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Configuring and Using the EMI 2|6
Emagic
EMI 2|6
About the Term “Latency”
The term “Latency” describes the delay that occurs when
audio signals are edited within a computer environment. It
occurs because the computer needs to buffer the audio data
between different stages of processing. This type of delay can
not be avoided completely. It is desirable, however (and possi-
ble with fast computers and good drivers), to keep latency
delays as small as possible. A reduction in latency figures will
allow the monitoring of a recorded signal through the computer
or live playing of a software synthesizer without noticeable
delay.
An area of confusion—particularly to new users of digital audio
hardware and software—is that the term “latency” is used to
describe several types of delays that can accumulate in certain
cases. As an example, each D/A or A/D conversion stage intro-
duces a delay of approx. 1 ms (millisecond—i.e. 1/1000th of a
second). If an audio signal is converted from analog to digital
and back, it is delayed by 2 ms. In addition to this value, the
latency from the audio driver itself plus a further (possible)
latency from within the program being used, need to be added.
It also makes a difference if an audio signal is monitored
through the computer or if it’s generated inside the computer.
To clarify—if you record a singer and monitor the signal
through the computer, the input plus output latency are
summed. If you play a software synthesizer from your MIDI
keyboard, the input-related latency does not occur as the syn-
thesizer’s signal is generated inside the computer. In this case,
only the output-related latency matters.
Audio Bit Depth Controls
The “Audio bit depth” panel allows selection of the bit resolu-
tion used by the EMI 2|6 for playback and recording. Either 16
or 24 bit resolution can be selected for both options. Due to
USB bandwidth limitations, the EMI 2|6 can only use 24 bit
resolution in one direction at a time—i.e. either for playback or