A specifier's guide to invisible audio for modern architecture
What to write in the spec, when to coordinate with which trade, what HST delivers versus what the local trades own, and a working checklist for the specifier taking the category to a live project.
The category is now a design decision, not an equipment decision. The specifier who introduces it to a live project is doing a familiar job — writing a spec, coordinating trades, signing off deliverables — with a small number of shifts from the standard AV workflow. This piece is the working guide for that job. It sets out what to write in the spec, when to coordinate with which trade, what HST delivers versus what the local trades own, and a checklist that the specifier can carry into the coordination meeting.
What to write in the brief.
A specification for architectural audio reads differently from a specification for a traditional AV package. The line item is a treated surface, not a fixture at a coordinate. The trade is the finishing package, not the electrical package. The deliverable is the surface behaving acoustically, not a speaker at a location.
The spec should identify each treated zone as an area — a wall between grid lines, a ceiling zone, a joinery face — with the finish it will carry and the intended acoustic use. The zone should be tagged to the finishes drawing set, not to the AV drawing set. The AV consultant continues to specify the rack, the sources and the control layer separately; HST supplies the zone specification that plugs into that rack.
Timing — schematic design forward.
The single decision that changes cost and outcome most is when the category is specified. The clean answer is schematic design. The workable answer is anywhere before finishes are ordered. The retrofit answer is possible but adds coordination cost.
- Schematic design — cleanest specification. The treated zones enter the finishes package at the same stage as the material palette itself.
- Design development — still clean. Coordination with plaster, joinery and stone trades enters the working drawings alongside the rest of the finishes coordination.
- Construction — treated zones can still be added if surfaces are not yet finished. Site-based coordination is required and adds a stage.
- Post-handover retrofit — case-by-case. Some finishes can be reworked; others cannot. A short technical site visit is the fastest way to scope realistically.
Coordination with the trades.
The category runs through the finishes package. In practical terms three trades usually own the surface work: plaster, joinery and stone. Upholstery becomes relevant on treated fabric panels. The AV integrator continues to hold the amplifier rack in a service room; the electrical contractor continues to run the amplifier feed and the control cabling. Nothing about the AV integrator's role changes at the rack.
The shift for the specifier is on the drawing set. The zone is drawn on the finishes plans, not on the AV plans. The specification note lives next to the material specification, not next to the speaker schedule. This is a minor change on paper and a material change in coordination: the trades receiving the zone specification are the trades that already own the surface, so the intervention becomes part of the finishes rhythm rather than a separate site stage.
What HST delivers versus what the local trades own.
A clean brief separates responsibilities up front. Setting them out early avoids the coordination friction that occurs when a category is new to a project team.
HST delivers:
- Patches, amplification and control components.
- Zone specification aligned with the finishes drawing set.
- Coordination with the plaster, joinery, stone and upholstery trades on the surface work.
- On-site technical supervision during the surface intervention.
- Calibration and sign-off at handover.
Local trades own:
- Installation of the patches into the specified surfaces, under HST supervision.
- The finish work on the surface — plaster skim, joinery veneer, stone polish, fabric — same as the rest of the finishes package.
- Coordination with adjacent trades on the same surface.
- Site protection and site cleanliness during the works.
AV integrator continues to own:
- Rack design, source selection and control layer.
- Amplifier installation in the service room.
- Cabling from rack to zone under HST guidance.
- Integration with the guest room management or home automation platform.
“The category integrates cleanly when the specifier writes it into the finishes package. It integrates awkwardly when it lands on the AV drawing set.”
A working checklist for the specifier.
The checklist below reflects what the specifier should have ready before the first HST coordination call on a live project. It is deliberately short.
- Project stage and expected handover date.
- Zone list — number of zones, finish per zone, approximate treated area per zone.
- Finishes palette per zone — plaster, joinery species, stone type, fabric — with weights and any acoustic treatment already specified.
- Rack location and available service space, including cable run lengths from rack to treated zones.
- Control platform — guest room management for hospitality, home automation for residential, with the specific platform named.
- Design intent for each zone — what the room should sound like, at what nominal level, and any acoustic wellness or dining programme requirements.
- Site access windows — when the surface trades will be on site and when the AV rack space becomes accessible.
How the live conversation actually runs.
A first coordination call between a specifier and HST typically takes forty-five minutes. The first fifteen are project context — stage, zones, palette. The next fifteen are the specification pass — what goes into the drawing set, what stays with the AV consultant, what the trades will need. The final fifteen are the timeline — when the surface work happens, when calibration happens, when handover is expected.
At the end of the call the specifier should have a working zone list, an understanding of what enters the finishes drawing set and what remains in the AV drawing set, and a first estimate of the surface coordination sequence. A scoped estimate follows within one working day of the qualified intake form.
The strategic reading of the category — useful before the operational conversation.
The longer editorial reading of the discipline.
How the category applies to villas, penthouses, chalets and private wellness rooms.
Guest suites, spa environments, signature dining rooms and executive lounges.
A closing note.
The specifier who introduces the category to a live project is not adopting an unfamiliar workflow. The workflow is familiar — writing a spec, coordinating trades, signing off deliverables — with the audio decision moved into the finishes package. The visible outcome is a room that reads uninterrupted. The invisible outcome is a project that runs without a late-stage compromise on the material palette. Both matter; both are what the specification is designed to protect.
The qualified intake form takes project stage, zone count and timing. A scoped estimate and coordination pass follow within one working day.
Questions we're usually asked
- Do we, as a design studio, coordinate the trades ourselves?
- You retain the drawing set and the coordination lead. HST works with the finishes trades on your project under HST specifications. HST supervises the technical work and signs off calibration; the studio stays in charge of the design language.
- How does HST hand off to our AV consultant?
- The AV consultant continues to design the rack, the sources and the control layer. HST supplies the zone specification and the surface work; the amplifier connects to the AV consultant's rack. The handoff is at the amplifier input.
- What drawings should we expect from HST?
- A zone overlay to the finishes drawing set — plan and elevation — with the treated area marked and the specification note. The overlay is issued to the specifier for inclusion in the coordinated drawing set.
- Can we introduce the category mid-project?
- Yes, as long as the treated surfaces have not yet been finished. Site-based coordination adds a stage but does not compromise outcome. Post-handover retrofit is scoped case by case.
- Does HST provide a written specification we can annexe to our set?
- Yes. A specification annexe is issued at the coordination pass. The annexe references the trades responsible, the surface treatment sequence, and the calibration acceptance criteria.
Written for the specifier taking the category to a live project. If a project is on the desk now, the qualified intake form is the fastest path to a scoped conversation and a written specification pass.
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