Banana pi BPI-M1 support two audio device HDMI and headphone
Banana Pi M1 支持2个音频输出接口，1个是HDMI接口另一个是3.5mm模拟音频输出接口
如何选择HDMI接口或者3.5mm接口作为默认的音频输出接口：
sudo nano /etc/asound.conf```
pcm.!default {
type hw
card 0 //If you want to set HDMI as output ,turn 0 to 1.
device 0
}
ctl.!default {
type hw
card 0 //If you want to set HDMI as output ,turn 0 to 1.
}
```
插入3.5mm耳机
speaker-test -twav -c2
The sound "sound left，sound right，sound left" will output from headphone.
sudo apt-get install espeak
espeak "hello" //say: hello
espeak "hello_bananapi" //say: hello banana pi