Appendix 1: Glossary
• Noise Level
The level of any undesired system noise signals over the audio spectrum, including AC mains
hum, white noises, stray magnetic field, etc.
Signal-to-Noise Ratio, the ratio of the maximum amplitude signal to the sum of the noise
energy. The higher, the better.
Total Harmonic Distortion plus Noise, measured by attenuating the fundamental signal with a
narrow band notch filter, then measuring the remaining signal which consists of harmonics of
various order. This implies the linearity of the audio converter and the lower, the better.
• Frequency Response
A measure of a device's ability to respond to a fixed input voltage, at different input
frequencies, and the difference in amplitude reproduced for each frequency. The flatter curve
at wider frequency range is better.
• Dynamic Range
The difference, usually expressed in dB, between the highest and lowest amplitude portions of
a signal which a device can linearly handle. Ideally it should be very close to SNR value and
the higher, the better.
Unwanted signal coupling from another channel of stereo or multi-channel transmission. The
lower value is better.
ASUS Xonar Essence STX Audio Precision Test Report