Continuous sound is not just heard — it accumulates. Sustained acoustic input builds as autonomic load even when the conscious mind has stopped noticing, and for autistic, AuDHD, and APD listeners the rate runs faster than the AS/NZS standards were written against. This module gives you the three highest-leverage Reversible moves to drop avoidable acoustic load at the room and at the listener, then routes you into the Bedroom Design Guide for the full tier ladder.
This module covers the acoustic environment — background noise levels, reverberation, transmission between rooms, signal-to-noise at the listening position, and the personal-scale tools that change the envelope at the ear when the room cannot. These are the variables that determine how much of your nervous system is busy managing sound rather than thinking, sleeping, working, or resting.
You'll finish with three Reversible-tier moves to install in your space this week, a numerical reference for the targets each move works toward, and a clear route into the Bedroom Design Guide for the bedroom-specific Reversible + Semi-Permanent + Permanent ladder. Architectural-scale and trade-led acoustic moves (party-wall decoupling, HVAC duct treatment, secondary glazing) live in the relevant room design guide or, for workplaces, in the Workplace Design Guide.
The AS/NZS 2107 acoustic envelope is the AU/NZ design standard for background noise and reverberation across residential, educational, and commercial spaces — it works well for general occupancy. For autistic, AuDHD, and APD occupants the standard's general-population baseline runs too loose: the P50 cortical-gating mechanism that backgrounds repeated sounds for neurotypical processing is significantly reduced, so background noise that costs a neurotypical occupant little after the first minute continues to cost the autistic occupant on the same per-event basis for the duration of exposure. The Sensori envelope sits at or under the bottom of the AS/NZS 2107 recommended ranges. That is a Sensori design judgement, and the standard's own text is what makes it defensible: AS/NZS 2107:2016 states that where acoustic performance is critical a specialist acoustic design is required — giving spaces for students with learning difficulties as its example — and places that design beyond its own scope. It defers this population rather than covering it.
Sensori's quiz reads auditory processing on Dunn's four-quadrant model — Sensitivity, Avoiding, Seeking, and Low Registration, the four cards below. Where those quadrants don't resolve to a single lead, the results screen reports one of two composite states instead: Managing (you register strongly and actively compensate — Sensitivity and Avoiding at once) or Variable (three or more quadrants elevated, no dominant pattern). Your results label names the lead pattern, so read the matching card first: a Managing result means read Sensitivity and Avoiding together; a Variable result means several quadrants are live at once, so work the Sensitivity and Avoiding moves first and add the Seeking note and the Low Registration callout where they fit. Understanding your pattern tells you which acoustic moves to prioritise and which to skip — and which moves risk costing more than they save for the profile you actually have.
You notice and are affected by sound others don't register — HVAC drone, conversation through walls, the kettle clicking, the next room's TV, lighting-transformer whine — and you process all of it silently. From outside you read as unbothered or "fine". From inside the cumulative acoustic load builds across the day with no relief valve, often presenting as late-day fatigue, headache, or sleep difficulty. The priority is reducing the input at the source: reverberation reduction at the room, transmission control at the door, and signal-to-noise raise at the listener.
You actively manage your acoustic environment — wearing ANC headphones on the bus, closing doors at predictable times, taking the quieter commute, requesting the corner seat in restaurants, leaving acoustically loud events earlier than other people. You're already doing the work. These interventions are the structural versions of what you're doing manually — give yourself permanent control rather than relying on workarounds every day.
You need auditory input to regulate — specific music, podcasts, controlled soundscapes, the radio at a certain volume to focus. Silent rooms feel flat or hard to settle into. Your interventions are about intentional, controlled auditory input rather than reduction: permission to wear headphones with audio content, predictable background soundscapes you choose, and acoustic separation between your input and other occupants — not forced silence.
You miss auditory cues — someone calling your name from another room, the kettle whistle, the timer, the doorbell, verbal instructions in a noisy room. The risk is functional: missed information, navigation, safety. Priority interventions are salient and paired cues — visible kettle indicators, vibration-alert timers, light-and-sound paired doorbells — that make the auditory environment more legible rather than only quieter.
Most people present with a mix across modalities — auditory Sensitivity in some contexts, auditory Seeking in others, and a third profile in the visual or proprioceptive channel. The interventions in Section 04 address Sensitivity and Avoiding primarily because the Reversible-tier acoustic moves that benefit those profiles are the highest-leverage at that tier. Seeking-profile considerations appear within the third card (ANC headphones with predictable soundscape pairing). Low Registration is addressed in a dedicated callout at the end of Section 04 — including the safety-critical case, where the very moves this module recommends (sealing the door, wearing noise-cancelling headphones) can close the channel a smoke or emergency alarm reaches you through.
If you did not take the quiz, this module is useful if you regularly find yourself unable to sleep through normal household sound, struggling to concentrate in workplaces with background conversation, wearing headphones for daily regulation, leaving acoustically loud spaces earlier than other people, or finding that the room reads as quiet to everyone else and yet costs you visibly across the day.
Auditory profile is modality-specific — being auditorily Sensitive does not predict visual or proprioceptive profile. The Visual Environment Module (Mo.01) covers the visual channel; the Thermal & Air Quality Module (Mo.03) covers thermal and ventilation. Combined profiles route via the quiz to the recommended sequence.
If you have an APD or listening-difficulty pattern. Sensori treats APD as a design constraint, not a diagnostic category — the three Reversible moves in Section 04 work regardless of diagnostic label, with one important contraindication on broadband masking for speech-comprehension surfaces. Section 03 carries the construct framing, the discipline-state and scope-of-practice boundary, and the referral pathway.
If your load is misophonia — specific trigger sounds. Misophonia is a strong, involuntary aversive response to particular sounds (chewing, breathing, tapping, a repeated click) rather than a general sensitivity to level. Sensori treats it, like APD, as a design constraint rather than a diagnostic category. The reduction moves in Section 04 help — sealing the transmission path that carries the trigger, and the personal-scale envelope that removes it — but the masking contraindication inverts for misophonia: low-level broadband or nature masking that covers the trigger sound is an aid here, not a hazard, because there is no speech-comprehension cost when the problem is the trigger itself. Read the masking caution in Section 04 as APD-specific — "not for you" if misophonia, not APD, is your pattern.
The recommendations in this module are grounded in AS/NZS 2107:2016 (the AU/NZ acoustic envelope spec), PAS 6463:2022 (BSI — Design for the Mind, the most authoritative published framework for sensory-environment design), and the autistic-auditory-processing research base at [SPR-01 §06d]. APD construct framing follows the BSA APD SIG 2018 Position Statement (the British Society of Audiology's expert group on the APD construct). The hybrid-work acoustic-privacy evidence is anchored at Gocer et al. 2025 — a large-N (n=5,644) AU workplace post-occupancy evaluation (POE) — whose load-bearing finding is that Privacy and Disruption (noise, interruptions, lack of visual privacy) is now the single strongest predictor of perceived productivity and self-rated health. The POE measures workplaces; the read-across — that the hybrid-work residential bedroom is now a load-bearing daytime acoustic surface, not only a sleep surface — is Sensori's extension of the same privacy-and-disruption logic to the home, not a finding of the paper.
Sound is not just heard; it accumulates. Sustained acoustic input — even background noise the conscious mind has stopped noticing — builds as allostatic load (the cumulative cost of repeated physiological adaptation) through sub-clinical autonomic activation that does not switch off when attention does. For autistic, AuDHD, and chronic-sleep presentations the accumulation rate is faster than the acoustic standards were authored against. Reducing avoidable acoustic load at the home envelope is Sensori's load-bearing acoustic move because the cost saved is cumulative and the change is durable.
Acoustic input enters the central nervous system continuously while the ear is open, regardless of attentional focus. Each event — a sustained HVAC drone, a sudden door slam, a distant conversation through a wall — carries a processing cost that the conscious mind does not register but the body still meets. Over hours and days these unremarked costs accumulate as allostatic load — McEwen's framing of the cumulative cost of repeated physiological adaptation, measurable across cardiovascular, metabolic, immune, and neuroendocrine markers. The load-bearing claim is the accumulation, not any single per-event autonomic signature — see the position note below.
For neurotypical processing, the P50 auditory gating mechanism (the brain's filter for repeated sounds) suppresses cortical response to repeated sounds within minutes — the brain backgrounds the predictable, paying less load over time. In autism (and to a lesser extent ADHD and AuDHD) the P50 gating response is significantly reduced: the autistic auditory cortex does not habitually background persistent sounds. Background noise that costs a neurotypical occupant little after the first minute continues to cost the autistic occupant on the same per-event basis for the duration of exposure. The hyperresponsivity (over-response to sensory input) prevalence of ~70% in the autistic population is the reason this mechanism is not a minority-accommodation framing but a load-bearing baseline across Sensori's audience.
What cumulative acoustic load feels like in practice. Picture an open-plan office at 50 dB(A) HVAC background. After the first 30 minutes a neurotypical colleague's brain has backgrounded the drone — they pay minimal attentional cost for the rest of the day. The autistic or AuDHD listener at the next desk doesn't get that handover; their auditory cortex processes the drone at full per-event cost from 9 a.m. to 5 p.m. By 3 p.m. the room reads as quiet to everyone, but the autistic listener has accumulated load the neurotypical brain offloaded automatically. The late-afternoon fatigue, the longer weekend recovery, the inability to switch off after work — these are the downstream signals of an envelope the room never asked you to consciously notice. Reducing the envelope at the source costs nothing to maintain once installed; the body stops paying.
The design move follows from the mechanism: reduce avoidable acoustic load at the envelope, not only at the moment of conscious distress. Reverberation reduction at the room envelope is the highest-leverage cumulative-cost move because reverberation time is a continuous multiplier on every sound event. Transmission control attenuates the unpredictable-event class of load — the sudden events the body cannot anticipate, which carry the highest per-event cost. Personal-scale acoustic substitution — over-ear ANC headphones — covers the cumulative-load reduction when the room cannot reach the target. The combined three-card stack at Section 04 is the Reversible-tier acoustic delivery of this framing.
Sensori position. The cumulative-cost framing holds regardless of how the polyvagal-mechanism debate around autonomic-state regulation resolves at the discipline-body level. Sensori commits to acoustic-load reduction as a design heuristic — design moves yes, mechanism claims at the polyvagal-specific vagal-tone level no. The McEwen allostatic-load framing is replicated and load-bearing across cardiovascular, neuroendocrine, and cognitive outcome literatures; the design move is robust either way.
Two channel-specific mechanisms operationalise this cumulative cost in rooms people actually occupy: reverberation as the load multiplier, and signal-to-noise as the speech-comprehension mechanism. Both follow.
Sound energy radiates from a source into a room and then bounces off every reflective surface — walls, ceiling, glass, hard flooring — until the reflected energy is absorbed or escapes. The decay rate is the reverberation time RT₆₀ (the time for the sound pressure level to fall by 60 dB after the source stops). A bedroom with hard floors, glass, and minimal soft furnishings runs at RT₆₀ ≈ 0.6–1.0 s; with carpet, curtains, upholstered seating, and a soft bed surface the same room runs at 0.3–0.5 s.
The mechanism at the reduced-gating profile is that each sound event leaves a tail; while the tail is still audible the next event arrives, and the two overlap in the cortical processing stream. Neurotypical processing backgrounds the tail via P50 gating within minutes; the autistic auditory cortex does not. So the tail of the previous HVAC pulse is still cortically present when the next syllable of speech arrives, smearing the temporal envelope the brain depends on for speech segmentation. The same applies to background-music tails masking conversation, conversation tails masking thought, and HVAC tails raising the noise floor the next signal has to clear.
Three consequences follow. Speech intelligibility falls off faster with reverberation than with raw noise level for APD-pattern and autistic listeners — the room can be quiet by dB(A) measure and still cost speech comprehension if the tail is long. The same room reads differently across occupants — a reverberant room occupied by neurotypical listeners reports as "lively" or "warm"; the same room occupied by autistic or APD listeners reports as "overwhelming". The mechanism predicts the difference; the room hasn't changed. Soft-furnishings intervention produces disproportionate perceived improvement at the same dB(A) noise floor — the dominant change is in the decay rate, not the level, but the cumulative-cost reduction is what the occupant feels.
The RT₆₀ reduction is the load-bearing room-acoustics move. The Sensori residential bedroom target is RT ≤ 0.4 s — a Sensori figure, not one read off AS/NZS 2107, whose residential rows carry no verifiable reverberation time. Reversible-tier delivery at the residential bedroom is the soft-furnishings card: rugs over hard flooring, heavy curtains over windows, upholstered headboard, soft bedding surface area, fabric artwork in place of glass. Each adds absorption; together they routinely move a bedroom from 0.7 s to 0.4 s without any installed acoustic treatment. Semi-Permanent and Permanent moves (acoustic panels, ceiling clouds, secondary glazing) route to the relevant room Design Guide; the architectural-scale residual (party-wall transmission loss; plant-room location; HVAC-velocity selection) sits at [ARR-01 §7] and is upstream of the room-side moves.
Sensori position. RT ≤ 0.4 s at the residential bedroom is a Sensori design heuristic, anchored against PAS 6463:2022's ND-aware framing and offered as the specialist design AS/NZS 2107 defers to for acoustically critical spaces. It is stated as a Sensori figure rather than as a reading of the AU/NZ standard, whose residential rows carry no reverberation value we can verify.
Hearing speech is not the same as hearing volume. The brain segregates a target signal (the voice you want) from background noise (HVAC drone, neighbour conversation, the next room's music) on the basis of signal-to-noise ratio (SNR), not raw loudness. For typical-population speech comprehension, SNR ≥ +15 dB is the conventional fully-intelligible threshold; for APD, autism, and the combined-profile presentations Sensori serves, the required SNR is typically +20 to +25 dB at the listener position — a 5–10 dB more-demanding standard than the AS/NZS 2107 spec table targets for general occupancy. The mechanism is auditory scene analysis — the central process by which the brain separates multiple simultaneous sound streams. For autistic auditory processing the segregation is more effortful even at normal pure-tone hearing thresholds; this is a central processing difference, not hearing loss.
What +20–25 dB SNR feels like at the dinner table. If the room is at 45 dB(A) background noise (typical conversation level with a dishwasher running two rooms away), a neurotypical listener follows speech comfortably when the speaker reaches 60 dB(A) — a +15 dB SNR. An APD-pattern or autistic listener following the same conversation needs the speaker at 65–70 dB(A), or the background to drop to ~40 dB(A). Without one or the other, comprehension does not fail dramatically — it degrades silently on a per-syllable basis, and the listener pays continuous cognitive load filling gaps that never resolve. By dinner's end the listener is exhausted and doesn't always know why. The +20–25 dB SNR target is the design move that closes that gap before it accumulates.
Three room-scale variables drive SNR at the listener. Source level at the listener — controlled by distance from the source (sound pressure level drops ~6 dB per doubling of distance in free field, ~3 dB in reverberant interiors) and by source elimination. Background noise level — the sum of all other sources reaching the listener position via direct path, room reflections, and transmission through envelope. Reverberation — which raises the effective noise floor by adding the previous-event tail to the current-event background. The Lombard effect compounds: speakers automatically raise their voice in noisy environments, raising the background noise for every other listener — a positive feedback loop that residential and workplace acoustic design exists to arrest.
Three observables follow. Room distance matters more than room level for SNR — a neighbour's TV three rooms away matters less than a hallway conversation two metres away even if the room-level reading is identical. Masking improves comfort but degrades comprehension — broad-spectrum masking (brown, pink, white noise) can improve perceived comfort for Sensitivity and Avoiding profiles by background-out specific peaks, but it raises the noise floor the target signal has to clear, so it degrades speech comprehension at the same per-listener cost. For APD this is contraindicated as a first-line acoustic recommendation. Personal-scale substitution covers what the room cannot — when the room envelope cannot reach the background-noise target, active noise cancellation at the personal scale delivers the SNR raise the room cannot.
Four design moves follow the mechanism. Source elimination first — the cheapest SNR raise is the avoidable source removed (decorative noise; plug-in speakers; unnecessary appliance run-time). Transmission control second — the door-seal, the heavy curtain over a glazed wall, the upgraded threshold seal. Distance and orientation — at the room scale, locating speech-significant activity away from sources, orienting listener positions to favour direct-path SNR over reverberant-path SNR. Personal-scale substitution — ANC headphones for the occupant when the room cannot reach target, with the construct-aware framing that for some Avoiding profiles the headphones are the primary intervention, not the fallback. The Section 04 three-card stack — soft furnishings, door seal, ANC headphones — is the Reversible-tier delivery of the room-side and personal-side SNR strategy.
Sensori position. Broadband masking is not a first-line acoustic recommendation in Sensori's intervention pyramid. The SNR-degradation cost it pays and the APD contraindication it carries make subtraction, transmission-control, and personal-scale substitution the higher-leverage moves at the channel-module register. Masking remains a library citizen for the profiles and presentations it serves — misophonia, where masking covers the trigger sound and carries no speech-comprehension cost, is the clearest case — but it does not occupy a top-3 Section 04 slot.
Before the numerical targets, one note on the construct framing that governs how the auditory channel reads here.
Auditory Processing Disorder is recognised by some clinical and educational bodies, contested in the broader audiology and developmental-disorders literature, and load-bearing for the acoustic design surface regardless of how the construct debate resolves. Sensori uses APD as a design constraint for acoustic environments — where the listening-difficulty pattern is present, the design moves are the same — and does not assert diagnostic standing.
Sensori position. Sensori uses APD as a design constraint for acoustic environments and integrates APD-aware framing into Section 02 (mixed-profile content) and Section 03 (mechanism and Sensori-defaults panels). Sensori does not assert diagnostic standing for APD, does not screen for APD in any clinical sense, and does not claim APD is empirically settled. The listening-difficulty pattern is treated as an actionable design constraint independent of the diagnostic-category debate: where the pattern is present — whether labelled APD, (C)APD (Central Auditory Processing Disorder), LiD (listening difficulties), the speech-in-noise component of autistic auditory processing, the attentional-gating component of ADHD auditory processing, the post-concussion auditory-processing pattern, or unnamed — the design moves are the same.
Discipline state. The APD construct, originally framed by the American clinical-audiology position in the mid-2000s as a deficit in the neural processing of auditory information not attributable to peripheral hearing loss, has been substantively critiqued in the post-2010 audiology and developmental-disorders literature — the central critique being that the construct overlaps with ADHD, language disorder, dyslexia, and autism at rates the available diagnostic-test battery cannot disentangle. Children diagnosed with APD typically also meet criteria for one or more of these conditions, raising the question whether APD is a distinct neural-processing disorder or a heterogeneous symptom cluster. The British Society of Audiology APD SIG 2018 Position Statement is the canonical reframing in the UK — APD as a label describing listening difficulties of various aetiologies rather than a discrete clinical entity, retaining the clinical reality of the listening-difficulty pattern while signalling that the discrete-condition framing is not currently supportable. The contemporary trend through the 2020s is toward the listening difficulties reframing — which retains the design-relevant population while acknowledging the construct-category limit.
Scope of practice. Sensori operates inside the environmental-design scope, not the clinical-assessment scope. What Sensori does for the listening-difficulty pattern: specify the acoustic envelope (reverberation, background noise, transmission, source location) per the Sensori-defaults panel; specify the design-tier intervention card set (the three-card stack: soft furnishings, door seal, ANC headphones); name the masking contraindication on speech-comprehension surfaces; route to qualified audiology or speech-language pathology assessment where the customer asks. What Sensori does not do: assess for APD clinically, recommend specific therapy protocols (auditory training, FM-systems clinical prescription, listening-and-spelling interventions), or claim acoustic intervention will treat APD. The acoustic intervention reduces the acoustic load the listening-difficulty pattern carries; it does not change the underlying neural processing.
Referral implications. Customer presentation indicating possible APD or listening difficulty routes to qualified audiology assessment (Audiology Australia practitioner register) for peripheral-hearing-threshold clearance and the auditory-processing-test battery; or to speech-language pathology assessment (Speech Pathology Australia practitioner register) where the receptive-language-and-comprehension component is prominent. Paediatric audiology or SLP services are appropriate for child presentations where developmental-disorders co-occurrence is in question; otolaryngology / ENT clearance is appropriate where conductive or sensorineural hearing loss requires clearance first. Sensori does not refer to specific diagnostic-test-battery vendors and does not endorse specific assessment protocols — the construct's contested standing means any single protocol's positive predictive value is uncertain. The referral is to a qualified clinician, not to a specific test.
The numerical targets the mechanisms above and the construct framing here all converge on follow next.
The specifications below are Sensori's defaults for ND-relevant residential and workplace acoustic environments. They sit at or under the bottom of the AS/NZS 2107:2016 recommended range for each space type, on the basis that auditory processing for the audience this module serves accumulates cost faster than the standard's general-population baseline assumes. They are Sensori figures, not the standard's recommendations — and the standard supports being given figures of this kind, since it puts acoustically critical spaces outside its own scope and calls for specialist design. One consequence belongs in any brief that quotes them: the reason AS/NZS 2107 sets a lower end to its ranges at all is that background sound masks intermittent intrusions, so a room taken to the bottom of the range has less masking, and the intrusions have to be handled at the envelope and by layout instead.
Reading the abbreviations: dB(A) is decibels A-weighted — sound level adjusted to match how the ear actually responds across frequencies. LAeq is the time-averaged version — the average dB(A) over a stated period, used for steady-state background noise targets. RT₆₀ is reverberation time — how long sound takes to fall by 60 dB after the source stops; lower is less echoey. STC and Rw+Ctr are sound-isolation ratings — how much sound a wall, floor, or door stops; Rw+Ctr is the AU/NZ rating that includes a correction for low-frequency traffic noise.
The reverberation defaults target the speech-intelligibility and startle-recovery pairing the auditory channel is most load-sensitive to for ND occupants — RT₆₀ 0.4 s shortens decay trails enough that successive sound events resolve rather than overlapping, which matters more for reduced-sensory-gating profiles than the AS/NZS standard's general-population target reflects. The background-noise defaults sit at or under the bottom of the AS/NZS 2107:2016 recommended range and are Sensori figures. Two properties of the standard's own numbers are worth knowing when you verify against them: they are background levels for a room unoccupied but ready for occupancy — measured empty with the services running, not during use — and they describe steady-state sound, not passing traffic, trains or aircraft. The party-wall NCC F5 Rw+Ctr ≥ 50 dB target is the AU residential floor for new construction — the Sensori position is that ≥ 50 dB is the floor not the design target, and projects should design for 53–55 dB where the envelope allows. The ventilation default acknowledges that mechanical-ventilation background noise is the dominant residual after envelope decisions are made, and that hybrid-work residential bedrooms are now load-bearing daytime acoustic surfaces — Sensori's read-across from the Gocer et al. 2025 workplace privacy-and-disruption finding to the home office and bedroom, not a direct finding of that POE.
These specifications are Sensori's canonical defaults across modules, design guides, and B2B audit deliverables. Updates propagate from a single internal register, so every Sensori product carries the same numerical thresholds and the same underwriting-standard anchors.
Where evidence quality for a specific claim runs lower — for example, the residential-bedroom RT₆₀ target is extrapolated from classroom-acoustics literature where empirical density is highest; the +20 to +25 dB SNR target for APD presentation shifts the population baseline rather than predicting the individual case — this is noted within the relevant mechanism. The design moves themselves remain robust: tightening reverberation, controlling transmission, and raising signal-to-noise at the listener (via room moves and personal-scale substitution) each address a different failure mode and none depend on the precise calibration of the others.
The three highest-leverage Reversible-tier moves on the auditory channel. No fixings, no trades, no permission required — accessible to renters with no end-of-lease cost. A reader who acts on these three has received the largest acoustic-load reduction the Reversible tier can deliver. Semi-Permanent and Permanent moves (acoustic wall panels, ceiling clouds, secondary glazing, decoupled plasterboard, mass-loaded vinyl on shared walls) live in the relevant room Design Guide; Fitout-scale moves for workplaces (HVAC duct attenuators, full-room acoustic ceiling tiles, decoupled wall systems) live in the Workplace Design Guide; architectural-scale acoustic limits (party-wall transmission loss, plenum and riser paths, plant-room location) sit upstream at [ARR-01 §7].
These three carry the highest cost-to-impact ratio of anything on the auditory channel at this tier. Each addresses a different failure mode — reverberation at the room, transmission at the door, and signal-to-noise at the listener. Read the Bedroom Design Guide for the bedroom-specific Reversible + Semi-Permanent + Permanent ladder; the forthcoming Workplace Design Guide extends the same depth to office and meeting-room scale.
Some of the product links in the cards below are affiliate links — Sensori Design earns a small commission at no cost to you. All recommended products are selected on merit against the evidence criteria in this module, not on the commercial relationship.
Hard surfaces extend how long each sound lingers in the room — soft furnishings shorten this, so sound events resolve rather than overlapping and accumulating for a brain that doesn't filter them efficiently. Prioritise this in hard-surfaced rooms (timber or tile floor, bare walls) where sound rings. Less load-bearing in an already carpeted, curtained, well-furnished room.
A well-furnished bedroom reaches the RT₆₀ ≤ 0.4 s target versus 0.6–1.0 s in an empty hard-surfaced room — sound events resolve faster and do not overlap, and the cumulative acoustic load is significantly reduced. For profiles with reduced sensory gating, reverberant rooms double the acoustic load because every sound event is followed by a decay trail that continues registering rather than backgrounding.
Sound travels through any air gap with almost no attenuation — a standard door undercut transmits noise nearly as effectively as an open doorway of the same area. A door rated STC 32 performs at ~STC 12 with a 5 mm undercut because the gap bypasses the door mass entirely. Prioritise this if internal household noise (a hallway, a living area, other occupants) reaches the bedroom. Less load-bearing where the dominant noise is external and enters through the window.
Perimeter compression seals reduce high-frequency leakage; the threshold drop-seal adds low-to-mid frequency benefit that perimeter sealing alone cannot. The published sleep-hours target is ≤ 30 dB(A); the door seal contributes 6–10 dB toward that envelope — but acoustic paths sum, so the final result is bounded by the next-largest leak (window, party wall, ceiling). Sealing the loudest path first is where the budget moves.
When the room cannot be changed — renter, shared or open-plan, party-wall transmission, continuous traffic or HVAC drone — the highest-leverage Reversible move is to change the acoustic envelope at the listener rather than at the room. Over-ear active noise-cancelling headphones (ANC) carry a typical 20–30 dB low-mid attenuation that earplugs cannot match and that no soft-furnishings programme reaches at continuous low frequencies.
Auditory hyperresponsivity is documented in approximately 70% of autistic individuals across meta-analyses; in ADHD the failure mode is attentional-gating rather than threshold, but the environmental consequence overlaps. Personal-scale acoustic tools (noise-cancelling headphones; desk fans; task lighting) are among the reasonable adjustments an employer may be required to make under the Disability Discrimination Act 1992 (Cth), and may be reimbursable via the Employment Assistance Fund administered by JobAccess.
The three moves above reduce input — the right priority for Sensitivity and Avoiding. Low Auditory Registration runs the other way: you miss cues others catch (a name called from another room, the kettle, the timer, the doorbell, an instruction in a noisy room), so the move is to add salience and redundancy, not subtract level. Make the signals that matter louder relative to their background, pair them across senses, and route them to a channel you reliably notice — a visible kettle indicator, a vibration-alert timer, a doorbell that flashes a light as well as sounds.
The safety-critical case. The reduction moves this module recommends work against you here: earplugs, personal-scale noise cancellation, a well-sealed door, and full blackout each close a channel a smoke or emergency alarm reaches you through — and the low-registration profile is already the least likely to be woken by a standard alarm. The fix is redundant alerting: interconnected smoke alarms (one sounds, all sound) with an alarm at the bed; a bed- or pillow-shaker tactile alert if you seal or mask your hearing; and a 520 Hz signal option, which wakes at-risk sleepers far more reliably than the standard high-pitched tone. The Bedroom Design Guide carries this as a full card (Make sure a critical alarm still reaches you); the point is flagged here because it is this module's own moves that open the gap.
The natural next step is the relevant room Design Guide. The Bedroom Design Guide carries the full Reversible + Semi-Permanent + Permanent ladder for the sleep environment — including acoustic wall panels at first reflections, ceiling cloud placement, mass-loaded vinyl on shared walls, secondary glazing comparison, and bedhead positioning relative to noise sources. Forthcoming Living, Home Office, and Kitchen guides extend the same depth to other rooms. The Workplace Design Guide carries Fitout-scale workplace acoustic interventions — HVAC duct attenuators, full-room acoustic ceiling tiles, decoupled-stud wall systems, zone separation between activity types. Where the architectural envelope binds — party-wall transmission loss, plenum and riser paths, plant-room location — the limits sit upstream at [ARR-01 §7] and are documented as project constraint, not design failure.
Each of these produces a meaningfully different result than either component alone. Worth knowing before you start spending. Combinations that involve Semi-Permanent or Permanent moves (acoustic panels + secondary glazing; soft furnishings + decoupled-stud wall) live in the relevant room Design Guide alongside the cards they combine.
Beyond the three Reversible moves at Section 04, this is where the higher-tier work lives — the structural moves that lift the envelope further, the sequencing question for combined-path acoustics, and the routes into the renovation-scale ladder. Each cell points into the Design Guide or upstream reference that carries the full detail.
This module is the channel-anchored profile-education plus the three highest-leverage Reversible moves on the auditory channel. The Bedroom Design Guide carries the full Reversible + Semi-Permanent + Permanent ladder for the sleep environment — the longer Reversible set, plus acoustic wall panels at first reflections, ceiling cloud placement, mass-loaded vinyl on shared walls, secondary glazing vs heavy curtain comparison, bedhead positioning relative to noise sources, and full sourcing — alongside spatial diagrams and integrated multi-channel sequencing for the bedroom specifically. Forthcoming Living, Home Office, and Kitchen Design Guides extend the same depth to other rooms; the Workplace Design Guide carries Fitout-scale workplace acoustic interventions.
Reading order is module first (channel-level mechanism + Reversible action), then the design guide for the room you spend the most time in (full tier ladder, room-specific implementation).
Evidence basis: Specifications and intervention priorities in this module are grounded in AS/NZS 2107:2016 (AU/NZ acoustic envelope spec), AS/NZS 1276.1:1999 (airborne-sound rating method underwriting NCC F5), AS 1668.2:2024 (ventilation noise provisions), NCC F5 (party-wall isolation Rw+Ctr ≥ 50 dB floor), PAS 6463:2022 (BSI — Design for the Mind), the BSA APD SIG 2018 Position Statement (APD construct framing), and Gocer et al. 2025 (AU hybrid-work workplace POE). Terminology for APD follows the BSA 2018 reframing and the contemporary listening-difficulties (LiD) literature. Where cost ranges are cited, these reflect Australian residential and commercial market pricing as of 2026 and will vary by location, supplier, and specification.
This module provides design guidance, not clinical advice. If you experience persistent listening difficulty in normal conversation, speech-in-noise difficulty that the acoustic envelope changes here do not resolve, or chronic auditory hyperresponsivity that suggests an underlying clinical pattern, seek assessment from a qualified audiologist (Audiology Australia practitioner register) or speech-language pathologist (Speech Pathology Australia practitioner register). The design heuristics in this module are robust independent of the diagnostic question and benefit the listening-difficulty pattern regardless of construct standing. If you are an employee seeking reasonable adjustments, personal-scale acoustic tools (ANC headphones, quiet workspace, reduced-stimulation breaks) are standard accommodations under the DDA 1992 (Cth) and may be eligible for Employment Assistance Fund (EAF) reimbursement administered by JobAccess. Readers with multiple-domain flagging, severe presentations, or unusual constraints can email hello@sensoridesign.com.au — one-on-one consultancy is an option where the design-guide path leaves the situation unresolved.
This is a Sensori intervention module — a free channel-anchored profile-education + Reversible-tier action surface. See sensoridesign.com.au for the full library, including paid design guides for room-by-room implementation.