50 to 65 percent reduction of noise.
Carpet noise fastrack.
One trick with fastrack is carpet with a medium high nap it fills the echo chamber base and really cuts down the noise.
In most cases you need to use an underlayment specifically designed for noise reduction between the carpet and the standard pad.
I ve run fastrack on carpeting and it s queiter but to me carpet still lets the sound to escape from under the track.
To eliminate all noise look for a rating that is 75 or higher.
Homasote absorbs much of the sound that gets through the carpet padding.
Even after doing these things fastrack tends to be a bit louder than traditional track but it makes the noise tolerable.