Birds, insects could be the sound makers. Cicadas are around each years and yes the the cycle could be 17 years but there are many different groups by year.
It depends where you are geographically. There are a couple of species of cicada that are annual, and then there is the periodical species, which have a life cycle of 13 or 17 years.
I grew up in the Midwest (Chicago area), and we heard them every year about this time.
This is a great question. Based upon the information provided, @Yetanotheruser‘s answer is most likely correct, as male cicadas are known to be loud, and they are annual, at least where I have lived in the Southern US. Is this what you are hearing?
@Devilishtreat You’re talking about the species known as “Magicada“http://www.magicicada.org/map_project/maps.php They are species which have life cycles of 13 or 17 years. As I posted above, Not all cicadas are periodical, there are several species of annual as well.
I’m in the hills of Northern CA. and we have some type of cicadas that are humming in the trees right now. They just start up out of nowhere for about 20 seconds then go silent again. It’s amazing how loud they are.
Here in NC, we’re having a good cicada year. But we also have tree frogs, crickets, and other assorted noise-makers. If it’s oppressively loud, it’s probably cicadas.