May 29th 2025 – KTD Acoustics

The Basics of Acoustics for Architects: When and Why to Bring in an Acoustical Consultant

As an architect, you’re juggling aesthetics, structure, systems, and functionality. But there’s one crucial element that often gets overlooked until it causes problems: acoustics.

Sound is invisible, but its effects are unmistakably real—whether it’s the low thud of a neighbor’s footsteps in a condo, the echo in a cavernous boardroom, or the hum of mechanical equipment in a serene yoga studio. If you’ve ever had a client come back with noise complaints, you already know: acoustic design matters.

So, do you need to involve an acoustical consultant? Often, yes. Here’s when—and why—it’s smart to do it early.

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Why Timing Matters: Get Acoustics In Early

The short answer: the earlier, the better.

Involving an acoustical consultant during the planning or early design phases can prevent costly rework, construction delays, and post-occupancy complaints. Retrofitting for sound after construction is expensive and often less effective. Even more importantly, many building codes and standards include acoustical requirements that might not be obvious at first glance.

Bringing in a consultant early helps you:

• Ensure compliance with building codes, zoning requirements, or standards like LEED, WELL, GCworkplace, and ASHRAE

• Translate design intent into real-world acoustic performance

• Prevent surprises from mechanical systems, construction details, or site-specific noise
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Three Pillars of Architectural Acoustics

Let’s break down the three key aspects of acoustical design every architect should be aware of:

1. Sound Isolation

This is about keeping sound from traveling between spaces—or from outside to inside.

• In multi-residential, commercial, or mixed-use developments, this is one of the most common acoustical concerns. Whether it’s footsteps from upstairs, or conversation from next door, unwanted sound transmission is a frequent client complaint.

We quantify this using:

• STC (Sound Transmission Class): airborne sound between rooms (voices, TV, music)

• IIC (Impact Insulation Class): impact sound through floor/ceiling assemblies (footsteps, furniture movement)

• OITC (Outdoor-Indoor Transmission Class): low-frequency exterior noise, especially relevant for buildings near roads, rail lines, or airports

How well your building isolates sound depends heavily on:

• Wall and floor construction

• Glazing and window performance

• Details at junctions, penetrations, and doors

Example: A condo development near a rail corridor needs high OITC-rated glazing and well-detailed wall assemblies. If not addressed early, these become significant cost and performance issues during permitting or after complaints.

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2. Interior Acoustics

This is about how sound behaves within a space. It’s especially important in:

• Offices and meeting rooms – where speech intelligibility is key

• Restaurants and retail – where excessive reverberation hurts comfort and ambiance

• Special-purpose spaces like theaters, courtrooms, music studios, gyms, or classrooms – where the acoustics of the space significantly affects functionality

Key parameters include:

• RT60 (Reverberation Time): how long sound lingers in a space

• NRC (Noise Reduction Coefficient): how absorptive surfaces are (ceilings, panels, furnishings)
• NC (Noise Criteria): how much background noise is in a space

Getting this right improves usability, comfort, and performance. For example, an office with poor acoustics might meet code—but still fail its purpose.

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3. Mechanical Noise

Even the best-designed space can be ruined by the whine of an HVAC system or the rumble of mechanical equipment.

While much of the mechanical system design fall to the mechanical and electrical consultants, architecture plays a key role:

• Planning overall layouts early in design so that noise from mechanical rooms, plumbing chases, and HVAC equipment doesn’t affect noise-sensitive spaces. 
• Partition construction can minimize sound transfer, including floating floors and acoustic ceilings

• Details at penetrations and junctions can make or break acoustic performance

We typically design to NC (Noise Criteria) levels, as outlined in ASHRAE or project-specific requirements. The goal: ensure that the background noise level doesn’t interfere with comfort, communication, or productivity.

Fun fact: The WELL Building Standard recommends NC-35 or better for open offices—a level that can be difficult to reach without deliberate acoustic planning.

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How We Help

Acoustics is complex, but it doesn’t need to slow your project down. Our team helps you integrate acoustics seamlessly into your design process—without overcomplicating things.

Here’s how we support you:

• Clarify (and help determine) project requirements based on the building type, client needs, and applicable codes and standards.

• Work alongside you from concept design through construction and commissioning.

• Translate design goals into measurable targets—(A)STC, (A)IIC, RT60, NC, NRC, SAA, CAC etc.—that can be built and tested.

• Review construction drawings and details to ensure acoustic goals are met on site.

• Perform post-construction testing, verifying performance through field measurements.

And because we know it’s not always obvious when you need input, we offer a free consultation on every project—no strings attached. Whether it’s a new development, a renovation, or even a second opinion, we’re here to help you get it right the first time.

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Final Thought

Acoustic design is invisible, but its impact is undeniable. Get it right, and no one notices. Get it wrong, and it’s all they talk about. Whether it’s isolation, interior sound quality, or managing mechanical noise, the earlier you bring in an acoustical consultant, the smoother—and quieter—your project will be.

Have questions or a project in mind? Reach out—we’re happy to help.