Active Crossover Network for Multi-Driver Headphones
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Solution Overview
Problem
Existing in-ear monitors and headphones face limitations in achieving high-fidelity audio performance across all frequencies due to the size constraints of single diaphragm or armature drivers, which often require multiple drivers and passive crossover networks, leading to frequency roll-off and mobility issues.
Innovation Solution
A headset with an active crossover network that separates incoming audio signals into multiple frequency regions using analog or digital filtering, amplifying each region with single or multi-channel amplifiers, and incorporating adjustable gain control, allowing for a combination of diaphragm and armature drivers to achieve balanced frequency response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a single diaphragm driver is used, then the device size is reduced, but the frequency response quality deteriorates with significant roll-off above 4 kHz
Solution Approach 1:
The audio frequency spectrum is segmented into multiple bands (low, mid, high frequencies) and assigned to different specialized drivers. Each driver is optimized for its specific frequency range, allowing the system to achieve full-spectrum high-fidelity audio while keeping individual drivers small enough for compact in-ear monitor design.
Solution Approach 2:
The system integrates multiple driver types (diaphragm and armature) within a single headset unit, allowing each driver type to perform its specialized function while collectively providing universal coverage across the entire audio frequency spectrum.
2Manufacturing precision
If multiple drivers are used to achieve high-fidelity audio, then the frequency response quality is improved, but the device complexity increases
Solution Approach 1:
The audio signal is segmented into different frequency bands that are processed by dedicated drivers. This segmentation allows each driver to focus on a specific frequency range, improving overall audio fidelity while managing complexity through functional specialization.
Solution Approach 2:
An active crossover network acts as an intermediary between the audio source and multiple drivers. This intermediary device intelligently routes different frequency bands to appropriate drivers, coordinating their operation to achieve high-fidelity audio without requiring complex mechanical integration of multiple drivers.
3Device complexity
If passive crossover network is used, then the device complexity is reduced, but the frequency response precision deteriorates
Solution Approach 1:
The passive mechanical/electrical crossover network is replaced with an active digital signal processing-based crossover system. This substitution enables precise frequency band separation and driver routing through electronic control, significantly improving frequency response accuracy while allowing for flexible adjustment without physical component changes.
Solution Approach 2:
The active crossover network allows dynamic adjustment of crossover frequencies and parameters through electronic control. This enables optimization of frequency response accuracy for different listening conditions and driver configurations without changing the physical structure of the crossover network.
4Object-affected harmful factors
If in-ear monitors operate at high sound pressure levels, then the ambient noise blocking is improved, but the hearing protection deteriorates
Solution Approach 1:
The system incorporates feedback mechanisms that monitor output levels and adjust amplification accordingly. This allows the in-ear monitors to effectively block ambient noise while maintaining safe listening levels through active control of sound pressure levels.
Solution Approach 2:
The active crossover and amplification system enables precise control of output parameters including volume and frequency distribution. This allows optimization of sound pressure levels to provide adequate ambient noise isolation while preventing hearing damage through controlled amplification levels.
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
The active crossover network enables high-fidelity audio performance across all frequencies while maintaining compact design, reducing ambient noise, and protecting hearing by allowing lower sound pressure levels, thus addressing the limitations of single driver systems.
Implementation Method 1
A controller is used to determine whether the first, or second, audio source is coupled to the active crossover network which, utilizing either analog or digital filtering, divides each channel of the incoming audio signal into multiple frequency regions
Implementation Method 2
The output from the network's filters is amplified using either single channel or multi-channel amplifier(s)
Implementation Method 3
Prior art in-ear monitors and headphones typically use one or more diaphragm-based drivers. Broadly characterized, a diaphragm is a moving-coil speaker with a paper or mylar diaphragm
Implementation Method 4
An alternate to diaphragm drivers are armature drivers, also referred to as balanced armatures. This type of driver uses a magnetically balanced shaft or armature within a small, typically rectangular, enclosure
Data Source
AI summary
A headset with an active crossover network is provided. The headset is coupleable to a first audio source using a wired connection and to a second audio source using a wireless connection. A controller is used to determine whether the first, or second, audio source is coupled to the active crossover network which, utilizing either analog or digital filtering, divides each channel of the incoming audio signal into multiple frequency regions sufficient for the number of drivers contained within the headphones of the headset. The output from the network's filters is amplified using either single channel or multi-channel amplifies. Preferably, gain control circuitry is used to control the gain of the amplifier(s) and thus the volume produced by the drivers. More preferably, the gain of the gain control circuitry is adjustable. The headset includes a power source that is coupled to the amplifier(s) and, if necessary, the network's filters. The power source can be included within some portion of the headset or included within the wireless interface. Alternately, an external power source can be used, for example one associated with the audio source.