Retailed for $800 for the pair in the 90s. Here's the stats:
The Harman Kardon Model Thirty is a two-way system designed for stand-mounting. Its 8-inch woofer operates in a vented enclosure, with the port on the front panel just below the woofer. The 1-inch soft-dome tweeter is above the woofer, near the top of the cabinet. The binding-post terminals, recessed into the lower rear of the cabinet, accept wires, lugs, and single or dual banana-plug connectors.
The owner's manual supplied with the speakers was sketchy, containing no specifications, only instructions about placement, connecting wires, and mounting. The speakers are not designed for placement close to a wall but for use on stands (floor spikes are recommended). The manual also recommends "breaking in" the speakers for at least 3 hours at medium volume before attempting critical listening.
The Model Thirty is handsomely styled and finished. The sides of the cabinet are glossy black, the rear panel is flat black, and the top and bottom are covered with a black cloth similar to the front grille. The edges of the cabinet are beveled, and the grille fits flush with the front panel to minimize diffraction of the sound around its periphery.
We mounted the H/K Thirty speakers on stands about 27 inches high and several feet from any room walls. Our composite response curve (formed by splicing the speakers' average room response with a close-miked woofer-response measurement) showed a gentle downward slope with frequency, although the output varied only 3 dB from 150 to 1,500 Hz. There was a drop of about 5 dB from 1,500 to 10.000 Hz and a return to the midrange level between 12,000 and 20,000 Hz.
Although the composite curve, whose maximum point was between 70 and 80 Hz, could be interpreted as covering 20 to 20,000 Hz within ±5 dB, that would not be consistent with the sound we heard from the speaker (or the capabilities of its drivers). As we have noted before, the anechoic-equivalent bass-response curve of a vented speaker, made by combining the outputs of the cone and vent in proportion to their sizes, frequently gives an overly optimistic impression of the speaker's true bass performance in actual use.
A response measurement made with one-third-octave bands of pink noise gave more realistic results. The curve was roughly similar to the midrange and treble portions of the composite curve, but the bass was more believable: ± 3 dB from 60 to 2,000 Hz.
Quasi-anechoic response measurements made with the MLS program of the Audio Precision System One showed a variation of about ±4 dB from 300 to 20,000 Hz. The response was within ±2 dB from 400 to 2,500 Hz, with a narrow dip of 6 dB at 4,000 Hz and smaller variations from 5,000 to 15,000 Hz.
Horizontal dispersion was good, with output variations over a 45-degree angle off the forward axis of about ±3 dB up to 7,000 Hz, -5 dB at 10.000 Hz, and -14 dB at 20,000 Hz. Impedance was a minimum of 4.8 ohms at 40 and 150 Hz and a maximum of 20 ohms at 70 Hz; it reached 12.3 ohms at 1,300 Hz. A 6-ohm rating could probably be justified by these measurements.
Sensitivity was 89 dB sound-pressure level (SPL) at 1 meter with an input of 2.83 volts of pink noise. The woofer distortion with 3.2 volts applied (corresponding to a90-dB SPL in a sensitivity measurement) was between 1 and 2 percent from 48 to 2,000 Hz and rose to 7 percent at 30 Hz.
With single-cycle tone-burst signals, the Model Thirty's woofer reached its excursion limits with a 100-Hz input of 720 watts into its 5-ohm impedance. At 1,000 Hz, the waveform began to distort gradually at about 200 watts, although the speaker absorbed the 550-watt clipping-level output of the amplifier without excessive signs of overload. The tweeter had no problem with the 840-watt maximum output of the amplifier at 10,000 Hz.
The Harman Kardon Thirty sounded very much the way its measured response would suggest. It was very smooth and free of peaks, with a slight warmth but very little upper-bass emphasis. The highs were smooth and totally devoid of harshness but noticeably less crisp than those of several other speakers with which we compared it.
