Crosstalk: Reducing Sound Leaks into Adjacent Rooms

by Nate Purscelley

Projectus CTO, Doug O’Brien and I were chatting this morning about a common issue that comes up with our clients. Sound privacy. Specifically, crosstalk of sound leaking between offices and conference rooms. The subject gets overlooked early on in the process. The floorplan gets laid out by the architects. The contractors come in and build beautiful spaces. The lighting, flooring and aesthetics are world-class. Unfortunately once the final bill has been paid, the office fills up, and it becomes obvious that sound privacy was not prioritized enough. Noise complaints start coming in. Contractors and specialists are brought back in to mitigate, but they can only do so much once the walls are up. Doug and I decided to come up with a few tips to consider early on.

First, we should mention the easiest solution: hire the amazing unified communications company, Projectus as your acoustic consultant during the planning stage. That said, we’ll assume you’re looking for advice because you may be further down the road on your project.

Let’s first discuss the difference between soundproofing and acoustic treatment. Soundproofing is reducing the crosstalk between spaces. In other words, it lessens the amount of sound leaking from one room to another. Acoustic treatment is done to make the sound within a room more pleasing – or less problematic. Acoustic treatment and dampening don’t do much to prevent crosstalk, and soundproofing does almost nothing to improve room acoustics.

Soundproofing is very important for privacy-centric applications. Legal, medical, and manufacturing are examples of industries with extra needs in reducing crosstalk between spaces. But anyone who has tried to work adjacent a noisy, non-soundproofed room will tell you: it can be very distracting. It can interfere with Zoom meetings, phone calls, and general concentration.

Acoustic treatment is most important in a room where microphones and speakers are used. Video and audio conferencing exposes echoey and poor-sounding rooms. Far side participants might have trouble communicating when the audio equipment can’t properly cancel out unwanted sound due to extra room reverberance. Aside from A/V equipment, good acoustics can also benefit those of us with less-than-perfect hearing, and thus improve worker productivity.

So what can you do to reduce this crosstalk? Firstly, seal up the gaps. Maybe caulk on a window. Maybe install a door sweep. Maybe patch a hole in the drywall. Sound can leak through surprisingly small spaces, and anything you can do to seal those spaces helps reduce sound transmission. Secondly, insulation. If you have drop ceilings, you can install insulation above the tiles. The increased mass will help absorb some of the rogue soundwaves trying to leave the space. If you have the option, extra insulation in the walls will help immensely. Thirdly, an option that doesn’t necessarily block crosstalk, but rather distracts our brains so the offensive sound isn’t as noticeable: sound masking systems.

In simplified terms, sound masking systems emit white noise throughout spaces, reducing the intelligibility of outside sound sources. Systems like Biamp’s Cambridge line consist of small speakers, or ’emitters’ spaced around 8-12 feet apart, and distributed throughout a room.