I changed it like you suggested. Thank you.

Hi there,

You need to add ticks object to yAxes options object. Here's an example:

      yAxes: [
        {
          gridLines: {
            display: true,
            color: "rgba(0, 0, 0, 0.1)"
          },
          ticks: {
            userCallback: function (tick) {
              return tick.toString() + 'dB';
            }
          }
        }
      ]

Best regards