deefstes wrote
So what is the story with vocals anyway? I've read in other threads also that recording vocals is a slightly more involved affair that recording a guitar. What makes it different? Why would you need a pre-amp? Isn't a microphone just another sort of pickup?
It's more a
mic thing than a
vocal thing. The same applies to any mic. Basically they have very low output levels that need more boosting to work properly.
A bit more in depth:
They are both transducers, but electric guitar pickups are electromagnetic (ferromagnetic strings vibrating in the magnetic field created by the pickup), while mics are electromechanical (a diaphragm moving to acoustic pressure, with a coil attached that moves in a fixed magnetic field).
Mics have a much lower output because they utilize a moving coil, so cannot be wound "hot" as it would add too much mass, affecting the response of the diaphragm. The lower output means that more (and better) pre-amplification is needed to get the signal up to line level and that the mic signal needs to be run as a low impedance balanced line from mic to preamp to avoid as much as possible picking up any noise.
Some mics get around this by building a preamplifier into the mic (condenser mics). The downside to this is that the preamplifier needs power to work and must be high quality to keep noise down. In "ye olde dayes", this meant valves and high voltages which consequently led to large mics with dedicated discrete power supplies, but the advent of transistors enabled the 48V phantom power standard and modern microelectronics even lets us use batteries. Because by this time mic inputs already had scads of gain, and dynamic mics still being the standard for live use, condensor mic outputs were still kept fairly low output to interface with the existing standards.
