God Is in the Details: Concealers for Hidden Microphones

Mick Sawaguchi 

Fellow, AES/IPS

UNAMAS-Label & Surround Terakoya 

Introduction

As filming techniques have evolved, there has been a rise in dynamic footage utilizing tools like Steadicams, drones, and large mobile cranes. This shift has created a need for greater mobility and immediacy in dialogue recording—moving beyond traditional boom microphone setups—leading to the widespread adoption of fitting individual performers with compact wireless microphones.

 In this article, I explore the practical use of "Concealers"—accessories specifically designed to ensure that hidden microphones deliver high-quality, usable audio. While manufacturers of compact lavalier microphones offer concealers tailored to their own models, specialized concealer manufacturers are introducing innovative products designed to address a wide range of specific situations with impressive ingenuity.

1 Goal for Concealed Microphone Setup

*   Preventing fabric-rubbing sounds and handling noise

*   Suppressing cable noise caused by the thin cables of lavalier microphones

*   Selecting compact, high-quality microphones

*   Preventing wind noise and breath pops

*   Using adhesives that ensure a secure hold even on small surface areas

*   Using medical-grade tape to prevent skin irritation when attaching directly to the skin

*   Preparing tape in colors that blend in discreetly with the clothing

2. Parts Suitable for Mounting

Here, we introduce the parts of the body where equipment can be mounted.

To illustrate how to mount usable audio gear in these locations, It present specific examples using "Concealers" from Babblbee and URSA—brands trusted by many production sound mixers. A visit to their respective websites reveals the truly extensive range of accessories available.

3. Specific Examples of Concealment Techniques

⚫️ Concealers to Prevent Clothing Rustle

While using a clip to create a gap is a simple method, there are other ways to create space between the microphone and the clothing using accessories such as faux fur, soft covers, or soft wrap tape.

⚫️ Shirt mounting and noise prevention: 

The cable is looped once to prevent cable noise—a technique likely born from practical field experience.

Here, It wrap the cable once before attaching it to provide wind protection and suppress cable noise.

⚫️ Adhesive tape for mounting lavalier microphones and clips to prevent the rustling of clothes

 

This clip—also found on products from other companies—is designed to create a gap that prevents the microphone from coming into direct contact with skin or clothing.

Due to the microphone's small surface area and its silicone rubber material, standard adhesive tapes tend to provide a weak bond. Adhesive tapes designed for concealment are characterized by their ability to hold firmly even on small surface areas. Here is an example of a setup where the microphone is attached to a sweater using this type of adhesive tape along with a clip designed to prevent friction noise from clothing.

⚫️ Attaching to Neckties or Bow Ties

Attach it to the knot of a necktie or bow tie. It is designed so that it rarely rubs against the fabric, making it unlikely to cause friction-related wear.

⚫️ Buttonhole

It is mounted in the gap of a buttonhole. Microphones such as the DPA-6060 or Countryman B-6 are ideal for this type of placement due to their ultra-compact size.

 ⚫️ Direct-to-Chest

Medical-grade tape is used, as it is applied directly to the skin.

Fur or a protective cover is also attached here to prevent chafing against clothing.

⚫️ Cable treatment Tape

Since the cable connecting to a wireless microphone transmitter is often surprisingly long, "Invisible Tape" is ideal for keeping it out of sight while ensuring it stays securely in place.　 

⚫️ Transmitter Pouch

The transmitter is carried in a belt pack, and there are some innovative products available for this purpose.

 Since the activity involves vigorous movement, the unit is secured to the torso with a belt.

 Secure to the thigh

 

 Ankle strap that secures around the ankle

 NOTE:

Although URSA is a British manufacturer, its founder was originally a production mixer; consequently, the company's defining characteristic is a lineup of concealer products designed with the various real-world scenarios the founder himself wanted to address.

A Practical Critical Listening Method for Developing “Listening Skills”

Mick Sawaguchi, Fellow member of AES UNAMAS-Label

Introduction

The author has long been in charge of sound design at the Tokyo University of the Arts. The practical critical listening method introduced here was developed during that time for students at the start of the new semester. In their end-of-year reports, students consistently praised this training as an extremely beneficial course.

In the academic realm, there are curricula titled “Aural Training” and “Critical Listening” that are adopted by educational institutions and audio equipment manufacturers. This ear training curriculum was originally developed by European educational institutions to train sound experts known as “Tonmeisters” and ensure sound music production; it is now implemented by educational institutions both domestically and internationally. In Japan, a book (with accompanying CD) titled “Cultivating Sensitivity to Sound” has been published by Ongaku no Tomo-sha, featuring the painstaking work of pioneers such as Mr. Otoichi Kitamura.

It is a theoretical program that is distinctly German in nature.

　　

Here, we introduce practical critical training methods for aspiring mix engineers to enhance their mental auditory perception and analysis skills. Unlike text or video, sound is a medium that cannot be paused or played in slow motion to examine details. Therefore, this training improves your ability to instantly recognize and analyze the real-time flow of sound, understand how specific sounds are used to construct the overall work, and discern the purpose behind complex sound design—such as the interplay of dialogue, music, sound effects, and Foley in film soundtracks. You will be able to take a bird’s-eye view of the overall flow and the role of individual sounds, moving beyond the myopic perceptions often attributed to Japanese people—such as “failing to see the forest for the trees” or “being skilled in combat but lacking an understanding of the overall system.”

1. Critical Listening to Improve Analytical Skills

Our ears are, in a sense, very capricious sensory organs. No one can verify whether everyone perceives the sound information emanating from the outside world as the exact same “sound.” As those involved in audio production and playback likely experience on a daily basis, from the perspective of someone on the production side like myself, the following scenario is a common occurrence in the studio.

Just how varied the comments on the balance of the FINAL MIX are among those involved, depending on their perspective…

*Some focus on the vocals or dialogue,

*Some focus on the continuity of background sounds,

*Some focus on specific instruments in the music,

*Some focus on the contrast during scene transitions,

*Some focus on how well the composition is structured to sell…

The reason for this is that the sound reproduced in each person’s mind differs depending on what they were focusing on while listening.

The area of the brain known as the “auditory-visual field” performs a kind of internal ‘mixing’ based on the parts the person wants to focus on, and then manifests the result as “sound.” This “intellectual mixing” is far more complex than the way we use mixing tools to blend sounds.

It is precisely for this reason that training is necessary to grasp, analyze, produce, and appreciate “objective sound.”

Since anyone can use this method, I recommend giving it a try whenever you have some free time. Below, I will outline a step-by-step critical listening method.

2. Procedure for Critical Listening Training

●    Use short commercials (15–30 seconds) as material

Since your brain isn’t yet accustomed to listening to complex soundscapes, start with short pieces. Then, use the chart below to record how the audio elements—dialogue, sound effects, and music—are structured. You may use whatever notation works best for you.

Play this 10 times, record your findings, and analyze where each sound element was placed. Once your ears have become accustomed to distinguishing all the sounds instantly, move on to a slightly longer piece and perform the same exercise.

 ●    Conducted using games, teasers, or trailers lasting about 3 minutes

The method remains the same, but this allows for analysis of slightly longer pieces.

● Conducted using music

Starting with a quartet—a relatively simple ensemble—we gradually progress to larger-scale arrangements, ranging from classical orchestras to large-scale pop music featuring strings, brass, and a rhythm section. In this case, the components consist of instrumental sounds, vocals, and choruses, so you’ll note down where each element is played. If you have the time, further improving your skills involves distinguishing where each instrument is positioned and assessing the sense of distance between them. Since music-based training involves more consistent patterns compared to film sound, your analytical skills will improve relatively easily.

●    Using Film Sound

For the final exercise, select a climactic scene from a film—where dialogue, music, and sound effects are intricately interwoven—and analyze that segment by playing it back about 10 times for roughly 5 minutes. When choosing a film, I recommend selecting one of your favorites from the Best Sound category of the annual Academy Awards. The Best Sound category is divided into the Best Sound Mixing award, which recognizes contributions to mixing, and the Best Sound Editing award, which recognizes contributions to sound design. I believe that selecting a film from the Best Sound Editing winners will allow you to analyze complex sound compositions. If you have the right setup, I also recommend playing back 5.1-channel surround sound or recent Dolby Atmos 11.1-channel audio sources. The reason is that as the number of playback channels increases, your cognitive ability improves significantly.

This critical listening training is characterized by its practicality—the ability to instantly distinguish sounds composed within actual works—as opposed to training that uses pure tones. If you practice this training for about a month, your ability to discern sounds will improve significantly.

As a result, your ability to instantly identify the “sound design structure” will improve, whether you’re mixing your own work or listening to your favorite pieces.

With just a few minutes of daily training, the entire information transmission pathway—from the outer ear to the middle ear, eardrum, cochlea, auditory nerve, auditory cortex, and finally to sound perception—is sharpened, enabling information to be transmitted and reproduced instantly and without loss.

●   How to Maintain Your Skills in Daily Life

After completing these ear training exercises, you can maintain your skills by regularly taking about a minute to “listen intently” in your daily life.

Listen carefully to sounds at moderate volumes—such as those at train stations, bus stops, parks, during walks, on school grounds, while hiking, or during intermissions at concerts—to enhance your concentration. This helps maintain the “cleaning” effect on your auditory information transmission pathway.

*PS—A Side Note

People living in the deserts of Africa or the vast plains of Mongolia can see movement from over a kilometer away. It can be said that the survival instincts developed from living on such vast expanses of land have significantly enhanced their eyesight. In today’s lifestyle, which relies heavily on computers and smartphones, we spend long periods focusing on objects at a distance of about 30 centimeters, causing our eyesight to deteriorate significantly. Similarly, urban dwellers exposed to high levels of environmental noise are experiencing a gradual increase in their auditory recognition threshold year after year... in other words, they are developing a tendency toward noise-induced hearing loss.

Speaking from my own experience, I was mixing at a resort studio in the highlands. On the day I arrived, the volume of the monitor speakers—which I thought was an appropriate playback level—measured 70 dB/ch on the SPL meter. After sleeping in an environment with nothing but the wind and birdsong, I played it back the next morning and found it sounded very loud, so I reset the playback level to match my initial perception. When I measured this with an SPL meter, I was surprised to find it was a full 10 dB lower at 60 dB/ch (measured using pink noise at -18 dB, C-weighted, slow response).

The First Dolby Atmos Award Winner "Gravity" sound design 85th Academy Award for Sound Editing 2013

Mick Sawaguchi

Fellow member of AES.ips

UNAMAS-Label・Surround Terakoya

Introduction

I analyze Gravity, the first Dolby Atmos mix to win the 85th Academy Award for Sound Editing. Originally planned for a 7.1-channel mix, director Alfonso Cuarón realize Dolby Atmos's emergence as the perfect medium to express immersion. He challenged both the music and sound design to embrace Dolby Atmos, realizing the world of Immersive Audio. The dynamic panning of dialogue and music within the vacuum of space, along with the innovative sound design concepts, make this a highly fascinating work.

*The first film to utilize the Dolby Atmos format was Disney/Pixar's Brave, released the previous year in 2012.

Director Alfonso Cuarón stated the following about this CINEMA:

{Inspired by a report stating that tens of thousands of defunct satellites currently orbit Earth's atmosphere, and that a collision with these—or even operational satellites—could pose an immense threat to human survival, I wrote the script in just three weeks.

The visuals are almost entirely VFX, shot at Shepperton and Pinewood Studios in the UK. Regarding the sound, I approached it as follows:

In conventional film sound design, dialogue is typically centered. I broke this convention by using Dolby Atmos' immersive spatial expression to dynamically pan both dialogue and music.

The advantage of Dolby Atmos is that intended sound localization is accurately reproduced in theaters. This proved especially effective for a film like this one, where characters move dynamically throughout the space.}

1　Production crew

Director: Alfonso Cuaron

Sound Design: Glen Freemantle

Final Mix: Skip Lievsay /Niv Adiri/Christopher Benstead 

At WB De Lane Lea London /WB Burbank　U.S.A

Music: Steven Price at Abby Road Studio/British Grove London

Foley Artist: Nicolas Becker

Production Sound: Chris Munro

Sound Recordist: Glen Freemantle/ Nicolas Becker

2. Story and Main Characters

The main characters are Dr. Ryan Stone, a medical engineer conducting her first space experiment, and Matt Kowalski, who commands the space shuttle. While working outside the shuttle, they receive an urgent order from NASA Houston: a massive debris field from a destroyed Russian satellite is heading their way, demanding they immediately halt operations and abort the mission.

However, they fail to evacuate in time and are thrown into open space. Somehow, they manage to return to the shuttle. Matt devises a plan: if they can reach the International Space Station, they'll transfer to a Soyuz spacecraft bound for the nearby Chinese space station Tiangong, then return to Earth aboard a Shenzhou rocket. They proceed together, but tragically, Matt drifts off into space. Left alone in the void, Ryan overcomes immense challenges and safely returns to Earth.

3. Distinctive Sound Design

3-1. Introduction: 00:00:00——00:24:23

The intro is brilliant: starting with the logo, a full-bit musical sequence plays for 37 seconds. When it cuts out, a 9-second non-monophonic sound represents space. In space, Dr. Stone and Kowalski conduct EVA while their colleague Sharif repairs the telescope's circuitry. The peaceful scene of their work continues. Kowalski, who says “I have a bad feeling about this,” receives a command from Houston: “Abort immediately and return.” After returning to the space shuttle, the two see the destroyed interior and plan to return in the Soyuz spacecraft. This scene explains the situation where, due to the accident, only two people are left stranded in space.

 In outer space itself, there is no sound. Therefore, all sounds heard on screen—such as Dr. Stone's breathing, the touch of the ISS, the rotation of screws—are solely sounds heard inside the helmet within the spacesuit. This material was recorded using various contact microphones that pick-up vibrations, then processed with effects to create a muffled sound quality. (Futz processing)

Communication voices from the NASA call center are randomly heard from any of the four height channels per phrase to emphasize height perception. This spatial localization is unique to the open environment of outer space.

An information comes in from NASA's call center: “Mission aborted! Return immediately!” But it's too late—Dr. Stone is hurled into outer space.

This is where Dolby Atmos' immersive audio design comes into play.

Amazingly, the entire soundtrack—Dr. Stone's breaths and dialogue included—spins 360 degrees.

3-2 Transition 00:24:23——00:44:46

As the two men connected by a rope advance toward the International Space Station, Kowalski's fuel runs out. He disconnects the rope and drifts alone through space, encouraging Dr. Ryan. Alone and isolated, Dr. Stone reaches the International Space Station and successfully enters it. Inside the oxygen-filled cabin, he finally removes his spacesuit and boards the attached Soyuz spacecraft, heading for China's Tiangong space station.

The scene where the two survivors, Dr. Stone and Kowalski, cling to the ISS battery panels also features the 360-degree rotating music.

Kowalski drifts off into space, leaving only Dr. Stone to reach the Soyuz. Upon entering the cabin, filling it with oxygen, and removing his helmet, the various noises within the cabin begin to be heard as normal sounds for the first time. Furthermore, the ME-style music used inside the cabin contrasts with the 360-degree music in space by being confined solely to the horizontal plane of the 5.1-channel sound field.

Suddenly, a fire erupts. Its flames race across the entire screen in a 360-degree rotation.

3-3 Main body 00:44:46——01:03:06

Dr. Ryan struggles to pilot the Soyuz toward “Sky.” But the satellite runs out of fuel. Drifting through space in despair, Aninga's DJ plays over the radio transmission received from Earth. Suddenly, a knocking sound is heard from outside the ship.

Dr. Stone's parachute, detached from the Soyuz spacecraft, snags on the spacecraft, creating another tense moment as an alarm sound appears with a 360-degree rotating effect.

In the scene where the parachute is cut away with a wrench, the sound of the rope being cut is heard inside the helmet. As mentioned earlier, sounds constantly heard inside the helmet utilize material recorded with underwater microphones or contact microphones.

3-4 Conclusion 01:03:06——01:23:54

The encouraging voice of Kowalski entering the cabin was Dr. Ryan's hallucination.

Summoning his courage, he transfers to the “Sky” module and enters the attached satellite “Shenzhou”.

Reading the green manual, he performed the landing procedures. At the critical moment of “life or death,” the parachute deployed safely, and Houston confirmed the “Shenzhou.” Landing on the ocean surface, Dr. Ryan panicked due to an internal fire but managed to escape the ship and reach the shoreline. Staggering to his feet, Ryan looked up at the sky, feeling Earth's gravity.

In the final scene of the twist, during Dr. Stone's hallucination where “Kowalski came to rescue him,” the 37 seconds he spends entering the ship are rendered in complete silence. However, when the alarm sounds and Dr. Stone snaps back to reality, he transfers to the Chinese sky. This music also employs a 360-degree expression.

Inside the sky, they board the small escape vessel “Shenzhou” and begin their journey back to Earth. As they descend, various debris falls from the rear and height channels in the background. I believe Immersive Audio design is optimal for expressing this sense of enclosed space.

*In the 2018 film A Quiet Place, it also proved effective in scenes like when monsters roam the first floor while a parent and child hide underground.

In the underwater scene where she lands safely, tense sound effects like ringing in the ears unfold in 360 degrees.

Dr. Stone, having swum ashore, walks while objectively hearing the sounds of insects and falling debris.

As Ryan slowly rises and begins to press his feet firmly against the ground, feeling its gravity, the final music—accompanied by a chorus sampling part positioned in the height channel—expresses the joy of being alive. However, I believe this SCORING and END MUSIC stand alone as superb Immersive Audio pieces when listened to separately.

 

3-5 End Credits: 01:23:54–01:31:00

After a 1h24'53" blackout, the staff roll begins and a communication tone appears.

4. Scoring Music

Key features include:

● Music for outer space scenes employs a 360-degree design utilizing all directions freely

● Music for scenes inside the spacecraft employs a flat 5.1-channel design.

Music occupies approximately 81% of the film's runtime, meaning some form of music is almost constantly present. This is likely because the music was produced more as ambient soundscapes than traditional scoring music, to support the drama unfolding in the silent vacuum of space.

Composer Steven Price stated that he wanted to create a new orchestral sound by sampling material at Abbey Road Studios and assembling the orchestra, rather than using conventional orchestral recordings. In particular, he mentioned in an interview that the glass harp material proved extremely effective.

 For the 360-degree panning in the music, they first pre-mixed the stems in 5.1 channels, then grouped several of those stem mixes together before performing the 360 panning. Besides Abbey Road Studios, they also recorded at British Groove Studio London. This studio is quintessentially British, boasting a rare, spacious environment in London alongside a vintage 60s console.

5. Foley. Sound Effects. Material Recording

The sound design was handled by veteran British sound designer Glen Freemantle. The author first took notice of his work through his sound design for Slumdog Millionaire (2008). (Winner of 8 Academy Awards at the 81st Academy Awards)

During the interview, they discussed how to represent the silent void of space with sound. They decided to consistently depict outer space itself with ME-style surround music, while contrasting it with actual sounds heard inside the helmet—heartbeats, breathing, and tactile sounds.

For this reason, Foley recording primarily utilized contact microphones, incorporating elements like guitar sounds recorded underwater. Additionally, for mechanical sound effects, the team visited General Motors to capture location recordings of robot assembly and air conditioning sounds.

The communication material with NASA was apparently recorded by him talking alone on Skype in a hotel room.

Chris Munro, credited as Production Sound Mixer, stated that this time he focused more on building the communication system to smooth the movements of the two actors in the studio than on recording dialogue. He has long favored Sanken microphones for production sound booms and hidden mics, particularly liking the natural sound quality of the COS-11 hidden mic. There was also the happy news that this very COS-11 won the 2021 Academy Scientific and Technical Award.

In Conclusion

Originally intended for a 7.1-channel mix, this work underwent an urgent shift to a Dolby Atmos mix following the advent of immersive surround sound technology. By dynamically panning both dialogue and music across 360 degrees, it stands as a landmark production that demonstrated the superior spatial expression capabilities of Atmos.

   

In the 1970s, three directors—G. Lucas, S. Spielberg, and F.F. Coppola—emerged championing an anti-Hollywood stance. Similarly, in the 2000s, three directors from Mexico rose to prominence.

These directors are Alfonso Cuarón, Alejandro G. Iñárritu, and Guillermo del Toro. Director Alfonso Cuarón went on to win an Academy Award for his film ROMA, distributed via the new Netflix distribution system in 2018. Director Guillermo del Toro won for his fantasy film The Shape of Water, and Director Alejandro Iñárritu won for The Revenant.

[End]