Hi @Bodor,
Please see this post on making the subset of blocks scrollable. Let us know if you need help adapting it to your use case!
Another option is to switch to Prodigy's new pages UI, where you can define series of annotation cards (pages) that all belong to the same task. Imagine that each page would contain a copy of the same audio block and a different text block. This way you could avoid scrolling altogether.