How to mike a roomful of computer operators?

I am trying to record audio of 8 computer terminals in a room. The computers are in two rows. The room has a fair amount of fan and air-conditioning noise. I would need to suspend the microphones from the ceiling.  I would like to get relatively clear audio of the computer operator sitting at the workstation and of people standing nearby. I am using digital video recorders to record video and audio.
Thanks, George C.

Reply:
I'd recommend using either:
(1) miniature omnidirectional condenser mics (lavalier mics like newscasters wear)
or
(2) boundary mics (mics meant to be used on surfaces such as desks)

If you have the budget for 8 microphones and a mixer, that would provide the clearest sound with the least background noise. Ideally the mixer would be an automated (gated) mixer, which turns off mics that are not in use. An example is the AKG AS-8 Automixer. Hang each mic near each computer operator. Connect the line output of the mixer to your video recorders' line inputs. If they have only mic inputs, insert a 40 dB attenuator circuit between the mixer and the camera's mic input. The link below shows the circuit.

40 dB attenuator circuit

If you have the budget for 4 microphones a mixer, hang each mic between every two computer operators, ideally at mouth height. If the mics get in the way of people standing nearby, hang them just above head height.

Another possibility is to tape a lavalier mic to each computer operator's monitor screen or desktop. Or place a boundary microphone on each computer operator's desktop. That way you don't need to hang the mics. Feed all the mics into a mixer.

Here are some suggested microphones with USD prices quoted from  www.froogle.com.

AKG C407L lavalier microphone, $89
Crown PZM-185 omnidirectional boundary microphone, $169
Crown MB-4 cardioid condenser microphone, $130
AKG AS-8 automixer, $1599
4-channel mic mixers are available for about $100.