Sennheiser solutions

Note added later: most of the problems listed in this post were resolved by running the tablet on mains power instead of on battery power.

Most of the remaining problems were then resolved by modifying the sensitivity and AF out levels as suggested below, and by recording in 16-bit mono instead of 8-bit mono.

The below is essentially a historical record of the problem and solution process.

Another technical post, this time on sound equipment.
I am still seeking a solution to my sound quality issues for my recordings. I am using a Sennheiser wireless transmitter and receiver (EW100G2) along with a Lavalier capsule microphone. The local support team have come up with various possibilities:
Input level set too high on the laptop. This was certainly the case for my first recordings, but after that I reduced the microphone input sensitivity level on the laptop to avoid this. Nevertheless (as you can hear on my recordings) I was still getting pops and distortions.
Interference? Other radio microphones in the area can cause interference. The local team reset my wireless frequency to a level that should be safely out of range of the other local microphones, but it did not solve the problem.
Sensitivity (on the transmitter) and AF output (on the receiver). I had thought that I had tested this, but I may have underestimated the difference between my talking voice and my lecturing voice. I originally had the sensitivity set to -10 and the AF out level at -12. Alan Mintey has now suggested that I try sensitivity -20 and AF out -18. Let’s see if this helps!

Bizarrely, my transmitter got into a state today where it was periodically peaking every few seconds (even with the microphone detached and the unit left alone on my desk). This went away when I switched from -10 to -20, and (as you might expect?) did not come back when I tried switching back to -10.

I am beginning to wonder whether using a wireless microphone setup introduces too many additional complications. There are so many places in the chain where something can go wrong. If I had a simpler stereo microphone setup (with a sufficiently long extension lead!) perhaps that would eliminate some of the problems?

Anyway, watch this space to see if these settings solve the problems!

Joel Feinstein

October 12 2009


4 responses to “Sennheiser solutions

  1. Well, my problems are not solved yet.
    I still had sound quality issues, so I experimented with a wired microphone instead: no improvement.
    See my comments on Camtasia Solutions for my next attempt!
    Joel Feinstein
    October 14 2009


  2. OK, so almost all of my problems were solved by using mains power for my laptop instead of running it on battery power. However, I am still getting hiss on my audio in the Camtasia recordings.
    Today I had help from Alec in the Rich Media Team at Nottingham: he brought along his own Sennheiser receiver + recording device to my 5PM lecture, and he tuned to my frequency. We even swapped receivers in the middle of the lecture. No hiss on his recording! So, the Sennheiser microphone, transmitter and receiver are blameless, and the problem happens further down the line. It could still be either software or hardware (or both!), but at least some of the suspects have been eliminated from the enquiry!
    Joel Feinstein
    October 27 2009


  3. Beware of the mute button!
    My latest Sennheiser incident occurred this last Tuesday morning, when I was unable to record audio. I turned on all the equipment and plugged it in, but the microphone appeared to be completely dead.
    After the lecture, I found the culprit very quickly: the mute button on the transmitter had changed position. It must have had a bump while inside the laptop case, or “in transit”.
    Be warned!
    December 10 2009


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