IVR Voice Configuration — Settings, Prompt Tricks, and Troubleshooting

This guide covers how to configure your IVR bot's voice, behavior, and speech settings. It also explains the difference between IVR-specific settings and the channel overrides, and includes tricks for improving how the bot greets callers and reads information aloud.

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What Is the IVR Voice Configuration?

Each phone number connected to Velaro has a Voice Configuration that controls:

• Which voice the bot uses (ElevenLabs or Polly)
• How quickly it responds after the caller stops speaking
• When to transfer to a live agent
• What to say during idle moments or at the end of a call
• Pronunciation rules and background noise handling

These settings are configured per phone line in IVR Settings → Voice Configuration.

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Key Settings Explained

Speech Detection (Deepgram)

Setting	What It Does	Default	Notes
End of Speech Timeout	Seconds of silence before the bot responds	3.0s	Increase for slow speakers; decrease for fast back-and-forth
Silence Duration	Milliseconds of silence before speech is considered complete	2500ms	Lower = faster response; higher = waits longer for pauses
Interrupt Sensitivity	How easily a caller can interrupt the bot mid-sentence	Low	Low = less accidental interruption; High = very responsive
Speech Model	Deepgram transcription model	nova-3-general	Best for most use cases; nova-2 is an option for high-noise environments
Min Confidence	Transcription confidence threshold below which input is ignored	0.50	Lower = processes more speech but may catch noise

Voice (ElevenLabs)

Setting	What It Does	Default
Voice ID	The ElevenLabs voice used for text-to-speech	Configured per line
Speed	Speaking pace — 1.0 = normal	1.0
Stability	How consistent the voice is — lower = more expressive variation	0.6
Similarity	How closely the voice matches the original — lower = more natural variation	0.85
Model	ElevenLabs TTS model	turbo_v2_5

Tip on Stability: If the bot sounds flat or monotone, lower the stability value (try 0.4–0.5). This allows the voice more natural variation. If it sounds inconsistent or "wobbly," raise it back toward 0.6–0.7.

Idle & Timeout

Setting	What It Does	Default
Idle Check-In (seconds)	How long before the bot asks "Are you still there?"	20s
Idle Hangup (seconds)	How long after the check-in before the bot hangs up	20s
Max Call Duration	Hard cap on total call length	30 min

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Escalation Options

You can configure which escalation paths are available when a caller asks to speak with a person:

• Bridge Call to Agent — Transfers the caller directly to a phone number. Requires Enable IVR Bridge Call to be on in your subscription and a Fallback Transfer Number to be configured.
• Offer Callback — Bot takes the caller's phone number and arranges a return call.
• Take Message — Bot collects name, issue, and callback number; sends a notification to your team.

You can enable or disable each option individually in Voice Configuration → Escalation.

If the bot says "live agent transfer is not available" but you have a transfer number configured: Contact support — the Enable IVR Bridge Call subscription flag may need to be turned on for your account.

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IVR vs. Email — These Are Separate Settings

A common source of confusion: the IVR channel has an option called "Suggest emailing documents to callers" in Channel Overrides. This teaches the voice bot to offer "Would you like me to email that to you?" during a phone call. It does not affect how the bot behaves in actual email conversations.

Email conversations (when someone contacts you through your email inbox) are configured separately under the Email channel in Channel Overrides.

These two settings are independent and do not sync — because a customer may want the voice bot to offer email delivery but keep email-thread behavior at default, or vice versa.

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Improving Your Greeting — Pacing and Tone Tricks

The welcome greeting is the first thing a caller hears. Here are tricks to make it sound more natural:

Add Natural Pauses

Use ... (ellipsis) between phrases where you want a beat:

Hello, and thank you for calling Sullivan Tire and Auto Service... your place for tires and auto service. How can I help you today?

The ... causes a brief natural pause in the voice output. Use it for emphasis or between distinct thoughts.

Add Energy to a Section

Ending a phrase with ! signals the voice engine to add more energy to that sentence. This works in the Welcome Greeting because that text goes directly to the TTS engine.

Important: Do not put anything in parentheses in the Welcome Greeting — the voice engine reads parenthetical text aloud, so (with warmth) would be spoken as the words "with warmth."

Tone Hints in the Bot Prompt (Not the Greeting)

If you want to guide the bot's tone throughout a call — not just at the opening — add a stage-direction hint to the bot's AI prompt in AI Settings → Bot Configuration:

When greeting a caller, speak with warmth and genuine enthusiasm — vary your rhythm so it doesn't feel scripted.

These instructions are read by the AI and shape how it phrases responses. They are never spoken aloud.

Read Phone Numbers Clearly

The system automatically instructs the bot to read phone numbers with natural pauses between digit groups:

> 2 0 7... 7 7 4... 8 4 7 3

If you find a number in your KB data that's being read too fast, check that it's formatted with hyphens: 207-774-8473. Hyphens help the TTS engine place natural pauses.

Never Asks "Do You Want Me to Give You That Number?"

The bot is instructed to give information directly without asking permission first. If you're seeing this behavior, it may mean the bot's AI configuration prompt is overriding this behavior — check the bot's system prompt under AI Settings → Bot Configuration.

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Voicemail & Email Handling on IVR

The IVR bot will never read an email address aloud over the phone — it says "the email we have on file" instead. This is intentional: callers can't easily write down email addresses during a phone call.

When the bot confirms contact information for a callback or follow-up, it will say:

> "I have your email address on file — is that still the best way to reach you?"

It will not say the actual address. This is by design.

URLs from your knowledge base are also never read aloud — the bot will offer to send the link via SMS or email instead.

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Troubleshooting: Calls Not Hanging Up

If the bot says a nice farewell but the call stays open for 30–60 more seconds, it means the bot's final message didn't include the word "Goodbye!" — which is the signal the system uses to know the call is done.

How it works: The bot is instructed to end every closing message with "Goodbye!" If it says "Have a great day!" without "Goodbye!", the system falls back to an idle timeout (about 40 seconds).

Workaround: In your bot's AI configuration, add this to the system prompt:

When ending a call, your final message must include the word "Goodbye!" at the end.

This is already a default system instruction — but if your bot's prompt overrides it, adding it explicitly will fix the behavior.

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Troubleshooting: Transfer Not Working

Bot says "transfer is not available" even though a transfer number is configured:

1. Check that Enable IVR Bridge Call is active on your subscription (IVR Settings → Voice Configuration → Escalation section)

2. Verify a Fallback Transfer Number is saved on the voice configuration

3. If both are set and it still doesn't work, the subscription flag may need to be enabled — contact support

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Pronunciation Overrides

If the bot mispronounces a brand name or acronym (e.g., "Sullivan" vs. "Sull-ivan", or "SUV" read as letters), you can add a pronunciation rule:

Go to IVR Settings → Pronunciation Rules and add:

• Word: the term being mispronounced
• Replace With: a phonetic spelling (e.g., "S-U-V" or "sport utility vehicle")

These rules apply to all voice output on your site.