Compare signals?

[Ruhe]

Is there a way (tool) to compare the original .wav with the converted .ogg file?
For example like this (http://www.geocities.com/gameplaya_15143/howto/waveformtest/index.html)

[Spoon]

It is not very reliable to test lossy codecs with such programs, as lossy are perceptial audio codecs (in that bits are removed which cannot be heard because of other frequencies).

[Ruhe]

I'm just interested in the difference of some encoding settings.