The problem with ceiling array mics

Edited on: March 1, 2024

In response to a growing demand for hybrid learning, higher education institutions are upgrading their learning spaces to accommodate both in-person and online participants. A challenge for hybrid setups is connecting the two student audiences – ensuring the students at home can hear their peers in class and vice versa. 

Accordingly, going hybrid requires universities to enhance their existing remote learning setups with microphones to capture in-class student questions, comments, and discussions for the benefit of remote attendees. 

Unfortunately, finding the best audio solution for lecture halls has proven to be difficult. 

There are by and large three solutions – giving each student a microphone, passing a handheld around, or using stationary ceiling/array mics to capture audio across the entire classroom. For most institutions, the first is too expensive and the second too disruptive, which leaves them with option three – array microphones. Many universities have come to find out that this solution, too, is less than ideal. 

Let's take a look at what ceiling array microphones are and what their appeal is, why they're not suitable for lecture halls, and what the secret fourth option is that institutions go with after being disillusioned with voice array microphones. 

What are ceiling array microphones?

Array microphones are just that – an array of microphones. These systems often use multiple mics, either within a single casing or in multiple locations around the room, in order to localize sound sources and focus on the speaker in the room. 

There are two types of array microphones:

-Static, beam-forming – in these solutions, the microphones are immobile, pointed in specific directions forming beams within which audio is captured. 

-Dynamic, beam-tracking – the microphones, powered by advanced algorithms, move to focus on the speaker and allow for various setups and configurations, including priority and exclusion zones. 

Typically mounted on the ceiling or wall, these solutions are attractive in that they remove the need for cables or space on desks. Whilst not technically a wireless microphone system, they offer the ability for speakers to move around the room freely without needing to worry about their proximity to the microphone. 

The appeal of beam-tracking array mics for lecture halls is clear – they're unintrusive and focus on the speaker, giving the opportunity to capture in-class student discussions in high quality. At least, in theory. 

3 reasons why ceiling/array microphones fail in lecture halls

In theory, array mics seem to be the key to enabling truly hybrid learning spaces. In practice, however, there are shortcomings that have proved critical enough for universities to seek alternatives. 

Here are 3 reasons why you should think twice about investing in array mics for lecture halls.

1. Sound quality is not ideal in lecture halls

Being mounted on the wall or the ceiling, the microphones are not close to the source of sound. While the audio capture beam might focus on a speaker, the distance between them results in any noise along or adjacent to the beam to also be captured. Open windows, student chit-chat, air conditioners, and more – disruptive background noise is all but inevitable. 

Further troubles surface during heated debates, as the audio can get messy when many students talk at once. With the beamforming array microphone struggling to isolate audio from a single speaker, remote students find themselves on the receiving end of a cacophony of noise. 

These issues can certainly be minimized through considerate discussion protocols and soundproofing the lecture hall, however, the latter would add to an already hefty price tag.

2. Array mics are expensive and complicated

As far as beamforming microphone price is concerned, a single mounted unit can cost upwards of $4k before installation, with larger spaces requiring several units for comprehensive coverage. Additionally, the installation will require external technical expertise, and the same goes for future maintenance.

This complexity means any technical hiccups are especially disruptive – lecturers need the AV department's assistance to sort them out, leaving remote students disconnected until a fix is found. Major, critical issues can lead to extended downtime. 

3. Designed for meeting rooms, not large classroms

The magic of array microphones is best put to use in smaller spaces such as meeting rooms, where short distances and little-to-no interference ensure optimal performance. 

Longer mic-to-speaker distances common to grand lecture halls lead to the aforementioned sound quality issues. Spaces near roads, unless soundproofed, are also unsuitable due to sound pollution. Moreover, ceiling mount microphones require existing technical infrastructure that might not be available in older buildings, and installing new wiring is not a step to be taken lightly, particularly in auditoriums with historical value. 

The issue is multiplied if a university has several such halls – since these ceiling microphone systems cannot be easily moved from one room to the next, a complete suite must be installed in every space used for hybrid learning. 

A different way of doing things: Catchbox Plus

The points above have been compiled from discussions we, at Catchbox, have had with various institutions that sought alternatives for hybrid classroom audio after either growing disillusioned with array mics or realizing the true scale of investment they require. 

Many of these are now deploying Catchbox Plus systems instead. If you recall the three options presented at the start of the article – giving each student a microphone, passing a handheld around, or using stationary ceiling/array mics – then Catchbox is an enhanced version of the second. 

A plug-and-play wireless microphone, encased in a soft, anti-microbial cover, the Catchbox succeeds where array mics fail: 

-It works everywhere – placed directly in front of whoever's speaking, it captures what's being said in premium quality whether they're in a small classroom or a giant lecture hall

-It's affordable and flexible – with the full Catchbox Plus system, you can capture perfect audio without it costing you an arm and a leg

-It's simple and flexible – install it by simply plugging it into a USB port, take it with you, and move it between learning spaces 

Audio for hybrid spaces doesn't have to be complicated. 

Conclusion

While ceiling array mics are brilliant systems that shine in certain use cases, student audio capture in lecture halls might not be one of them. Perhaps, as the technology is refined, this will change. But, for now, we invite universities to be careful before committing significant investments into technology that might seem like the only option.

The reality is – there are alternatives.