Limiter Mode:
The MicTel is equipped with fast acting audio limiters in both the main and auxiliary
audio channels. The limiters’ job is prevent distortion that can happen when a loud
audio passage occurs while the MicTel is outputting at near its maximum level. This is
common during live sporting events or even during telephone interviews. Whenever the
MicTel is overdriven, the limiter instantly reduces the output gain, preventing clipping
distortion in the MicTel’s output. The limiter is designed to be transparent to low
amplitude signals and only effects audio whose peak amplitude exceeds +6dBm as
measured at the MicTel’s outputs. Jumper JP4 controls the main channel’s limiter.
When the jumper is “on”, the limiter is engaged. When the jumper is removed, the
limiter function is bypassed. JP8 controls the auxiliary channel limiter. When the
jumper is “on”, the limiter is engaged. When the jumper is removed, the limiter function
is bypassed. The MicTel is shipped with both limiters enabled.
SideTone & Headphone Modes:
When audio from the main input such as the microphone is mixed with the incoming
telephone audio, this is called sidetone. Sidetone can be useful because it gives the
MicTel user control over the relative mix levels of the incoming telco audio and their own
microphone. For example, if you are doing an interview with a caller, that caller might
sound louder in the output than your own microphone does. This is because some
phone systems employ something called a hybrid. The hybrid’s job is to separate your
send audio from that caller’s receive audio. In a regular telephone, this prevents
feedback from the transmitter to the receiver of your phone handset. As a result of the
hybrid, the level of your own audio that you receive back from the phone system can be
substantially less than the incoming caller’s audio. The sidetone function lets you
compensate for this by increasing the amount of send audio that is heard at the aux
audio output port or the headphones. A second benefit of the sidetone is that the send
audio that is mixed with the receive audio is not frequency limited by the phone system,
making the send audio sound more natural as the sidetone level is increased. Jumper
JP12 controls the sidetone and works in conjunction with the sidetone trimmer control.
When Jumper JP12 is removed, sidetone audio is disabled. When JP12 is on the (A)
position, the sidetone is mixed with the aux channel audio and its level is adjustable
from all the way off to fully on by the use of the sidetone trimmer control. Sidetone
audio will be present at both the Aux. audio output and the headphones. When JP12
is on the (B) position, the sidetone is mixed only with the headphone audio & does not
appear in the Aux audio output. This allows the talent to hear more natural sounding
audio without it being present in the mix. The factory default is “A” jumpered.
JP13 lets you hear Auxiliary channel audio in either pre-fader mode (position “B”), post
fader mode (Position “A”) or not at all (JP13=off). In pre-fader mode, audio present at
the Aux inputs, cell phone output or telephone output is routed directly to the
headphones. This gives you a single control to conveniently monitor the incoming audio
on your headphones. When JP13 is set to the post fader mode, audio from the
MicTel’s Auxiliary output amplifier is fed to the headphone amp. This position lets you
hear the actual audio that is being sent out of the Aux. output jack. Post-fader audio is
controlled by both the headphone control and by the Aux. Volume control. Because the
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