The sound driver used by BPS version of Tetris for Famicom has a bug, where the triangle channel constantly plays low C note when there should be silence on that specific channel. This might be barely noticeable when the Famicom is connected to TV, this usually depends on the frequency response of given input, or the frequency response of TV's audio hardware, however when using headphones, this hanging low C note on triangle channel can be heard.
![Hirokazu Tanaka - “Tetris (NES)” Full Soundtrack [Oscilloscope View]](http://i.ytimg.com/vi/ndaKQbQMZNw/mqdefault.jpg)
![Hirokazu Tanaka - “Tetris (NES)” Full Soundtrack [Oscilloscope View]](/img/tr.png)
Beep boop bap beep boop beep
The sound driver used by BPS version of Tetris for Famicom has a bug, where the triangle channel constantly plays low C note when there should be silence on that specific channel. This might be barely noticeable when the Famicom is connected to TV, this usually depends on the frequency response of given input, or the frequency response of TV's audio hardware, however when using headphones, this hanging low C note on triangle channel can be heard.
I see, I just presumed that it was part of the music and was intentional.
*promosm*