15M would be listenable with a state of the art audio codec like Opus, but not transparent. 15Mb for 63.5 minutes would translate to 32 Kbit/s. Which is pretty

15M would be listenable with a state of the art audio codec like Opus, but not transparent. 15Mb for 63.5 minutes would translate to 32 Kbit/s. Which is pretty low, but I'm going to compress it with Opus and listen to it. Apparently there have been some improvements on low bitrate speech coding which would make it good for saving podcasts or text to speech files. I used to save some space on my PocketPC by re-compressing podcasts to wma acelp.net in the previous century. ‎