We've been receiving a significant number of reports from users indicating that the iPhone's earpiece and speakerphone volume are too low, even at the loudest setting. Readers note that compared to most other mobile phones, the iPhone's sound output -- for voice functions, at least -- is subpar.
iPhone Atlas reader Sharon, for example, writes:
"I have found the volume on the iPhone to be very low, even when turned up to the highest setting; it is also low using the headset for calls. It seems fine when listening to music."
Users have also lamented low volume for the iPhone's ringer, which can be controlled using the Sounds pane of Settings.
An odd factor in this issue is that volume when playing music using the iPod function through the built-in speakers or headset is significantly louder than when using phone-based functions (including the speakerphone).
Another oddity is that some users have reported differences between individual iPhone units, with some being louder than others. In house, all of our iPhones generate similarly quiet sound output.
Apple may issue a firmware update to boost the iPhone's earpiece and speakerphone volume as it has done for some Mac portables through Mac OS X updates. As aforementioned, the iPhone does have the capability to generate louder output when in iPod mode, so a simple software tweak could very well boost earpiece/speakerphone volume.