code: def _db_to_amp(self, x):
      return np.power(10.0, x / self.spec_gain)
  
imports: import librosa
  import soundfile
  import numpy
  import scipy.io.wavfile
  import scipy.signal
  from TTS.tts.utils.data import StandardScaler
label_desc: Use image node_id 9 for calling the AudioProcessor obj's underlying member method code with example usage: obj._db_to_amp(x) and returns: np