Peterson AutoStrobe 490ST - Manual (Page 9)

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11. MUTE — The AutoStrobe 490-ST has an external input and “through” output with mute to allow silent on-stage tuning
of instruments without having to disconnect the tuner from your audio signal chain. When MUTE is active, any audio
signal (originating from the EXTERNAL INPUT jack or built-in microphone) to the front-panel EXTERNAL THRU
jack is suppressed. Each press of the MUTE button toggles the MUTE function on or off. When engaged, the word
“MUTE” appears on the third line of the RUN screen on the LCD display. The MUTE button is connected in parallel
with the 1/4-inch jack at the rear of the tuner labeled “MUTE SWITCH”. Any momentary-close contact device such
as a footswitch may be used in place of or in addition to the MUTE on/off button. (The front-panel button will continue
to operate with a device plugged into this rear jack unless the device is held in the closed position—make sure that the
device operates in a momentary-close fashion. A proper footswitch is available from peterson as part #: 140070.)
2. AUTOMATIC AND MANUAL NOTE SELECTION ON THE AutoStrobe 490-ST
Your AutoStrobe 490-ST tuner can function in either of two ways: MANual mode or AUTOmatic mode. Unless you choose
to change the default, the tuner will power up in the AUTO mode. In this condition, any strong audio tone input to the built-
in microphone (or EXTERNAL INPUT jack) will be internally analyzed—usually in well under a second—and the standard-
pitched semitone nearest in frequency to that of the input sound will appear on the LCD screen. The motor for the strobe
disc will automatically adjust in speed so that you can view the tuning of this input sound relative to this nearest standard
pitch. Although it is rotating very rapidly, one or more circular bands on the disc will appear to be moving very slowly or
will appear to be standing still. The lowest band exhibiting this effect indicates which octave the audio input signal occupies.
If the rotation appears to be to the left (counter-clockwise), your input sound is flat compared to this nearest standard-pitched
semitone. If the rotation appears to be to the right (clockwise), the input sound is sharp compared to the standard. If the
image appears to be standing still, the input is perfectly in tune with the standard. Furthermore, the slower the disc appears
to be rotating, the closer the input sound is to the standard. This makes for a very simple and natural visual feedback when
bringing an input sound into tune.
To tune to a different note, simply cease the current audio input and sound a different pitch. If the new input is closer to a
different standard-pitched semitone, the tuner will re-analyze the input, indicate this new pitch on the LCD screen, and, once
again, automatically adjust the motor so that the disc will properly indicate the relative tuning of this new input to the nearest
standard-pitched semitone.
The AutoStrobe 490-ST can also be placed in MANual mode by pressing the “2” button while the label above it in the LCD
screen indicates “MODE” (that is, when the normal RUN screen is active). Directly above this MODE label on the LCD,
an indication of the currently active note-select mode—AUTO or MAN—appears. Pressing the “2” button will toggle this
note select mode and the LCD indication will be updated.
KEY= C
A=440 C 00 ¢
AUTO
SETUP MODE
1 2 3 4
2
KEY= C
A=440 C 00 ¢
MAN
SETUP MODE
1 2 3 4
Accessing Manual Note Select Mode