Breakdown of Sollte die Raumtemperatur sinken, wird der Sänger frieren.
sollen
should / ought to
der Sänger
the singer
werden
will (future auxiliary)
frieren
to freeze
Questions & Answers about Sollte die Raumtemperatur sinken, wird der Sänger frieren.
Why does this sentence start with the verb Sollte, and where is the wenn?
In German, you can drop the word wenn (if) in conditional sentences by moving the conjugated verb to the very beginning. Here, Sollte die Raumtemperatur sinken means exactly the same as Wenn die Raumtemperatur sinken sollte (If the room temperature should drop).
Does Sollte refer to an obligation or recommendation here?
No. In conditional clauses, using sollte (the Konjunktiv II form of sollen) expresses a remote possibility. Just like in English, it means you think the temperature dropping is unlikely, but you are stating what will happen just in case.
Why is there a mix of Konjunktiv II (sollte ... sinken) in the first half and Futur I (wird ... frieren) in the second half?
It is perfectly normal to mix them when the condition is seen as unlikely (Konjunktiv II), but the consequence is seen as an absolute certainty if that condition is actually met (Futur I). You could say würde der Sänger frieren, but using wird emphasizes that the freezing is guaranteed.
How could I apply this lesson's Was ... ist ... (pseudo-cleft) structure to emphasize what the singer will do?
You can use a pseudo-cleft sentence to put the spotlight heavily on the final action. For example, you could say: Was der Sänger tun wird, sollte die Raumtemperatur sinken, ist frieren. (What the singer will do, should the room temperature drop, is freeze).