When an avatar with an audio source that does not have an associated ONSPAudioSource enters a VRC_Player Audio Override region with Far Limit set to 0 (and Gain limit left at 10), the sound becomes slightly louder. Avatars with an ONSPAudioSource become silent as expected. Additionally, note that if Far is left at the default of 40, entering a player override region does not increase the volume as observed here.
ONSPAudioSourceが入ってないアバター音源がFar制限がゼロなVRC_Player Audio Override範囲に入ると、音量が逆に若干上がります。ONSPAudioSourceがある場合は無音になります。また、Far値がデフォルトの40だと、この音が大きくなる現象が起こりません。
Audio configuration: https://twitter.com/Aetoriz_in_VR/status/1154976117389848576 has the configurations for both avatars (one with, one without ONSP)