To measure the quality of equipment objectively, you should disable any possible processing of the signal in the driver, including timbre control, application of special effects, and audio formats conversion. With X-Fi based audio cards this is only possible in the Audio Creation mode if the Bit-Matched Playback option is turned on and the card’s clock corresponds to the sampling frequency of the reproduced signal. The Wave source helps make sure that the original and reproduced signals are identical.
I performed my measurements at the maximum sampling frequency the cards support at recording, 96kHz. You can click on the summary table for a full report.
The results are somewhat discouraging: the signal-to-noise ratio and total harmonic distortion do not correspond to the declared 115dB. Compare them to the results of the Creative X-Fi Elite Pro:
This card has a 10dB advantage in every parameter. However, these measurements were performed over the cards’ own line inputs whose quality is not yet verified. Besides, RightMark Audio Analyzer displays the averaged result for both channels of the card but they differ greatly in the X-Fi Prelude 7.1 as you can see from the THD spectrogram.
It’s clearly not all right with the left channel, the level of second, third and fourth harmonic being 10dB higher than in the right channel. To identify the weak link, the signal from the Auzen X-Fi Prelude was recorded on the line input of the Creative X-Fi Elite Pro which would only live together with the Auzen card in one system after some serious installation effort.