Today I picked up a
Samson C01U mic so that I can have better audio in my WindowsClient.net videos than I had in some
previous screencasts. The mic is the same one that Scott Hanselman
has used when recording podcasts from his setup.
I spent the better part of the afternoon messing around with the
mic, trying to get something with usable audio. The gain just
seemed way too low, barely registering one bar in the Windows 7
audio device setup dialog.
I made sure to crank up the gain in that dialog (it's set
really low by default). but that made only
marginal difference.
I tried it on my netbook to check levels (which seemed slightly
higher there, but still not usable) I even tried switching it
around between different USB ports on my PC in case power was an
issue. I tried it both on-board and in an external powered USB hub.
The tip for that came from Bill Reiss in the Camtasia forums here (excerpted below, emphasis mine).
I had an issue with the Samson C01U microphone levels on Windows
7 (Vista should be very similar), the microphone was very quiet.
It turns out that it was the USB port I was plugging it
into, it must not provide enough power. I switched to another USB
port on the other side of the laptop and it was fine.
If you try switching to another USB port and this doesn't
help, you may want to consider a USB hub that has external AC
power.
Hope this helps, I didn't find any advice like this online and was
about to give up on this microphone before I figured it out. Now
I'm very happy with it.
So, before I completely gave up on what I was sure would be a
good mic, I decided to try some other ports. My external powered
hub has two ports sticking out of the top which look like they
might be special. I tried one of those and bam! I suddenly had
sound levels in the red. I guess those two are the only ones
getting additional juice.
Condenser mics need external power because they rely on voltage
changes in a capacitor to capture sound. This makes them more
sensitive than other types of mics, but also means they need power
where others do not.
In Windows XP you can use the special pre-amp software to work
around this, but I imagine the USB power issue remains simply
masked.
It appears that not all USB power is created equal. Now the mic
sounds great.