In message <j4o6mi+dnim@...>, dated Tue, 13 Sep 2011, Tony Casey <tony@...> writes:
Of course you are correct in the case of a single MC driver, but due to poor (crossover) design, some systems exhibit ridiculously low impedance at some places in the frequency band.
Some might; I know one well-known manufacturer had crossovers burn up about 40 years ago due to a 'parasitic' series-tuned circuit in the crossover than no-one had noticed. However, there is also a dynamic effect which causes high peak current demands even though the steady-state impedance is well-behaved. This effect was pointed out by Matti Otala (he of TIM ?fame?), with fairly complex examples. But Peter Baxandall pointed out that a simple RC circuit does it with a low-frequency square wave voltage applied. As, of course, LTspice will willingly demonstrate (must get back on-topic somehow!).
In cases like this, it is entirely possible that the resistor improves things, but only insofar as it disguises a design failing.
But 0.22 ohms is really too little, in most cases, to fix the problem. There is a long story to this, featuring another of P Bax's invaluable contributions, but it really is OT here.
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