D4 Support

D4 sound science · Fort Mill Ventures

Turn D4 on

1. Open D4 and tap Turn on D4.
2. In the list, choose D4 sound science.
3. The green “D4 is ON” confirms it. iOS keeps its checkmark on iPhone Speaker; that is normal.

Turn D4 off

Open D4 and tap Turn off D4. The sound goes back to the iPhone speaker.

The sound stopped when I closed D4

iOS ends an app you swipe away, and only D4 can play the enhanced sound. Leave D4 open in the background. D4 shows a notification if it was closed. In D4, Settings → Help → Keeping D4 on shows a Shortcut that reopens D4 when you open your music or video apps.

Voice messages won’t record

Some apps, like WhatsApp and Voice Memos, stop recording after they play a clip while D4 is on. This is an iOS limitation. Close that app from the App Switcher and open it again. Turning D4 off first avoids it.

Requirements

iPhone with iOS 27 or later.

Contact

support@d4soundscience.com · We usually answer within two business days.

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