If you’re like me and have any pair of wireless earphones or headphones from Sony which work with the Sound Connect app, then you’ve probably seen the option to switch between connection modes (Bluetooth Connection Quality). The two options are to Prioritize Sound Quality or Prioritize Stable Connection. On newer products I believe they default to the stable connection option, likely to give users a better overall experience. However, I found out that there is some nuance to this setting depending on what device you have.
For this test, I currently own two compatible products, the WH-1000XM3 and LinkBuds S (WF-LS900N). Both of these are running on the latest firmware.
Lets take a look at the older XM3. According to the help guide, this product supports AAC, aptX + HD and LDAC. This was the last model of the series to support aptX before dropping it. The guide also says that switching to the stable connection mode will only allow SBC, even though AAC can operate at a lower bitrate and would technically be even more reliable.
As expected, switching to the stable connection mode only allows for SBC. There does not seem to be any changes to the max bitrate in this mode, just a restriction on the codec used. These headphones are by default on the sound quality option, so this limit has to be chosen by the user.
Let’s look at one of their newer products, the LinkBuds S. These came out a bit after the WF-1000XM4 so they inherit some of their features, including their firmware. Sony appears to have moved to a newer firmware architecture as the options available are much more consistent on their newer products. This includes the sound quality options.
The LinkBuds S are on stable connection mode by default. These only support AAC and LDAC, so you would expect that SBC is the only option in this mode. However, they have changed this behaviour and now only restrict LDAC usage. In that case there is no need to switch modes for the typical user right? Well, that was my first thought but upon closer inspection it appears that there is indeed lower sound quality in this mode.
I didn’t want to pay for Bluetooth Tweaker on Windows, so I used my Mac to check the connection bitrate and codec being used. On prioritize connection stability, the max bitrate detected was 192kbps, on AAC. Switching to prioritize sound quality, this changes to 256kbps, which is the standard for AAC Bluetooth playback, matching the Airpods. In both modes on both devices, they operate on a VBR (variable bitrate) connection, which is expected to minimise disruption during playback.
As you can see, there is a difference between the modes besides just a restriction to the codec. I think this information is particularly important more for their newer models as I couldn’t find this information anywhere else.
Hopefully this helped you understand the difference between the modes more clearly. If I made any mistakes please let me know!