I recently reinstated my vintage 1991 Noble & Cooley Horizon set to main recording set. While in the process I found that I could no longer get a good bass drum sound from this set and in general they were not quite like I remembered them sounding, but the bass drum wasn't even close. After literally 3 days of experimenting with heads, microphones, various EQs and pulling what's left of my hair out I decided something was definitely wrong with the drum. I took the bass drum to Chris Heuer who is known in Los Angeles as THE GUY. Chris is drum tech to the likes of Vinnie Colaiuta, Peter Erskine, Matt Chamberlain, Curt Bisquera and basically all the greats you can imagine. It turned out the bearing edges had shrunk on 2 sides and air was escaping. To get the best sound you want an airtight seal between the head and the bearing edge. If air is escaping so is your low end. That was exactly what was happening. My bass drum sounded like paper. Thanks to Chris it's absolutely booming again. I didn't hesitate to bring every drum I owned to him immediately. If your drums are older they more than likely need to be looked at. Newer drum really shouldn't but that depends on the manufacturing. Sometimes a new edge on a medium priced set can really make a difference. I am playing vintage drums almost exclusively at this point. My 1965 Ludwig set sounds really good, but after Chris tweaked the edges it became an addicting instrument to play. Wood drys and shrinks with age which is exactly what happened to my 2 vintage sets. I am extremely careful now when I take heads off. Don't let your edges touch anything that can dent or scratch them, seriously this makes a difference.