Can I speed up decodeAudioData sampling from Web Audio API

I'm using Web audio api decodeAudioData() method to decode audio files (45min duration, about 40MB, mp3 format) stored on my ubuntu web server. When user enter on some website page I need to preload Audio file, but it takes too long, about 1min 10s. Is it possible to do something to speed up this process? I'm getting arraybuffer through xmlhtttprequest and then decoding it, but it is very very slow.