- HA: Microphone
- Mic, Receiver
- ADC & Filter
- Amplifier
- Directional microphone (1)
- Directional microphone (2)
- Adaptive noise reduction
- Speech Enhancement (1)
- Speech Enhancement (2)
- Speech Enhancement (3)
- Active Occlusion reduction & compression (1)
- Compression (2)
- Compression (3)
- Compression (4)
- Feedback (1)
- Feedback (2) & Classroom acoustics Intro
- HAT