頻率響應圖疑問(歌蘭蒂)

[qoo810513]

http://img.auctiva.com/imgdata/9/0/4...9_o.jpg?nc=581

請問Grundig此響應圖為什麼有兩條線? 左邊代表兩格是10db?

以下附全圖:
http://www.auctiva.com/hostedimages/showimage.aspx?gid=904755&ppid=1122&image=785671469&images=785671499,785671031,785671460,785671447,785671437,785671138,785671046,785671038,785671102,785671088,785671127,785671115,785671060,785671513,785671524,785671484,785674969,785671469&formats=0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0&format=0

感恩萬分!

[arty]

這是主動是的喇叭
我猜測兩條線是因為量測的音量不同
所以在高音量與低音量下會有不同的響應