I liked the idea of testing it on SSTV decoders, so I compared it to a real SSTV audio file (Example: ) It seems to be spaced out much more, so maybe the audio file was slowed down, I have a strong feeling the file was manipulated in some way at least.

It also, might be worth to note, that the audio file frequency is 22,050hz which is a frequency used mostly in FM radio, digital audio media tends to be 44100hz.