CekuraBench

GPT-4o mini TTSvsSmallest Lightning v3.1

GPT-4o mini TTSSmallest Lightning v3.1
Compare

Speed and accuracy

Left is faster. Higher reads more hard parts right.

Fast and accurate60%70%80%90%100%00.5s1s1.5s2sTime until the caller hears the voice
  • GPT-4o mini TTS688 ms · 82.7%
  • Smallest Lightning v3.1357 ms · 81.3%

GPT-4o mini TTS is better on accuracy. Smallest Lightning v3.1 is better on non-streaming latency, streaming latency, naturalness and price.

Last updated Methodology by Dileep Chagam

Which is better at what

Measure by measure, the same sentences, the same place.

MeasureGPT-4o mini TTSSmallest Lightning v3.1
  • Non-streaming latency (median)Smallest Lightning v3.1 is better688 ms357 ms
  • Streaming latency (median)Smallest Lightning v3.1 is betterCan't stream363 ms
  • Extra audio after a stopNo stop messageNo stop message
  • Hard parts read rightGPT-4o mini TTS is better82.7%81.3%
  • Naturalness (1 to 5)Smallest Lightning v3.1 is better4.434.49
  • Price per 1M charactersSmallest Lightning v3.1 is better$25.70$19.50
Hard parts read rightGPT-4o mini TTSSmallest Lightning v3.1
  • Numbers and shorthand7 a.m. · 20% · 36°F · approx.78%78%
  • Codes and addressesSAVE20 · help@north-clinic.org · 1-800-555-019978%81%
  • Read from contextSt. Mary's on Main St. · Dr. Okafor96%75%
  • Medical termslevothyroxine · gastroenterology94%97%

An estimate: speech-to-text transcribers scored it, not people.

Hear both

The same sentence, read by each voice.

19 sentences, the same for both
  1. 01A greetingThanks for calling Cedar Valley Family Practice, this is Riley. How can I help you today?
  2. 02MoneyYour current balance is $1,347.09.
  3. 03A dateThe order was placed on 2026-03-14 and shipped two days later.
  4. 04Tracking codeThe tracking number is 1Z 7A4 X29 0341 8867.
  5. 05Email addressI have m.rivera88@example.org, is that still current?
  6. 06An Irish nameSiobhan Ó Briain called about the invoice.

How each ranks among all 26

MeasureGPT-4o mini TTSSmallest Lightning v3.1
  • Non-streaming latency (median)21 of 2617 of 26
  • Streaming latency (median)n/a16 of 18
  • Extra audio after a stopn/an/a
  • Hard parts read right12 of 2614 of 26
  • Naturalness (1 to 5)7 of 264 of 26
  • Price per 1M characters11 of 257 of 25

Related comparisons

GPT-4o mini TTS vs Smallest Lightning v3.1 FAQ

  • Smallest Lightning v3.1. GPT-4o mini TTS: 688 ms. Smallest Lightning v3.1: 357 ms.

  • Smallest Lightning v3.1. GPT-4o mini TTS: Can't stream. Smallest Lightning v3.1: 363 ms.

  • Neither has a figure. GPT-4o mini TTS: No stop message. Smallest Lightning v3.1: No stop message.

  • GPT-4o mini TTS. GPT-4o mini TTS: 82.7%. Smallest Lightning v3.1: 81.3%.

  • Smallest Lightning v3.1. GPT-4o mini TTS: $25.70. Smallest Lightning v3.1: $19.50.