Network Audio Players/Servers

Lumin’s new custom DAC renders comparison of the X2 with any previous Wolfson- [HFN Jul ’20] or ESS-based units [HFN Jul ’22 & Apr ’24] redundant. Distortion, noise and even the behaviour of Lumin’s ‘Resampler’ are all fundamentally different. For example, the X2 has a uniformly higher noise floor than previous streamer/DACs with a sub-16-bit 94dB A-wtd S/N ratio. However, this noise will be inaudible, and its subjective impact on ‘digital grain’ may be no bad thing. Distortion is low through bass and mid, hitting a minimum of 0.0004% over the top 10dB of its dynamic range [black, Graph 1] but it increases more markedly at 20kHz [cyan] where it ranges from 0.004% at the peak 5.9V balanced output to 0.2% some –30dB down. With the Qrono filter engaged [see boxout] the DAC clips at 20kHz/0dBFs [dashed blue trace] – the ‘native’ DAC mode possesses higher digital headroom. There is no significant difference in distortion with Qrono engaged but the A-wtd S/N falls further to 93dB; jitter is very slightly higher at 50psec vs. ~10psec; and there’s a more pronounced HF roll-off of –0.1dB to –0.5dB/20kHz, –0.8dB to –10dB/45kHz and –6dB to –10dB/90kHz with 48kHz, 96kHz and 192kHz files, respectively.

Lumin’s ‘Analog Audio Resampling’ is entirely synchronous, but in all instances there’s now an alias component popping up that was not seen in earlier implementations. It’s seen here as a 28kHz peak alongside a 20kHz signal upsampled from 48kHz to 96kHz [red spectrum, Graph 2]. This same signal converted to DSD64 [green spectrum] shows higher and additional alias images (and requantisation noise) while the native 48kHz/24-bit signal is the ‘cleanest’ [black spectrum]. PM