Digital audio measures the sound pressure many thousand times per second (the sample rate) and stores each measurement with a limited number of steps (the bit depth). This app plays a short synthesised riff and lets you lower both, so you can hear what each kind of coarseness does to the sound. Press Start audio first.
What to notice: lowering the sample rate adds a metallic, whistling shimmer (aliasing: frequencies above half the sample rate fold back down as new, unrelated tones), while lowering the bit depth adds hiss and grit (quantisation error). This simple simulation deliberately leaves out the anti-aliasing filter a real converter would use, so the aliasing is easy to hear.