Microphone Equalisation. ASL INTERCOM SMC02G

SMC02G/SMC02F/Variants - Product Manual

Menu: Configuration Æ System Æ Router Æ Inputs Æ Mic/Line Æ < I/P # nn – MIC/LINE nn >

Æ < Zoned Fire Microphone or Paging Microphone > Æ Audio Æ EQ

Possible values: –12dB to +12dB (1dB steps)

System default configuration: ‘0dB’

A 3-band equaliser is provided on Mic/Line inputs in order to balance the input tone. This equaliser has a shelving HF (treble) adjustment, shelving LF (bass) adjustment, and a fixed MID section adjustment.

A High Pass filter is also configurable. This would typically be used on microphone inputs to prevent excessive ‘pop’ noise.

5.7.5 Microphone Fade Up and Down Times

Menu: Configuration Æ System Æ Router Æ Inputs Æ Mic/Line Æ <I/P # nn – MIC/LINE nn >

Æ < Zoned Fire Microphone or Paging Microphone > Æ Audio Æ Fade

Possible values: 00 to 50 (Time in tenths of a second. Divide by ten for the time in seconds.)

System default configuration: ‘Up=00’ and ‘Down=00’

It is possible to specify a fade up and fade down time for each Mic/Line input or Music input. This can be set to provide the desired changeover fading, e.g. when a broadcast interrupts background music, or a lower priority broadcast.

This is typically used on background music where a slow fade-up, in particular, is desirable.

The Fade Down time is:

• The time it takes for the signal to fade down when turned off (un-routed);

• The time it takes for the signal to fade down before an overriding broadcast is made in its place

The Fade Up time is the time the signal takes to fade up when:

• Turned on (routed);

• Override removed.

The diagram in Figure 10 illustrates the sequence of events during the enabling and disabling of a single audio source (e.g. background music).

Issue: 02 complete, approved

Page 44 of 60

SMC02G/SMC02F/Variants - Product Manual

Figure 10 Sequence of Events for Single Audio Source

T1

MUSIC

FADE UP=T1

FADE DOWN= T2

MUSIC AUDIO

T2

ON

OFF

The diagram in Figure 11 illustrates the sequence of events during the override of a background music source by a Paging Microphone with chime.

Note that the background music Fade Down time (T2) not used in this instance. Instead the microphone

Fade Down time (T4) is used.

Figure 11 Sequence of Events for Paging Microphone Chime Overriding a Background Music

T4

T1

MUSIC AUDIO MUSIC AUDIO

MUSIC

FADE UP=T1

FADE DOWN= T2

ON

MICROPHONE

PTT

OFF

CHIME AUDIO

T3

MIC AUDIO

MICROPHONE

FADE UP=T3

FADE DOWN= T4

T4

ON

MICROPHONE

SPEAK-NOW LED

OFF

Configure the microphone signal fade up and down times as required.

It is important for Fire or Zoned Microphones, such as the standard SMC02 units, to be able to override other sources quickly. Therefore Fire or Zoned Microphones are set-up for a short

Fade Down time.

Issue: 02 complete, approved

Page 45 of 60