SportSound/Audio: Feedback coming from the system.

Feedback can be reduced/eliminated in most instances by coinciding with the following statements:

1. Proper placement of the microphone. Use the headset whenever possible. Lapels are more prone to feedback. You want the mic as close as possible to the mouth and ensure that the furry windscreen is attached.
2. Reference DD2945863; Referee Microphone Best Practice.
3. Ensure the mic/line switch on the back of the receiver is set to the proper to match the mixer, MIC, if the receiver plugs into a Mic level input and LINE if plugged into a Line level input. It is possible the mixer may have a switch selectable Line/Mic input for the mixer, in this case the receiver output and mixer input setting should match.
   1. SSR-100 - Set Wireless switch to LINE
   2. SSR-200 (Soundcraft EPM-8) - Set Wireless switch to MIC
   3. SSR-300 (Yamaha 01V96 or TF1)  - Set Wireless switch to LINE (the DFR22 doesn't do its job well on mic)
4. Proper setup of the gain structure throughout the system. Start from the source (wireless mic system) and ensure you have good levels.
   1. Have master output off at this point. We don't need anything coming out of the system.
   2. Speak into the microphone on the field. Check the signal level coming in. Monitor the audio meter and the audio LED. The audio meter should display at least 3 bars and the audio LED should be green. Adjust the gain on the receiver front panel by pressing the arrow buttons.   This is in reference to Shure QLXD receivers which are standard in all Daktronics standard racks today.
      1. Green = normal
      2. Yellow = signal approaching limiter threshold
      3. Red = limiter engaged to prevent clipping
   3. At the same time, check the RF bars. This ensures we have proper signal level making it to the receiver. We want as many bars as we can. Minimum of 3 bars should be displayed. If we are unable to get 3 bars, look at the connections and the location of the antennas. Make sure the referee's body is not between the bodypack and the receive antennas. (Try and keep the bodypack positioned on the side of the ref not the backside)  The receive antennas may need to be moved outside the press box or high gain antennas installed for increased RF bars.
       
      "Good" -  Green LED, with 3 bars
       
      "Caution" - Yellow LED, approaching limit
       
      "bad"  - Red LED,  Audio level overloaded (OL), and limiter engaged. Turn down receiver gain.
   4. Once the signal level on the receiver looks good, then PFL the mixer channel (if equipped)  and adjust the input gain on the mixer channel so its outputting line level at an average of 0dB on the meter
   5. Then turn up the channel and master to send audio through the sound system.  Test the microphone at various locations to ensure there is not feedback.  Feedback will be most likely the closer you are to the sound system. Make sure those areas are checked.
5. Try and use a different mic if the mic is just feeding back and have exhausted previous options.  Cardioid mics will have a higher gain before feedback than Omni-directional mics.  The drawback is that cardioid mics will have more Wind noise versus Omni-directional.  So it kind of becomes what's worse, wind noise, or the risk of feedback.  (Obviously, if feedback is of high risk, we would much rather just hear wind noise as its not going to make people cover their ears.)
6. There may be more areas prone to feedback. For instance from the 20 yard line and in towards the sound system.  If this is the case, it needs to be communicated to the referee they shouldn't be making announced calls past a certain point on the field.
7. Depending on the mixer, there can be some cuts that could be used on the low and high end. This can help eliminate feedback in those frequencies. Also the mid frequency EQ can be notched where feedback is most prone. To set this you may need to create feedback and be very careful not to blow speakers as too much feedback can damage them.
8. There may be advanced feedback reduction methods available for some systems