SoundPrint developers found the microphones and iPhones to be comparable to a professional sound level meter.

SoundPrint的开发人员发现麦克风和苹果手机可以与专业的声级计相媲美。

We used a sound level meter to detect the outside volume level and then looked at how I adjusted my volume on my iPhone in turn.

我们用音量测试器来检测外界的声音，接着看我如何调整 iPhone的音量大小。