Problems with the woofers
Often there are also problems with this audio system where individual speakers are not in function. Often several speakers are affected. The amplifier can be read out with the workshop tester. The error memory usually shows error messages about the woofers. For example, Subwoofer front left interruption. A failed woofer is not necessarily perceived, since low notes only rel. hard to locate. In many cases, the problem is only noticed when several woofers fail. The suspicion that in such a case, the amplifier is defective, is quite justified here. However, experience has shown that it is actually due to a break in the speakers. The following photos show why the woofers often fall silent here.
Voice coils have been realized with copper windings for decades. In the woofers of the factory-installed Dynaudio system, the coils are wound with aluminum wire. Whether the lighter aluminum wire "audiophile fine grinding" is used or it is only a cost savings in the production, remains uncertain. The fact is that the coil wires and junctions on the electrical connections are more susceptible to oxidation. If woofers have failed, please do not simply send the device in, but please check whether it is a fault on the loudspeaker.
For a continuity measurement on the voice coil, a resistance measurement with a conventional multimeter is sufficient. The measurement can also be done on the plug after disconnecting the amplifier so that the door panels do not need to be removed separately.
It should be measured at a working woofer 6-8 ohms.