E-mu 20K

E-MU 20K is the commercial name for a line of audio chips by Creative Technology, commercially known as the Sound Blaster X-Fi chipset. The series comprises the E-MU 20K1 (CA20K1) and E-MU 20K2 (CA20K2) audio chips.

The 20K1 chip was launched in August 2005, and ever since it has been used in a variety of audio solutions from Creative, and more recently third-party manufacturers, such as Auzentech and Audiotrak.

The audio processor on X-Fi was the most powerful at its time of release, offering an extremely robust sample rate conversion (SRC) engine in addition to enhanced internal sound channel routing options and greater 3D audio enhancement capabilities. A significant portion of the audio processing unit was devoted to this resampling engine. The SRC engine was far more capable than previous Creative sound card offerings, a limitation that had been a major thorn in Creative's side. Most digital audio is sampled at 44.1 kHz, a standard no doubt related to CD-DA, while sound cards were often designed to process audio at 48 kHz. So, the 44.1 kHz audio must be resampled to 48 kHz (Creative's previous cards' DSPs operated at 48 kHz) for the audio DSP to be able to process and affect it. A poor resampling implementation introduces artifacts into the audio which can be heard, and measured as higher intermodulation distortion, within higher frequencies (generally 16 kHz and up).[1] X-Fi's resampling engine produces a near-lossless-quality result, far exceeding any known audio card DSP available at the time of release. This functionality is used not only for simple audio playback, but for several other features of the card such as the "Crystalizer", a technology that claims to improve the clarity of digital music through digital analysis (supported by all X-Fi models, including the Xtreme Audio and X-Mod).

The X-Fi name has also been applied to cards based on the CA0106 and CA0110 chips, which belong to the previous generation Live!/Audigy series.