Flute sounds maybe not so good on long-held notes

[✧]

There's a weird repeating sound that you can hear when you play and hold a single note on the flute. I can hear it fairly easily on the F and G notes above middle C. It seems to play about twice a second.

To my ear it makes it sound unpleasant to hold a single note on the flute.

[jorb]

The sound could be looped better, I think.