questions about SPL...help plz

[saikit_2003]

i got some question here...
1. what happens to mics in High SPL???
2. actally what is SPL?signal pressure level? what does it do?
3. Dynamic and condensor mics---> how they operate, common???

please help me!

 

[Kansnatchas]

SPL refers to Sound Pressure Level, measured in decibels. The higher the SPL the greater the level and the volume. Most engineers mix at or around 85 dBSPL. Dynamic mics like the SM 57 can handle anything you can throw at it(120dBSPL+), some condensers are more sensitive and can be damaged. Ribbon mics, depending on the model, are very sensitive to high SPLs. Hope this clears up at least some things.

 

[TuoKaerf]

Dynamic Mics-

Uses electromagnetic induction to generate an output signal (the signal going into your preamp).

A dynamic mic usually has a thick Mylar diaphram with a core of wire attatched to it. Whenever acoustic pressure (singing into the mic) hits the diaphram, the coil is displaced in the magnetic field in proportion to the amplitude and frequency of the wave, making the coil move across lines of magnetic flux that's is given by the magnet. This sends the electrical signal through the coil and out the output leads.

Condesner Mics-

Use electrostatic principles instead of electromagnetic. The capsule usually consists of two plates, one movable diaphram and one fixed. The plates form a capacitor, which stores the electric charge. The mic needs Phantom Power (+48v) which provides a charge for the capacitor.

In laymans terms, when you talk into the mic, the capsule expands and collapses, and that causes the signal to get send out of the mic.

 

[TuoKaerf]

Think of SPL as the more pressure you put on the mic's diaphram the higher in SPL you go. So the louder you play into the mic, the more strain that is put on the diaphram.

If you exceed the Mic's SPL rating, your sound will distort, or you will blow the mic out.

SPL=Sound Pressure Level is the acoustic pressure that is built up within a defined space (usually a square centimeter).

So the louder you get, the more pressure, the higher the SPL.