Floor Loudspeaker Reviews

So far, as part of my quest to find good affordable box loudspeakers, I have reviewed 16 models, in the August, October, and November 1987 issues of Stereophile (Vol.10 Nos.5, 7, & 8). This fourth group of loudspeakers expands the price range covered, down to $329/pair and up to $1349/pair, and includes one model from California (Nelson-Reed), one from Canada (Paradigm), and one, Monitor Audio's "flagship," the R952MD, from the UK.

As can be seen in "Letters" this month, some readers take exception to this series of reviews: "I know of no-one . . . who really gives a damn about $400 loudspeakers . . ." writes Thom Lieb of Riverdale, MD. Well, while I would not disagree that dipole speakers, in the shape of ribbon, Magneplanar, or electrostatic systems, can give sonic results that are undoubtedly high-end, the fact remains that most audiophiles use dynamic loudspeakers of some kind, for reasons of cost, taste, domestic acceptability, and the minimizing of the room interaction problems endemic to panel designs. And when you examine box speakers en masse, apart from a rough rule that a $3000 system will be probably better than one costing $300, in that it will go louder and deeper and give a better-focused stereo image, there is little correlation between purchase price and the degree of musical enjoyment to be obtained.

A designer of genius can produce an excellent, simple, well-balanced two-way design intended to sell at $500, which will sound better than a $1000 three-way design produced by an engineer who is merely talented, which in turn will give more musical enjoyment than a multiway loudspeaker selling for $2000 produced by an entrepreneur who has no idea how to design a speaker other than to throw a number of drive-units into a big box, the whole being held together by a textbook crossover which makes no allowance for such matters as the real, complex, and complicated impedances of the drive-units. (Thankfully, such speakers don't last long in the marketplace.)

I make no apologies, therefore, for letting the focus of my attention roam where it will. The end result, I hope, will be that readers of Stereophile will be able to find loudspeakers which offer a taste of high-end performance for a price somewhat lower than they expected to pay.

Monitor Audio R952MD: $1349/pair
Introduced at the Chicago CES in June 1987 and the top of this British manufacturer's range, the R952MD is a floorstanding loudspeaker, available in a number of real-wood veneers. With its tandem woofers either side of the tweeter, it appears similar in concept to the Mission 780 Argonaut, reviewed in Vol.10 No.6, and coincidentally is manufactured not a million miles away from the Mission factory. Any resemblance is only skin-deep, however, as the '952 represents a growing design philosophy in the UK, in which considerable attention is paid to getting the drive-units to roll off naturally and smoothly out of their intended passbands. As with the inexpensive loudspeakers produced by Acoustic Research for so many years, any crossover can then be very simple, and the current thinking in the UK is that the less complicated the crossover, the more transparent will be the sound. Less will be more.

This reinventing of the wheel was pioneered in 1984 both by Mordaunt-Short's Phil Ward, with his MS100 speaker, and by Robin Marshall with his Epos 14 speaker; Martin Colloms designed an LS3/5A-size DIY speaker conforming with this philosophy for me at HFN/RR in the Spring of 1985; and now Robin Marshall's thinking is embodied as a new series of speakers from Monitor Audio, starting with the R852MD and R952MD. The '952 uses three drive-units but is a two-way design, the two 6.5" woofers operating over the same range. The crossover network is quite simple: a series ferrite-cored inductor in the feed to the two woofers to give a first-order, 6dB/octave electrical low-pass roll-off, and a series capacitor feeding the tweeter to give a complementary first-order high-pass filter action. Connections to the drive-units are hard-wired.

The drive-units themselves, designed and tooled by Monitor, are manufactured and assembled by Elac of England (not to be confused with the West German Elac cartridge manufacturer), and are suitably high-tech. The tweeter uses a 1" aluminum dome, glued to a vented aluminum voice-coil former and suspended with a small roll surround. The dome is protected by a perforated cover, ferrofluid is used in the magnetic gap, and the hollow pole-piece is stuffed with foam to modify any cavity resonance. (A version of this tweeter appears in the new models from British Fidelity.) The woofers are constructed on diecast chassis and are said to have a vented-magnet, one-piece voice-coil assembly, to confer high power capability. Bass loading is infinite-baffle, and a horizontal tension rod ties the cabinet sides together level with the lower woofer, thus splitting each long piece of wood into two unequal areas. This should spread the panel resonant frequencies somewhat.

The cabinet is constructed from MDF, veneered on both sides to avoid warping, and is lined with 2" acoustic foam. The veneer covers the sides and front, with the drive-units neatly rebated, and although a grille is supplied, I used the speakers without, as is my wont. Holes in the speaker's base take bushes for carpet-piercing spikes—the bushes should be glued in at the factory, I feel, rather than by the user. Electrical connection is via five-way binding posts in a recess on the cabinet rear, with the minimal crossover wired on a board attached to the rear of the terminal posts.

The Sound
As no placement instructions were included, I started off with the speakers positioned well away from the rear and side walls of my room, toed-in toward the listening position. As with all speakers I test, I started the review by putting on pink noise at a moderate level overnight to free things up. I seem to be unlucky with Monitor Audio products; readers will remember that I blew one of the R352 woofers toward the end of the listening session. Anyway, the following morning, the sound was not right—yes, this time I had taken out a tweeter! Kevro Electronics' Robert Sinclair couldn't have been more helpful: "I'll send you a new dome for the tweeter so you can repair it."

I explained that he should send a complete new tweeter, drive-unit-assembly not having been on the college curriculum back in the 1960s. "No problem," quoth he. The next day, a Federal Express package awaited my attention in the office. Inside was not a replacement tweeter but a dome/voice-coil assembly. It turned out that my fears were groundless. All that needed to be done was to remove the tweeter faceplate, unsolder the connections, remove the old assembly and drop in the new one, the voice-coil sliding into the magnetic gap. Locating pins on the magnet assembly engage with holes in the laminate holding the dome assembly, and the tolerances are close enough that the repaired tweeter should match the old one sonically.