Suddenly Change in ohms of my 3 way speaker Aiwa

I guess you measured that 6R with a DC multimeter, not an impedance (AC resistance) meter. The speakers probably have somewhat lower DC resistances than AC impedance but there may be capacitors in there that block DC and so, interfere with that test, should a cap. be faulty or wired incorrectly .

The best simple test is just to feed the same tone or a simple audio signal into both L&R inputs, adjust the balance control to midway and check that you have audio output from the speakers at roughly equal balance of both channels. To be more precise, compare measurements of the output of a steady tone audio signal on an AC meter range and use a medium audio frequency tone of say, 300-1000Hz. Beware that simple multimeters are only capable of limited AC accuracy up to about 400-1000 Hz.
 
Last edited: