In this experiment, the signal-to-noise (S/N) ratio and the total harmonic distortion (THD) are measured by converting a 1kHz sine wave. A 1kHz sine wave in 24bit 44.1kHz format is converted into 24bit 48kHz using SSRC without dithering. 123.15dB of S/N ratio and less than 0.00001% of THD are observed.

A 1kHz sine wave with 24bit 48kHz format is converted into 24bit 44.1kHz using SSRC without dithering. 128.58dB of S/N ratio and less than 0.00001% of THD are observed.

Impulse Response

Frequency characteristics are observed by converting impulse responses. An impulse in 24bit 44.1kHz format is converted into 24bit 48kHz with SSRC without dithering.

An impulse in 24bit 48kHz format is converted to 24bit 44.1kHz with SSRC without dithering.

Here is the spectrum of the non-dithered output at the same point. We can see some harmonic distortions.

New noise shapers

As of version 1.32, new noise shapers are available. Users can now
choose from noise shapers with 7 different strengths made from 2
different ATH curves, for 44.1kHz or 48kHz output fs. New noise
shapers are also available for other frequencies, i.e. 8k, 11k, 22k,
88k, 96k, 192k, although not all strength/curve pairs are available
for all frequencies.

The following graph shows the frequency characteristics of the new
shapers made from the first ATH curve, which is used for SSRC for long
years.

The following graph shows the frequency characteristics of the new
shapers made from another ATH curve.

The following graph compares the new shapers and the old shapers. ID
90, 91 and 92 are low, mid and high settings in the previous versions,
respectively. As you see in the graph, the frequency characteritics
for the new noise shapers are much smoother than the previous shapers.