ConvolverNodes potentially allocate a lot of memory when assigned a buffer. It seems this memory is never released after use or after setting the buffer to null. On iOS Mobile Safari this causes low memory warnings and crashes. On Safari for Mac it can lead to allocation of 10G+ and crashing too. To reproduce:
When used in an OfflineAudioContext, the memory is never released either.
FYI I filed the same bug for Chrome as well: https://bugs.chromium.org/p/chromium/issues/detail?id=603256