Are you rooted?
no, been thinkin bout it though. worried id screw something up. always been good at that stuff though- o.g. xbox, xbox 360 modding- i call it modding, im just old school i guess. just dont want to have to explain to verizon, why i shouldnt pay another 199.99 for a phone i have a warranty for & insurance on, cause i wanted to get away with doing what i want. lol.
I had the same problem with the notification sound just making a ringing sound upon phone startup. It may be that the phone doesn't want to play a long sound upon startup? If you want to make it stop go on your phone here:
menu -> settings -> sounds & display -> uncheck the "SD card notifications" box.
Then you won't have any startup sound. It will play for other notifications. If you wanted it to play when your phone boots up, sorry can't help there.
I was able to add custom notifications to the /system filesystem using adb shell remounting readwrite and copying the files to the correct locations using adb push see Write on the Android Read-only file system « PocketMagic