Final answer:
Editing a recorded voice and playing back the modified sound involves digital signal processing, which can be achieved using Python libraries like librosa, matplotlib, and sounddevice. Without the actual code or error message, only a general approach can be suggested, which includes loading the audio file, modifying its amplitude, speed, and possibly reversing it, plotting, and playback.
Step-by-step explanation:
To modify a recorded voice and playback the altered audio, you need to manipulate the sound's waveform data using digital signal processing techniques. The code you require will likely involve reading in the recorded sound, making changes to the amplitude (volume), speed (playback rate), and possibly reversing the sound, then plotting the modified waveform and playing back the sound. Unfortunately, without seeing the specific error message or the code you are using, it's difficult to provide a precise solution. However, I can suggest a general approach.
If you're using Python, the librosa library can be handy for manipulating audio signals. You can adjust the amplitude by simply multiplying the audio signal array by a factor for volume increase or decrease. To change the speed, you might stretch or shrink the audio waveform using the librosa.effects.time_stretch function. For reversing the audio, numpy arrays can be simply reversed. Finally, you can use matplotlib for plotting the waveform and sounddevice or pyaudio for playback.