I agree with Monte that chatter or detector noise you will still get as the headphones will respond to what the detector sees. If it is trash you will hear it,if it is minerals deposits you will hear it. Where a high quality headphones will help is the response to some of those weaker signals will be better, you can blockout unwanted background noise with a set of good headphones that fits tight.Many of the top of the line headphones that are made for us detectorist have a bigger ear cup with a very soft ear pad, these will sit on your head more than push on your ears like the cheapies do. This will let you detect longer as your ears dont get so sore.
There is many good headphone out there and I have tried most them all as I need the volume because of my bad hearing. I found the Timberwolfs,the Troy Pros,my Uniprobes headphones and the SunRay Pro has the volume I need. I find the Gray Ghost NDT have a replaceable cord you can change in the feild if needed, which we know is about the only problem headphones have is the cable going bad. I find the new Troy Pros have the best looking cord that looks like it will out last the others as it is heavy duty. The reg Gray Ghost and the Killer Bees are great too,but dont quite have the volume I need, but for normal hearing they are great.
I wish for the price we pay for the upper end detectors that the manufactures would include one of these top of the line phones instead of the cheapest things they can find as it does make a difference. I try to work a good set in with the deal on any new detectors.
Rick