Description: Hybrid loudspeaker system. Drive-units: 12" cone woofer in a sealed enclosure; electrostatic panel, 15" W by 44.5" H. Crossover frequency: 125Hz. Crossover slopes: second-order, 12dB/octave. Frequency response: 28Hz–22kHz, ±2dB. Presence control switch: +2dB, 1–5kHz. Bass control switch: –5dB, 60–150Hz. Nominal impedance: 8 ohms (minimum 2 ohms). Phase angle: less than 45 degrees. Sensitivity: 90dB/W/m (2.83V). Recommended amplifier power: 80–200Wpc.
Dimensions: 72.75" H by 19" W by 13" D. Weight: 125 lbs each.
Finishes available: light oak,…
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Sidebar 1: Specifications
Sidebar 2: The Sonic Quest
Martin Colloms's discussion last year of some of the imponderable elements of loudspeaker reproduction (Stereophile, November 1992, Vol.15 No.11, p.76) reminded me of something written nearly a quarter-century ago (in Wireless World, November 1970) by metal-cone speaker pioneer Ted Jordan. Ted asked the rhetorical question: "What is the aim of a loudspeaker?" He then proceeded to examine a number of possible answers. The most objective answer possible, and one that would surely impress our engineering alter egos, was: to reproduce the electrical input signal…
Sidebar 3: Measurements
Despite the Z modification making the Quest easier to drive, it's still a demanding load for an amplifier, the impedance dropping to 2.7 ohms in the midbass and lower midrange and dropping below 2 ohms above 16kHz (fig.1). The minimum value is a punishing 1.4 ohms at 25kHz—fortunately, there is no high-level musical information up there. Note the moderate phase angle, however, which ameliorates matters. With the bass set to –5dB, the impedance does become a little kinder in the bass, staying above 4 ohms below 160Hz. The woofer tuning is revealed by the peak at…
I live in a house that has a pyramid-shaped roof, so I guess you could say that I have a thing for pyramids (footnote 1). That's probably why I was immediately drawn to the Green Mountain Audio Diamante. I'm also attracted to floorstanding speakers with small footprints, since my listening/video room is only 13' by 16'. My Holy Grail of loudspeakers is a small speaker that's flat between 20Hz and 20kHz, can do 110dB sound-pressure–levels without straining, and costs less than $1000/pair.
Dream on, Steve.
While the Diamante is quite a bit more expensive than my $1000/pair ideal…
Sidebar 1: Specifications
Description: Floorstanding loudspeaker system with cast onyx-resin "Anechoic Transmission Line" enclosure and separate base. Drive-units: 8" polymer-laminated cone woofer with a vented coil; 4" Nomex/Kevlar/honeycomb cone midrange unit with carbon-fiber frame; 1.1" linen-dome tweeter with ferrofluid-cooled aluminum voice-coil. Crossover frequencies: 350Hz, 3.2kHz; first-order, 6dB/octave slopes. Frequency range: 42Hz–23kHz (no tolerance given). Impedance: 5.3–18.9 ohms. Sensitivity: 88dB/W/m. Recommended amplifier power: 35–350Wpc. Dynamic range: >115dB/pair…
Sidebar 2: System
I don't make drastic changes to my audio system from month to month, because then it would be very difficult to tell what component is doing what to the sound. If the following list looks similar to my system list in prior reviews, that's because it largely is. The following equipment was used:
Analog sources: Thorens/Chadwick 125 Mk.II turntable mounted with a Graham 1.5 tonearm, with arm tubes fitted with Denon 103 C/van den Hul, EMT/van den Hul, Fidelity Research FR-1 Mk.III van den Hul, and AudioQuest BH-200 cartridges; in my large listening room, I used a…
Sidebar 3: Measurements
The Diamante's impedance magnitude and phase are shown in fig.1. The single rise in the bass, to 15.5 ohms, suggests that the ATL loading does act as a true transmission line rather than as some kind of perverted reflex, though its frequency, 51Hz, implies limited low-frequency extension overall, as SS found during his auditioning. When the speaker is used with an amplifier having a high output impedance, this 51Hz impedance peak will result in an effective boost at this frequency. I suspect that this is why SS found his Atma-Sphere tube amplifier not to be a good…
Manufacturer's Comment
Editor: I was very pleased that Steven Stone and John Atkinson were impressed with the Diamante. They heard what our many owners and retailers report: that this is a product which does not call attention to itself. My primary design goal is to be true to the music—our speakers must be revealing, yet always enjoyable. After several months of living with our loudspeaker, Steve reported that the Diamante "allows the music to come through, with very little editorializing." Some of the factors that make this possible are dynamic accuracy, dispersion, time coherence, and…
Looked at from one viewpoint, DVD-Audio and SACD appear to be exercises in sheer profligacy. In the case of DVD-A, why provide a maximum bandwidth almost five times what is conventionally taken to be the audible frequency range, and couple it to a dynamic-range capability far in excess of that achievable by the microphones used to record the sound? In the case of SACD, why provide a potential bandwidth in excess of 1.4MHz, only to fill more than 95% of it with quantization noise?
These questions have answers, and the topics they encompass are anything but trivial: they relate to…
Slope
The third graph in each set will be a complete novelty to most readers. At first glance you might presume it to be a plot of amplitude vs time, just as you would see if you were to view the track in audio editing software (albeit here with the left and right channels superimposed, blue and red traces respectively). But this is actually a graph not of amplitude vs time but of the rate of change of amplitude vs time; ie, of how rapidly the signal changes from one sample to the next. In less elegant parlance, it depicts the signal's slew rate.
The third graph in each set will be a complete novelty to most readers. At first glance you might presume it to be a plot of amplitude vs time, just as you would see if you were to view the track in audio editing software (albeit here with the left and right channels superimposed, blue and red traces respectively). But this is actually a graph not of amplitude vs time but of the rate of change of amplitude vs time; ie, of how rapidly the signal changes from one sample to the next. In less elegant parlance, it depicts the signal's slew rate.
Slew rate is usually specified in…