Aurender W20SE Music Server

Gilding the Lilly

Equipment report
Music servers and computer audio
Aurender W20SE Music Server

An entirely new feature in the W20SE is PCM upsampling from 44.1kHz or 48kHz to two times, four times, or eight times the original frequency (88.2kHz/96kHz, 176.4kHz/192kHz, and 352.8/384kHz). Why pairs of sampling frequencies so close together? So that the upsampled frequency is an integer multiple of the base frequency. Such integer-multiple upsampling is easier to realize and sounds much better than non-integer upsampling. The highest output frequencies of 352.8kHz and 384kHz require dual-wire connection to a dual-wire-capable DAC. The upsampling works only on the AES/EBU, TosLink, and SPDIF outputs, not on the USB output—the upsampling is performed by hardware via a field-programable gate array, not in software by the CPU, and the FPGA doesn’t feed the USB output. Aurender believes that software-based digital signal processing degrades the signal.

The W20SE will also convert DSD to PCM with user-selectable PCM output sampling frequencies of 88.2kHz, 176.4kHz, or 352.8kHz. You can also select the DSD low-pass filter frequency (24kHz, 30kHz, 40kHz, or 50kHz). This DSD-to-PCM conversion is useful because many DACs support DSD only on their USB inputs. The DSD-to-PCM conversion isn’t performed in software by the CPU, but rather by a field-programmable gate array using thousands of filter taps. Aurender maintains that their FPGA approach sounds better than software-based DSD-to-PCM conversion.

MQA Core decoding is now standard rather than an added-cost option. MQA Core decoding “unfolds” the MQA signal to either 88.2kHz or 96kHz sample rate for decoding by your non-MQA DAC. This approach isn’t as good as feeding a DAC that has full MQA decoding, but is a significant improvement over sending 44.1kHz to your non-MQA DAC. Of course, if you have an MQA-compatible DAC the W20SE will pass the MQA signal to the DAC for full MQA decoding. 

Overall, the updates to the W20SE are significant. But it speaks volumes about the rightness of the original W20’s fundamental design that this new flagship is based on the same technologies and architecture. 

It was easy to identify the sonic differences between the W20 and W20SE; I had both in my rack at the same time and was able to make direct comparisons. Moreover, I was so familiar with the sound of the system with the W20 that the improvements in the SE were readily apparent.

First, the W20SE is smoother than the W20, with greater timbral liquidity and ease. The SE’s treble is more refined and better integrated into the music’s fabric. By comparison the original W20 had a hint of sibilance on Nora Jones’ voice on her album Day Breaks, causing treble to stand out a bit in the mix. Similarly, Roy Haynes’ cymbals on Like Minds (with Gary Burton, Chick Corea, Pat Metheny, and Dave Holland—what a band!) through the W20SE were slightly softer sounding, but no less present or energetic, a consequence of less treble hash. I also heard greater delicacy through the treble, which was apparent not just on cymbals but also on strings, which sounded more lifelike and organic.

The SE is more analog-like overall, with greater dimensionality and space between instruments. Instrumental images are more solid, tangible, and three-dimensional, with a greater impression of body. These images are presented in a much larger and more expansive soundstage, with spatial cues such as hall reverberation better resolved. Although the soundstage is larger, the overall perspective is a bit more present and immediate, not in a forward-sounding way but rather by virtue of the greater tangibility of instrumental images.