Monitor Audio Platinum 300 3G

Loudspeakers from British manufacturer Monitor Audio have consistently received favorable reviews in Stereophile over the past decades.

- JOHN ATKINSON

From the R952MD I reviewed in January 1988 to the Silver 500 7G reviewed by Rob Schryer in February 2022, Monitor Audio speakers have offered excellent sound quality and high-quality engineering. So when I was offered the company's Platinum 300 3G for review, I readily agreed. Having lived with standmounts and mini-monitors for the past year, I felt it would be good to spend some time with a pair of large, full-range, three-way floorstanders.

The Platinum 300 3G

With its elegant-looking enclosure featuring a gently curved front baffle and sidewalls and a concave rear panel, and its drive unit array of folded ribbon tweeter, 4" midrange unit, and two 8" woofers, Monitor Audio's Platinum 300 3G looks very similar to the Platinum PL300 II loudspeaker that Robert Deutsch reviewed in November 2016. Those speakers cost $14,496/pair back then; the 3Gs cost $17,900/pair, which, adjusted for inflation, is a lower price than that of its predecessor.

There are significant differences, however, all intended to reduce distortion and increase driver bandwidths. The new Micro Pleated Diaphragm (MPD) III tweeter, a variant of the Heil Air Motion Transformer (AMT), was developed for Monitor Audio's 50th Anniversary flagship Hyphn loudspeaker. The crossover from the midrange unit is set at 3kHz, and the tweeter's passband is said to extend to above 60kHz compared to >40kHz for a typical AMT tweeter. Monitor Audio's downloadable brochure mentions a gentle rise on-axis to maximize high-frequency detail. The square tweeter diaphragm is surrounded with a waveguide to control directivity.