Setting Up A USB Computer Mic On Your MacintoshYour Mac's mic settings can be configured and verified in OS X System Preferences > Sound pane. The Sound preferences panel lets you choose various available audio devices for your preferred sound input source and output device. There you can test your mic's device input sensitivity. After attaching a USB mic or headset to your Macintosh's analog jack or USB port, if you do not see signal response indication in the Sound Preferences pane, disconnect and reconnect the mic to your Macintosh.
The low-level drivers needed for USB audio devices are already built into OSX, although additional vendor provided utilities may give additional control over the mic or headset's core functionality. All versions of OSX include generic USB audio drivers to support a huge range of USB sound devices right out of the box. The System Preference pane > Speech can be used for alternate input device access. In newer versions of OSX like Sierra, Yosemite and Mavericks - and since OSX Mountain Lion - you can also use your external or internal mic to perform Speech To Text translation using Apple's Dictation Services now built into the operating system.
Input-level response bars will help you visually check your mic sensitivity for optimal, distortion-free sound. When the bars don't respond to hollering or to taps on the mic, you'll need to trouble-shoot your connection in Apple's System Profiles. It's important to insure you haven't unintentionally muted the mic: Some desktop USB mics and headset solutions provide a mute button. Some also feature an LED light to indicate if and when the audio device is muted. Some Apple-friendly USB headsets may also offer an in-line mute button on the cord or on the USB audio dongle that connects to your Mac's USB port.
Once you've confirmed live voice input as indicated by the Input Level bars, you may also need to make sure you've set audio properly in your recording app or video-chat program's preferences. Video and audio conferencing programs like Skype, ISPQ, iChat, and Apple's Messages or FaceTime, may offer SEPARATE input settings within their built-in application preference settings besides the system-level Apple Menu > Preferences > Sound. Make sure that your new mic has been selected in whatever chat or sound capture program you're using to its set optimally.
In OSX Yosemite, Mavericks, Lion, or Lepoard you can hold down the Option key and click the volume control icon up in the menu toolbar to select your preferred audio input and output options without needing to go through any extra steps to get to Apple's System Preferences.
Many PC compatible analog mics require power on the mini jack input and may not work on Macintosh systems. For many years the PC world used different voltage levels than Apple did. Most PC laptops and desktops also used SEPARATE 2-conductor speaker and microphone jacks. Apple more agressively pursued a single FOUR-conductor mini-plug to combine both audio functions into one.
When buying any Analog headsets or mics, try to ascertain Macintosh compatibility. Otherwise a low-cost Analog to Digital USB audio dongle with separate 1/8" headphone and microphone jacks can covert a PC headset for use on a Mac. Some headsets ship with this dongle included. Unamplified PC mics often won't work in 1/8" - 3.5 mm mic input jacks. As of 2009 and later - MacBook Pros (and iPads) are now compatible with Apple iPhone mic headphones. Just plug you headphones into the unified headphone jack, and the mic will be listed in your input sources. The volume/play/pause controls will work if in iTunes.
There's a wide range of Macintosh compatible computer mics, USB stereo computer headsets and 1.8" analog mic options for Apple MacBook, Macintosh mini and Pro towers, iMac and MacBook Air computers. Check out some of the best quality mics for professional voice, music and radio recordings, Prosumer podcasting and videocasts. Apple Macintosh home consumer mic options also are great for use with VOIP, online Macintosh Skype calls, iChat, FaceTime, and other voice supported webcam chat applications.
USB Mic Connection Tip: Using USB Hubs
Most Apple compatible mic solutions are USB-based. Ideally, you want to connect the mic to a USB port directly on your Macintosh. Sharing a Mac's mic on a USB hub may be problematic, especially if you have other high-bandwitdth, hi-demand devices trying to share the audio stream packets. Low transmission devices like a digital camera, card keyboard, moust or reader, aren't usually a problem. Other high-speed, high-demand isosynchronous Mac USB gadgets especially other audio video accessories, HDTV tuners, video capture dongles, SSD and HDD backup drives along with a USB mic on a device sharing hub may be a bit problematic. A good indication that device contention on the USB hub is problematic if you find USB devices locking-up and becoming non-functional unless you unplug and replug them.