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  • Sennheiser EW100 G3 Wireless Lav – Strange AF Peak Behaviour

    Posted by Grant Mcnair on December 4, 2015 at 9:08 pm

    Hi,

    I have been using Sennheiser EW100 G3 wireless lavs for years. Recently I have encountered a strange behavior, twice now. In certain rooms in a particular building the mic transmitter’s AF level displays full and the AF Peak light comes on, but the room is silent (beyond normal ambient HVAC etc). When I bring the transmitter out of the room the peak light turns off and the AF level drops to 0.

    When the transmitter AF is full, the AF bar stays at 0 on the receiver end, but when monitoring quiet sounds cut in and out. I have tested this on several bank/frequencies. I have also tested this with multiple G3 mic transmitter units and even with different mics attached to the transmitter (ME 2 and MKE 2). They all act the same in this room. Any ideas what would cause this?

    Grant Mcnair replied 10 years, 5 months ago 4 Members · 7 Replies
  • 7 Replies
  • Brian Reynolds

    December 5, 2015 at 12:28 am

    What is the low freq. roll off filter set to?

    Its awhile since I’ve used a set of G3’s but there may be a roll off in the advanced section of the menu .

    Edit; Just checked a set and NO they don’t have a roll off….. sorry.

    My thought is it maybe low frequency rumble from room air conditioning or similar.

  • Eric Toline

    December 5, 2015 at 8:25 pm

    Motion sensor electronics in the room perhaps?

    “I push the RECORD button and hope for the best”

  • Ty Ford

    December 5, 2015 at 10:49 pm

    Hello Grant and welcome to the Cow Audio Forum,

    Good suggestions from others, but how about the possibility of another system on in the room?

    I ran into some weird stuff a few years ago and the problem was another mfgrs xmitters on on the same frequency (or close enough) to cause spooky action at a distance on my gear. I found one of the tech employees and he confirmed that they had multiple wireless mics. After he turned the transmitters off, no problem!

    Also, I once ran into problems when hanging a wireless xmitter on a guy who was also wearing a nuclear powered smart phone. I tested and was getting 100 feet or more. My range went to 0 feet when I rigged him with a mic. As soon as he left the room, I could get 100 feet again.

    Make any sense?

    Please report back with with you find.

    Regards,

    Ty Ford
    Cow Audio Forum Leader

    Want better production audio?: Ty Ford’s Audio Bootcamp Field Guide
    Ty Ford Blog: Ty Ford’s Blog

  • Grant Mcnair

    December 6, 2015 at 2:17 am

    Hi,

    Yes, there is a motion detector in the room that controls the lights. I know very little about motion sensor tech, could you explain how would this cause AF level peaking?

  • Grant Mcnair

    December 6, 2015 at 2:21 am

    Hi,

    Good thought, but it’s a small 12x 12 meeting room – no tech built in. Low to no chance of other wireless mics in the area.

  • Ty Ford

    December 7, 2015 at 2:39 pm

    Heh, go back in and power up the wireless gear. Disconnect the mic from the xmitter.
    The audio level meter should not show any reading.

    If it’s ultrasonic or sub sonic audio, it may, with a mic connected, but I can’t think of a situation in which you got that much spl in only one room unless, as mentioned, you have an ultrasonic security system emitter in the room.

    I have seen meter readings on my G3 (actually on a 442 mixer fed by a G3) while standing in an industrial building hallway while waiting for an elevator.

    I figured it was some machinery in the bowels of the building throwing noise up the elevator shaft.

    Please DO let us know if you discover the source.

    Regards,

    Ty Ford
    Cow Audio Forum Leader

    Want better production audio?: Ty Ford’s Audio Bootcamp Field Guide
    Ty Ford Blog: Ty Ford’s Blog

  • Grant Mcnair

    December 7, 2015 at 9:31 pm

    Hi,

    So, I went back to the room and there was a Phillips OccuSwitch Classic motion detector mounted on the ceiling. I downloaded the manual and opened it up. I turned off the ultrasonic detection, and presto – the AF levels immediately dropped to 0 on my xmitter! As soon as I re-enabled the ultrasonic motion detection on the Phillips unit the AF peaked once again. Problem solved!

    Thanks you for the suggestions.

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