I was in need of headphones and couldn't really afford metal detecting headphones " I had a gift card to Fred Meyer went to the electronics dept. they had the equiv to the Koss 30 But I went ahead and got A pair pf Phillips noise reduction headphones U put a triple A in and it really cuts out the outside sound. I checked the freq on the box and they are well within the ones needed for the X-70 I've noticed I can hear on them a lot better and hear nothing from the outside world. Has Anyone tried these? They were on sale reg. $110.00 on clearance for $59.99 I was gonna get them last week at the 110 price good thing I waited! any feed back on this would be great I'm hearing good tomes loud and clear so I guess there OK to use for metal detecting. One of my hobbies is car electronics so I know frequencies and speaker capability ohms ETC... what benefits do the really expensive detector headphones have? Just curious thought I'd share my use of these noise reduction headphones. Grant