The Vs. Recorder audio glitch refers to a very minor glitch in Pokémon HeartGold and SoulSilver.
Usually when the player uses the Vs. Recorder the game will very slightly lower the music's volume until it is closed again when the game restores the music back to the normal volume.
If the player previously changed the music to a certain track via the Poké Gear in Pokémon HeartGold and SoulSilver, then using the VS Seeker may result in the volume of the music being unchanged.
This glitch does not apply to the Piano in the Villa in Pokémon Platinum.