L-C filters connected at the Class-D output are a relatively good option, since the inductor can offer high impedance at higher frequencies hence providing sufficient of EMI filtering and prevent high frequency switching currents. The downside to LC filters is the following: High price and foot print of inductor (BOM cost) and extremely high current at resonant frequency of the filter, which can cause device shutdown. The key advantage however is that LC Filters are linear, which means there is not THD+N degradation at the output of the filter (across the speaker)