What I never got is how we can say that recorded music is a kli shiur, and therefore assur during sefira, but still say that it constitutes kol isha… What is it, a kli or a person?
I assume you mean that recorded vocals are considered klei shir (some poskim hold that way, but many don’t), otherwise your question doesn’t make sense.
If you understand the issur of kol isha as based on hirhur, it makes sense to not limit it to what is technically kol isha.