Moderate Clipping
Figure 4A - Moderate Clipping
Increasing the gain further (another 6dB), the waveform is now visibly distorted, and if you look at the green trace (the tweeter) you can see that there are very noticeable 'dropouts'. When the overall signal clips, sections of high frequency signal are simply lost, and replaced by harmonics of the clipped waveform. These harmonics do not replace (musically speaking) the frequencies that were removed by clipping.
The relative amplitudes of the tweeter signal and the full range signal show us that while the tweeter voltage has increased to 8.9V, the overall is now 24.7V. This is an increase of 7.6dB for the tweeter, and 6.9dB for the overall signal (compared to the unclipped waveform).
Figure 4B - Tweeter Spectrum, Moderate Clipping
The overall level is now much greater than before - it has risen quite dramatically over the entire spectrum. Not only are the wanted frequencies at a higher level, but so are the harmonics of the lower (clipped) frequencies. However, the background 'noise' of the harmonics is still more than 10dB below the peaks, so the contribution from harmonics is not great.
What we do see is the increase of signal level to the tweeter, with the moderate clipping example showing a 7.6dB increase. Remember that this translates to an average power increase of over 5 times to the tweeter. If the tweeter would normally be expected to handle a peak power of 15W and an average power of perhaps 5W (based on Figure 1 and a 100W amplifier), a 7dB increase will take that average to 25W! The tweeter
will not survive.