Audio Amplifier Gain Mapping for Loudspeaker Thermal Protection
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Solution Overview
Problem
Audio amplifiers struggle to limit thermal power in loudspeakers without reducing user-perceived volume gain, often resulting in overheating and 'hunting' phenomena due to difficulties in adjusting variation speed limits.
Innovation Solution
A method that determines the effective intensity applied to loudspeakers, calculates a maximum volume gain using desired gain, thermal characteristics, and an increasing monotonic function to adjust applied volume gain, ensuring the image of the maximum desired volume gain equals the maximum volume gain, while applying the minimum of this variable gain to prevent overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If time constants are added to limit the variation speed of desired volume gain, then thermal power is limited, but the devices become difficult to adjust and produce hunting phenomena
Solution Approach 1:
The patent applies preliminary action by pre-calculating the maximum volume gain based on loudspeaker thermal characteristics before the user adjusts the volume. The system determines the maximum admissible power and calculates the corresponding maximum volume gain in advance, then uses this pre-computed value to immediately adjust the applied volume gain when thermal limits are approached, avoiding the need for complex time constants and hunting phenomena
Solution Approach 2:
The patent implements feedback by continuously monitoring the effective intensity applied to the loudspeaker and comparing it against thermal characteristics. The system uses this feedback to dynamically adjust the applied volume gain through a monotonic function, ensuring the loudspeaker operates within thermal limits while maintaining user-perceived volume stability
2Reliability
If automatic volume gain reduction is applied to limit thermal power, then loudspeaker overheating is prevented, but the user perceives variation in sound level
Solution Approach 1:
The patent applies parameter changes by introducing a monotonic function that transforms the desired volume gain into an applied volume gain based on thermal conditions. This function smoothly adjusts the gain parameter according to the effective intensity and thermal characteristics, preventing abrupt changes that users would perceive while still limiting thermal power dissipation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively limits thermal power dissipation in loudspeakers without user-perceived volume variations, preventing overheating and eliminating 'hunting' phenomena by smoothly adjusting volume gain, ensuring stable operation near amplification limits.
Implementation Method 1
An electrodynamic loudspeaker is an electromechanical device used to convert an electrical voltage that is applied across its terminals to an acoustic pressure
Implementation Method 2
Due to the resistance of the coil of the loudspeaker and the current circulating therein, thermal heating appears
Data Source
AI summary
A method is provided for adapting an applied volume gain in an audio amplifier controlling at least one loudspeaker of an enclosure according to a desired volume gain selected by a user on a scale increased by a maximum desired volume gain, including determining effective intensity applied to the loudspeaker, calculating maximum volume gain from the desired volume gain, an effective intensity applied to the at least one loudspeaker, thermal characteristics of the loudspeaker, and the maximum desired volume gain, then calculating a variable applied volume gain according to an increasing monotonic function providing a variable applied volume gain according to the desired volume gain such that the image of the maximum desired volume gain by the monotonic function is equal to the maximum volume gain, and applying to the amplifier as applied volume gain, the minimum of the desired volume gain and the variable applied volume gain.