Audio Recording Apparatus Dynamic Threshold Compression
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Solution Overview
Problem
Conventional multi-track recorders face difficulties in executing effective compression processing during the mastering process, especially when the mixdown level is inappropriate, leading to ineffective compression due to preset limitations and inability to adjust threshold values adaptively.
Innovation Solution
A recording apparatus with a peak value detection unit, threshold adjustment unit, and compression unit that dynamically adjusts the threshold for compression processing based on detected peak values, ensuring effective compression and normalization of audio signals regardless of their level, and includes a mixdown unit to produce stereo audio signals and a normalize unit to amplify processed signals to a target reference level.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If preset compression processing is used in multi-track recorder, then mastering process can be simplified, but compression processing becomes ineffective when mixdown level is inappropriate
Solution Approach 1:
The threshold value is made dynamically adjustable based on the detected peak value of the audio signal. The threshold determination unit automatically sets the threshold according to the actual signal level, allowing the compression processing to adapt to different mixdown levels and maintain effectiveness without requiring manual adjustment or multiple presets.
Solution Approach 2:
The system performs self-adjustment by automatically detecting the peak value of the input signal and setting the threshold accordingly. This eliminates the need for manual intervention or preset selection by the user, allowing the compression processing to automatically adapt to the specific characteristics of the recorded material.
2Stress or pressure
If compression processing is applied to low level audio signals, then sound pressure can be increased, but compression becomes meaningless when level does not reach threshold value
Solution Approach 1:
The threshold parameter is changed dynamically based on the detected peak value. When the audio signal level is low, the threshold is automatically lowered to match the signal characteristics, ensuring that the compression processing remains functional and effective across a wide range of input levels.
3Speed
If threshold value is fixed in compression processing, then processing speed is maintained, but adaptability to different audio signal levels is reduced
Solution Approach 1:
The peak value is detected and the threshold is determined in advance before the compression processing is applied. This preliminary action allows the system to quickly adapt to the signal characteristics without adding significant processing delay during the actual compression operation.
Data Source
AI summary
There is provided a recording apparatus which can effectively execute compression processing regardless of the mixdown level, and which can thereby carry out the mastering process easily. A DSP mixes down audio signals assigned to a plurality of tracks into a stereo audio signal. When performing the mastering process, the DSP uses a peak value detected during the mixdown to adjust a threshold value for the compression processing, and carries out the compression processing using the adjusted threshold value. Subsequently, the DSP performs normalization processing so as to produce a master data, and records the master data in a recorder.