The vast majority of web cameras sold these days already feature a built-in microphone, so finding a Mac mini webcam with one isn't hard. But a few don't such as the Microsoft Xbox Cam, The Cubie or iMage from eCamm, and a few others. Some of the higher end HD cameras for Mac include dual or stereo microphones on each side of the webcam's lens.
Im my testing, most no-name, cheap import webcams are just that; Cheaply constructed with less than optical quality webcam lenses and sensors, and equally sub-par microphones as well. Some of these cheap $10-30 cams had ok or so-so images and microphones that often sounded either muffled, harsh sounding, or hollow and thin. Some use a separate 1/8" analog cable for the microphone which often doesn't work at all on Mac's because of differences in Mic vs Line-Level input voltages. Any Apple compatible webcam with mic should use just a _single_ USB cable for both video and audio. All in all, these cheap import webcams are proof that you sorta get what you pay for when you seek out a dirt-cheap camera with built-in mic from the bargain bin. If your Mac mini webcam needs aren't demanding that might be 'good enough.'
On better quality HD webcams from companies like Logitech, Creative Labs, HP and Microsoft -- We're seeing dual noise canceling or stereo microphones built in to cameras for quality audio capture to match the razor-sharp High-Definition images these premium webcams deliver. Similar to what Apple is doing with directional 'Beam-Forming' mics in the recent Retina MacBooks, dual microphones can use differential voltage signals between the two mics to help with background noise and echo cancellation and give a clearer, cleaner video clip audio capture, or improve an Apple Messages, iChat, Skype or voice conferencing experience.
A webcam with stereo microphones does add ambience and directionality - especially in multi-person chat. But because web cameras are small and the mics are placed rather close to each other on each side of the camera lens, the stereo separation is very subtle, not dramatic.
The FOV of webcams has generally increased over time. Logitech's most recent camera, the Brio 4K Ultra HD webcam has a native 90 degree Field Of View, but is changeable via software to 65 or 78 degrees if you prefer. This chart of Creative Labs webcams shows how narrow or wide-angle their various models have been over the years.
The real question for those buying a Mac compatible wide angle web camera will be if they really want the C930e's wider 90 degree wide angle perspective that the web camera delivers. This might be ideal for security and surveillance monitoring or group video conferencing. But for the majority of Mac users doing 1:1 Face To Face interactions, wide angle web cameras might include far more of your surroundings and background space than you really want.
If you want room surveillance with the W-I-D-E-S-T wide-angle field of view that's currently shipping, an alternative is the UVC compliant Genius WideCam F100 who's 120 degree view will cover more visual area than most other conventional Mac compatible USB webcams:
If 90-degrees is suitable for your needs, here's some of the features of the wide-angle Logitech C930e Web Camera:
Wide Angle Webcam Lens
The C930 HD Webcam has a W-I-D-E-angle 90 degree field of view. Most webcams for Mac offer a narrower 60-70 degree FOV - Field Of View. With wide-angle cams, some distortion typical of a ‘Fish Eye Lens’ can occur. Logitech’s C930e claims to address and compensate for this issue to maintain a more accurate view of a business conferencing room or a couch full of friends or family at home. Do note however, that some folks may not like this trend towards the ever-wider wide-angle conferencing webcams. For more casual personal and adult 1 on 1 video chat, capturing more of what’s around or behind you in the room isn’t necessarily ideal, nor preferred.
USB 2.0/SuperSpeed USB 3.0 Connection
Hi-Speed USB 2.0 certified and SuperSpeed USB 3.0 ready connectivity. Full HD 1080p video calling (up to 1920 x 1080 pixels) and 720p HD video calling (up to 1280 x 720 pixels) -- Much of this depending on the CPU horsepower and internet bandwidth available on your Mac as well as the OSX video capture and conferencing applications you use.
Webcam Support For H.264 - SVC Video Compression
This Apple compatible HD camera supports hardware-based H.264 and SVC video compression, which part of the updated UVC 1.5 webcam specification. Realtime hardware compression reduces data sizes for smaller video files on your hard drive, and also addresses optimizations for negotiating the best video call performance and frame rates in single or multiparty HD conferences. This is an important advancement since the bandwidth available and packet delivery rates on internet cable, DSL, T1 and other network connections can vary between users in, and during a video conference. Bandwidth negotiation and monitoring during video chat is getting more sophisticated.
Stereo Webcam Microphones
Like the C910 and C920 cams which preceded it, the C930 features built-in dual stereo microphones as well. Dual microphone arrays can help with noise cancellation as well as deliver a more accurate aural presence to the room. In my testing with other dual-mic webcams -- yes, they really are stereo, but given how close they are in physical proximity don’t expect breathtaking ambient 2-channel audio.
Webcam Autofocus and Light Management
The 930e HD cam features super-smooth autofocus and their RightLight 2 automatic low-light correction technology that helps insure a clear image and better frame-rates in various lighting environments, even in low light. From my experience Logitech’s smooth and responsive autofocus took huge strides forward a few years back when they introduced the Mac Vision Pro. Far too many other Mac compatible web cameras have a rather ‘STEPPY’ and lagged auto focus. That can be distracting as a lesser webcam struggles to keep up and adjust to movement within the frame. Not so with the C930.
Optical Quality Webcam Lens
As with their previous premium webcam models, Logitech continues to use the awesome optical quality glass Carl Zeiss lenses for spectacular image clarity few other Mac compatible webcam brands deliver.
Webcam Privacy Shutter
A small, flip-down external privacy shutter that snaps on to the Logitech 930e Mac compatible webcam is included with the camera. However, I think an optional piece of clip-on plastic a rather chintzy ‘security solution.’ Other webcam manufacturers have used more elegant and integrated sliding lens covers built-in to the camera over the years with no separate pieces to break off or lose.
Optional Webcam Tripod Mount
Also welcomed is a standard camera tripod mount. It's integrated into the universal clip that also fits various Mac laptops, LCD screens, or sits atop CRT monitors on your desktop. Many Apple users are frustrated by the limited angles and range of, say, a MacBook, iMac or Cinema Display’s built-in iSight camera. So there’s a very healthy demand not just for external webcams for Mac in general - but some really want the stability and precision placement a tripod mount webcam can provide.