tonistry.

Connections & formats

aptX

Also called aptX HD, aptX Adaptive, aptX Lossless

aptX is a family of Bluetooth audio codecs from Qualcomm, found on most Android phones and many headphones but not on iPhones. aptX HD and aptX Adaptive raise the bitrate and quality; aptX Lossless claims to deliver CD-quality audio bit for bit when conditions allow.

05001,0001,500kbpsSBC328AAC256aptX352aptX Adaptive280–420aptX HD576LDAC330 / 660 / 990aptX Lossless~1,100FLAC (CD)~700–1,000CD PCM1,411
Bitrates of the aptX family: aptX 352 kbps, aptX Adaptive about 280 to 420, aptX HD 576 and aptX Lossless about 1,100 kbps, shown against SBC, AAC, LDAC and the 1,411 kbps of uncompressed CD-quality PCM.

The original aptX runs at 352 kbps and was an early step up from SBC. aptX HD reaches 576 kbps with 24-bit input, and aptX Adaptive varies between about 280 and 420 kbps to balance quality against a stable link and low latency. Both devices need the same version for it to be used.

aptX Lossless, part of Qualcomm’s Snapdragon Sound platform, can pass 16-bit/44.1 kHz audio without loss at over 1 Mbps, which few phone and headphone pairs support so far. Across the family, independent tests find the differences from LDAC at similar bitrates to be small; the Bluetooth headphone itself is the larger variable.

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