Metric Halo Mobile I/O User Manual

Page 357

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Glossary

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with a DB25 to DB25 cable, or you may use a DB25 fan-out to interface with
other types of connectors, such as XLR or TRS.

dB

Decibel; a logarithmic unit of measurement used to describe sound levels
relative to a reference level, both acoustically and electrically. There are
several suffixes added to dB to indicate the reference quantity or weighting
function used:

• dBFS: Decibels relative to full scale; 0 dBFS is the maximum level in

a digital audio system, since the level cannot go over 0.

• dBu: Decibels relative to 0.775 volts, across a 600 Ω load.
• dBV: Decibels relative to 1 volt, with no impedance specification.

DI

Direct Inject. Used to connect a high impedance, low level unbalanced
signal to a low impedance balanced input. The DI input provides a high-
impedance to the source keeping the input from loading down or filtering
the source. DI inputs are used to connect guitar, bass and keyboards to the
interface. Sometimes also called Direct Input.

Direct out

An output that allows you to route a signal without going through a bus. In
MIO Console’s Mixer, both inputs and busses have direct outs that allow you
to send audio to FireWire channels or physical analog/digital outputs.

Dither

The process of intentionally adding low-level noise to a signal to remove
quantization distortion. Dither is most commonly used when preparing 24
bit material for CD delivery (which is 16 bit) and should be the last step in
the process.

Dry

An uneffected audio signal. If you were to record a signal before and after
running it through a reverb, the pre-reverb signal would be dry and the post-
reverb signal would be wet. Many processors have controls to let you set
the wet/dry ratio.

DSP

Digital Signal Processing. This can mean:

• A physical integrated circuit that processes audio- “All Metric Halo

interfaces have a DSP chip in them called 2d.”

• The program that makes a DSP chip do useful things, usually referred

to as plug-ins- “The MIOStrip DSP plug-in gives me gating, compres-
sion and EQ right in the interface!”

F

Fader

A form of level control; inputs in the Mixer have faders that set the level at
which they send audio to busses, and busses have faders that set their output
level.

fs

Stands for sampling rate. For example, fs=44.1k means that the sample rate
is 44,100 samples per second.

G

Gain

The measure of a device’s ability to increase the level of an audio signal.
In audio, gain is usually referred to in dB; for example, the mic preamps in

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