неискренний тон('I think I must have been rather over-acting my delight, and that she detected a hollow ring in my congratulations, for I saw her eyebrows rise a little, and she glanced at me curiously.' (Sir Arthur Conan Doyle)ART Vancouver)
быть пустым звуком(для кого-либо – to someone: Threats that the west will help Ukrainian resistance in the event of occupation may ring hollow in Moscow, given Russia’s 100% success rate in suppressing resistance movements of this kind.theguardian.com4uzhoj)