Complex sentence: This is far better than telephone quantization but CD audio representing low signal levels would still sound noticeably'granular' because of the quantizing noise, were it not for the addition of a small amount of noise to the signal before digitization.
Split into simpler sentences: This is far better than telephone quantization but, CD audio, representing low signal levels, would still sound noticeably'granular' because of the quantizing noise. However, sometimes an addition of a small amount of noise is added to the signal before digitization.