What’s intersample clipping?
Digital audio is by nature, a quantized format. When a converter reconstructs old-fashioned sound from a digital signal, it basically is doing a lot of math to figure out what shape of a wave is defined by these digital numbers. Sometimes, even if the numbers themselves don’t exceed a certain maximum, the mathematical curve the define could loop up past it. This is known as “intersample clipping†– namely, clipping that happens to your signal between the individual sampling points. It’s generally not a big deal, but it can add some audible harshness to your signal. The easiest way to avoid it is to not peg your meter at 0db – these intersample peaks are rarely much higher than the samples around them, so adding a bit of headroom basically keeps this from happening.