我需要增加使用 AVAudioPCMBuffer 创建的音频缓冲区的十进制级别

Question

我已经产生了不同频率的声音，但我需要增加声音的分贝。

import Foundation
import AVFoundation

class AVTonePlayerUnit: AVAudioPlayerNode {
    let bufferCapacity: AVAudioFrameCount = 512
    let sampleRate: Double = 44_100.0
    
    var frequency: Double = 440.0
    var amplitude: Double = 0.25
    
    private var theta: Double = 0.0
    private var audioFormat: AVAudioFormat!
    
    override init() {
        super.init()
        audioFormat = AVAudioFormat(standardFormatWithSampleRate: sampleRate, channels: 1)
    }
    
    func prepareBuffer() -> AVAudioPCMBuffer {
        let buffer = AVAudioPCMBuffer(pcmFormat: audioFormat, frameCapacity: bufferCapacity)!
        fillBuffer(buffer)
        return buffer
    }
    
    
    func fillBuffer(_ buffer: AVAudioPCMBuffer) {
        let data = buffer.floatChannelData?[0]
        let numberFrames = buffer.frameCapacity
        var theta = self.theta
        let theta_increment = 2.0 * .pi * self.frequency / self.sampleRate
        
        for frame in 0..<Int(numberFrames) {
            data?[frame] = Float32(sin(theta) * amplitude)
            
            theta += theta_increment
            if theta > 2.0 * .pi {
                theta -= 2.0 * .pi
            }
        }
        buffer.frameLength = numberFrames
        self.theta = theta
    }
    
    func scheduleBuffer() {
        let buffer = prepareBuffer()
        self.scheduleBuffer(buffer) {
            if self.isPlaying {
                self.scheduleBuffer()
            }
        }
    }
    
    func preparePlaying() {
        scheduleBuffer()
        scheduleBuffer()
        scheduleBuffer()
        scheduleBuffer()
    }
}

我成功地产生了声音，但我需要听到不同分贝级别的声音，并且需要知道如何做到这一点？ 实际上，我是这个音频缓冲的新手，如果我得到这个答案，这将对我的项目有很大帮助。

有什么办法可以提高缓冲音频的分贝水平？