Wave File obfuscation

The file header once decoded shows that your wav file is over 320Mb. (the 4 bytes after "data")
The key changes every 512 bytes, so if they are set in advance you would need 625520 stored keys. This is of course very unlikely.
I think only the first key is frozen, the others can be just the XOR of the first 2 bytes of each group of 512 bytes.
To verify it would require a greater number of data, at least 1Mb, or better the complete zipped file.

It looks like the file is xored by key 0xA7 0x23. After xoring the very first bytes, the header looks like this:

52 49 46 46 0C E1 16 13 57 41 56 45 66 6D 74 20 RIFF.á..WAVEfmt

So mostly like correct wave header.