Of course CDs are lossless. PCM in, PCM out. Is an audio signal lossless? That question doesn't make sense. Analog audio is limited by bandwidth and signal-to-

Of course CDs are lossless. PCM in, PCM out. Is an audio signal lossless? That question doesn't make sense. Analog audio is limited by bandwidth and signal-to-noise. Digital audio is limited by its Shannon-Nyquist parameters. (Monty's show and tell for geeks is great if you have even the slightest interest in these things!)