SDAA588 November   2026 TAS2563 , TAS2573 , TAS2781

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1 Introduction
  5. 2 How a Speaker Works
  6. 3 Smart Amp Monitoring
  7. 4 Smart Amp Protection
    1. 4.1 Excursion Protection
    2. 4.2 Thermal Protection
  8. 5 Factory-Line Calibration
  9. 6 Modelling Accuracy
  10. 7 Blocked-Port Reliability
  11. 8 Smart Amp: Full System
  12. 9 System Cost Savings
  13. 10Summary
  14. 11References

2 How a Speaker Works

Before getting into how a smart amp protects a speaker, it is worth noting what a speaker actually is: a small, purpose-built motor.

How a Speaker Converts an Electrical Signal Into Sound Figure 2-1 How a Speaker Converts an Electrical Signal Into Sound

An amplifier sends a varying electrical signal into a coil of wire that sits inside a fixed magnet. Whenever current flows through a wire inside a magnetic field, a physical push/pull force is generated in the wire using the same principle that makes electric motors spin – in this case the force pushes the coil in a straight line instead of turning a shaft. The cone is glued firmly to the coil, so the cone experiences the same force, pushing and pulling the air in front of it. This moving air is what is heard as sound.

Two properties of the electrical signal map directly onto two properties of the sound: how fast the signal swings back and forth becomes the pitch (frequency), and how wide the coil swings becomes the loudness (amplitude). This is why loud, deep bass is difficult for a small speaker to reproduce safely: low-pitched bass notes require the cone to physically travel much farther per cycle than high-pitched notes do, for the same perceived loudness. Such big cone excursions are risky and can result in over driving and damaging the speaker, but a fixed safety margin deprives the listener from enjoying bass content.