Audio management and the cache

Manage cached audio, interaction styles, and pronunciation corrections.

Level 2 — Lesson 5 of 8 — Understand and manage the audio cache for optimal performance.

Audio Management controls how TTS output is generated, cached, and replayed. Without understanding caching, teams often think changes “didn’t apply” when they’re hearing old audio.

Understanding the audio cache

What caching is

Cached audio stores previously generated TTS so it can be replayed instantly, reducing latency and keeping repeated phrases consistent.

Cache requirements

Audio is only cached if the same utterance is generated at least twice within a 24-hour window.

One-off utterances will not persist in cache by default.

Managing cached audio

1. Open Audio Management

   Navigate to Channels > Voice > Audio management in the platform.

2. Review cached utterances

   Check the list of cached utterances:

   • Greeting
   • Transfer / handoff language
   • SMS offer phrasing
   • Closings and confirmations
3. Adjust individual utterances

   For any high-frequency utterance:

   • Open it and review how often it has been used
   • Adjust stability and clarity for that utterance only if needed
   • Use the play button to preview changes
4. Ensure stability for critical phrases

   If an utterance must remain stable:

   • Generate it multiple times within 24 hours, or
   • Upload a static audio file to overwrite the cached version

Check your understanding

Interaction style (response latency)

Interaction style controls how quickly the agent responds after detecting user speech. This directly affects interruption rate and perceived naturalness.

Turbo

~400ms latency

Extremely fast, higher interruption risk.

Swift

~1200ms latency

Prioritises speed.

Balanced

~1600ms latency

Default for most use cases.

Precise

~2000ms latency

Slower, more deliberate, fewer interruptions.

Barge-in

What is barge-in?

Barge-in determines whether callers can interrupt the agent mid-speech.

When to use it

• Useful for Turbo mode
• Can feel chaotic if enabled without careful phrasing and latency tuning

Pronunciations

Ensure domain-specific terms are spoken clearly and correctly in Call.

Pronunciations are defined in the Pronunciations tab under Channels > Voice > Response Control and applied globally. They modify how text is converted to speech, without changing the underlying text.

When to use pronunciations

Brand names

Product names that are mispronounced

Proper nouns

Locations, people, departments

Numbers or IDs

Structured read-back requirements

Pacing

Phrases where pacing matters for comprehension

How pronunciations work

Matching is done using regular expressions. Replacements can be:

IPA

International Phonetic Alphabet

For precise pronunciation control

SSML

Speech Synthesis Markup Language

Such as <break> for pauses

Regex capture groups

Pattern matching

\1, \2, etc. for reformatting

Examples

IPA correction

Regex: \bLouvre\b

Replacement: /ˈluːvrə/

Case sensitive: FALSE

Phone number formatting with pauses

Regex: (\d{3})[ -]?(\d{3})[ -]?(\d{4})

Replacement: \1 <break time="0.5s" /> \2 <break time="0.5s" /> \3

Best practices

Incremental

Add pronunciations one at a time

Test thoroughly

Test each change in Call before adding more

Keep it simple

Prefer clarity over cleverness—overly complex regex is hard to maintain

Check your understanding

Verification checklist

After any voice or phrasing change:

• Start a new call session
• Confirm you are hearing updated audio, not a cached version
• Validate that turn-taking still feels natural after changing latency or barge-in
• Mispronounced terms are corrected consistently
• Pauses improve comprehension rather than slowing the call excessively

Try it yourself

1. Challenge: Fix a mispronounced brand name

   Your agent says “Hopper” but it is consistently pronounced incorrectly (sounds like “Hooper”). You also want phone numbers read back with a natural pause between each segment.

   Write both pronunciation configurations:

   1. IPA correction for “Hopper”
   2. Phone number formatting with 0.5s pauses

   Hint

   For the IPA, write out what “Hopper” sounds like phonetically. For the phone number, use regex capture groups to split the digits and insert SSML <break> tags.

   Example solution

   Brand name correction:

   • Regex: \bHopper\b
   • Replacement: /ˈhɒpər/
   • Case sensitive: FALSE

   Phone number with pauses:

   • Regex: (\d{3})[ -]?(\d{3})[ -]?(\d{4})
   • Replacement: \1 <break time="0.5s" /> \2 <break time="0.5s" /> \3

Check your understanding

← Previous: Response Control

Lesson 4 of 8

Next: Global ASR →

Lesson 6 of 8