The crinklesound is a plastic sheet. Clean tortilla chip bags work pretty well. You can sew it right into the inside seam allowance.
I find a lot of sound and bell boxes in old toys scavenged from yard sales and thrift shops, since there really isn't a supply house that sells most of these items. There seems to be an edless supply of discarded plush toys and the parts like these can be salvaged.
You can get some nice squeekers and growlers, and music boxes, both the electronic press button and mechanical wind up or pull string type from Bear making supply shops-
http://www.bearessentials.co.nz/stor...20a98edf461356http://www.dollspart.com/spgm.cfm?dp...=23&item=T1205
Be sure that you are using fabric that won't tear open, when sewing soft toys for babies and toddlers who put everything in their mouths and can tear parts off when teething. When fabric gets wet, it loses a lot of tensile strenth-- combine that with the twisting and yanking, and you could have a small parts choking hazard. Babies can choke on the tiniest ribbon or string. The ribbon can tickle the throat and cause the gag reflex and produce vomiting, which then could be aspirated. The utmost care should be taken when making soft toys for under three y.o.
