uses-sdk:minSdkVersion 16 cannot be smaller than version 23 declared in library

You need to edit the build.gradle file located inside your project directory like your_project_folder\android\app\build.gradle and find and edit this line minSdkVersion 16 to minSdkVersion 23 then save the file use flutter clean command and run it.

The defaultConfig should look like this inside the build.gradle file

defaultConfig {
        // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
        applicationId "com.your_package_name_here"
        minSdkVersion 23
        targetSdkVersion 29
        versionCode flutterVersionCode.toInteger()
        versionName flutterVersionName
    }

Hope the above solution will work.

Or better use the old version of audioplayers. Edit in your pubspec.yaml file

dependencies:
  flutter:
    sdk: flutter

  cupertino_icons: ^0.1.2
  audioplayers: ^0.10.0