Why is There No Sound When Recording from My Phone?¶
When recording from your phone via Type-C DP, you may notice that your phone’s speaker stops working. This is normal behavior, not a malfunction.
Understanding the Behavior¶
What happens:
When you connect your phone to RecDual Dongle via Type-C DP:
DisplayPort takes over the audio output channel
Your phone treats RecDual Dongle as an external display with audio
Audio is routed to the DP output, not the phone speaker
The phone speaker is temporarily disabled
The audio IS being recorded:
Audio is embedded in the video recording
Your recordings will have sound
Only live playback through the phone speaker is affected
This is a standard DisplayPort feature, not a RecDual Dongle issue.
How to Hear Audio During Recording¶
Option 1: Use the AUX Port (Recommended)
Connect headphones to RecDual Dongle’s AUX port
Audio plays through your headphones
You can monitor audio while recording
Option 2: Use HDMI Passthrough
Connect HDMI OUT to a TV or monitor
Audio plays through the TV speakers
Useful for shared viewing
Verifying Audio is Recorded¶
To confirm audio is in your recordings:
Stop recording
Access the recorded file
Play it back (on phone, computer, or via RecDual Link App)
Audio should be present
If there’s no audio in the playback, check:
Source content has audio (not muted)
Audio settings on source device
Common Misconceptions¶
“My phone is broken” - No, this is normal DP behavior.
“RecDual Dongle muted my phone” - The DP connection routes audio externally.
“Recording has no audio” - Audio is recorded; check playback on another device.
Technical Explanation¶
DisplayPort Alt Mode over USB-C:
Carries video signal from phone to RecDual Dongle
Also carries audio signal through the same connection
Phone detects external audio output (DP)
Disables internal speaker (standard behavior)
Audio routes to DP output → recorded by RecDual Dongle
This is the same behavior you’d see connecting to any DP monitor or TV.
Tips¶
Have headphones ready before starting Type-C recordings
Test audio routing before important recordings
Use HDMI passthrough if you prefer speakers
Check recordings to confirm audio is captured
This Doesn’t Happen with HDMI Recording¶
When recording HDMI sources:
HDMI source has its own audio output
Connect to HDMI passthrough for live audio
No audio routing through your phone