For DIYers on a budget and who isn’t? I recommend a package of safety locks – the kind you put on cabinet doors to keep babies from opening them. They are plastic and spring-loaded so they provide upward tension against an object. Their height makes them ideal to literally be bolted inside most drums by simply using one of the upper bolts to any tension rod boss – 100% non intrusive and very cheap. Just use doublestick tape to attach some high density foam ($5 at your local fabric store for a 1″ by 12″ square), then attach piezo to that, cover the piezo (for protection) and mount. Works GREAT.