The switch on the right is for controlling the microphone's gain. The Auto Gain setting allows you to use one of the HandyRecorder app's three auto-gain settings: Concert, Solo, and Meeting. The Concert setting is for loud sound sources, Solo is for quiet sources, and Meeting is for non-musical sources. Flick the switch to the Limit setting and you can adjust the mic's gain with a Mic Gain wheel found on the side of the iQ5, if the audio coming into the mic is so high that distortion could result, the iQ5 attempts to limit the mic's gain. You can disable this limiting, but still set the gain manually, by using the Off setting.
On the left side of the iQ5 are Mini-USB and headphone ports. The USB port lets you charge (but not sync) your iOS device while the iQ5 is connected. The headphone port is for monitoring recording and playback; it's a nice convenience, as the iQ5 blocks the headphone port on some iOS devices.
If I have any complaints about the design of the iQ5 it's that the Lightning-connector port isn't the most robust anchor for accessories such as this. It's a minor complaint because it's the nature of the beast — Lighting connectors are small, and unless you want to junk up your accessory with clamps to more firmly keep it in place, you're going to risk unseating it.
The handiness of HandyRecorder
Although you can record using the iQ5 with any iOS recording app, there are benefits to using Zoom's own HandyRecorder. To begin with, if there's new firmware available for the iQ5, HandyRecorder is the means for installing it. (The app automatically detects if the mic's firmware is out of date and offers to install the latest firmware.) But it provides other advantages as well.
I've already mentioned the options for adjusting the Auto Gain setting. You can also configure an auto record setting that causes the app to stop recording after a few seconds of silence and start recording again when the mic picks up sound that's louder than a specific volume level. This is a useful feature when you don't want your recording to contain long gaps of silence from a meeting or lecture. You can also pick your recording format: By default, the app records to 44.1kHz .wav files, but you can instead choose 48kHz .wav, or AAC files captured at 64, 128, or 160 kbps. You can also swap the left and right channels, and choose to monitor your recordings using the iQ5's headphone jack. (If you don't enable this option, you'll hear a slight delay between the audio coming into the mic and the audio coming out of the headphone jack.)
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