I'm in the northeast corner of Maryland and the 17 year cicada noise is probably peaking right now. Interestingly enough, my neighbors in a town 9 miles south of me are not reporting any noise, so locations where they are emerging are apparently spotty. Outside our house, my wife calls it a high pitched roar. She's retreated inside to avoid the it. It just doesn't seem to bother me that much. Sounds like a sound effect from a B-rate alien movie!

Using my phone and a dB meter app (no guarantee of accuracy) I measured about 70 dB as compared to 55dB inside the house. Similarly, using a tone generator, I was able to pick 1314 Hz as the primary frequency with triangle wave harmonics matching it most closely. Square, sawtooth and of course sine didn't come close. When I changed to a triangle wave at 1314 Hz the phone output seemed to completely blend in with the cicada song.

Spectrum analyser app on Android phone.

 

Ah, violin like then.

I am just north if their range in Massachusetts. They stop atLong Island, I think.

Bob

 

https://www.cbc.ca/news/science/cicadas-brood-x-1.6014406

 

Please keep in mind Im English, we are to cold and wet for these things,

The times I have been to Florida
there always seems to be a "cheeping noise" at night, quiet loud
which apparently is "Cicadas"

So do these things breed every year, but every 17th is a big one,
or are the locals telling us foreigners that anything that cheeps is a cicada ?

Also, is it always 17 years ?
or is it sometimes 16 some times 18 say ?

Do they all come out on a set day ?

I assume they die fairly soon, ( matting exhaustion I guess )
what happens then ?

 

MrChips's link gives some good detail on them, including the differences between the "Periodical" vs "Common" cicadas.

The times I have been to Florida
there always seems to be a "cheeping noise" at night, quiet loud
which apparently is "Cicadas"

Indeed, those are "Common Cicadas". In my area they're far more dispersed so the noise never amounts to the din from the periodical cicadas.

So do these things breed every year, but every 17th is a big one,
or are the locals telling us foreigners that anything that cheeps is a cicada ?

Also, is it always 17 years ?
or is it sometimes 16 some times 18 say ?

I'm sure some of them don't get the memo and wake up either a year early or late. Those numbers are so small that any that do emerge off cycle probably die off for failure to mate and procreate. Keep in mind that these things are estimated to number in the trillions. If I had a dollar for every cicada...

Do they all come out on a set day ?

They emerge as the temperature rises. At my latitude they came out in mid-May. The first few days the noise wasn't particularly notable. Right now it's just loud.

I assume they die fairly soon, ( matting exhaustion I guess )
what happens then ?

They lay their eggs and die. Around my house they're not particularly concentrated, but I've heard stories of the smell getting pretty bad as they die off over a short period of time. On my commute to work a lot of them have blundered across the highway resulting in gory green splats on windshields.

 

Many thanks
I just did not know,

Looking forward to 2038 ?

 

Since 2038 is also the standard Unix time expiration date it could get very interesting. Unix stops working in January and then cicada’s die all over. Something to look forward to.

 

Unix stops working in January and then cicada’s die all over.

At least there'll be fewer bugs when it's all over...