The frequency response or range, total harmonic distortion, and signal-to-noise ratio these three factors are frequently used to calculate quality of audio adapter.

The frequency response of an audio adapter is the range in which an audio system can record or play at a steady and clear amplitude level. Many cards support 30Hz–20 KHz. As wider spread, better the adapter.

The total harmonic distortion calculates an audio adapter linearity and straightness of a frequency response arc. The harmonic distortion is a compute of correct sound reproduction. Any nonlinear components cause alteration in form of harmonics. As smaller the percentage of distortion is better. This harmonic distortion factor might create difference between cards that utilize similar audio chipset. Cards with cheaper parts have better distortion, making them generate poorer-quality sound.

The signal-to-noise ratio (S/N or SNR) computes strength of sound signal relative to background noise. The superior the number, better the sound quality. E.g. top-of-the-line Sound Blaster Audigy 2 sound card elements an SNR of 106db, but older Sound Blaster Audigy is rated at 100db and the AWE64 series has an SNR of 90db.

These things affect all kinds of audio adapter utilize, from WAV file playback to speech recognition. Remember that low-quality microphones and speakers can corrupt performance of a high-quality sound card.