Conferences and trade shows are full of moments that are hard to connect to a phone. A keynote reveal, a booth demo, a sponsor's stage segment: attendees see and hear it, then walk away. Inaudible tones give those moments a digital follow-up. A short tone played through the room's speakers can tell an opted-in event app or exhibitor app to show the right content at the right time, without a QR code or a typed link. This guide covers where tones fit at events, what to plan for, and how to measure results.
Where tones fit at an event
Tones work best when they mark a specific moment that people are already paying attention to:
- Keynotes and main-stage sessions. Unlock the slides, a product page, or a session survey the moment the speaker mentions it.
- Booth demos. Trigger a spec sheet, a meeting booking link, or a follow-up offer at the end of each demo loop.
- Sponsor segments. Give sponsors a measurable action tied to their time on stage, not just a logo on a slide.
- Session check-ins. Confirm that an opted-in attendee was in the room for a session, for example for continuing-education tracking, where the organizer's rules allow it.
The common thread is a clear reason for the attendee to want the content. A tone that leads somewhere useful earns attention; a tone that leads to a generic page does not.
Consent and permission come first
A phone has to listen for a tone to recognize it, so the app needs microphone permission, and iOS and Android both ask the user before granting it. At an event, that ask should be clear and well timed:
- Explain the value before the system prompt. Tell attendees what they get, such as slides or a booth offer, and that the app listens only for event tones.
- Make it optional. The event should work fine for attendees who say no. Offer a QR code or link as a fallback.
- Disclose it plainly. Put tone use in the event app's privacy notice and on signage where tones play.
Our consent and permission UX checklist for tone apps goes deeper on the permission flow.
Plan for show-floor audio
Exhibit halls and ballrooms are loud, echo-filled spaces, and every venue sounds different. A few planning points help tones play reliably:
- Know the sound system. Main-stage tones usually play through the house audio system. Booth tones play through the booth's own speakers. Confirm with the AV team that the system can reproduce the tone's frequencies cleanly.
- Keep booths from overlapping. Neighboring booths playing tones at the same time can confuse detection. Coordinate timing and coverage with the organizer.
- Mind the volume. Tones should be played at levels set with the AV team and within venue rules, not turned up to compete with crowd noise.
- Test in the actual room. A rehearsal on the show floor, with a range of phones at different distances, tells you more than any lab test.
Measure the moments
Events move fast, so set up measurement before doors open. Track how many attendees have the app, how many granted microphone permission, how many tones were detected, and how many people took the action each tone offered. Break results down by session, stage, or booth so organizers and sponsors can see which moments performed. Our guide to measuring opt-in rates for tone-triggered campaigns lays out that funnel step by step.
Frequently asked questions
Can attendees hear the tones?
GhostTones tones are designed to be inaudible to most people, so they can play alongside a keynote or demo without interrupting it.
Do attendees need to download an app?
Yes. Tones are recognized by an app that includes tone detection, such as the event's own app or an exhibitor app, and only after the attendee grants microphone permission.
Will tones work in a noisy exhibit hall?
Show floors are loud and every room is different, so plan speaker placement with the AV team and test on site with several phones before the event opens.
Can GhostTones help plan an event pilot?
Yes. GhostTones works with organizers, exhibitors, and agencies to plan tone moments, the consent flow, on-site testing, and reporting.
Plan an event pilot
GhostTones builds B2B inaudible-tone and experiential audio programs for brands, agencies, and their partners. Talk with CEO Curtis and CRO Jerry Reid about your next conference or trade show at ghosttones.com.
Plan an event pilot and we will help you map the moments, the consent flow, and the measurement plan before the show floor opens.