The Marantz HD 550 is a 3-way loudspeaker model manufactured by Marantz between 1977 and 1980 in Japan. It features a unique design with a brown color finish and dimensions of 324 x 571 x 241 mm (WxHxD). The speaker has a nominal power handling of 75 W and a music power handling of 120 W, making it suitable for a variety of listening environments. With an efficiency rating of 88 dB and a frequency response range of 35 Hz to 20,000 Hz, the HD 550 offers a wide audio spectrum. The transitional ranges are set at 800 Hz and 3,000 Hz. The speaker uses an 8 Ohm impedance, providing compatibility with a range of audio equipment. One of the unique features of the HD 550 is the level control for midrange, treble, and super treble frequencies, which allows for customized sound preferences. Additionally, it includes a Vari Q, a variable shutter for the bass reflex port that enables adjustments to the tuning of the speaker. It was originally priced around 140 US dollars in 1977 or 500 DM per piece.
