Sony SCD-1 Super Audio CD/CD player Measurements, SACD player

Sidebar 5: Measurements, SACD player mode

But it is as a Super Audio CD player that audiophiles will judge the SCD-1. How does it measure up?

Fig.13 shows its replay response at -3dBFS (footnote 2) with the "standard" output setting (lower traces above 40kHz) and with the "custom" setting (upper traces). DSD can certainly be seen to offer the promised extended HF response. Measuring channel separation was difficult due to the high levels of ultrasonic noise present. But playing an 80kHz tone at 0dBFS in the left channel and performing a wide-bandwidth 1/3-octave spectral analysis on the right-channel analog output gave the result shown in fig.14: a slight blip at 80kHz at -105dBFS can be seen disturbing the otherwise smooth ultrasonic rise in the noise-floor curve, which is nothing to get worried about.

Fig.13 Sony SCD-1, balanced SACD frequency response at -3dBFS with "standard" (bottom) and "custom" (top) output settings. (Right channel dashed, 5dB/vertical div.)

Fig.14 Sony SCD-1, balanced crosstalk SACD spectrum, right, undriven channel analyzed, left channel driven with 80kHz at 0dBFS (10dB/vertical div.).

As indicated in the sidebar, DSD involves very aggressive noise-shaping to achieve its baseband dynamic range. This can be seen in fig.15, which shows wideband 1/3-octave spectral analyses of the player's right-channel output while it plays back 1kHz tones at -60dBFS and -120dBFS (!) (footnote 3). There are two plots for each signal, one taken with the "standard" output setting, the other with the usually blanked-off "custom." There is a significant amount of ultrasonic noise present in each case, though the standard setting provides about 10dB greater filtering at 100kHz.

Fig.15 Sony SCD-1, right-channel spectra of 1kHz tones at -60dBFS and -120dBFS, with noise and spuriae, DSD data. (1/3-octave analysis, "standard" output setting bottom at 80kHz.)

Footnote 2: 0dBFS for a SACD is defined as 50% of the theoretical maximum DSD signal level.

Footnote 3: The test SACD has tones going down in 10dB steps to -160dBFS!

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