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Better sound quality and ultrasonic spectra

Editor: Thanks for John Atkinson's interesting and informative article about sounds above 22kHz. I was already pretty convinced, after reading the James Boyk paper referenced in the article, that musical instruments do indeed make sounds above 20kHz, and JA's results nicely confirm this. I agree that the most likely reason for audible improvements of sampling rates higher than 96kHz, or of upsampling, is getting the filter artifacts further away from the music,…

Editor: In the penultimate paragraph of his article in the October 2000 Stereophile, John Atkinson wrote: "Something other than pure frequency response must be going on."

Well, yes, John, it is. That's because we don't hear music as a frequency-domain phenomenon, it isn't processed by our recording/reproduction chains as a frequency-domain phenomenon, and it isn't created as a frequency-domain phenomenon, and certainly not a steady-state frequency-domain phenomenon (which is what would be required for the Fourier analysis that gives…

After I had finished measuring the review sample of the first DVD-Audio player to reach these shores, Technics' $1200 DVD-A10, for Jonathan Scull's report in the November 2000 Stereophile, I set it up in my listening room.

Basically, I thought the Technics was okay as a CD player—not in the first or even second rank, but its sound was better than I'd expected: excellent clarity, no treble grain. Playing the two sampler DVD-As that were all that I had available to me in October 2000, the Technics' sound quality went up a notch,…

What you are seeing in these two graphs is evidence that, despite being labeled as a 24/96 recording, the Steely Dan was mixed and mastered apparently at 48kHz,…

Figs.9 and 10 show spectrograms for the introduction of the Gershwin Piano Concerto in F (Classic DAD 1018) and for an extract from the Scherzo of Dvorák's "New World" Symphony, from the unofficial Japanese DVD-A sampler. Both were mastered at 96kHz; though the former is from an analog tape and the latter from a digital tape, they don't differ appreciably in their ultrasonic content, which extends to about 30kHz, with brass and cymbals the primary…

California Audio Labs CL-20: DVD/CD player with remote control and HDCD capability. DAC outputs: 96kHz sampling, 4Hz-44kHz (DVD); 48kHz sampling, 4Hz-22kHz (DVD); 44.1kHz sampling, 5Hz-20kHz (CD). Audio S/N: 110dB (20-bit resolution). Dynamic range; 100dB. THD: 0.005%. Analog audio output voltage: 2V RMS. Analog audio output impedance: <50 ohms. Outputs: two Dolby Digital AC-3 5.1/48kHz PCM digital (coax and TosLink), two 24-bit/96kHz PCM digital audio (double-speed coax and AES/EBU). RS-232 digital interface for future software upgrades/control. Composite…

Despite the temptation to find optimum mating components for each of these devices, I felt it was necessary to confine these auditions to a fixed context: Beyond the source components that are the topic of this review, everything in the system was held constant.

The balanced outputs of a Simaudio Moon P-5 preamp were connected to the balanced inputs of a Simaudio Moon W-5 amp by 20' of JPS Balanced Conductors. The amp drove a pair of Genesis 500 speakers via 6' of Straight Wire Maestro II cables. The players or DACs under test were connected by 1m…

Perhaps because it uses a DVD transport, the CL-20 offered superb error correction. It played without a glitch through the Pierre Verany Test CD's track 35, which has a 2.4mm gap in its data spiral, breaking up only on track 36. However, its use of a single CD-compatible DVD pickup meant that I couldn't assess its jitter: the test signals for the Miller Audio Research Jitter Analyzer are carried on a low-jitter CD-R, which couldn't be recognized by the CAL player.

The maximum output from the analog jacks was a fraction of a dB above the CD Standard level…

Similar changes have occurred in electronics. Audio Research, a leading American manufacturer of tube power amplifiers and preamplifiers, introduced a line of solid…