Register sounds using DeferredRegister

ModSounds.java

@Mod.EventBusSubscriber (modid = MODID)
public class ModSounds
{
    
    public static void registerSounds()
    {
        SOUNDS.register(FMLJavaModLoadingContext.get().getModEventBus());
    }
    
    private static final DeferredRegister<SoundEvent> SOUNDS = new DeferredRegister<>(ForgeRegistries.SOUND_EVENTS, MODID);
    public static final RegistryObject<SoundEvent> SOUND_123 = SOUNDS.register("123", () -> new SoundEvent(new ResourceLocation(MODID, "123")));
    
}

MYMOD.java

@Mod ("mymod")
public class MYMOD
{
    public static final String MODID = "mymod";
        
    public MYMOD()
    {
        ModSounds.registerSounds();
    }
}