Det som skrivs om dynamisk kompression är intressant.
http://sound.whsites.net/lr-passive.htm"A crossover that at ambient temperatures had a nice stable (and well defined) crossover frequency of 3kHz, now has a 1.1kHz overlap! The audible effect is a disaster, since there will be quite a prominent peak (almost 5dB) at around 2.8kHz - the approximate centre frequency of the overlap region. Needless to say, if the tweeter had an equivalent temperature rise, then the overlap region becomes greater, and the peak is worsened - the amplitude will be relatively unaffected, but the peak will be wider as the two speakers are reproducing the same frequencies. The effects on relative phase and dispersion are less predictable, but we can safely assume that the outcome will be undesirable! (To put it mildly.)"
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"The truth is, this is far less of an issue when an electronic crossover is used - the power compression still occurs, but there is no shift of the crossover slopes, so the effect is only on relative levels, and not the designed crossover frequencies. It is a simple matter to adjust the relative outputs of the electronic crossover to match the average power that will be used, so one could have a switch, marked 'Soft', 'Normal' and 'Loud' if desired ."
Passiva filter ändrar alltså delningsfrekvens variabelt i takt med att spolar och ingredienserna i själva elementen värms upp.
Figure 3.12 - Combined Crossover Response at Elevated Temperature