FFMPEG blank tiny audio spot when concating

Ok, im trying to concat some mp3 audio files with the following command:

ffmpeg -y -i concat:"1.mp3|2.mp3|3.mp3" -c copy output.mp3

After concating output.mp3 isn't perfect, it leaves some tiny blank audio spots between the two audios, looking output.mp3 with Audacity i have:

http://ift.tt/1wG1xNb

Is there some functionality from FFMPEG that i can use to fix this?