Effects of flat surface near the 1st reflection point

（中文在後）
The effects of a flat surface, here a door, near the 1st reflection point of a speaker are quite visible in the first impulse-response chart. Asking a person to walk over and stand in front of the door makes immediate, visible differences as in the 2nd chart.

喇叭的側方第一反射點附近的平滑面的影響，可以在第一個 impulse response 圖明顯看到。請一位朋友站在門前，就立刻造成第二圖裡明顯可見的差異。

What do the magnet and pole pieces in an MC cartridge look like?

（中文在後）

What do the magnet and pole pieces in an MC cartridge look like? Figure 1 and 2 show a typical example. The cylindrical part is the magnet, and the attached metal parts are the pole pieces. Figure 3 and 4 show the ultra compact version, where the middle dark-colored piece is the magnet and the shiny parts are pole pieces. After the pole pieces are attached to the magnet, they need to get magnetized using an electrical device, as in Figure 5, before the whole assembly can be used.

典型MC 唱頭的磁鐵與磁極，如圖1與2。圓柱狀的部分是磁鐵，其它前後金屬部分是磁極。圖3，4是特別縮小的設計，中間暗色部分是磁鐵，前後是磁極。在組裝成唱頭之前，磁極必須用工具經過灌磁的手續，如圖5。