need help with custom sounds

[half life 1 einstein]

while i was trying to get some custom music for my map and tried running it (the map) i got this error

Engine Error
Cache_TryAlloc:58028640 is greater then free hunk

i converted (changed the mp3 into the .wav file) it into the correct file ,it showed up in the folder ,i could select it in hammer normally ,but ofc there was an error. When i converted a sound file from the original folder (HL2Song_14) it worked fine. i dont know what i did wrong

[ComDoll]

How big is the music file? That might be an issue, since error basically means running out of memory.

[half life 1 einstein]

the first one is 05:02 and the second one is 05:53

[ComDoll]

The file size, not length of the soundtrack.

[half life 1 einstein]

55,3 mb and the second one is 59,6

[ComDoll]

Well that's bad, your single song file is bigger than whole Half-Life OST. Try lowering the sample rate and/or bitrate.

Valve Dev Wiki about MP3s