Working the Mic
Remote scrums are hard work. The first clue that something was wrong was when our sole remote coder volunteered to stop attending the scrum because he didn't find it useful.
This is a danger sign. Further probing determined that it wasn't that the format was wrong; it was just that he couldn't hear anyone. We're using Skype video calls, with the laptop sitting on a chair in its place in the circle, using the Macbook's built-in mic and speakers. While the mic's okay for 1:1 conferencing, it's not sensitive enough for people standing a couple of metres away.
No problem; I bought a £15 omnidirectional mic from Amazon. But now he couldn't hear us at all.
It turns out that Macbooks - even the new ones - don't have a mic-in port. They have a line-in port. Microphones work at much lower voltage, and can't be used there.
Okay. We have a Plantronics headset adapter that inputs a stereo jack and outputs USB. It doesn't work with the new mic, though.
So we needed a preamp. I bought an iMic; £30 of glossy white plastic that also inputs a stereo jack and outputs USB. It even has a "mic mode" switch that activates the internal preamp. Should be perfect, right?
It doesn't work. This omnidirectional conference mic is not the same as the 1:1 headsets that the iMic is designed for; it's a 'boundary microphone' that provides a weak signal even for a microphone. It turns out that microphones are described in terms of impedance, measured in ohms, and divided into 'low-impedance' (±1000Ω) and 'high-impedance' (±10000Ω). A high-impedance mic, like ours, won't work with the iMic and requires a more powerful preamp.
I'm still chasing that down. I'm not looking for production-quality here, just something good enough for intelligible speech.
In the meantime, we're passing the mic around - it works well enough if we speak directly into it, just not in 'omnidirectional' mode. This actually has some benefits, since it acts as a token - only the person with the mic speaks - and makes us all feel like radio announcers. We're hoping to get a USB speakerphone, which ought to be fully integrated, soon.
In 2009, setting up a video conference should not require an audio engineer. But it does.