The vibration modle of the paper cone of alto loudspeakers under different frequencies were studied by means of photo holography. The disjunction vibration node points and nodal cycles on the paper cone of the loudspeakers are demonstrated. A new model of tome alto loudspeaker with excellent frequency response was successfully designed under the guidence of holographic results. The new ino del loudspeakers had relatively large diaphragms

the low frequenty toss oer point is as low as 350 Hz and the diameter of magnet is small