Offices Acoustic Design Checklist

1) Project overview: what, where, who, and why

In Q1 of 2026, Sonus Gear Flow was asked to document the acoustic design process for a new corporate office build-out in Austin, Texas. The client, a 120-person software company, had leased the 7th floor of a refurbished concrete-and-glass building and wanted a space that felt open and collaborative without the usual acoustic penalties of open-plan layouts.

The scope included three primary zones:

• Open office: ~6,300 sq ft with 84 desks, exposed ceiling at 11.5 ft, polished concrete floor.
• Meeting suite: six rooms (2 small, 3 medium, 1 boardroom), plus two phone booths.
• Client-facing studio corner: a 300 sq ft “podcast/voice booth” for marketing content and remote webinars.

Stakeholders were clearly defined early. The client’s project manager controlled schedule and budget. IT owned AV standards (Teams/Zoom-first). HR owned comfort and privacy expectations. Sonus Gear Flow’s role was to design the acoustic strategy, specify treatments, align with MEP, and validate performance after installation.

The “why” was not abstract: the previous office had high turnover complaints about noise, and leadership tied productivity to fewer interruptions. The explicit success criteria were: reduce distraction in open seating, improve speech clarity in meeting rooms, and make the small recording area usable without a full studio build.

2) Challenges and requirements at the outset

The first site walk revealed the classic combination of acoustically hostile finishes and constrained mechanical design:

• Hard surfaces everywhere: concrete floor, exposed concrete deck, glass perimeter, minimal soft furnishings in the initial interior concept.
• Open ceiling with mechanical noise risk: VAV boxes and long duct runs; target background noise was uncertain.
• Privacy requirements: HR requested “no intelligible speech” at 12–15 ft from meeting room doors during sensitive discussions.
• AV performance requirements: Teams Rooms in four spaces, ceiling mic in the boardroom, and reliable far-end intelligibility.
• Schedule: 10 weeks from design sign-off to move-in, with only 3 weeks for procurement of specialty acoustic materials.
• Budget: initial acoustic line item capped at $78,000 including design, materials, and install labor.

Performance targets were agreed in measurable terms:

• Open office RT60: target 0.6–0.8 s (500 Hz–2 kHz), recognizing open ceilings rarely hit “studio” numbers.
• Meeting rooms RT60: target 0.4–0.6 s with tight midband control for speech.
• Noise floor: target NC 35 in open office, NC 30 in meeting rooms, NC 25–30 in the podcast corner.
• Speech privacy: target STI < 0.20 outside meeting rooms during normal speech inside (pragmatic “low intelligibility”).

Constraints were equally explicit: no full dropped ceiling in the open office (architectural requirement), and minimal reduction in glass frontage. That meant acoustic control had to come from a mix of ceiling clouds/baffles, wall panels, furniture absorption, and careful HVAC coordination.

3) Approach and methodology chosen

We used a three-layer approach: (1) control reverberation, (2) manage noise and masking, and (3) improve separation where privacy mattered. The workflow combined rapid predictive modeling with field measurements to keep decisions defensible under a tight timeline.

Tools and methods:

• Baseline measurements on the empty floor using a Class 2 SPL meter and calibrated measurement mic (Earthworks M23) with REW for quick RT and noise snapshots.
• Room acoustic modeling in a simplified 3D model to estimate absorption needed per zone (Sabine estimates for first pass, then refined based on layout).
• MEP coordination to confirm duct velocities, diffuser types, and VAV placement, since HVAC noise often becomes the unplanned “acoustic feature.”
• Post-install verification using impulse response measurements (sine sweep) and spot-checking NC via 1/3-octave readings.

The key decision was to treat the project like a repeatable checklist rather than a one-off creative effort. That kept scope creep under control and made it easier for the client PM to sequence trades.

4) Step-by-step execution narrative

Step 1 — Week 1: Baseline survey and “worst-case” reality check

The empty floor measured brutally live. A quick midband RT60 estimate in the open area came back around 1.4–1.7 s, with obvious flutter between glass and the concrete core wall. Ambient noise with HVAC running at partial commissioning was NC 40–42, with a distinct 250 Hz bump likely tied to duct resonance.

We documented three “must-fix” items immediately:

• Flutter echo on two long glass runs (audible hand-clap test confirmed it).
• Overly live boardroom shell (large glass wall + drywall + slab floor).
• HVAC tonal component around 250 Hz that would reduce perceived comfort even if average NC was acceptable.

Step 2 — Week 2: Translate goals into an acoustic quantities plan

We converted target RT values into absorption area requirements. Rather than chase perfect modeling, we used a conservative approach: assume lower real-world performance due to mounting height, partial coverage, and furniture variability.

The open office plan called for:

• Ceiling treatment: 72 clouds, 2" thick mineral wool core, 2' x 4' each, hung 12–18" below deck (approx. 576 sq ft face area, higher effective absorption due to air gap).
• Perimeter wall absorption: 30 panels, 2' x 6', 2" thick, placed to break glass-to-wall reflections.
• Soft zoning: carpet tiles only in the circulation spines and collaboration nooks (architectural compromise), plus fabric-wrapped dividers between desk clusters.

Meeting rooms received a more prescriptive template: one treated wall (40–60% coverage) plus ceiling clouds and a controlled reflective wall behind displays to keep the room from becoming too dead for natural speech.

Step 3 — Weeks 2–3: Coordinate with MEP before ordering anything

We held a focused session with the mechanical contractor and the commissioning agent. The aim was to stop HVAC noise from dictating the final experience. Two changes were negotiated:

• Diffuser selection: swap high-throw diffusers in meeting rooms for low-velocity perforated face diffusers.
• Duct lining: add lined duct sections (internal acoustic liner) upstream of the boardroom and podcast corner branches; keep velocities under 900 fpm where possible.

This was also where we protected future microphone performance: ceiling mic pickup patterns and HVAC air noise interact. Lower turbulence mattered as much as absolute SPL.

Step 4 — Weeks 3–5: Procurement and mock-ups

With lead times tight, we standardized the acoustic product set:

• Ceiling clouds: 2" mineral wool, NRC ~0.95, factory-wrapped in light gray fabric, wire-hung with adjustable cable grippers.
• Wall panels: 2" mineral wool, NRC ~1.00, mix of 24" x 72" and 24" x 48" to fit elevations.
• Door seals: perimeter gasketing + automatic door bottoms on three sensitive meeting rooms.

We installed a mock-up: four ceiling clouds over a 12-desk zone plus six wall panels on the nearest reflective surfaces. The subjective change was immediate, but we still verified with measurements: midband RT in that zone dropped from about 1.6 s to ~0.9 s even before furniture arrived. That gave the client confidence to proceed with the full order.

Step 5 — Weeks 5–8: Installation and on-site adjustments

Installation was sequenced to avoid conflict with lighting and sprinkler work. We issued a reflected ceiling plan that treated clouds as “no-fly zones” around diffusers, sprinkler throws, and lighting photometrics.

Two field adjustments were required:

• Lighting glare: a row of clouds near the glass caused unwanted reflections in afternoon sun. We rotated those clouds 90 degrees and shifted them 18" to align with lighting lines.
• Boardroom flutter: initial panel placement didn’t fully address a slap echo between the glass wall and the opposite painted drywall. We added four 2' x 6' panels on the drywall side at ear height.

Step 6 — Weeks 8–10: AV commissioning and acoustic verification

AV systems were commissioned after major furniture arrived (important: chairs, bodies, and soft goods change results). Equipment choices were practical and serviceable:

• Boardroom: Shure MXA920 ceiling array feeding a Q-SYS Core, with AEC tuned for Teams; two in-ceiling speakers for voice lift and far-end playback.
• Medium rooms: integrated Teams Room bars with table mics where needed; we avoided ceiling mics in the smaller rooms to reduce complexity.
• Podcast corner: a small treated nook with a heavy curtain track, dynamic mic options (Shure SM7B) plus a clean preamp/interface (Focusrite Scarlett 2i2 class), and a laptop-based recording chain.

Verification included RT60 checks in each room, spot NC readings, and a practical intelligibility test: two people speaking at normal levels inside the boardroom while a third stood outside the door and hallway intersection at ~15 ft. We documented what could be understood and adjusted seals accordingly.

5) Technical decisions and trade-offs made

Several choices were deliberate compromises rather than “perfect” acoustics:

• Open ceiling kept, clouds used instead: Dropped ceilings would have been more predictable acoustically, but the architectural requirement held. We traded uniform absorption for targeted ceiling coverage and placed clouds above primary noise-generating zones (collaboration tables, printer area, coffee point).
• Carpet limited to circulation: Full carpeting would have helped, but the client wanted concrete aesthetics and rolling-chair performance. The compromise was carpet tiles in the paths plus more ceiling absorption. Result: slightly higher low-mid reverberation than a fully carpeted office, but acceptable mid/high control for speech.
• Speech privacy via seals + masking, not heavier walls: Upgrading wall assemblies (e.g., double-stud, thicker drywall) would have blown the schedule and budget. We focused on door leakage control and introduced a low-level sound masking system in the open office perimeter near meeting rooms.
• Podcast corner is “good enough,” not a studio: Instead of building a room-within-a-room, we treated early reflections, managed HVAC noise, and used close-mic technique (dynamic mic) to minimize room pickup. The trade-off is reduced isolation from occasional office noise, but it meets marketing’s needs without construction overhead.

6) Results and outcomes with specific details

After furniture and occupancy, the measured outcomes were:

• Open office RT60: average 0.75 s at 1 kHz (ranging 0.68–0.82 s across zones). This was a substantial reduction from the ~1.6 s empty-shell baseline.
• Meeting rooms RT60: small rooms averaged 0.45–0.55 s; boardroom landed at 0.55 s after the extra wall panels.
• Noise criteria: open office stabilized around NC 36–38 during typical HVAC operation; meeting rooms were NC 30–32. The podcast corner measured NC 28–30 when the nearby VAV was at steady state.
• Speech privacy: outside the three sensitive rooms with upgraded seals, intelligibility dropped markedly. At ~15 ft in the corridor, speech was present but not reliably understandable, meeting the client’s pragmatic privacy definition.
• AV performance: far-end participants reported fewer “hollow room” complaints. In the boardroom, AEC convergence was stable, and we could run the ceiling array at lower gain because the room wasn’t feeding back reverberant energy.

On the operational side, HR reported a measurable drop in noise-related complaints during the first month of occupancy (tracked through internal helpdesk tags). The client PM also noted fewer last-minute AV changes, attributing it to “getting acoustics right before microphones went in.”

The final acoustic spend came in at $74,600 (design, materials, install), slightly under the cap due to standardization and avoiding custom-shaped clouds. Timeline: design sign-off at end of Week 2; all treatments installed by Week 8; verification and AV tuning completed by Week 10, aligned with move-in.

7) Lessons learned and what could be done differently

• MEP noise needs earlier leverage: We caught the 250 Hz issue early enough to mitigate, but not early enough to fully redesign duct paths. On the next project, we would request preliminary diffuser schedules before interior finishes are locked.
• Door performance is the weakest link: Walls can be rated well on paper, but a 1/8" gap under the door will erase it. The automatic door bottoms delivered outsized value relative to cost, and should have been specified for all meeting rooms, not just the “sensitive” ones.
• Mock-ups prevent opinion-driven changes: The small cloud-and-panel mock-up avoided a late pivot to “let’s just add more plants.” Plants have value, but they are not a substitute for predictable absorption.
• Podcast corner expectations must be written: Marketing initially assumed “studio quiet.” The solution worked because we defined it as a close-mic voice capture space with managed reflections, not as an isolation booth.

8) Takeaways applicable to other projects

Below is the checklist we now use as a baseline for office acoustic design. It reflects what actually mattered on this project.

1. Set numeric targets (RT60, NC, privacy criterion) before picking products. If the target can’t be stated, it can’t be verified.
2. Measure the shell early: quick RT and 1/3-octave noise measurements reveal whether the project is a “treatment” problem, an “HVAC” problem, or both.
3. Prioritize ceiling absorption in open plans: if the ceiling stays exposed, clouds and baffles become your primary lever. Use air gaps for better low-mid effectiveness.
4. Break up glass-to-hard-wall paths: flutter echo is common and easy to underestimate. Place panels at ear height on opposing surfaces, not randomly.
5. Coordinate with lighting, sprinklers, and diffusers: acoustic plans that ignore reflected ceiling constraints get value-engineered away in the field.
6. Design meeting rooms for speech first: target 0.4–0.6 s RT60, avoid fully reflective rooms, and don’t overdamp to the point that in-room talk feels unnatural.
7. Assume doors leak: add perimeter seals and automatic bottoms where privacy matters; don’t rely on wall ratings alone.
8. Handle HVAC noise as an audio system input: low turbulence and avoiding tonal artifacts often matter more than shaving 1–2 dB off broadband levels.
9. Specify AV with the room in mind: ceiling arrays and AEC perform dramatically better in controlled reverberation. Acoustics is an AV feature, not an interior decoration.
10. Verify after furniture arrives: final RT and noise readings should happen in near-real conditions, then be documented for future adjustments.

The core lesson: office acoustics succeeds when it’s treated like an engineered system—measurable targets, coordinated trades, and verification—rather than a late-stage aesthetic add-on. When that discipline is in place, even an exposed concrete-and-glass office can become a workable, intelligible environment for both humans and microphones.