Automatic gain control Echo cancellation Noise suppression

IA model GPT-4o Realtime Preview GPT-4o Realtime Preview (2024-10-01) GPT-4o Realtime Preview (2024-12-17) GPT-4o mini Realtime Preview GPT-4o mini Realtime Preview (2024-12-17) Voice Alloy Coral Sage Shimmer Ash Ballad Echo Verse Start