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Even though the Sharp follows its output stage with passive low-pass filtering, the aggressive noiseshaping used in the Sharp's digital encoder results in this residual HF noise. There will also be a contribution from its switching output stage. The noise made it difficult to measure the SX-100's harmonic distortion. The bottom trace in fig.4, for example, shows the distortion residual on a 1kHz tone (top trace): it is random HF noise. Using an additional 6th-order passive filter (supplied by Sharp) on the amplifier's output, however, gave the trace shown in fig.5. What distortion the…
Because its output stage is switching between the full ±32V voltage rails all the time, even when there isn't an output signal present, the Sharp doesn't clip like a conventional amplifier. Looking at the output waveform on a 'scope while I drove it into overload—don't try this at home, gentle readers—revealed the sinewave to become triangular in shape, with bursts of ultrasonic noise increasingly becoming apparent on the positive and negative peaks.
I investigated the Sharp's peak power delivery with the Miller Audio Research Amplifier Profiler, a "virtual instrument" (realized on a…
Increasing the measurement bandwidth to 200kHz and changing the input data to 16-bit "digital black" gave the traces shown in fig.11. Again, the high noise floor in the audioband and the 500kHz spectral component can be seen, but so can the full extent of the noiseshaping. The noise peaks at -35dB around 120kHz, even after its processing by the amplifier's internal passive filter!
Fig.11 Sharp SM-SX100, 1/3-octave spectrum of digital black, with noise and spuriae, 16-bit data (right channel dashed).
Finally, I assessed the Sharp's rejection of wordclock jitter using the…
Yamaha once made a loudspeaker shaped like an ear. I felt sorry for the guy (especially if he was an audiophile) who had to write the ad copy explaining why a speaker shaped like an ear would sound better than one shaped like a shoebox or a wedge of cheese. An ear-shaped loudspeaker makes about as much sense as an eyeball-shaped television. But what about a loudspeaker that is designed like a musical instrument?
When Sonus Faber's Franco Serblin began creating his Homage series of loudspeakers (footnote 1) to honor the great violin makers of Cremona—Amati, Guarneri, Stradivari—his design…
When you're accustomed to narrow-baffled speakers, being confronted by two wide expanses of wood can be jolting. Because the Stradivaris have more of a "room divider" presence than most moving-coil–based speakers, they affect room acoustics even when silent. I could "hear" them. I wondered how music—especially the imaging and soundstaging—could not be affected. As I sat down to listen for the first time, the visual cues took me back to 1986, to the first time I heard Harry Pearson's Infinity IRS system, which presented another set of wide-baffled (line-source) speakers just a few feet away…
Given the Stradivari's drive-units and the attention paid to its cabinet, you might expect exceptional dynamic abilities. You wouldn't be disappointed. Like all great, large, expensive speakers, the Stradivari delivered the musical goods with a confident grip at both ends of the scale, and without breaking a sweat. Most noticeable were the low-level dynamics, especially in the bass and midbass region, where, at the ends of familiar bass lines, the speaker seemed to reveal a last bit of decay that had been previously obscured. Played at high SPLs or at a whisper, the Stradivari remained open…
Sidebar 1: Specifications
Description: Three-way, floorstanding loudspeaker. Drive-units: Scan-Speak 1" silk ring-radiator tweeter, Audio Technology 6" pulp-cone midrange unit, two SEAS 12" aluminum/magnesium-cone woofers. Crossover frequencies: 300Hz, 4kHz. Frequency range: 22Hz–40kHz. Sensitivity: 92dB/W/m. Nominal impedance: 4 ohms.
Dimensions: 53.5" (1360mm) H by 25.6" (650mm) W by 19.7" (500mm) D. Weight: 165 lbs (75kg).
Finishes: violin red, slate gray.
Serial number of units reviewed: 003.
Price: $40,000/pair. Approximate number of dealers: 12.
Manufacturer: Sonus…
Sidebar 2: Associated Equipment
Analog sources: Simon Yorke S7, T+A G10 turntables; Immedia RPM-2, Graham 2.2, SME M2 tonearms; Graham Nightingale II, Lyra Titan, Lyra Helikon SL, Shelter 301, T+A C 10 cartridges.
Digital sources: Musical Fidelity Tri-Vista, Krell Standard SACD/CD players, Alesis Masterlink CD-R recorder.
Preamplification: Manley Steelhead, BAT VK-10SE phono preamplifiers; Musical Fidelity kWp preamplifier.
Power amplifier: Musical Fidelity kW.
Cables: Interconnect: AudioQuest Cheetah, Sky; Harmonic Technology LAM. Speaker: Harmonic Technology Magic Woofer.…
Sidebar 2: Measurements
The drop-dead gorgeous Stradivari Homage is specified as having a very high 92dB voltage sensitivity; to Sonus Faber's credit, my estimated figure was even higher, at 93dB(B)/2.83V/m. However, the speaker asks the partnering amplifier for a lot of current capability, its impedance (fig.1) dropping to 3 ohms and below for much of the upper bass and midrange. And the combination of 4.4 ohms impedance magnitude and –48 capacitive phase angle at 55Hz will give lesser amplifiers conniptions.
Fig.1 Sonus Faber Stradivari Homage, electrical impedance (…
Sidebar 1: Specifications
Description: Solid-state, 5-channel digital surround A/V receiver.
Inputs: 7.1-channel analog: 1 set for use with external processor. Line-level: 10 sets Analog Input (Phono, CD, DVD, VDP, TV/DBS, V-AUX, VCR-1, VCR-2, MD/Tape-1, Tape-2. Audio only: 4 sets, 2 with tape loops. Digital: 8 sets: 5 optical, 3 coaxial. Composite Video: 6 sets, all with S-video connectors: DVD, VDP, TV/DBS, V-AUX, VCR-1, VCR-2. Component Video (2 sets): DVD, TV/DBS.
Outputs: 1 optical digital audio. Audio line-level: 1 set 8-channel preamplifier (Front L/R, Center, Surround L/R,…