CekuraBench

Grok TTSvsSmallest Lightning v3.1

Grok 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
  • Grok TTS358 ms · 87.4%
  • Smallest Lightning v3.1357 ms · 81.3%

Grok TTS is better on streaming latency, stopping, accuracy and price. Smallest Lightning v3.1 is better on non-streaming latency and naturalness.

Last updated Methodology by Dileep Chagam

Which is better at what

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

MeasureGrok TTSSmallest Lightning v3.1
  • Non-streaming latency (median)Smallest Lightning v3.1 is better358 ms357 ms
  • Streaming latency (median)Grok TTS is better157 ms363 ms
  • Extra audio after a stopGrok TTS is better0 msNo stop message
  • Hard parts read rightGrok TTS is better87.4%81.3%
  • Naturalness (1 to 5)Smallest Lightning v3.1 is better4.174.49
  • Price per 1M charactersGrok TTS is better$15.00$19.50
Hard parts read rightGrok TTSSmallest Lightning v3.1
  • Numbers and shorthand7 a.m. · 20% · 36°F · approx.82%78%
  • Codes and addressesSAVE20 · help@north-clinic.org · 1-800-555-019986%81%
  • Read from contextSt. Mary's on Main St. · Dr. Okafor100%75%
  • Medical termslevothyroxine · gastroenterology99%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

MeasureGrok TTSSmallest Lightning v3.1
  • Non-streaming latency (median)18 of 2617 of 26
  • Streaming latency (median)7 of 1816 of 18
  • Extra audio after a stop1 of 6n/a
  • Hard parts read right8 of 2614 of 26
  • Naturalness (1 to 5)25 of 264 of 26
  • Price per 1M characters2 of 257 of 25

Related comparisons

Grok TTS vs Smallest Lightning v3.1 FAQ

  • Smallest Lightning v3.1. Grok TTS: 358 ms. Smallest Lightning v3.1: 357 ms.

  • Grok TTS. Grok TTS: 157 ms. Smallest Lightning v3.1: 363 ms.

  • Grok TTS. Grok TTS: 0 ms. Smallest Lightning v3.1: No stop message.

  • Grok TTS. Grok TTS: 87.4%. Smallest Lightning v3.1: 81.3%.

  • Grok TTS. Grok TTS: $15.00. Smallest Lightning v3.1: $19.50.