Install Amazon Voice Service Alexa on Raspberry Pi 3 B with wake word and Airplay support. You can use Raspberry Pi as Airplay Speaker or as Amazon Echo. This AlexaPi has been implemented without using pulse audio and hence you do not have any crackling of audio.
Links Instruction txt file: https://mega.nz/#!XkgG2LAb!PvKQwLI8bskY43RcYrq6eHy1hbwxjEAGp4QJdQfnTQI
Git hub: https://github.com/alexa-pi/AlexaPi
Win32 Disk Imager: https://sourceforge.net/projects/win32diskimager/
SD Card Formatter: https://www.sdcard.org/downloads/formatter_4/
For installing on windows, check this out.... https://www.youtube.com/watch?v=ifYlhnXAd_M