Metric Halo Mobile I/O - Manual (Page 358)

Glossary
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the ULN-8 have 92.5 dB of gain. This means that they can take an incoming
signal and increase its level by 92.5 dB.
Graph A free-form area for creating signal processors. Inputs are on the left and
outputs are on the right. DSP building blocks are placed in the Graph and
connected by dragging virtual wires between the inputs and outputs of the
blocks and the Graph itself. Graphs can be saved for repeated use. More in-
depth information is available in the
Graphs section of the DSP Implemen-
tation Guide .
Group See Stem
H
Head amp Head Amplifier - another term for microphone preamplifier.
Headroom The amount that an audio signal can go above a nominal point before dis-
tortion. The maximum level in a digital system is 0 dBFS, so if we say the
nominal point is -18 dB, the system has 18 dB of headroom. Exceeding the
headroom in a system or device will cause distortion.
I
Impedance The opposition of a circuit to alternating current. In audio, it is important to
match the impedance characteristics of inputs and outputs:
• High impedance sources (guitar, bass, keyboards) should be plugged
into a DI. These are commonly called “Hi-Z”.
• Low impedance sources (microphones, line-level devices) should be
plugged into mic preamps or line-level inputs. These are commonly
called “Lo-Z”.
Insert There are two kinds of inserts used by Metric Halo:
• Analog: The ULN-2 and ULN-8 offer insert points that allow external
processors to be patched between the onboard mic pres and A/D con-
verters. The output is called the send, and the input back into the in-
terface is the return.
• DSP: MIO Console has 10 insert slots per strip that allow plug-ins,
Graphs, and sends to be placed in the signal path.
L
Latency The delay between when an audio signal enters and exits a device, process
or sound system. A system with high latency sounds "behind" the performers,
because there is an audible delay between when they make a sound and it
is heard from the audio gear.
Line level Describes the electrical signal level used to connect audio devices together.
Common nominal line levels are +4 dBu and -10 dBV.
Linear fade A fade up or down which has a constant gain change over time. In the ex-
ample below, the linear fade causes the straight lines in the fade in and out.