Instruct: Classify Amazon reviews into positive or negative sentiment
Query: A good night's sleep

I purchased this machine for my 14 year old son's bedroom. We've had it for a month now and know he gets a sounder sleep; he wakes up each morning without a fuss and is more alert in the mornings than I've ever seen him. We did not get the machine to drown out noise but rather make a consistent white noise, hoping that it would help him sleep. It works. I like the speed controls but he keeps it on high, the loudest, which he prefers.