Term
| Microphone frequency response |
|
Definition
| : the ability of a microphone to pass frequencies through itself in relation to be original frequencies in the sound wave. |
|
|
Term
| If a microphone passes all frequencies at the same |
|
Definition
| we consider it to have a flat frequency response. Most microphones however tend to emphasize or de-emphasize certain frequencies. |
|
|
Term
| On-Axis and off-Axis Frequency response : |
|
Definition
| directional microphone will have quite different frequency responses with sounds that come from directions off axis compared to on axis. (On Axis refers to the directions at wich a mic is the most sensitive. Off Axis refers to the angles the is least sensitive to sound. |
|
|
Term
|
Definition
| almost all buildings transmit low frequencies that microphones will pick up. These low frequencies often come from heating and air conditioning system, elevators nearby traffic or even wind, they literally shake the building. Sometimes the very instruments you are recording will cause low frequencies can have enough energy to shake a microphone stand and cable and can be picked up by a microphone. |
|
|
Term
|
Definition
| can significantly reduce the amount of non-acoustic vibration transmitted to a microphone. |
|
|
Term
|
Definition
| : how quickly and accurately a microphone can react to a sound. The transient response can vary a great deal from one type or model of microphone to another. |
|
|
Term
|
Definition
| typically have better transient response than a dynamic mic, however the weight stiffness of the ribbon do not allow it to react to sound as accurately as a condenser mic….particulrly with high frequency waves because they have less |
|
|
Term
|
Definition
| the lower mass of a small diaphragm will react quicker to sound, return to its original position quicker and can be more accurately moved by high frequency waves that have less energy. |
|
|
Term
| Outputs characteristics of microphones |
|
Definition
1. Sensitivity- the output of a microphone in volts in comparison to the input in spl
2. Equivalent noise noise created by the microphone itself usually rate in dba
3. Overload distortion from a sound too loud for the mic to handle
4. Impedance an electrical rating that helps match the output of a microphone the the input of a microphone preamp. Impedance is measured in ohms. Ohm symbols z or low impedance microphones are usually better. |
|
|
Term
| Balanced unbalanced cables balances cables |
|
Definition
| have at least three conductors’ wires. Unbalanced cables have just two wires. Having a third wire in a balanced cable allows cancellation of interface. Also the ground cable helps shield the two conductors from interface. |
|
|
Term
|
Definition
| a microphone’s ability a pickup sound from different directions. We measure directional response in a full circle (360) around the microphone. When we make a graph of this circle to represent how well the mic picks up sound from all angles, we call this a polar pattern. |
|
|
Term
|
Definition
| mics are pressure microphones, meaning the diaphragm reacts the same to sound pressure variations, no matter the direction of the sound source. The rear side of an omnidirectional microphone is enclosed. Therefore sound only creates pressure on the front side of the diaphragm regardless of from what direction it is coming. |
|
|
Term
|
Definition
| microphones puck up sound better from some angles while regecting sound from other angles. All directional mics are pressure gradient microphones. Sound is allowed to strike the front and back of the diaphragm. The differences in pressure created by sound striking both sides of the diaphragm will cancel out sound from some directions. |
|
|
Term
| Bidirectional or figure 8 microphones |
|
Definition
| are the simplest form of pressure gradients mics. If a sound comes directly from a side of a full exposed |
|
|
Term
|
Definition
| microphones pick up sound in a heart shape towards the front of the mic. Slots call ports in the side of the mic body allow sound to reach the back of the diaphragm about 90degrees out of phase from wen it reaches the front of the diaphragm. This creates destructive interference when sound comes from in back of the mic an constructive interference when the sound comes from the front |
|
|
Term
| These same types of directional pickup patterns can be created electronicall by shifting the phase of dual capsule condenser microphones |
|
Definition
Leave both capsules in phase and you’ve got an omnidirectional pattern.
Shift the rear capsule out of phase and you have a figure 8 pattern.
Shift the place in increments between the two and you get various shapes of cardioid patterns.
Proximity effect when a directional microphone is brought closer to a sound sorce low end frequencies are more prominent. |
|
|
Term
|
Definition
| generally consist of a stiff mylar diapragm of roughly o.35 mil thickness. Attached to the diaphragm is a finely wrapped core of wire called a voice coil that's precisely suspended within a high level magnetic field. |
|
|
Term
|
Definition
| operate on an electrostatic principle other than an elctromagnetic principle used by a dynamic or ribbon mic. the capsule of consist of two plates to form a capacitor. |
|
|
Term
|
Definition
| of conductors for an even better job of rejecting interface. The cable two pairs of wires one pair for the positive and one pair for the neutral conductors. |
|
|
Term
|
Definition
| are the most often neglected link in the sound chain. |
|
|
Term
|
Definition
| techniques how and where you place a microphone can be just as if not more important than the choice of the microphone itself. |
|
|
Term
|
Definition
placing a mics 3 or more feet from the sound source.
Licks up more of the tonal qualities of the instrument than closer placement
Picks up more reflected sound. |
|
|
Term
|
Definition
placing a mic within 3ft or less of the sound source
Creates a sense of nearness of presence
Can cover up room noise
Can reduce reflected sounds or other instruments.
Because of the close proximity to the instrument the microphone receives more acoustic energy in the form of direct sound when close miking. Other sounds will be somewhat diminished. Less leakage from other instruments |
|
|
Term
|
Definition
| to lessen leakage and phase problems for each unit(feet inches) that a mic is placed from its sound source it should be spaced 3 X that distance from the nearest mic. Example if you mic a guitar at a distance of 2 feet, the instrument and the mic next to it should be 6 feet away. |
|
|
Term
|
Definition
| : is a medium distance techniques that can bring out (accent) an instruments in an ensemble withot the “in your face” sound of a close miking. This allows the accented instrument to sound more natural in comparision to the distan mics. |
|
|
Term
|
Definition
| is intended to picup more of the reflected sound of the room than the direct sound of the instruments. |
|
|
Term
| The spaced pair (a/B) techniques |
|
Definition
uses two cardioid or omni directional microphones spaced 3-10 feet apart from each other panned in left/right configuration to capture the stereo separation is very wide.
The distance between the two microphones is dependent on the physical size of the sound source. For instance If two mics are placed ten feet apart to record an acoustic guitar the guitar will appear in the center of the stereo image. This probably too much spacing mic placement should be used in this situation. |
|
|
Term
|
Definition
| uses tow cardiod microphones of the same type and manufacture with the two mic capsules placed either as close as possible (coincident) or withing 12 inches of each other( near coincident and facing each other at an angle ranging from from 90 -135 degrees depending |
|
|
Term
| Mid side The M-s or technique |
|
Definition
| involves a cardiod mic element and a bi directional mic element, usually housed in a single case, mounted in a coincident arrangement . the cardiod (mid) faces directly at the source and picks up primarily on axis sound whle the bi directional (side) faces left and right and picks up off axis sound. The two signals are combined via the M-S matrix to give a variable controlled stereo image by adjusting the level of mid vesus side signals, a narrower or wider image can be created without moving the microphone, this technique is completely mono compatible and is widely used in broadcast and film applications. |
|
|
Term
|
Definition
| includes 3 omnidirectional microphones in an upside down “T” pattern the left and a right mics are placed about 6ft apart and the third is placed 3ft and centered infront. To mix the side mics are panned hard left and right and the output of the middle mic is then sent to both leaft and right channels. |
|
|
Term
|
Definition
| allows you to patch an instrument particularly guitar s and basses with pickups directly into your mixer or recording device. No microphone is necessary |
|
|
Term
|
Definition
| are simple transformers that just reduce the impedance of the signal from the guitar pick up from around 50K to a mic level around 100-200 |
|
|
Term
|
Definition
| have a built in preamplifier and be set to line or mic level can provide phantom power gain control and some even have effects processing. They do however require a power supply. |
|
|
