVR25 to be a fine performer in the Harman Kardon tradition. That heritage is most evident in the hefty output power levels available for 4-ohm loads. Most of the other amplifier measurements also showed very good performance. The tone controls produced a non-flat frequency response when centered, however: a very slight bass rise and a -1-dB shelf above about 2 kHz. We were able to achieve flat response by turning the treble control to its 1-o’clock position and nudging the bass control down to just below its detent. But an easier way to even out the receiver’s frequency response is simply to hit the Direct button on the front panel, which bypasses the tone-control circuits altogether.

The tuner section was more middle-of-the-road in its performance. Capture ratio, AM rejection, and alternate -channel selectivity on the FM band were very good, but the frequency response, image rejection, sensitivity, and stereo signal-to-noise ratios were only average. Pilot-carrier leakage was unusually low (good). AM frequency response was typically dismal.

In general, the measured Dolby Pro Logic performance was also typical of a receiver in this price class. In Wideband operation, the center channel rolled off at low frequencies earlier than we usually find. Since most installations will use the Normal setting, which shunts center-channel bass to the front left and right speakers starting at an even higher frequency, this is of no major consequence. The slightly extended surround-channel treble response, relative to a more typical 7-kHz cutoff, was due mainly to a 2.3-dB peak near 7 kHz that delayed the required rolloff to a higher than normal frequency.

Pro Logic separation figures were fine, but the measured surround-channel noise was higher than we’re used to seeing (it wasn’t annoyingly audible, though). The surround-channel overload margin indicates that there is a theoretical possibility of clipping that channel of the Pro Logic decoder with the very rare soundtrack that has high peak levels in the surround channels (or with a videodisc player with much higher than normal output). But we heard no evidence of overload in our listening tests.

Another surprise was the distinctly low surround-channel noise-reduction calibration point, which could lead to the surround outputs being overly prominent in laserdisc playback. Admittedly, many people think that even properly decoded surround outputs are too soft, so the AVR25’s behavior here may not always be considered a fault. Moreover, the lowish calibration level probably brings the decoder more into line with the audio output levels of most VCR’s, which are typically about 3 dB lower than those of laserdisc players.

Hookup was easy, thanks to the nicely arranged rear-panel facilities. I missed a subwoofer output, but the Pre-Out/Main-In connections are suitable for feeding a powered subwoofer or two, especially those with loopback high-pass-filtered outputs such as we used in our listening tests.

The AVR25’s remote has all the controls necessary for balancing speaker levels in Dolby Pro Logic mode, a stupendous improvement over the AVR30’s front-panel-only center-level knob. The speaker-balancing test signal mutes for a fraction of a second when cycling between channels, however, which makes aural level comparison more difficult (surround speaker balancing should preferably be done with an inexpensive sound-level meter in any case). The 2-dB steps provided for the center- and surround-speaker adjustments are also too large for really precise balancing. On the test bench, trying to match the levels of the other channels to that of the left front, I could do no better than 0.8 dB high on the center and 0.4 dB low on the surrounds. The disparity between fronts and surrounds therefore exceeded 1 dB, which can easily throw off a carefully balanced sound effect. During listening tests, I never felt confident that the level matches I obtained from the built-in test signal were any better. Such behavior is not unique to the AVR25, however. I would prefer to have a reduced control range on the center and surround outputs (the AVR25 provides an overly generous 70 dB) and finer gradations (more like 0.5 dB).

Once set up, the Dolby Pro Logic decoder proved accurate in imaging and sound steering. Use of a powered subwoofer (highly recommended with any medium-powered A/V receiver) enabled the AVR25 to produce sometimes enormous sound levels with special-effects-laden movies.

In contrast to my experience with some of the modes in the AVR30 — and many other A/V receivers, for that matter — I found it difficult to make the AVR25’s two ambience-enhancement modes sound bad. That is actually high praise for processing that can be effective in adding spaciousness to many kinds of music. There is little audible or measurable difference between the Theater and Stadium modes when they are at the same delay setting. Both send a single simulated reflection to the surround speakers, derived from the difference between the two input channels and delayed by a user-selected interval. There is no recirculating, dense-echo reverberation, however, which is probably just as well, such artificial reverberation being much easier to get wrong than right. Better safe than sorry.

A handsome component that is easy to set up and use, the Harman Kardon AVR25 is on the whole a very good receiver in its class. It is a safe recommendation for someone seeking solid but simple home theater performance at a reasonable price.

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