04 Impala sounds like crickets with a cold inside my car?

I have a 2004 Impala LS. I've owned it since brand new and it now has 205,000 miles on it. It still drives really nice and never had any major issues with it. But one thing lately I've noticed is when driving, it sounds like crickets with a cold... basically like crickets but a lower key inside my car. The "chirping" seems to speed up a little bit with the higher RPMs of the engine, but not a ton. But you can only hear the "cricket type noise" inside my car. I can't hear it outside my car. My car still drives really nice. Just the weird noise.

It could possibly be the blower motor.

Although, I noticed a "chirpy" noise in my Grand Prix one day and finally after looking everywhere for the noise I realized it was the lid on the sunglass holder on the overhead console rattling.

Blower motor- change speeds on blower see if noise changes...

It isn't the blower motor. I've had that go out twice in my car. It's an after market autozone blower motor. The new one sounds significantly different than the OEM one... works but it's different and it's not the sound.

I'm attaching audio. It's hard to make the sound out in an audio file. It's easier to hear towards the start of the file.

Go to the parts store and get a product you add to the oil for sticky valve lifters. This is a common problem on older vehicles.

Remove the serpentine belt, start engine and see if the noise is gone....

If noise is gone upon serpentine belt removal, then replace with same belt - but put it on the reverse direction that you took it off- this will solve 90% of belt squeaking-- Some people rotate their tires- I rotate my belt..

Sorry, when I attempted to attach it earlier from my phone, it didn't attach. The audio is attached now. I recently changed my serpentine belt.

I don't know why I can't get it to attach...

Attachments on the site are weird. You need to host it on another site and post the url.

Here's a link to hear the noise... Again, it's more noticeable towards the start of the file. I know it's hard to hear.

https://www.dropbox.com/s/hjpqbisw92fqcyf/Voice%20001.m4a?dl=0