Instruct: Classify a given Amazon review as either positive or negative.
Query: Returning my 2nd pair - Noise & feedback

I received my first set as a gift and experienced the low frequency noise in the left earphone others have described here. After a few minutes of use (in active mode) the feedback in the right earphone was unbearable. I was forced to turn these earphones off to use them. I can buy better headphones for this money without the NC technology. I returned the first pair in hopes this was a defect. My second set (brand new not refurbed) exihibit the same problems.The background noise seems to build (sounds like thousands of crickets on a hot night) until they break a threshold level and begin a high pitched squeal of audio feedback.I am in the process of returning the second pair and requesting a refund. Luckily, I have all of the paperwork.I'm very disappointed Sony let this product get into the market. I only gave one star because there wasn't a choice for zero stars.