I use a white noise CD. I'm sure pink noise is just as good.
Something like this.
http://www.amazon.com/Ultrapure-White-Noise-Joe-Baker/dp/B00387FU84/ref=pd_sim_15_5?ie=UTF8&refRID=04S1RATRYCNFGX34ZDB1
Something like this.
http://www.amazon.com/Ultrapure-White-Noise-Joe-Baker/dp/B00387FU84/ref=pd_sim_15_5?ie=UTF8&refRID=04S1RATRYCNFGX34ZDB1