Config for the Stable Audio Open 1.0 multi-conditioner.
The conditioner bundles three sub-conditioners — a T5 text encoder
(prompt) and two NumberConditioners (seconds_start / seconds_total)
— into the (cross_attn_cond, cross_attn_mask, global_embed) triple the
DiT consumes. The architecture is fully specified by the official
stable_audio_tools MultiConditioner config; the constants here
mirror that.