From the viewpoint of broadcasters and content production, audio capture plays a crucial role in the overall quality of the content. Many people assume that when starting a live broadcast or recording audio for a film/TV production, image quality is the most important factor to consider. This assumption ignores the fundamental importance of audio quality.
Humans are visual creatures by default, however our sense of sound is absolutely integral to communication, making audio an essential aspect of any broadcast. Even excellent video quality will be ruined if the audio has not been well recorded.
For professional quality results, audio engineers and production teams need to be aware of the major factors contributing to poor audio capture. These include poor quality equipment, badly designed acoustics, and prevalence of background and wind noise.
Keeping up with Video Quality
With the continued move towards higher quality resolution in broadcasting and production, how can audio technology providers ensure that audio quality keeps pace? At the same time engineers need to ensure that audio data can be efficiently transported and integrated with the production workflows of broadcasters and studios. In this special report, Digital Studio speaks with audio capture specialists to understand how the technology is progressing. Technical specialists at manufacturers of professional high end audio recording equipment discuss audio capture innovation and product development, and the trends and technologies driving advances in the audio capture field.
DPA Microphones manufactures professional quality microphones for various uses in broadcast. René Moerch, Product Manager at DPA Microphones (above), discusses the importance of using high quality audio recording products.
Moerch, says that audio capture with today’s hardware is already capable of good quality. “The issue is how it integrates with the video signal and how much of their budget broadcasters are prepared to spend on good quality audio equipment. Poor audio does have a big impact on the user experience, so it is important to make sure audio is recorded properly in the first place. You can also improve the user experience by integrating things like loudness control into the audio chain.”
Moerch points out that the recently launched CORE range of mics by DPA, includes “new amplifier technology that minimizes distortion and increases dynamic range, or workable area. This new technology lives within our miniature lavalier, headset and instrument microphone products where it also provides water and moisture resistance through nano coating and hermetic sealing of the sensitive electronics.”
“We developed CORE by DPA to create an even clearer sound from the ‘highest of the highs’ to the ‘lowest of the lows’, and it has already been adopted as standard by many top rental companies and broadcast engineers.”
DPA is also focussed on the mobile audio capture segment for electronic field recording, Moerch says that DPA has also recently launched “d:vice, an audio interface for iPhone, MAC and PC users that takes two inputs from any of our mics and converts them to digital signals. With one of these, quality audio follows the video content gathered on the go by journalists.”
What are the best practices recommended for audio capture of live sports and events and in post-production for studio and film audio recording? “The golden rule in audio capture is to invest in the best equipment you can afford and record high quality, clean audio as close to the sound source as you can because it is impossible to fix mistakes in the mix,” Moerch says.
“The microphone is the first link in the audio chain, so it pays to use one that gives you a clear, natural sound with minimal distortion and the necessary directionality to avoid picking up background noise. Also, make sure your distance and close mics both have the same sonic characteristics so that you can easily switch between them in the mix,” he adds.
With more and more digital content creation taking place for streaming platforms online content creators will need to ensure they are capturing high quality sound. Will there will be an increase in the demand for pro level audio capture products? “Yes,” says Moerch, “because if you want more content you need to record more sound sources, therefore you need more microphones. You should also pay even more attention to capturing high quality sound because the actual process of streaming can have a detrimental effect on audio quality.”
Sennheiser is a well-known brand in the audio technology field producing a whole range of audio capture and processing products for both the AV world and the broadcast market. What sets apart their technology from competitors in the field and how does Sennheiser ensure that audio signal transport can maintain quality within a digital workflow?
Ryan Burr, Head of Technical Sales & Application Engineering at Sennheiser (above) says that there are “many different components within the audio path like microphones, processing, and mixing consoles that need to be considered when maintaining the highest quality and resolution but it is what links them all together that is often overlooked in doing so.”
Burr points out that “while traditional methods of audio transport have been analogue based, the move towards digital has meant that all manufacturers now need to have a digital option when it comes to inputting, processing and outputting the signal. However, there is a need for more standardisation as many of them use proprietary formats and different types of conversion from analogue to digital or even digital to digital that can have a degenerative effect on the signal/audio quality.”
“The first part of the signal flow is the audio capture element, the microphone. However, in many industry professionals’ eyes, this has been the last element of the signal flow to be ‘digitised’,” says Burr. “The actual methods of acoustic transduction or conversion of acoustic energy into electrical energy have remained mostly unchanged for decades but it’s the materials used in these transducers and what we do with the electrical signal that could be considered as what sets Sennheiser and Neumann apart from most other manufacturers. For example, the use of AES-42 in Neumann’s range of wired digital mics and the first fully uncompressed digital wireless microphone system, Digital 9000, from Sennheiser.”
Shure is another manufacturer with a long standing reputation for high quality audio capture products. Shure Technical Engineer Support for Pro Audio, Andrea Granata says, “in the audio domain we saw two different trends with the advent of digital technologies: the capability to record produce and manipulate hi resolution contents together with the growing demand of compressed audio to simplify the diffusion via web and streaming services. For a manufacturer like Shure is important to offer tools that can guarantee the maximum quality and reliability for every kind of application.”
Granata further explains: “I think that in the current scenario the keyword is scalability: we cannot have the same tools for a production company and for a youtuber. It means that, other than the sound quality, for professional we invested in reliability and resilience as interference detection and avoidance for wireless systems and for the consumer market we offer similar functionality in a more affordable and easy to use product. As an example: a shotgun microphone for professional is about 50 cm long with interchangeable capsules and preamplifier, but we offer a camera-mount version that includes a flash recorder in a much smaller format.”
Ambisonics: Spatial Audio for Immersive Content
With the increasing amount of AR/VR content production how can audio engineers make sure that the audio experience integrates with the new formats? If the audio is a stagnant stereo track, the VR experience will feel flat, which can leave viewers unimpressed. While surround sound formats have been around for long, with immersive content, we are dealing with an additional dimension.
Spatial audio, also called ambisonics, is a full sphere surround-sound technique that uses a dimensional approach to audio to mimic the way we hear in real life. By channeling the characteristics of sound as it travels through space and time, spatial audio makes 360° immersive video even more realistic. Putting it simply, ambisonics is a multi-channel technique that lets you spherically capture the sound arriving from all directions, at a single point in space. This makes ambisonics the most appropriate tech for VR and other applications involving 3D sound.
Above: Sennheiser's AMBEO VR mic
During playback this representation is rendered binaurally, allowing you to virtually rotate the orientation of the perspective in all directions, horizontally and vertically. Ambisonics techniques for immersive sound are now supported by most of the major post-production and playback tools on the market.
Digital Studio asked the audio specialists about their plans to develop new products for capturing spatial audio for immersive content production.
Ryan Burr of Sennheiser agrees that “Virtual and Augmented Reality (VR/AR) has been a hot topic in the Middle East and while the video capture element has received due attention, the importance of 3D audio has been largely overlooked.”
“At Sennheiser, we are playing a lead role in addressing this, both through the development and introduction of highly innovative products such as the AMBEO series of microphones and headsets, and by regularly conducting workshops on immersive audio in association with other manufacturers as well as organizations such as a Dubai International Film Festival (DIFF).”
Especially designed for 360° spatial audio recording, the easy-to-use AMBEO VR Mic is an ambisonic microphone fitted with four matched capsules in a tetrahedral arrangement. This special design allows the capture of surrounding sound from one single point.
René Moerch of DPA Microphones says they are well positioned to address the audio capture market for immersive content. “20 years ago,” says Burr, “we were among the pioneers of high-end quad-headed microphone techniques and had products for ambisonic recording. Our miniature microphones are also used for binaural recording. At present, we don’t offer a DPA branded solution to suit this market but re-entering it would be straightforward as we have the technology to support it. Right now, we are watching and waiting to see how it will develop.”
Andrea Granata hinted that Shure has some plans to enter in this space as well: “While I obviously cannot talk about upcoming products I saw an effort to give access to the best technologies to a larger audience. We recently upgraded the software for a small microphone that can be mounted on iOs devices, MV88, based on M-S technology: it has different polar patterns and can easily be controlled using the app even from someone that has no audio background.”
Low Budget Audio Capture for Content Creators
More and more content creators produce content for online platforms but with lower production budgets. DS asked the manufacturers if there is a need for more audio capture equipment to be made available on a lower budget. Will there be a move towards greater convergence between the AV products used by hobbyists and online content creators, and the broadcast quality products used by the professionals for audio capture?
“There has always been a certain amount of crossover between AV and broadcast markets. It’s more about the feature set of what comes with the capture element that defines the different uses. For example we produce wireless microphone systems that can be used for installation in an auditorium, but this same range has the ability to be connected directly to a camera for use in electronic news gathering,” commented Ryan Burr of Sennheiser.
“As with the types of video equipment being used, there is a definite appetite for more budget conscious products for audio capture, however I wouldn’t necessarily attribute this to streaming platforms. Digital content creation has had an impact because the type and format of camera being used has changed to become more affordable. Once you have the likes of DSLRs and even mobile phones being utilised for content creation, it soon becomes evident that you need to add better audio capture equipment in order to improve the overall production quality of that content. We have introduced the Audio for Video range of products to cater for this segment of the market with the MKE-440 for DSLR and the HandMic Digital for iOS, to name but a few.” says Burr.
Not in audio capture feels René Moerch of DPA Microphones. “With AV, most content is intended for presentations, so it is created in advance and post produced. It is rarely captured live. Broadcast is the opposite – you need automated technology and standardized formats that optimizes workflows so that you can cope with live situations and doing things on the fly. You also need simplified content gathering tools, i.e. equipment that focuses on getting more content out faster, smoother and wider.”
Above: Kieran Walsh, Director of Application Engineering (EMEA) at Audinate
Kieran Walsh, Director of Application Engineering (EMEA) at Audinate feels there are certainly fine examples of a “blurring of the lines” between AV and broadcast products. “Particular examples include work by NewTek and Quicklink in their offerings of products that leverage Microsoft’s Skype Tx broadcasting solution. This allows remote contribution, without the need for “specialist” hardware. Furthermore, the cross pollination, certainly in corporate and government communications, which are already leveraging non-linear broadcast paradigms, appears to be a maturing trend, which appears to be here to stay,” says Walsh.
Shure’s Granata says we are moving very fast towards a greater integration. “The common ground is the software and IT based approach that is becoming the centre of most productions nowadays.” “Content creation and distribution is now more easy and affordable than ever. Definitely audio capture equipment on a budget is already an important part of our offer and probably will be even more important in the future. The challenge is to offer products with performances similar to the ones used by professional, but make it more user friendly,” says Granata.
Audio over IP – potential for cost savings
Digital audio capture also brings the opportunity to integrate audio into the broadcast workflow using IT networking tech. Digital Studio took the opportunity to ask how the move towards networked audio and audio over IP will affect broadcast and production.
Ryan Burr of Sennheiser says Audio over IP allows broadcasters to integrate all AV capture, mixing, routing and equipment as well as legacy systems onto their existing network architectures. “They can thus realise significant cost savings by eliminating the need to plan audio cabling around existing utility structures and architectural hurdles, while utilizing the network that is already in place,” says Burr.
“What broadcasters have to pay attention to is the protocol they chose to implement. Because the industry is still in a state of consolidation with manufacturers calling for standardisation of the protocols used in digital audio networks,” Burr commented on the move towards audio over IP.
DANTE is one audio standard well suited for digital audio transport in broadcast and live streaming environments. Audinate's Dante platform distributes digital audio signals over computer networks, and is designed to bring the benefits of IT networking to the professional AV industry.
Kieran Walsh, Director of Application Engineering (EMEA) at Audinate “As a provider of network services for audio distribution, we are well placed to take advantage of improvements made in both silicon and partner manufacturer’s implementations of the capture stage of digital audio. Dante is built upon existing networking standards, and these are well-suited to the challenges of carrying large amounts of traffic, and are constantly evolving to deliver more capacity, and higher dependability.”
“Much is possible with IP technology, says Walsh. “The potential for media asset management and delivery in broadcast over the same infrastructure is highly attractive, and a “file-based” workflow is firmly established. As network capacities increase, the potential for live streaming of audio and broadcast video become less experimental and more de rigueur. There is already much confidence in the use of IP to transport digital audio, and exciting conversations are increasing about the finesse of a solution. Data networks give the ability to achieve fine grained access to resources, and tight management of sessions.”
This next phase of conversation thinks Walsh will be about where a simple “transport” becomes properly understood as being distinct from a mature “complete solution”. “We have seen this development on the public Internet, from BBS to WWW, and in telecoms communications networks, where “digital” phones became fully integrated and managed virtual PBX solutions. Indeed, if the evolutions of these global game-changers are mapped into audio over IP for broadcast, some of the decisions taken by parallel technologies will help to rapidly provide real solutions for high-quality content distribution in the broadcast facility, and facilitate seamless integration with remote contribution locations, regardless of the ownership,” Walsh says.
“I think it’s something that’s already happening,” says Granata of Shure. “This is making complicated tasks easier than ever and less time consuming, increasing the flexibility and resilience of our devices. Thinking to be able to transfer hundreds of audio channels on a single cat 6 cable, splitting them to different destinations with few clicks of the mouse without all the expensive tools required just some years ago is definitely a sign of the possibilities offered to our industry by the integration with the IT world.”
René Moerch of DPA Microphones says that some of the most dominant developments in the Pro Audio landscape have involved the use of audio over IP leading on with Dante. “This will allow the industry to be more efficient and make it cheaper for new broadcast stations and production houses to set up, because ensuring your audio architecture by using simple IT infrastructure components is more cost effective.”
“As both audio and video is converging into IP, a lot of the traditional workflows and break-in and outs of embedded/deembedded signals are slowly fading away. In the other hand, however, you need to ensure that you are creating content that can live in the various eco environments, i.e. traditional broadcast platforms, OTT platforms and so forth. You may cut some of the beast’s tail, but the beast’s head keeps growing, so you have to keep up by ensuring smart automated workflows.”