Acoustics troubleshooting
Introduction to acoustics troubleshooting
Acoustics design ensures that the sound is detected correctly with a microphone and properly radiated to
the outside of the device by the speaker. The acoustics of the phone include three basic systems: earpiece,
EANC error microphone, EANC reference microphone, stereo integrated handsfree (IHF) and two digital uplink
microphones.
The sound reproduced from the earpiece readiates through a single hole on the front cover (A-cover). The
EANC error microphone is located in the opening in front of the earpiece. The error microphone is soldered
on a flex PWB in front of the earpiece. The reference microphone is located at the bottom side if the PWB
and its sound hole is in the back of the phone near the camera. The sound reproduced from the 2 IHF speakers
radiates from the sound holes located in the top part of the phone at the sides. The uplink microphones are
located on the top side of the PWB. The sound hole of the primary microphone is in the bottom end of the
phone at left. The sound hole of the secondary microphone is in the keyboard between the left soft key and
the send key.
For a correct functionality of the phone, all sound holes must be always open. When the phone is used, care
must be taken not to close any of those holes with a hand or fingers. The phone should be dry and clean,
and no objects must be located in such a way that they close any of the holes.
Figure 31 EANC error microphone
RM-424; RM-564
BB Troubleshooting and Manual Tuning Guide
Issue 1
COMPANY CONFIDENTIAL
Page 3 –61
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