What Bluetooth profiles are available for headphone connections on iPhone and iPad?

Getting good sound quality on Bluetooth headset seems to depend far more on the Bluetooth profiles used on a connection than the quality of the headset itself.

AAC is quoted in many articles as "the profile you need for Apple devices", and although I found helpful information about finding out the Bluetooth profile used on a given connection, there seems to be no reliable information whether or not AAC really is the only available high-quality audio profile on Apple's mobile OSs.

So, which Bluetooth profiles are available for headphone (stereo audio from device to headphone only) and headset (stereo audio from device to headset, likely mono audio from headset to device, simultaneously) use when used with iOS and iPadOS 14?

Solution 1:

The audio codec and the bluetooth profile are completely separate things. The linked site confuses the terminology. In fact a device, including audio devices, may operate several profiles simultaneously and there are supported profiles that have no audio at all, such as Braille accessories.

If you actually want to know about profiles, the list of currently supported Bluetooth profiles is listed here: https://support.apple.com/HT204387

To summarize:

1. Hands-Free Profile (HFP 1.7)
2. Phone Book Access Profile (PBAP 1.2)
3. Advanced Audio Distribution Profile (A2DP 1.3)
4. Audio/Video Remote Control Profile (AVRCP 1.6)
5. Personal Area Network (PAN) Profile
6. Human Interface Device (HID) Profile
7. Message Access Profile (MAP 1.1)
8. Wireless iPhone Accessory Protocol (WiAP)
9. Braille

With an important disclaimer: The profile’s functionality might vary, depending on the Bluetooth accessory that you use. The accessory manufacturer, not the iOS or iPadOS device, controls these variations.

In short, if you actually want to know you must consult the engineering documents of the accessory manufacturer.

Solution 2:

Isn't AAC a codec, not a BT profile?

Seems AAC is nested in A2DP - ref. Wikipedia

From the Apple documentation https://support.apple.com/en-ca/HT204387 "Advanced Audio Distribution Profile (A2DP 1.3) This profile works with iPhone 5s and later, iPad Air and later, and iPod touch (6th generation) and later."

The technical specs for A2DP are available at bluetooth.org - https://www.bluetooth.com/specifications/archived-specifications/ -- A2DP v. 1.3 here

There's an interesting section in this article about Apple's M1 proprietary BT chip... https://www.howtogeek.com/338750/whats-the-difference-between-bluetooth-a2dp-and-aptx/

Also, maybe take a look at Apple Accessory Device Guideline Specs document here

• specifically "33. Advanced Audio Distribution Profile (A2DP)"

Apple's proprietary-environment business model means they're probably keeping some info close to their chest so they can BEAT(s) out the competition (pun intended).