Sound for Video Session: Wireless Hop from Mixer/Recorder to Camera with Sennheiser G3

In this week’s sound for video session we had a chat with Gregg Palmer, one of our friends and fellow sound mixers from Oregon. Gregg explains his experience using Sennheiser G3 wireless systems to send audio from your recorder/mixer to the cameras so that they also record high quality production sound.

Greg discusses the following gear:

Sennheiser G3 Wireless Lavalier System (Be sure to research whether this frequency band can be used in your local area)

Cable to Adapt from G3 Receiver to XLR input for Camera (if your camera has an XLR input)

Cable to send audio from Zoom F8 or F4 to G3 Transmitter and from G3 to camera

Sennheiser AVX Wireless Lavalier Kit (MKE2 Microphone)

Ethics statement: Some of the links above are affiliate links which means that if you click on them and buy, I get a small commission. You don't pay more by clicking these links than if you just went to the retailer’s web site on your own. I use the proceeds to buy additional gear to review and help you improve your sound, lighting, and video. Thanks for your support!

*Added 2 Jan 2017*

Mark Kirchner added additional technical information for those who would like to use this method to optimize the signal from the mixer to the transmitter:

Your guest on your G3 hop video can optimize the signal with a custom cable to turn his transmitter into a hop-transmitter that will receive a "tape level -15 dB audio signal. The wiring on the TX side should not be soldered to the tip of the TRS plug. The transmitter want to "see" a mono "unbalanced" signal, not a L/R signal like your video guest was sending it using stock TRS to TRS mini 3.5 plugs. E.T. designed this cable for me to "sum" the left/right channel(left/right mix-bus) to the G3 transmitter.  The audio signal leaves the mixer as L/R unbalanced signal (tape level -15 dB). To use this tape level signal correctly it must be sent (soldered) to the "ring" of the TRS plug.  If you like I will make you one for free for your Sound Devices 633 and then you can try it with a G3 TX and RX yourself.

The following are notes from a conversation with E.T. He designed this cable. I know you are not a "soldering guy" and purchase your XLR cables. It will take awhile to understand what I have written. Unity Gain, Reference Level, Gain Staging and Unbalanced/Balanced are concepts that take time, but worth the struggle to put them into the old gray matter. You might find it helpful to draw a diagram of the 2 connectors, using colored pens and different colors for each conductor.

Last, my family roots come from Grantsville Utah. There was a film made about my second cousin Kimball Johnson called "Pigweed Philosopher." Check it out it is about film-making. If you have been to Grantsville, you may have seen the old Victorian house on main street. That's the Johnson house, our family house. I saw you have not been on this sight in a while, so this letter may find you in 2017.

Best,

Mark Kirchner mkirchnersound@gmail.com

PS Thank you for interviewing "The Senator" Mike Michaels!

WIRELESS HOP from the 442 MIXER w/ SENNHEISER G3

Set-up

1.    Use the Sound Devices 442 Tape/Mix out (TA3) connector.

2.    Tape/Mix Out = -10 dB *

3.    Use Custom E.T. Mix-Out Hop Cable**

4.    Connect 442 to the G3 Tx

5.    Starting recommendations from E.T.; settings for the Tx –12 dB sensitivity.

6.    Set the Rx about the same and test.

*The Tape/Mix out of the 442 sends both left and right signals at a –14 dB level if the mixer is set for a "0" dBu reference level. All left channel assignments (channels 1-4 on the 442 mixer) will be “mixed” and output as a discrete “mixed left channel.” The right channel will mix all right channel assignments.

**The E.T. Hop Cable sends a unbalanced, left and right signal to a TRS connector, assigning the left and right signals to a single terminal (ring) on the TRS connector making a “summed mono signal” that the Sennheiser G3 transmitter needs for the proper signal input.

Note; The Sound Devices manual for the 442 mixer lists the maximum output level for the Tape/Mix Out as follows.

Page 24  Tape/Mix Out +6 dBu

Page 26  Block Diagram Inputs and Outputs

The schematic diagram (page 26) displays the Mic / Tape / Line  as  0/-14/-40 which should be written as Mic – 40 / Tape – 14 / Line “0” .

A “Tape Level Signal” is normally –10dBu. The designation of “tape level as –14” is based on an “0” dBu reference level. The Sound Devices schematic is based on a “0 dBu” reference level (-14 dBu @ “0” reference level = -10dBu @ +4 dBu reference level).

E.T. WIRELESS HOP CABLE (Sennheiser G3)

This cable was engineered for use with the Sound Devices 442* “mix/tape out” output on the TA3 output.

TA3f Connector

Redco TGS-1 Cable (2 conductors + shield and drain)

TRS 3.5 Mini locking connector

TA3f connector (output)

Pin 1 Ground  (Eric used drain wire)

Pin 2 Signal (+) red conductor (Left)

Pin 3 Return (-) clear conductor (Right)

TRS 3.5 Mini Connector **

Tip        No Connection

Ring      Signal and Return (+ @ -)

Sleeve   Ground (drain wire)

Notes:

*The Tape/Mix out of the 442 sends both left and right signals at a –14 dB level. All left channel assignments (channels 1-4 on the 442 mixer) will be “mixed” and output as a discrete “mixed left channel.” The right channel will mix all right channel assignments.

**The E.T. Hop Cable sends an unbalanced, left and right signal to a TRS connector, assigning both left and right channels to a single terminal (ring) on the TRS connector making a “summed mono signal” that the Sennheiser G3 transmitter needs for the proper signal input.

Sennheiser AVX Dynamic Range and Outdoor Distance Tests

https://youtu.be/uUSd_ulXdno Sennheiser recently introduced their new digital wireless system called the Sennheiser AVX. There are various kits available and in this episode I used the kit with the transmitter, receiver, and MKE2 lavalier microphone (their higher-end pro lavalier microphone).

We did a few tests to see how well the AVX does in terms of outdoor distance (keeping its signal without dropping out), and the dynamic range feature Sennheiser touts as preventing clipping and distortion when the sound gets much louder.

The outdoor distance test was as expected: Solid up to 50 meters, and my first dropout occurred at around 75 meters. You need to pretty much be in line-of-sight to get a solid signal at 50 meters. I never shoot this way, but it is good to know the limits of one's tools.

The dynamic range feature was way more impressive than I expected. It really works and sounds good! I feared it might be like Automatic Gain Control like they include in many of the DSLRs and that AGC feature is awful in those cameras. It stupidly pushes the gain up through the roof during silent sequences and that just makes an unbearably noisy mess of the audio. But on the AVX, it sounds very transparent and clean. I really like it!

Final review should be here later this week. Let me know if there are other things you'd like me to test before I have to send it back to my friends at B&H Photo.