Greeting everyone, time to jump into Part II of our assessment of lossy Bluetooth music transmission.
In Part I, we examined the use of an Android 10 device (Huawei P30 Pro) as audio transmitter showing the differences between the codecs as played back with the AIYIMA A08 PRO amplifier and its Qualcomm QCC5125 Bluetooth SoC. Please refer to that article for details about the methodology and comparison with the output from a high resolution Topping desktop DAC.
For this Part II, let's focus on the Advanced Audio Coding (AAC) codec which has become a very popular option. Other than the universal default SBC, AAC is probably the most common one for music transmission on account of the fact that the "elephant in the room" - Apple - uses this across its product lines as their standard codec running at 256kbps. Given the amount of use, this is basically a practical standard for quality music transmission over Bluetooth.
Given the broad range of computers/tablets/phones used among family members here, when I'm looking for wireless headphones, I would want to make sure the device supports AAC; probably more so than aptX or LDAC.
Note that there is actually a "family" of AAC profiles from the early Low Complexity AAC (LC-AAC) originating in 1997 up to later versions like Extended High Efficiency AAC (xHE-AAC) released in 2012. As end users, we're generally not privy to such details so I'll just use the generic term "AAC" in this article.