You can do this with OffsetSampleProvider
var songDelayed = new AudioFileReader(filePath_1);
var offset = new OffsetSampleProvider(songDelayed);
offset.DelayBy = TimeSpan.FromSeconds(10);
// or if you don't have latest NAudio source:
// offset.DelayBySamples = songDelayed.WaveFormat.SampleRate *
// songDelayed.WaveFormat.Channels * 10;
myDirectSoundObj.Init(offset);
myDirectSoundObj.Play();