The summer of 2014 shall always be remembered as the season of boom. I spent 4 months in Boomcity! From the beaches of Panama on "Dating Naked" to the gator infested water traps of the mid-Atlantic on "Ballhogs", I've been consistently challenged with recording dialog on typical reality format shows with atypical reality sound protocol- no lavs.
Most recently on Ballhogs, I've been working with golf ball divers as they spend their days reclaiming, and reselling, the golf balls that are lost in water traps across the Carolinas and Georgia. The bulk of the shooting took place on the banks of ponds as the divers went into and out of the soup, bringing sacks of balls with them (teehee). Obviously, the 16' boom ruled supreme, occasionally paired with a lav if there was a partner on the shore. On typical reality productions you'd shoot in the field and sprinkle in a few OTF's and stage interviews to round out the content and story collected.
Ballhogs was fortunate enough to have some underwater communication equipment provided by Ocean Reef Group for a portion of our shoot. They're an Italian company specializing in dive masks and integrated video and communication equipment. Using the gear and adding the dimension of under water communication between the divers themselves, as well as direction from dry land, was definitely a treat!
Now, let me preface this by saying I'm not a diver and don't claim to know the first thing about diving. I'm hoping to share my experience with working with Ocean Reef underwater comm gear as a way to gather dialog between divers.
Ocean Reef provided us with 3 x Neptune Space dive masks, M105 Digital surface transceiver, M105 Digital Mixer and 3 x GSM DC underwater transceivers.
The company is Italian and finding any literature regarding the comm gear was a challenge. There were plenty of YouTube videos discussing the more traditional dive gear and how to adjust it properly but I had no luck on my quest for self-education in regard to their comm systems. Even the literature sent with the gear was a bit tough to understand at times as it's clear English is not their primary language.
But no matter! When has lack of instruction ever kept a man from pressing on?! Huzzah!
Obviously I was excited and curious to see how well wireless communication worked underwater. We all know that humans are mostly water; The larger the human, the larger the body of water, the worse the RF. Even waterproof Lectrosonics transmitters, though try as they might, don't hold up well when fully submerged, in regard to RF strength. Ocean Reef describes it's comm gear as an "ultrasonic, digitized, through-water, communications system". Per the website, the GSM has a range up to 600' and up to 30 hours of runtime on a single 9v. Also worth noting is that, from what I read all, of Ocean Reef Group comm gear operates on the same fixed frequency of 32.768 kHz.
Ocean Reef Group GSM transceiver with microphone. The unit is connected to the mask by the clear plastic tab and threaded microphone casing.
Here you see the "front" of the microphone and "headphone" driver
Setup is fairly simple, the GSM transceivers, which are used with the divers, take a single 9v held in a waterproof housing and are attached directly to the dive mask. They consist of a waterproof "headphone" attached to the side of the mask externally via two plastic locking pins and a push-to-talk (PTT) microphone installed inside the mask near the mouth via threaded port near the respirator. The microphone is sealed with a hydrophobic membrane which is permeable to air, but not water.
View inside the mask of the microphone with it's back facing the diver's mouth
GSM mounted to side of the mask where it rests beside diver's ear
Ocean Reef also claims the permeability of the microphone maintains equal pressure on the element and maintains usability to any depth. It's advised that when installing the GSM you turn the front of the microphone AWAY from the diver's mouth in the mask to help manage plosives and breathing noise.
The GSM is activated in water and can only be tested while fully submerged, I'm guessing due to the "ultrasonic" nature of the transmission? Unfortunately I wasn't able to suit up myself and test the GSM from diver to diver, nor was I able to listen to see how they actually sounded. According to the divers they did work between each other and the sensation of hearing a walkie transmission underwater was described as "weird" and "kind of shocking." So we'll take those comments as a good sign.
For the purpose of this review though I am more interested in how well the gear allows us to pull usable dialog for video. That's where the M105 Digital Surface transceiver and M105 Digital Mixer come in to play.
GSM all hooked up. Spend too much time in the water and you'll turn into a dive tank!
Just as the name implies, the M105 Digital Surface transceiver is used for communication from dry land to divers underwater. The unit comes built in to a small Pelican case that houses the electronics and rechargeable battery. On the face of the unit there are four DIN connectors, a headphone jack, a volume knob, a channel button, power switch and a built in speaker.
Ocean Reef Group M105 surface transceiver with M105 Digital Mixer
The connections are labeled for the transducer cable (antenna), external power/battery charger, audio output and mic input. The unit ships with a traditional CB style PTT mic. I'm not entirely sure what the channel button is for as Ocean Reef Group says all of it's comm gear operates on the same frequency enabling any piece of gear to function as plug and play, ready to go with any other piece, right out of the box.
M105 Digital Specs
The transducer cable needs to be coupled with water in order to transmit, just like the GSM units. It's a 35' long cable with a weight at the end. The manual specifies that you should keep the cable off the ocean floor and suspended, ideally, above the divers for optimum range and clarity. Since we weren't out in open water I used a few floats I found in the Golf Ball Hogs warehouse to help keep the cable afloat above the divers and off the bottom of the pond. I had one of our divers run the transducer cable out to it's full length to maximize range. The pond was about 150' x 50' x 25' deep and I had solid reception even when the divers were on the opposite side of the pond.
Ocean Reef Group M105 Digital Surface Transceiver and M105 Digital Mixer
Back side of M105 Digital Mixer
Setting up the M105 Digital mixer was as simple as connecting the attached cables to the corresponding labeled connectors on the M105 transceiver. With the M105 Digital Mixer you can pull audio from standard phono outputs and mix the control output level of the surface and underwater transmissions with their respective volume knobs. For the purposes of a location sound recordist this particular piece of gear is most useful.
Using RCA- 1/4" TRS - XLRM cables/adaptors I came into my Sound Devices 788T at line level. The audio from the divers came through strong and fairly clear. None of us had used this type of gear before and getting used to the slower pace of speech and speaking between breath cycles took some practice. The bubbles were clearly audible over speech if the divers were speaking during an exhale and that made it very difficult to understand what they were saying. Frequency response is quite narrow at 300-3300Hz. All in all, it sounded like you were having a walkie conversation with someone at the bottom of a pond. So I'd say that can be counted as a success.
The PTT mic provided for transmission from the surface was easily distorted at the source and there is no way to control the input gain, so slow and relaxed speech at the surface is important to maintain clear dialog free from distorted plosives.
Below are some audio samples pulled from one of our dives. I grabbed a small portion of communication between two divers and a producer on the surface. This brief conversation took place about an hour into our dive and the divers were starting to get used to using the gear and how to pace their speech.
Both audio samples have an L2 limiter applied for increased volume. The second sample also has both Izotope RX Denoiser and Digirack EQ3 applied (both quite hastily!) to give a sense for how it might clean up with some processing. **Worth noting is that our producer was wrong when he said Darrell's comms weren't working. As you can hear for yourself, Darrell responds shortly there after.
All in all I found the Ocean Reef Group underwater communications equipment quick to set up, easy to use and robust. With a little more practice you should be able to maximize the gear's ability through better controlled speech and optimized transmission conditions. Though narrow bandwidth and clarity limit the possible end result for any dialog recorded off this comm gear, if you are looking to record interactive dialog in real time between divers and someone on the surface Ocean Reef underwater comm gear may be just the thing you're looking for!