Digital audio samples can represent waveforms whose continuous analog output exceeds 0 dBFS between samples

When a DAC reconstructs the continuous signal from samples, it applies a reconstruction filter that smoothly interpolates between sample values. This interpolated curve can peak higher than any individual sample. These inter-sample peaks (‘overs’) can cause clipping in DAC output stages or downstream limiters set to 0 dBFS. High-frequency content is most affected: at Nyquist, alternating maximum and minimum samples produce a reconstructed sine that exceeds the sample amplitude. There is no theoretical upper limit to how much higher the reconstructed peak can be relative to sample values. In practice, most music with inter-sample overs stays within approximately +3 dB, and modern DACs have sufficient headroom to handle them gracefully.

Examples

True-peak metering (ITU-R BS.1770-4) oversamples at 4× to measure the reconstructed signal. Keeping 2–3 dB of digital headroom below 0 dBFS eliminates most inter-sample overs. Some high-end DACs (e.g. Benchmark Audio) explicitly spec +3.5 dB headroom above 0 dBFS.

Assessment

Explain why alternating +1.0/-1.0 samples at the Nyquist frequency can produce an analog output that clips even though no individual sample exceeds the maximum value. Then name one mastering-stage practice that guards against this.