Qualcomm at CES 2019.

The meteoric rise of wireless earbuds has audio enthusiasts frantically searching for the best wireless headphones. Fortunately, some manufacturers are returning the headphone jack and are being rewarded with Qualcomm’s latest Aqstic smartphone audio codecs, the WCD9375 and WCD9370. These promise to further improve mobile audio. One of the first smartphones to support them is the Xiaomi Redmi K20.

Qualcomm employed the “Golden Ears,” certified experts who register otherwise imperceptible changes in sound. The title leans heavily into pseudoscience territory, but the participants helped engineers create digital filters for the new codecs. Most of us are unable to perceive sound differences quieter than 1dB, about half the loudness of someone breathing. However, the idea behind Golden Ears is that they discern even more minute pressure changes, thus allowing them to observe subtle changes in harmonics.

 WCD9375WCD9370WCD9341 (old)
Dynamic range (playback)123dB120dB130dB
Total harmonic distortion + noise (playback)-105dB-96dB-109dB
PCM (playback)384kHz/32bit192kHz/24bit384kHz/32bit
Dynamic range (recording)109dB104dB109dB
Sampling (recording)192kHz/24bit192kHz/24bit192kHz/24bit
Total harmonic distortion + noise (recording)-103dB-97dB-103dB
Power consumptionHigh performance: 28.52mW
Low power: 6mW
High performance: 16.1mW
Low power: 6mW
High performance: 34mW
Low power: 6mW

Prior to the WCD937x line, Golden Ears testing was reserved for exorbitantly priced audio equipment. Roping a few Golden Ears into helping with the latest codecs may be Qualcomm’s way of piquing consumer interest, but the actual specifications above are impressive. Granted, there doesn’t appear to be a huge improvement between the new WCD9375 and the older WCD9341 codecs. In fact, the older version boasts a greater dynamic range and less total harmonic distortion than the WCD937x family. Power consumption, however, does see a marginal improvement between the new and old codecs, which is good news for power users.

Specifications don’t paint a complete picture, as audio is both an objective and subjective matter. Perhaps the Golden Ear filter will be emblematic of great mobile audio. Until more phones support the codecs, its legacy is hard to definitively predict. We’ll be sure to keep you looped in on any updates and changes to the codecs.

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