I thought the stress should lie on the first syllable, not the second.
That would be Spanish, “Cálmate”. Most italian words have the stress on the penultimate syllable.
I just had the idea that Italian verb forms kept their stress even when you hang pronouns at the end, just like in Spanish.
In italian you have to keep that melody. Here an example:
“Ora prova questo esercizio: le frasi seguenti hanno le stesse parole ma una pronuncia diversa fra italiano standard e regionale. Puoi sentire la differenza?”
Every word with more than 1 syllable have their stress on the penultimate syllable.
Mi dispiace, ma non sono convinto
In my experience, stress in Italian is really a lot more complicated than that. I just now ran into the sentence “Ci siamo sbrigati per paura di essere in ritardo per la scuola.”, and here the audio puts the stress on the first, antepenultimate, syllable of “sbrigati”, as if it were a reflexive imperative and not the past participle, which takes it on the penultimate.
Now I think I know what is happening: the voice thinks that “calmati” is the part participle of “calmare”, as in “ci siamo calmati”, not the singular second person imperative.