Hitachi HS-300 (1975)
A wide-dispersion floorstander with a folded cloth surround on the woofer and a diffraction grating over the tweeter.
Overview
The HS-300 is a two-way, vented floor-standing speaker. Hitachi built it around an 8-inch woofer and a 2½-inch cone tweeter. The claimed crossover is 3.8 Hz, which is almost certainly a typo in the manufacturer's own spec sheet for 3.8 kHz, so treat that number with suspicion. The system is rated 8 ohms nominal, 50 watts maximum music input, and a stated 55 to 16,000 Hz at −8 dB (or 45 to 19,000 Hz at −15 dB). It measures 11½ inches wide, 27 inches tall and 10⅝ inches deep, and it weighs 28.6 lbs. The original price was $189.95.
The woofer is the interesting part. Instead of the usual outer-edge surround, Hitachi used a gathered-edge suspension, a pleated, accordion-like fold you can see from the front. Audio (March 1975, p.49) admitted the reviewer's first instinct was that a rigid-looking fold shouldn't work at all. Light finger pressure on the cone showed it moved freely and over a long throw. The motor is serious for the price: an aluminum voice-coil bobbin, both aluminum and copper shorting rings in the magnet circuit, and a coating on the back of the cone to suppress breakup. The tweeter sits behind what Hitachi calls an acoustic lens. Audio's reviewer thought it looked more like a diffraction grating, but whatever the name, it spreads the top end horizontally.
The cabinet is a 30-liter (1830 cu. in.) vented box with absorbing material inside for damping, finished in natural wood on the sides and top. The connections are well-marked quick-access terminals in a recessed cavity on the rear. The front grille is removable, though with no level controls up front there's little reason to take it off. Each speaker shipped with its own set of measured curves, which Audio (March 1975, p.49) called "putting it on the line" for a manufacturer. It also came with a well-written instruction manual and a three-year warranty to the original purchaser.
The same review gives the listening verdict. Audio (March 1975, p.49) found the extreme low bass absent, the low and mid bass up to the octave below middle C slightly prominent, the mids somewhat irregular, and the extreme top down in level. A touch of treble control restored the highs. Pulling the speakers slightly away from the wall cured more of the bass heaviness than any tone control could. Overall the HS-300 is unobtrusive: no extreme coloration, no listening fatigue, and a polite sound that renders piano and voice reasonably accurately. Transient response on percussion was good, and lateral stereo imaging was solid enough that you didn't need to sit on a chalk mark. The image was two-dimensional, though. Instruments were placed correctly left-to-right but compressed in depth, most noticeably on choral material. The reviewer called that a taste call.
The measurements show where the limits are. Audio (March 1975, p.48) found harmonic distortion stayed low up to roughly 75 watts except at the very bottom, with a sudden overload above about 80 watts average. Above 10 watts the air moving through the front vent was enough to push the damping material and the inner mesh grille into contact. That produced a buzz audible on high-level sine waves, though not on music. The reviewer's practical advice was not to pile on bass boost, and to consider a two-ampere fast-blow fuse if you like it loud. Intermodulation distortion stayed low all the way to 100 watts. The speaker also handled a 20 dB crescendo over a middle C inner voice without muddying it, even at peaks over 300 watts, and hand claps and cymbal crashes came through clean.
Placement matters more than usual here. The HS-300 launches sound in a slightly vertical direction, as a floor-mounted system should, so ceiling and floor reflections are part of the deal. Audio (March 1975, p.48) noted that floor placement costs some middle-frequency accuracy to scatter, and that getting the speaker off the floor may pay off depending on the room. Keep lamps and bookcases away from the sides, since the wide dispersion means nearby objects reflect substantially. The left speaker of a pair tends to run slightly hotter than the right at average placement, so a small level nudge to the right channel balances the pair.
For a collector, the HS-300 is a modest piece, a $189.95 two-way from 1975 and not a statement speaker. It is well documented, though, since each unit left the factory with its own measured curves, and the woofer design is more thoughtful than the price suggests. The gathered-edge surround is the thing to inspect on a used pair. The vent buzz above 10 watts on test tones is a design characteristic, not a fault, so don't chase it as a repair. Expect the polite, slightly bass-heavy, depth-shy presentation the period review describes, and place them accordingly.
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