There is a difference in volume between the left and right sides, or the bass (low frequency) sound is insufficient.

If you feel that the bass (low frequency) sound is low or there is a difference in volume levels between the left and right sides of the headphones, change the earbuds to another size that comfortably and snugly fit both ears.

• M-sized earbuds come attached to the headphones at the time of purchase.
• Try the earbud sizes in order from the larger sizes to the smaller sizes, and use the ones that feel more sealed. The best size earbuds may be different for left and right ear.
• Make sure that you are wearing the earbuds properly:
  • For WF-1000XM5, WF-1000XM4, and LinkBuds S, you can measure the air-tightness of the earbud tips using the Determines Optimal Earbud Tips function of the Sony | Headphones Connect app. For details, refer to the How to wear the headphones properly and select most suitable earbud tips article.
  • Using the WF-SP800N as an example of wearing method, when you insert the units into each ear, twist the earbud to secure the arc supporter into your ear grooves. For details, refer to refer to your model's Help Guide.