What Is A Microphone Array?

The use of technology in the classroom is becoming increasingly prevalent in today’s educational landscape. As schools and universities adopt new and innovative solutions to enhance the learning experience for students, one area of focus has been improving the quality of audio in the classroom. The DDMC recently sat down with Steven Pretzer, an AV support tech at Fuqua School of Business, to discuss the installation of three new microphone arrays in the McClendon and HCA classrooms. In this article, we will explore the benefits of microphone arrays over traditional tabletop microphones, the challenges of implementing them in a classroom setting, and best practices for their use.

  • What is a microphone array, and how does it differ from traditional table microphones?

 A microphone array is a microphone system that uses multiple microphones arranged in a specific pattern to capture audio in challenging acoustic environments. It uses beamforming technology to enhance sound coming from specific directions while reducing unwanted background noise and reverberation. The microphones are combined to create a virtual microphone that can be aimed and steered to capture audio from a particular area. It is often used in situations where multiple speakers are present, such as in a panel discussion or a classroom lecture and can provide high-quality audio for remote participants in video conferencing systems.

 A microphone array differs from a tabletop microphone in several ways. First, a microphone array is typically mounted on the ceiling or wall and can capture audio from multiple directions simultaneously, while a tabletop microphone only captures audio from a single direction. This allows microphone arrays to pick up a wider range of sounds and voices in a classroom setting, improving the overall quality of audio.

  • What are the benefits of using microphone arrays in a classroom setting?

 Using microphone arrays instead of tabletop microphones in a classroom setting offers several benefits, including the ability to capture sound from a wider area, reducing background noise and reverberation, being more discreet, and being more cost-effective in the long run. This enhances the learning experience for students and teachers alike by providing clear and intelligible audio in a range of challenging acoustic environments.

  • How do microphone arrays improve the quality of audio in a classroom environment?

 Microphone arrays improve the quality of audio in a classroom environment by providing clear and intelligible audio that can be easily understood by students and teachers. This is achieved through a combination of features, including the ability to capture sound from a wider area, reducing background noise and reverberation, and the ability to steer and focus the audio in real-time towards the person speaking. In contrast, traditional tabletop microphones can often be garbled and difficult to distinguish between speakers, particularly in larger classrooms or lecture halls. By using microphone arrays, the need for additional equipment, such as lavaliere microphones, can also be reduced, resulting in a simpler and more streamlined audio setup that is easier to manage and maintain. Overall, the use of microphone arrays can significantly enhance the quality of audio in a classroom environment, improving the learning experience for students and teachers alike.

  • What are some of the challenges associated with implementing microphone arrays in a classroom, and how can they be addressed?

 Implementing microphone arrays in a classroom can present several challenges that need to be addressed to ensure optimal performance. One of the main challenges is the complex acoustic environment of a classroom, which can include a variety of sound sources, such as students talking, moving around, and rustling papers. In addition, the shape and size of the classroom, as well as the placement of the microphones, can also affect the quality of the audio captured.

 To address these challenges, it is important to carefully plan the installation and setup of the microphone array system. This may involve using specialized software to analyze the acoustic environment and optimize the placement and configuration of the microphones. It may also involve walking the room and testing the system to ensure that it is capturing clear and intelligible audio from all areas of the classroom.

  • What factors should be considered when selecting a microphone array for a classroom setting?

 Installation type and location, backend interface. All play into the choice.

When selecting a microphone array for a classroom, factors such as installation type and location, backend interface, size and shape of the room, number of students and teachers, and the acoustic environment of the room should be considered. Ceiling-mounted microphones may offer wider coverage and be more discreet, while wall-mounted microphones can provide better directionality and control. The interface should be compatible with the existing audio system and any additional equipment that may be needed. Advanced noise reduction capabilities may be necessary for classrooms with high levels of ambient noise. By carefully considering the specific needs of the classroom and the capabilities of different microphone array systems, schools and universities can select a system that provides clear and intelligible audio for students and teachers.

  • How do microphone arrays improve the learning experience for students and teachers?

 Clarity, Clarity, Clarity!

 Microphone arrays can greatly enhance the learning experience for both students and teachers in the classroom. They improve the clarity of audio, reduce the need for repeating questions, and help the classroom flow more smoothly. Microphone arrays can create a more inclusive learning environment, making it easier for all students to hear and understand what is being said. This is particularly beneficial for students with hearing impairments or those who may struggle to hear in a crowded or noisy classroom. Overall, microphone arrays can greatly enhance the learning experience in the classroom by improving audio quality and creating a more inclusive environment.

  • Why use ceiling mounted microphone arrays in a classroom?

Ceiling-mounted microphone arrays can offer superior audio quality compared to other types of microphones, thanks to their advanced beamforming technology. This technology allows the microphones to focus on the speaker and filter out unwanted background noise, resulting in clear and intelligible audio for all students. While other types of microphones, such as wall-mounted or portable microphone arrays, may be suitable for certain classrooms, ceiling-mounted microphone arrays offer several key advantages that make them a superior solution for most classroom environments. By providing wide coverage, reducing disruptions, and delivering high-quality audio, ceiling-mounted microphone arrays can greatly enhance the learning experience for both students and teachers.

  • What are some best practices for using microphone arrays in a classroom setting?

A In line ducker in the DSP. Gain Structure. Focused on speech. High Pass filters. NOM limit of 1 with the ceiling arrays to keep the noise floor low and a lower hold time on the gating auto mixer to ease the transition between open mics.

 If something you’re doing is not making it better? Don’t do it!

 To optimize the use of microphone arrays in a classroom setting, there are some best practices that should be followed. Firstly, it is important to use an in-line ducker in the DSP, which will automatically lower the volume ofany background noise when someone is speaking. This can greatly improve the overall audio quality and intelligibility.

Secondly, attention should be paid to gain structure, ensuring that the microphones are set at the appropriate level to capture speech without picking up unwanted noise. Additionally, the microphones should be focused on speech, with any background noise or reverberation minimized using high-pass filters.

 Finally, it is important to remember that if a certain adjustment or change is not making the audio quality better, it is better not to do it. This can prevent unnecessary tinkering and ensure that the microphone arrays are being used in the most effective and efficient way possible. By following these best practices, the use of microphone arrays in a classroom setting can be optimized, resulting in improved audio quality and a more effective learning environment.

 Additionally, the advanced beamforming technology of microphone arrays allows them to filter out unwanted background noise, resulting in clear and intelligible audio.

 When selecting a microphone array for a classroom setting, factors such as installation type, location, and backend interface should be considered. Ceiling-mounted microphone arrays are often a superior solution, thanks to their wider coverage and advanced beamforming technology, but other types of microphones may be suitable for certain classrooms.

 To optimize the use of microphone arrays in a classroom setting, best practices such as using an in-line ducker in the DSP, paying attention to gain structure, and minimizing background noise using high-pass filters should be followed. By following these best practices, the use of microphone arrays can be optimized, resulting in improved audio quality and a more effective learning environment.

The use of microphone arrays in a classroom setting can greatly enhance the learning experience for both students and teachers. By providing wider coverage, reducing disruptions, and delivering high-quality audio, microphone arrays can ensure that everyone in the classroom can be heard clearly without the need for passing microphones around.

Meet Steven Pretzer

A skilled audio engineer and AV support tech at Fuqua School of Business. With a degree in Recording Industry Production and Technology and a minor in Mass Communication, Steven’s passion for audio began at an early age. After working as a freelance audio engineer in Nashville for several years, Steven moved to Chapel Hill in 2008 where he focused on playing bass in several bands and continued to do independent recordings from his home studio.

In 2017, Steven became a contractor at Fuqua through Duke temporary services and in 2019, he was hired in the position of AV support tech at Fuqua. As an AV support tech, Steven’s primary job is to support faculty, staff, and students regarding classroom technology. Utilizing his background in audio engineering, Steven has been able to focus on and improve communication in Fuqua classrooms.

In addition to his experience, Steven has received several Biamp certifications including Tesira Forte and Tesira Servers as well as Dante level 1. With his expertise in audio and classroom technology, Steven has been able to implement microphone arrays in Fuqua classrooms, greatly enhancing the learning experience for both students and teachers.


AI Tools

In the world of audio and video production, having the right tools can make a huge difference in the quality and efficiency of your work. In this article, we will be discussing three powerful applications that can help you take your audio and video production to the next level: Fliki, Dall-E2, and Descript AI. Each of these tools offers unique features and capabilities that can be used to create high-quality content quickly and easily.

Stephen Toback, does caution the use of the tools in a responsible and safe way before unleashing the magic of what these tools will do, and not putting Duke at risk. He highlights that the tools require users to give some information to it, and it’s important not to put any data into any of these applications that Duke hasn’t approved as public data. He also advises users to create accounts on the sites with alternate IDs, not Duke email address, and not to use the same net ID password. Additionally, he mentions that these tools are changing rapidly and should not be built into critical business applications yet. He encourages users to join an ongoing conversation about the tools in a Microsoft teams chat (Staff AI).

David Stein presented several AI tools such as Fliki a text-to-audio application that allows users to create high-quality audio recordings with a wide range of voices and emotions. Dall-E2 is a powerful application that has a wide range of potential uses, including the ability to generate detailed prompts for video and audio production. Descript AI is a web-based, collaborative system for video and audio editing that includes built-in capture from Zoom, green screen function, and stock images, music, video and sound effects. Together, these tools make it possible to generate high-quality content quickly and efficiently, with the added bonus of using ChatGPT for script and dialogue generation.

For More Details Please Review our Recorded Discussion Here

Another Script-Based A/V Editing Option: The Camtasia-Audiate Integration

Descript, a new video and audio creation and editing tool, has been making waves recently on campus with its ability to generate a script file for your project, and allowing you to edit the video simply by making changes to the script. One of the more useful things you can do with this approach is to automate the elimination of awkward “um’s” and pauses, adjust the speed and pacing of your project, and tighten things up quickly in other ways to make your media more listenable.

Some of you might not know, however, that there is a similar approach for those who already use Camtasia. Like Descript, Techsmith’s Audiate utilizes cloud-based speech-to-text technology to generate a script for your audio project. And like Descript, the changes you can make in Audiate, which include many of the things you can do in Descript, get exported back to your audio file without your having to touch that file in a timeline based editor. While Audiate in itself is geared for podcasters, those who are working with video or screen animation can get the full package via Techsmith’s roundtrip integration between Camtasia and Audiate. One cool feature of this integration we wanted to point out is that if you are working with a screen animation where you are using a cursor, Camtasia/ Audiate animates the movement of the cursor between cut points so your viewers don’t see it randomly jumping around on the screen. See below for a demo of Camtasia/ Audiate in action.

Pricing for Audiate at first glance seems to be about the same for Descript, so if you are working with video and are not already a Camtasia user, it probably makes the most sense to use Descript. However, there are discounts available for the Camtasia/ Audiate package.

Since interest seems to be growing in these types of tools and workflows, we would love to hear from you if you’ve tried either of them, and would especially be interested to hear how you think Camtasia/ Audiate stacks up to Descript for your use cases.

Audio Engineering Society

The Audio Engineering Society Convention

AES New York 2022

What is three days in a crowded convention hall full of audio engineers like?

It’s a completely immersive experience!

Mic Placement

Abbey Road Studio 2


The theme of this years edition of the AES convention was clear. Immersive and spatial audio is going to be the wave that propels the future of audio industry.  The range classes covered the entire work flow of how to plan, set up, record, mix, binauralize and distribute audio for the masses. Middleware like Wwise, Dolby Atmos and game engines like Unity and Unreal Engine will give audio engineers the tools they need to transition their audio tracks from stereo to an immersive aural experience.



Some of the highlights of the show floor that will be of interest include a sit-stand ready made podcast table and Ultra Low Profile Adjustable Mic Boom from Forecast and  O.C.White Co.

Magewell Capture & Combine USB Fusion is a multi-input USB video capture devise with integrated sourse switching and layout control. Offering two HDMI inputs and one USB webcam input, USB fusion can switch between sources or combine two inputs simultaneously into one output (picture-in-picture or side-by-side) for capturing into popular software via its USB 3.0 interface.


Magewell Fusion

The Klover Mik 09 parabolic microphone is by far one of my favorites of the show! Engineered for the modern videographer, the KLOVER MiK 09 parabolic microphone is known as our “shotgun killer.” Attach it to the camera’s shoe mount, mount it to a light pole, attach a pistol grip, or even hang it from the ceiling, for long-range audio that’s always ready. By far the most comprehensive and effective demonstration I have ever been apart of!

This mic rig deserves an award all by it self!

Mi Demo


Over the years I found that going to gathering like this often reward us with information that you never knew you needed or simply not aware of. Conversations with peers lead to things you simply cannot live without.

Like Krisp’s AI-powered, bi-directional Noise Cancellation eliminates background noise from your microphone and your speaker.

krispWith Krisp toggled “on,” you can rest easy knowing that your voice—and your voice only—is heard clearly. But Krisp doesn’t stop there. Sounds on the other end of the line are identified and eliminated, so there are no distractions to break your focus during that important meeting.

For more information about these products and more.

Please contact me via Teams


The DDMC welcomed Ryan Budvitis & Brooks Platts from Shure’s conferencing and meeting product line up today. The STEM ECOSYSTEM audio products fill that gap just below professional audio products like the Microflex and the home office product lines at Shure. When you have a meeting space that can host 5-15 people and you would like to keep the AV simple and user friendly. The Shure STEM audio products is the right fit. The Audio Fencing feature reduces the busy streets and noisy offices that often encroach into most of our web conferences.

Additional features that include room design, one button room adapt, room check, and remote management are more features that helps the STEM ECOSYSTEM stand out in a very crowded USB peripheral market.


Need more more detail?

Review todays recorded meeting or contact The DDMC.


We had great turnout for our July 27th DDMC presentation with the kind folks at Crestron Electronics. Representatives Ryan Bernt and Greg Coddington showed up with a wealth of information. New and improved online and in person training, camera tracking, BYOD product updates, and cloud based control platforms.


Be sure to check out the recording for more details!

Crestron at the DDMC

Extron Electronics

Mark Bednarcik & Don Mitchell with Extron Electronics dropped into the DDMC and gave us a run down on some of the powerful tools that Extron has available for Collaboration spaces, Conference Rooms, and Lecture Halls. Also highlighting control and their new Virtual Control platform that will allow control of up to 50 rooms on one box.

Mark and Don pointed out the expansive online and in-person training that Extron offers. Worth checking out! Especially if your are in need of CTS or BICSI continuing education credits.

If you would like to review the meeting please follow this link to the DDMC Panopto to this video!

Panasonic Education Solutions

The DDMC met with our good friends at Panasonic this afternoon. All of us know they provide high quality classroom projectors. We just now discovered is they have a “pimp my projector” option with custom vinyl wraps! Custom Graphic/Logo/Colors. A 5-10 day Business day turnaround will get you stylin n’ profilin before the fall semester!

Also new to the Panasonic line of education products is their entry into wireless microphones with (11) new products that aim to be intuitive to use, lightweight and secure. Designed for lecture halls, auditoriums, the system has the flexibility to deliver excellent quality in spaces small too large.

New and notable is the Panasonic Lecture Capture & Auto – Tracking system. An all-in-one system to automatically track, record and stream video. Delivering a high quality, rich multi-source viewing experience. Co-developed & certified with Seneca and Panaopto for plug and play capabilities that should make for easy integration into existing AV systems. I have requested a (4) camera on site demo! So, stay tuned for further developments.

Check into our Zoom call here

2022 Northwest Managers of Educational Technology Conference Summary

This April I attended the Northwest Managers of Educational Technology conference held this year in Coeur d’Alene, Idaho. Since there’s nothing quite like this group in the Southeast, it felt well worth it to me to fly across the country to enjoy a little normalcy and connect in person again with fellow A/V professionals focused on education. Of course, I can’t deny that the location for this year’s event on the shores of beautiful Lake Coeur d’Alene was an added draw. The conference was well attended (I’m guessing ~100 attendees), and exceptionally well run. NMET is a close organization with a history that spans several decades going all the way back to the beginning of the AV industry as we know it in the era of analog media.

Lake Coeur d'Alene


  • Responses to the pandemic and various school’s efforts to work toward a “new normal” 
  • The CARES Act as a catalyst for A/V classroom upgrades: UNLV launched a huge new program during COVID called RebelFlex using CARES funds that is seen as largely successful that would likely not have been possible otherwise. (Duke, along with several other top private universities such as Harvard and Princeton chose not accept CARES act funding.)
  • COVID as a driver for A/V initiatives and standardization: Many schools saw decision-making for A/V and IT-related projects shift to the provost level and higher as schools developed alternative teaching strategies such “emergency”, “HyFlex,” “hybrid,” “co-mingled,” and remote teaching as pandemic responses. In most cases timelines for implementing major A/V projects sped up significantly as well.
  • COVID as a driver for A/V standardization: Oregon State University described how COVID helped their campus standardize on an enterprise A/V strategy that centered on Kaltura, Canvas, and Zoom, and quieted demand for competing tools. Interestingly, OSU does not use a dedicated recording tool such as Panopto but instead utilizes Zoom for all recording and pushes this content to Kaltura within Canvas course sites. 
  • Faculty support models for hybrid teaching: UNLV’s RebelFlex program experimented with hiring students who were assigned to in-person classes as tech support. While overall this seemed successful, there were challenges, such as the diminishment of the need for tech support as the semester went on and faculty became familiar with the new technologies involved. Additionally it was observed that faculty members tended to morph the roles of their student help into roles resembling TAs and research assistants over time, including using these helpers as moderators for their Zoom chats.
  • Building a Networking Group like NMET: Some of the conference attendees were surprised I came all the way from North Carolina to attend the conference. “You mean the Duke?” several asked. I explained there’s nothing in the southeast comparable to NMET, an education-driven organization focused on the intersection of A/V and IT. That’s sad, but not surprising in a way, since a successful organization like NMET isn’t built overnight. NMET began holding conferences in 1979 and is the result of the hard work and passion of several generations of A/V professionals who have comprised NMET.
  • The A/V Superfriends Podcast (https://www.avsuperfriends.com/): Some of the members of NMET together with other A/V professionals extending beyond that group maintain a very cool podcast for A/V professionals focused on the intersection of A/V and pedagogy in higher ed. They were actually recording new episodes of the podcast live in the exhibit area. Members of this group led several interesting conference sessions focused primarily on the impact of COVID for classroom technology. Recent topics of their podcast include: 
    • Managing PO’s and supply chain issues
    • Campus support structures
    • Auto-framing and auto-tracking cameras
    • Cabling infrastructure and TIA standards
    • The intersection of A/V and IT in hiring new staff
    • AV replacement cycles–do we set arbitrary schedules of 5, 7, 10 years or tie AV refresh projects to capital projects?
    • Bootstrapping light video production switchers into classroom systems
  • AV over IP: It was argued by some that the NDI (Network Device Interface) protocol represents the wave of the future, and that we should future-proof our classrooms by purchasing NDI-capable cameras
  • Benefits and drawbacks of Zoom certification: It was discussed this may be OK as long as not mandated or exploited for commercial benefit (cross reference Tandberg)
  • “Hybrid” (instructor-driven) vs. “HyFlex” (student-centered) classrooms
  • USB as the “common language of hybrid learning spaces”
  • Elevating sound quality in the rush to add A/V infrastructure to classrooms 
  • Keeping classroom AV UI’s simple and standard even in classrooms where there is great complexity under the hood
  • ePTZ (auto-tracking) cameras: Importance of good lighting, fixed positions are better than continuous tracking
  • Making a virtual lightboard: One presenter showed how he used Procreate and a green screen in front of presenter to make a virtual lightboard 


  • Kaltura: Kaltura was one of three main sponsors of the conference. As mentioned above, Oregon State University, which was the main organizer of the conference, is a Kaltura customer. It was noted that Kaltura, unlike most other vendors, still offers an unlimited storage and bandwidth licensing tier, although it was mentioned it is “expensive.”
  • Panasonic: Panasonic was another major sponsor of the conference. Their projectors and displays were used in conference venues.
  • Elmo was showcasing its wide array of document cameras from a $200.00 USB to similarly portable wireless options starting at ~$800.00 to its flagship 4K, 12x optical zoom version designed for fixed classroom installations, the PX-30E (MSRP $3700.00). Interestingly, while WolfVision is the 500lb gorilla in the doc cam space, Elmo actually invented the document camera, and is the older company.
  • Epiphan was showcasing its well-known Pearl live encoder lineup along with its cool new device, the LiveScrypt. The LiveScrypt connects to Epiphan Cloud to add live ASR-based captions to your live production. These captions can be embedded with your live streams or sent out to monitors in the room for display for in person or hybrid events. There is a charge of $10.00/ hr to use the cloud-based ASR service in addition to the $1,500.00 cost of the device itself.
  • Alfatron had its wide range of PTZ cameras on display, ranging from a MSRP of $700.00 to $2150.00.
  • Shure had a booth showcasing equipment by Stem, a company they recently acquired. Stem offers complete solutions for outfitting conference and meeting rooms with a range of mics, including tabletop, wall, and ceiling mounted ones, together with a hub and an integrated control system for managing the individual elements.
  • Smart was demoing its latest lineup of interactive displays
  • Legrand AV showcased a wide range of products focused on physical classroom infrastructure, including displays, display mounts, projectors, PTZ cameras, speakers, device controllers, and network switches. Legrand is a large company that owns Vaddio, Chief, Da-Lite, and Middle Atlantic Products.
  • Cleardigital featured its modular display wall called Vue featuring very smooth touch surfaces and replaceable panels as well as other products such as a PTZ cam, the RL400, a portable doc cam and an all-in-one conference camera.
  • Newline Interactive was featuring its newest interactive and non-interactive displays ranging from 27” to 98”
  • AVer gave a conference session demo-ing its new autotracking PTZ camera, the TR333V2. The TR333V2 offers:
    • 30x optical zoom
    • Sophisticated pre-set configuration, including the ability to move in and out of continuous tracking and fixed position mode based on how an instructor moves in the classroom
    • 4k
    • 3G-SDI, HDMI, IP, and USB output 
    • Full or half body tracking


The DDMC hosted Sennheiser’s Steve Wingo who spoke about two very interesting technologies that might serve our community.

Team Connect 2

The TeamConnect Ceiling 2, with its patented automatic dynamic beamforming technology, was already a leader in conference room audio technology. Now, with the addition of TruVoicelift and advanced zone control, TeamConnect Ceiling 2 combines the advantages of a boundary microphone and a microphone array. Therefore, it is the best solution for both (video) conferencing and in-room audio, for example in classrooms, lecture halls and boardrooms. TeamConnect Ceiling 2 now offers our customers unparalleled levels of control with the addition of a priority zone (allowing a single area in the room to be highlighted), 5 advanced exclusion zones (for pinpoint targeting and removal of unwanted noise sources) and more. All of these new features are activatable and configurable via the latest firmware update for the TeamConnect Ceiling 2 and via the latest version of Sennheiser Control Cockpit. Easy to install and, due to a flexible microphone ceiling mount system, easy to integrate. Let us help you understand the difference TeamConnect Ceiling 2 can make for you and your business.


MobileConnect consists of three main components: The MobileConnect Station is the “audio-to-network bridge” that picks up the audio signal in the room and streams it to any preferred streaming network. Using the pre-existing WiFi access points, the signal is provided to up to 100 smartphones per Station, using the MobileConnect App as a receiver. When using multiple Stations, the MobileConnect Manager can be used as the single point of administration for all MobileConnect Stations. If not needed, MobileConnect can also be operated in the so-called Standalone Mode, where single MobileConnect Stations can be run and administered using a local web interface.


Take a look at our Zoom Call for more information: https://duke.hosted.panopto.com/Panopto/Pages/Viewer.aspx?id=66a9a1eb-f4cc-498e-99ac-ae6100fed53c