Adding a Hi-Gain Line Level Mic to a v-Panel via the Audio DB25

Under normal conditions, one can connect a second headset to a v-Panel using the DB25 AUDIO connector on the back of the panel. One would then use the AUDIO MIXER on the PANELS page to select the crosspoint from the second headset’s mic and route it to the MATRIX.

However, sometimes we need to bring in a line-level mic in order to bring the external microphone through a precarious cable routing scheme, so it pushes the interference in the noise floor.  It is best practice to make gain changes in smaller steps, so as not to overdrive or over attenuate and one gain stage. In a case like this we would not put that line-level source directly in the HS2 MIC connector directly, but first, bring it in via the EXT1 and out the EXT1 output and THEN into the HS2MIC input, thus giving us more gain stages to work with.

Instructions

Bring the external microphone (line level, so it pushes the interference in the noise floor) with pins 12 (+) and 25 (-) of the Audio DB25 into EXT 1, as you have done. Now, in that panel’s AUDIO MIXER select the volume at the Crosspoint from EXT 1 IN to EXT 1 OUT. (You may need to adjust this level, but maybe not). Now send it out of EXT1 by soldering the proper pins (Pin 8 to pin 1  and  pin 21 to pin 14)  on the DB 25 Audio Connector) so it goes into the HS2 Mic pins.  Now Select the HS2 to MATRIX 1 Crosspoint to zero dB in the Panel’s MIXER SETTINGS  (Again,  if you need more or less gain, here is another place to do that). SAVE and EXIT the AUDIO MIXER page and apply the Map to the Matrix. (See Audio Mixer below)

Now the external mic will function as the panel mixer will.  Make sure the H/S mic button is not engaged.  If there is still a gooseneck mic inserted in the v-panel, it will function alongside the external mic, so you may want to remove it.

This process gives you three or more gain stages, so if adjustments need to be made, no single gain stage needs to be amplified or attenuated by a large excursion and smaller adjustments can be made across the several stages. 

If the operator needs to use a foot pedal to trigger their mic, look up “v-panel footswitch” in the SOLUTION FINDER’S Search area to find several of those solutions.