Both tools can make an MP3 with more than one speaker
ttsMP3's public US English page offers MP3 downloads. Its examples show speaker tags inside the text, such as [speaker:Brian], and markup for breaks, emphasis, speed, pitch, and whispering. It says the regular input limit is 3,000 characters per day and offers a separate 24-hour premium option. Those details were visible on 14 October 2026; check the current page before committing to a long script.
TTS Lines also makes MP3 and supports different speakers. Instead of putting speaker tags into the script, choose a voice under each editable line. The free model downloads first, then generates speech on your device. You can export one joined MP3 or WAV, one MP3 per line, a ZIP of clips, and line-timed SRT captions.
Try the correction that will happen in a real edit
Write three short lines, with a name or number in the middle one. Generate the draft, change that middle sentence, and see how you get the corrected audio into your project. In TTS Lines, the changed line becomes stale until you regenerate it; the others stay playable. Download just the new clip if your timeline already has the other lines.
For ttsMP3, test the same text with its speaker and prosody markup. The public page explains its speech controls and MP3 download, but it does not document TTS Lines' exact line-clip handoff. Check the live export interface for the file shape you need.
Which one fits?
Choose by the next step in your work. For an MP3 with a particular voice and spoken emphasis, ttsMP3's markup may be the easier route. For a video cut where a single sentence is likely to change, TTS Lines' separate clips are useful. Neither product can be judged on sound quality from a feature list; listen to the same script in the voices you would actually use.