Term of the Moment
Computer History Museum
Definition: aptX
A family of audio codecs from Qualcomm that are designed to improve the quality of wireless audio transmission. Developed by CSR plc, Cambridge, England and introduced in the 1990s as a DSP chip, aptX encoders are available in both hardware and software for any device with audio output. This entry summarizes aptX for Bluetooth stereo transmission, known as the Bluetooth Advanced Audio Distribution Profile (see Bluetooth audio).
AptX for Bluetooth Speakers and Headphones
The aptX codec is found in smartphones, tablets and Bluetooth speakers in order to provide better sound than the standard Bluetooth SBC music codec, which degrades audio quality. Both sending and receiving devices must be aptX enabled; for example, aptX is used in many Android devices and Mac computers, but not Apple mobile devices.
AptX Is Better for MP3
When an aptX device is given an MP3 file, it first decompresses the MP3 format back to the original 1.411 Mbps of the original linear PCM CD track. It then compresses this "baseband" bitstream to 352 Kbps via ADPCM without any change to the music data. The result is a non-destructive format compared to SBC (see Bluetooth audio). See ADPCM, SBC and Kleer.
An aptX Speaker
aptX and More
AptX for Bluetooth Speakers and Headphones
The aptX codec is found in smartphones, tablets and Bluetooth speakers in order to provide better sound than the standard Bluetooth SBC music codec, which degrades audio quality. Both sending and receiving devices must be aptX enabled; for example, aptX is used in many Android devices and Mac computers, but not Apple mobile devices.
AptX Is Better for MP3
When an aptX device is given an MP3 file, it first decompresses the MP3 format back to the original 1.411 Mbps of the original linear PCM CD track. It then compresses this "baseband" bitstream to 352 Kbps via ADPCM without any change to the music data. The result is a non-destructive format compared to SBC (see Bluetooth audio). See ADPCM, SBC and Kleer.
Crutchfield highlighted the aptX technology in its 2014 catalog for the Klipsch GiG Bluetooth speaker as an example of a quality product.
Bayan Audio's Soundbook stands out in a crowd with its quad 1.5" drivers. Supporting aptX for premium sound, the aluminum case adds rigidity and eliminates resonance.