How to fix empty MP3 output in a Tkinter text-to-speech app on macOS: switch to gTTS and use asksaveasfilename

Troubleshoot empty MP3 files in a Tkinter text-to-speech app on macOS. Learn why pyttsx3 saves fail, when to use asksaveasfilename, and how gTTS saves audio.

When you wire up a quick text-to-speech flow in a Tkinter app, it’s easy to assume the save step is trivial. Yet a common symptom is a zero-byte or otherwise empty MP3 file that does get created but contains no audio. That’s exactly what happens in the snippet below based on a straightforward pyttsx3 setup on macOS.

Problem setup

The intent is clear: prompt the user for a destination and let pyttsx3 synthesize speech to that file. The result, however, is an empty MP3 even though the file exists.

out_target = filedialog.asksaveasfile(filetypes=(("MP3 files", "*.mp3"),
                                                ("All files", "*.*")))  # ask user for a path
speech_engine = pyttsx3.init()  # create engine
speech_engine.setProperty('rate', 100)  # set speaking rate
speech_engine.save_to_file('Hi and welcome to my audiobook.', out_target)  # attempt to save audio
speech_engine.runAndWait()

The behavior persists even when the snippet mirrors documentation examples. The environment here is macOS, and installing espeak-ng is not part of the setup.

What’s going on

The observable outcome is an empty MP3 file. The issue is reproducible in this configuration. Two practical notes follow from the context. First, the file dialog call above uses asksaveasfile; a note recommends using asksaveasfilename instead. Second, switching to gTTS proves to be a working alternative and simplifies the path from text to an MP3.

Working alternative

Replacing the save dialog call and swapping pyttsx3 for gTTS produces a compact solution that writes a valid MP3. The trade-off is that speed and other fine-grained settings are not being defined in this approach.

out_path = filedialog.asksaveasfilename(filetypes=(("MP3 files", "*.mp3"),
                                                 ("All files", "*.*")))  # get destination path
speech_obj = gTTS(text=text, lang='en')  # build gTTS object
speech_obj.save(out_path)  # write MP3 to the chosen location

This keeps the UI prompt for a filename and leverages gTTS to produce the audio. As noted, gTTS is easier to use in this scenario, while pyttsx3 allows adjusting speed and other properties.

Why this knowledge matters

Small differences in how you acquire a destination and how a library expects to receive it can result in files that exist but contain no valid content. Recognizing the symptom—an empty MP3—and knowing that swapping to a filename-based prompt and using gTTS is a viable path saves time. It also helps set expectations: if you require tuning parameters such as rate, pyttsx3 offers that flexibility, while the simplified flow shown here emphasizes quick and reliable output.

Takeaways

If you hit empty MP3 output in a Tkinter + TTS workflow on macOS, focus on two levers you can control right away. Prefer asksaveasfilename for the save dialog, and consider gTTS for a streamlined conversion pipeline. If speed customization is a requirement, keep in mind that pyttsx3 provides those adjustments, whereas the demonstrated gTTS flow prioritizes simplicity over parameter tuning.