Alarm script proof of concept that works even if your computer is in hibernation.

alarm.sh

#!/bin/bash
set -x

MUSIC=(~/Music/Africando\ -\ All\ Stars\ Betece/*mp3)
START="$(date +%s -d 'tomorrow 08:00')"
#START="$(date '+%s' -d '+ 5 minutes')"
STOP="$(date '+%s' -d 'tomorrow 19:00')"

sudo sh -c "echo 0 > /sys/class/rtc/rtc0/wakealarm"
sudo sh -c "echo $START > /sys/class/rtc/rtc0/wakealarm"
if [[ "x$(</sys/class/rtc/rtc0/wakealarm)" -ne "x$START" ]]; then
    echo "FAIL TO SET WAKE"
    exit
fi

while (( $START > $(date +%s) )); do
    sleep 1
done

for f in "${MUSIC[@]}"; do
    if (( $(date +%s) > $STOP )); then
        exit 0
    fi

    sudo sh -c "echo 0 > /sys/class/rtc/rtc0/wakealarm"
    sudo sh -c "echo $(date '+%s' -d '+ 5 minutes') > /sys/class/rtc/rtc0/wakealarm"

    mpg123 "$f";
done