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FluxCore™ Built for the hard part

Control the bass.
Build with strength.

Discover The FluxCore Effect: multi-density decoupling with load-bearing steel construction. Designed around layered walls, ceilings and project-engineered equipment mounts. Mechanical load and compression testing by SINTEF. Completed-building sound-insulation results from our Kolbotn reference project.

Private cinemasRecording studiosDemanding residential projects
ProSilence FluxCore Clip — decoupling support for walls and ceilings
Mechanical decouplingPatent pending
Low-frequency isolationLoad-bearing designEN 13501-1 · B-s1,d0SINTEF mechanical tests · Kolbotn field resultWhole-system planning

01 See the principle

The FluxCore Effectvisually explained.

A softer inner core. A firmer outer core. A different approach to the connection between a room and its structure. Watch the FluxCore film, then explore the measured performance of the complete wall system.

Watch here on ProSilence. The embedded YouTube player loads only when you press Play.Sound and fullscreen controls in the player.

01 / Decouple

Rethink the connection.

FluxCore combines two elastomer cores in the mechanical connection supporting the lining. The softer inner core works within a firmer outer core.

02 / Measure

Let the data speak.

Explore the measured result from the completed Kolbotn music studio. The project report explains the room construction, frequency data and measurement scope.

03 / Build

Turn the idea into a room.

Connect the clips, channels, floor supports, damping compound and supporting materials in the System Planner.

The FluxCore Effect — technically explained ↓

ENGINEERED TO SUPPORT The load-bearing side of FluxCore

More load per clip.
More freedom to build.

Soft core. Serious support. FluxCore pairs multi-density decoupling with a load-bearing steel clip. Use the capacity for substantial board mass and additional local equipment loads — from studio loudspeakers to private-cinema installations. Fewer clips where suitable. More load headroom where it matters.

SINTEF / CEILING PULL-OUT475 N per clip.

Calculated permissible ceiling load with safety factor 2.5 — about 48.4 kg mass equivalent. Mean laboratory failure load: 1,503.5 N. Wall shear has separate 350 N guidance for intended decoupling function.

FluxCore clip and furring channel mounted to timber framing
THE CONNECTION BEHIND THE FINISHFluxCore Clip + Furring Channel

HEAVY OBJECTS / LOCAL SUPPORT

Plan the mount.
Keep the isolation.

A loudspeaker needs more than a spare kilogram figure. Include the lining, speaker, bracket and load spreader in the load plan. Reinforce the local field rather than relying on screws in the board alone.

01 / WALL

Spread the load across channels.

For a 20 kg loudspeaker, plan a suitable load spreader over at least two horizontal channel rows and two stud positions. Add clips on every stud locally, at 600 mm centres, including neighbouring supports. Bracket leverage and pull-out need separate checks.

02 / CEILING

Add local clips before closing the lining.

Use a designed mounting field across neighbouring channels, retaining the normal staggered layout outside that field. Shorten clip spacing locally, with suitable structural backing for each added clip. Check all fixings and any required secondary restraint.

03 / ISOLATION

No rigid shortcut to the building.

The load spreader belongs to the isolated lining. Do not create an unintended rigid connection past the clips. Additional clips and reinforcement have their own weight and must be included.

PER-CLIP LOAD BUDGET / CEILING EXAMPLE

Same support area.
Different load headroom.

For this comparison only, every clip supports 0.36 m² at 30 kg/m²: 10.8 kg of uniformly distributed ceiling lining load. A common 600 × 600 mm grid isolates the per-clip capacity comparison from separate spacing examples.

Assumed lining loadArithmetic reserve to the stated limit
ProSilence FluxCore475 N permissible ceiling load / safety factor 2.5

10.8 kg lining + 37.6 kg reserve = 48.4 kg source limit

37.6 kgarithmetic reserve / clip

SINTEF strength-based ceiling recommendation. Mean laboratory failure load was 1,503.5 N; acoustic performance at 475 N was not assessed.

Kinetics IsoMax / 25 ga channel16.3 kg design load / safety factor 2.5:1

10.8 kg lining + 5.5 kg reserve = 16.3 kg source limit

5.5 kgarithmetic reserve / clip

16.3 kg with 25 ga channel at 2.5:1. Kinetics also publishes 20.4 kg at 2:1. Strength-based clip-and-channel capacity, not an acoustic working-range measurement.

Kinetics IsoMax / 22 ga channel21.8 kg design load / safety factor 2.5:1

10.8 kg lining + 11.0 kg reserve = 21.8 kg source limit

11.0 kgarithmetic reserve / clip

21.8 kg with heavier 22 ga channel at 2.5:1. Kinetics also publishes 27.2 kg at 2:1. Both channel variants are shown; the lower-capacity channel is not presented as the only option.

GenieClip RSTManufacturer maximum design load

10.8 kg lining + 5.2 kg reserve = 16.0 kg source limit

5.2 kgarithmetic reserve / clip

Published design-load limit per clip, not a failure load.

MuteClipManufacturer maximum load

10.8 kg lining + 5.2 kg reserve = 16.0 kg source limit

5.2 kgarithmetic reserve / clip

iKoustic additionally targets 75% of maximum: 12 kg, leaving 1.2 kg in this example.

015304560 kg

Load-budget illustration, not a rated point load. Reserve at one clip is not a permissible loudspeaker weight, and reserves cannot simply be added to rate a mount. Bracket leverage, unequal load sharing, channels, backing, anchors and dynamic forces govern the actual equipment design. The sources use different load definitions; this is not a matched load test.

WORKING LOAD IS NOT FAILURE LOAD

Use strength reserve.
Do not spend it twice.

Our normal wall dead-load planning target is at most approximately 25 kg per clip. The preferred ceiling model range is approximately 9–26 kg per clip. These are ProSilence planning choices, not SINTEF-certified acoustic optima.

Local equipment fields require a separate check of the actual reactions. More clips do not automatically mean equal load sharing. The difference up to the strength limit is not a rated loudspeaker allowance.

Mechanical capacity and safety margin

SINTEF PR26-00288, 22 September 2026, calculates 475 N per clip for ceiling pull-out after statistical reduction and a 2.5 safety factor. Wall shear gives 543.5 N on the strength basis; the report recommends 350 N to preserve intended function. The test results require the specified assembly and tightening. Acoustic performance at the ceiling strength limit was not assessed.

Choosing a lower working-load target does not remove the safety factors in the strength assessment. The complete installation still needs suitable channels, anchors, load distribution and project-specific verification.

01 / BOARD LAYERS

Build with mass.

Design multi-layer gypsum-fibre linings as a complete load-bearing assembly. Select the number and spacing of clips for the board weight, compound and finish.

02 / EQUIPMENT

Plan for more than plasterboard.

Include speakers, projector mounts and other equipment in the load plan. Use suitable backing, fasteners and additional clips where concentrated loads require them.

03 / THE WHOLE SYSTEM

Keep the load path isolated.

Design the mount into the decoupled structure rather than unintentionally bridging it. Check the complete connection, not the clip alone.

Equipment mounting requires project-specific design for total load, local load distribution, leverage, backing and anchors. A per-clip figure is not a permissible load on an arbitrary screw in a gypsum board, and the board weight already uses part of the system capacity.

Mechanical test results, recommended loads and comparison basis

SINTEF PR26-00288, version 01, 22 September 2026: four samples in each orientation. Before dividing by the safety factor, the calculation reduces the mean failure load to account for the variation between samples. For the ceiling tests: (1,503.5 − 3.96 × 79.3) / 2.5 = 475.8 N, stated as 475 N in the recommendation. Mechanical capacity and acoustic behaviour under load are different questions.

FluxCore Clip with the tested ProSilence channel and fixings
Result / load basisCeiling orientationWall orientation
Mean laboratory failure load1,503.5 N1,485.5 N
Calculated permissible load, safety factor 2.5475 N
About 48.4 kg mass equivalent
543.5 N
About 55.4 kg mass equivalent; see functional limit below
Report recommendation for intended acoustic functionAcoustic performance at the 475 N load was not assessed in this mechanical test.Limit to 350 N
About 35.7 kg mass equivalent; recommendation based on deformation behaviour, not a separate acoustic test at this load

Failure loads are not working loads. On walls, the report's 350 N recommendation takes precedence over the higher strength-based calculation when preserving the intended decoupling function. The report calls for each installation to be designed individually.

Selected competitor reference: Pliteq publishes a maximum design load of 16 kg for GenieClip RST. iKoustic publishes a maximum of 16 kg for MuteClip and recommends planning below 75% of that maximum. These are manufacturer load definitions, not results of the same test method or evidence that either product fails at 16 kg. No ratio of break strength to a competitor's working load is presented.

GenieClip RST product specification / maximum design load ↗
MuteClip manufacturer guidance / load and operating margin ↗

FIRE PERFORMANCE / EUROPEAN CLASSIFICATION

B-s1,d0.Tested — not assumed.

Fire behaviour matters in real building projects. The tested FluxCore U-boat has been laboratory classified B-s1,d0 for reaction to fire according to EN 13501-1:2018.

LABORATORY CLASSIFICATION / REACTION TO FIRE

FluxCoreB-s1,d0.

EN 13501-1:2018
Report XDD06260125071501FAR

Test scope and details ↓
FIRE BEHAVIOURB
SMOKE PRODUCTIONs1
FLAMING DROPLETSd0

Classification of the tested FluxCore U-boat. s1 denotes the lowest smoke-production class within this classification system; d0 denotes no flaming droplets or particles under the applicable test criteria.

Fire-test method, scope and classification

Laboratory tested and classified B-s1,d0. BST Testing (Shenzhen) Co., Ltd. classified the FluxCore U-boat according to EN 13501-1:2018, report XDD06260125071501FAR, dated 15 July 2026. The classification basis includes EN 13823:2020+A1:2022 and EN ISO 11925-2:2020 testing.

Scope matters: the classification applies to the tested FluxCore U-boat product parameters, with A1 or A2 substrates and mechanical fixing as stated in the report. It is a reaction-to-fire classification of the tested product — not an EI/REI fire-resistance rating for a complete wall, ceiling or floor, and not a type approval or product certification.

* The same FluxCore elastomer material is used in FluxCore Clip. The EN 13501-1 classification report itself identifies the U-boat as the tested product.

02 Understand the measurements

The FluxCore Effecttechnically explained.

Compare the measured low-frequency sound reduction of selected complete wall constructions at 50, 63 and 80 Hz. The graph shows each system alongside its total wall thickness and source information.

LOW-FREQUENCY WALL COMPARISON50 / 63 / 80 Hz

Total wall thickness: outer finished face to outer finished face, including both board packs, the frame and the decoupled lining. Not the clip depth or added lining alone.

Selected wall assemblies: low-frequency sound reduction and total wall thicknessSelected results at 50, 63 and 80 Hz. Shared vertical scale: 10 to 45 dB, not zero-based. ProSilence: 182 mm nominal total wall thickness, calculated from the manufacturer-corrected build-up including the 34 mm clip offset. Knauf W623: approximately 185 mm finished wall depth with published laboratory values. IsoMax AT001058: 187 mm, unofficial low-frequency data. MuteClip Double: approximately 184 mm calculated total. GenieClip TL07-670: nominal 197 mm, with only the 80 Hz point available. Complete walls, not clip-only measurements or a whole-spectrum ranking.Sound reduction R / TL, dBHigher is better · Y-axis starts at 10 dB101520253035404550 Hz63 Hz80 HzMuteClip DoubleiKoustic lab-performance data · lab not identifiedApprox. 184 mm totalGenieClip RSTPublished test report · TL07-670197 mm totalKinetics IsoMaxExternal lab · Riverbank / LF values unofficial187 mm totalKnauf W623Knauf laboratory · ISO 10140-2Approx. 185 mm totalProSilence FluxCoreExternal lab · SINTEF Community182 mm total26.131.338.4Frequency / logarithmic spacing · common cropped vertical scale

ProSilence FluxCore

External lab · SINTEF Community

SINTEF 102036124-2-1

182 mmTOTAL WALL THICKNESS

Nominal total from the corrected ProSilence build-up

98 x 48 mm timber studs (98 mm wall depth) + four 12.5 mm gypsum-fibre boards + 34 mm clip offset on one side = 182 mm.

External laboratory measurement by SINTEF Community; provisional data sheet

Kinetics IsoMax

External lab · Riverbank / LF values unofficial

AT001058 / RAL TL02-40

187 mmTOTAL WALL THICKNESS

Reported total wall thickness

89 mm timber frame; two 15.9 mm boards per side; clips on one side.

Riverbank external-laboratory assembly test; Kinetics states the supplementary 31.5–80 Hz values were calculated from additional measurements and are unofficial R&D data

Knauf W623

Knauf laboratory · ISO 10140-2

SWC 21 093-05 / W623

Approx. 185 mmTOTAL WALL THICKNESS

Reported finished wall depth (FWD)

90 mm timber frame with 80 mm mineral wool; 40 mm cavity; CD 60/27 resilient lining on direct vibration hangers; 12.5 + 15 mm Diamant board layers to both faces.

Knauf-published laboratory measurement at Knauf Gips KG Iphofen; report SWC 21 093-05, dated 22 February 2022

MuteClip Double

iKoustic lab-performance data · lab not identified

Timber wall / source page 11

Approx. 184 mmTOTAL WALL THICKNESS

Calculated total, not a measured total

95 mm timber frame; one 15 mm board opposite two 15 mm boards and Tecsound.

Published by iKoustic as lab-performance data; the cited sheet gives source/receiving-room volumes but does not identify the laboratory or an independent report number

GenieClip RST

Published test report · TL07-670

TL07-670 / timber wall

197 mmTOTAL WALL THICKNESS

Manufacturer nominal total wall thickness

One timber frame; two approx. 16 mm boards per side; clips on one side.

Pliteq-published TL07-670 test-reference data; Pliteq states GenieClip assemblies are tested in NVLAP-certified laboratories, while the cited brochure does not name the laboratory for this report

Test provenance is shown for every series because these low-frequency datasets do not have identical verification status. Selected complete walls, not a ranking of every configuration sold under each brand. Knauf W623 is the approximately 185 mm published configuration, chosen because its total depth is close to the 182 mm FluxCore assembly. Missing 50 and 63 Hz GenieClip values are left blank, not inferred. IsoMax low-frequency values are Kinetics-published supplementary calculations from additional measurements and are explicitly marked unofficial R&D data by Kinetics. MuteClip values are published by iKoustic as lab-performance data, but the cited sheet does not name the laboratory or an independent report number. ProSilence values are external SINTEF laboratory measurements from the provisional data sheet. All thicknesses refer to complete wall constructions.

Selected complete wall assemblies, not interchangeable clip tests. Lines connect the measured frequency bands; they do not add unmeasured values. Different board masses, construction details and test sources limit direct ranking.
Wall constructions, measured values and source documentation
Selected clip assemblies / 50-80 Hz / R or TL in dB
Tested wallTotal wall thickness50 Hz63 Hz80 HzSource status
ProSilence FluxCore
External lab · SINTEF Community
SINTEF 102036124-2-1
182 mm
Nominal total from the corrected ProSilence build-up
26.131.338.4External laboratory measurement by SINTEF Community; provisional data sheet
Kinetics IsoMax
External lab · Riverbank / LF values unofficial
AT001058 / RAL TL02-40
187 mm
Reported total wall thickness
24.030.036.0Riverbank external-laboratory assembly test; Kinetics states the supplementary 31.5–80 Hz values were calculated from additional measurements and are unofficial R&D data
Knauf W623
Knauf laboratory · ISO 10140-2
SWC 21 093-05 / W623
Approx. 185 mm
Reported finished wall depth (FWD)
19.623.739.0Knauf-published laboratory measurement at Knauf Gips KG Iphofen; report SWC 21 093-05, dated 22 February 2022
MuteClip Double
iKoustic lab-performance data · lab not identified
Timber wall / source page 11
Approx. 184 mm
Calculated total, not a measured total
22.123.324.4Published by iKoustic as lab-performance data; the cited sheet gives source/receiving-room volumes but does not identify the laboratory or an independent report number
GenieClip RST
Published test report · TL07-670
TL07-670 / timber wall
197 mm
Manufacturer nominal total wall thickness
——31.0Pliteq-published TL07-670 test-reference data; Pliteq states GenieClip assemblies are tested in NVLAP-certified laboratories, while the cited brochure does not name the laboratory for this report

ProSilence: SINTEF 102036124-2-1, test date 25 August 2026, marked provisional/internal use only. The manufacturer-corrected nominal build-up is 98 mm timber frame + four 12.5 mm gypsum-fibre boards (50 mm total) + 34 mm clip offset on the inside = 182 mm. This replaces the earlier 150 mm figure, which omitted the clip offset. The dimension is calculated from the stated component sizes; the unchanged acoustic values come from SINTEF laboratory measurements.

IsoMax AT001058: Kinetics identifies Riverbank Acoustical Laboratories / RAL TL02-40 as the external testing agency for this wall. Kinetics separately publishes 31.5–80 Hz values and states that these supplementary values were calculated at additional test frequencies from measurements made using ASTM E90-99 procedures; Kinetics explicitly classifies them as unofficial research-and-development data, not part of the standard test range. The 50/63/80 Hz points shown here are therefore external-lab-derived measurements with manufacturer-published supplementary calculations, not an in-house simulation.

Knauf W623: Knauf report SWC 21 093-05 documents an approximately 185 mm finished wall depth and third-octave sound reduction of 19.6 dB at 50 Hz, 23.7 dB at 63 Hz and 39.0 dB at 80 Hz. The test was carried out at Knauf Gips KG Iphofen to ISO 10140-2 and is used here because the complete wall depth is closely matched to the 182 mm FluxCore assembly.

MuteClip Double: iKoustic publishes the 50/63/80 Hz values in its MuteClip Systems Performance Data and links that material as lab-performance data. The cited sheet lists source and receiving room volumes and the treated timber-wall construction, but it does not identify the laboratory or an independent report number. We therefore label it as manufacturer-published lab-performance data with the laboratory not identified, rather than calling it independently verified. Approximately 184 mm remains a calculated total, not a measured overall dimension in the sheet.

GenieClip TL07-670: Pliteq publishes TL07-670 as a test-report reference for the 197 mm timber wall and publishes 31 dB at 80 Hz and 39 dB at 100 Hz. Pliteq states that GenieClip assemblies are laboratory tested and its specification requires assembly testing in NVLAP-certified laboratories; the brochure cited for TL07-670 does not name the laboratory. We therefore identify it as published test-report data and avoid assigning a specific laboratory that the source does not state. No 50 or 63 Hz values are published for this assembly in the cited brochure.

Kinetics: IsoMax assembly and report references ↗
Kinetics: supplementary low-frequency source ↗
Knauf: W623 185 mm laboratory result / SWC 21 093-05 ↗
iKoustic: performance sheet, page 11 ↗
iKoustic: 74 mm lining-depth specification ↗
Pliteq: construction and results, printed pages 14 and 20 ↗

The homepage is deliberately limited to 50-80 Hz; the linked source material is not truncated. The substantially thicker 254 mm IsoMax AT001090 wall and other non-matched wall configurations are outside this initial comparison. Adding two further 12.5 mm boards on the stiff side would make a nominal 207 mm wall (182 + 25 mm), with two layers on the isolated side and four on the stiff side. This proposed assembly is not represented by the current acoustic curve; a future test must have its own results, date, layer schedule and measured thickness.

PROSILENCE / FIELD REFERENCES

Real installations.
Measured performance.

Completed rooms. Documented field results. See what each installation achieved, what the measurements mean and how they relate to acoustic classification and private cinema guidance.

FIELD RESULT / APPARENT SOUND REDUCTION

74dB
R′w

Weighted apparent sound reduction index for the completed installation.

C −2 dBCtr −8 dB

RECALCULATED / STANDARDIZED LEVEL DIFFERENCE

73dB
DnT,w

Approximate check value recalculated from the main measurement set. See the report for the calculation basis.

KOLBOTN, NORWAY

A dedicated music studio.
Exceptional isolation in practice.

One of the strongest sound isolation results we have measured in a completed room. This ProSilence music studio has a reported R′w of 74 dB, with DnT,w recalculated at approximately 73 dB.

Installation: a dedicated room without windows, with a sound-rated door and ventilation. The walls and ceiling have two layers of gypsum-fibre board with damping compound, combined with ProSilence decoupling and carefully detailed junctions. The field result captures the completed construction and its real-world transmission paths.

Measurement context: even at maximum Norsonic source output, the studio transmitted so little sound that several bands approached the practical measurement limit of this setup, despite a very quiet receiving room. With stable background noise, these limits can conceal even better isolation. The report explains the conservative reporting principle, the observed background variation and the low-frequency method qualifications.

Two ratings of the same measurement: R′w describes apparent sound reduction, accounting for the separating area and the receiving room's absorption. DnT,w describes the level difference between rooms, standardized to a reference reverberation time. Their different normalizations and the room geometry explain why the two numbers differ.

Measured 21 September 2026 · Norsonic Class 1 instrumentation
Measurement: ISO 16283-1 · Rating: ISO 717-1 · Client: AVshop

FULL DOCUMENTATION / ENGLISH PDF

Kolbotn · full measurement report

Room construction, test setup and frequency data, with the noise-floor explanation and qualifications for the low-frequency measurements.

11 pages · Revised September 2026
Download English report
INTERNATIONAL / ISO CLASSIFICATIONCLASS A BENCHMARK · ABOUT +11 dB

The recalculated DnT,w of approximately 73 dB is about 11 dB above the 62 dB Class A benchmark for ordinary separation between dwellings in ISO/TS 19488:2021, using its permitted DnT,w descriptor. Class A is the highest class in this international dwelling framework. Here, it provides a residential reference point for the music-studio measurement.

ISO/TS 19488:2021 · dwelling classification ↗
NORWAY / NS 8175 · RESIDENTIAL CONTEXTRESIDENTIAL BASELINE · +19 dB

R′w 74 dB is 19 dB above the 55 dB Class C airborne-insulation baseline for separation between dwellings in NS 8175:2012. With the extended low-frequency term included, R′w + C50–5000 = 65 dB, 3 dB above the 62 dB Class A airborne benchmark in NS 8175:2019. This comparison includes frequencies down to 50 Hz and is subject to the 50–80 Hz method qualification explained in the report.

Standard Norge · acoustic classes ↗
CEDIA / CTA-RP22 · PRIVATE CINEMA ISOLATIONApproaching RP22 Isolation Level 4.

RP22 describes DnT,w field results as typically 4–6 dB below Rw and gives STC/Rw 80 as the typical Isolation Level 4 benchmark. Against that broad guidance, Kolbotn's recalculated DnT,w of approximately 73 dB approaches this benchmark, alongside R′w 74 dB. This is an indicative comparison; neither field rating converts directly to Rw or STC. Full RP22 classification also involves construction, services and other performance criteria.

RP22 isolation guidance, pages 92–93 ↗

These comparisons concern measured airborne sound insulation. They provide residential and cinema design context, rather than a complete acoustic classification of either building.

View frequency data and measurement notes

Frequency-by-frequency performance

Third-octave apparent sound reduction index, R′. The ≥ markings reproduce the measurement export's limit flags. With stable, representative background noise, a noise-floor limit is conservative: background sound can conceal lower transmitted sound and therefore even better insulation.

The report also documents background variation, so the overall result is not an unconditional guaranteed minimum. Read the full measurement context alongside the frequency values.

Reported result, 21 September 2026: R′w (C; Ctr) = 74 (−2; −8) dB. DnT,w ≈ 73 dB is a separate check recalculated from the same main measurement set, not a value copied from its R′w export. The frequency table reproduces the R′ values in that export.

Extended low-frequency rating: the final export gives C50–5000 = −9 dB. R′w + C50–5000 is therefore 65 dB. This descriptor is used for the Norwegian Class A comparison, subject to the report's qualification concerning the undocumented 50–80 Hz corner procedure in the small receiving room. The separate supplementary source-corner survey could not be completed because bass traps occupied the corners; this does not change the ordinary 25% measurement-position data.

Kolbotn · field sound insulation
Frequency / HzR′ / dB
50≥26.1
6339.6
80≥40.8
100≥47.2
125≥59.4
16062.3
20064.1
25063.6
31568.8
40070.5
50069.6
630≥70.8
800≥73.6
1,000≥72.2
1,250≥80.8
1,600≥87.2
2,000≥92.1
2,500≥90.7
3,150≥91.9
4,000≥88.6
5,000≥86.2

FIELD RESULT / APPARENT SOUND REDUCTION

67dB
R′w

Weighted apparent sound reduction index for the completed installation.

C −5 dBCtr −13 dB

FIELD RESULT / STANDARDIZED LEVEL DIFFERENCE

72dB
DnT,w

Weighted standardized level difference between the rooms.

HOLMENKOLLEN · OSLO, NORWAY

A residential installation.
Exceptional isolation in practice.

Measured between an apartment and the main house, this completed ProSilence residential installation achieved R′w 67 dB and DnT,w 72 dB.

Installation: a residential building with windows, doors and ventilation. The measurement ran from a bedroom in the apartment to the living room/kitchen in the main house. The field result captures the completed construction and its real-world transmission paths.

Measurement context: the receiving room was almost unfurnished and unusually reverberant. Both standardized ratings account for reverberation; the result describes the measured separation in this completed residential installation.

Two ratings of the same measurement: R′w describes apparent sound reduction, accounting for the separating area and the receiving room's absorption. DnT,w describes the level difference between rooms, standardized to a reference reverberation time. Their different normalizations and the room geometry explain why the two numbers differ.

Measured 14 October 2025 · Norsonic instrumentation
Measurement: ISO 16283-1 · Rating: ISO 717-1 · Measurement provider: AVshop

FULL DOCUMENTATION / ENGLISH PDF

Holmenkollen · full measurement report

Airborne and impact sound results, construction and test conditions, acoustic-class comparisons and the original measurement sheets. The report explains the different dates in the source exports.

10 pages · Revised September 2026
Download English report
INTERNATIONAL / ISO CLASSIFICATIONCLASS A BENCHMARK · +10 dB

DnT,w 72 dB is 10 dB above the 62 dB Class A benchmark for ordinary separation between dwellings in ISO/TS 19488:2021, using its permitted DnT,w descriptor. Class A is the highest class in this international dwelling framework. Here, it provides a residential reference point for the apartment-to-main-house measurement.

ISO/TS 19488:2021 · dwelling classification ↗
NORWAY / NS 8175 · RESIDENTIAL CONTEXTRESIDENTIAL BASELINE · +12 dB

R′w 67 dB is 12 dB above the 55 dB Class C airborne-insulation baseline for separation between dwellings in NS 8175:2012. The result describes the measured separation in the completed installation. Higher-class comparisons use the extended low-frequency rating R′w + C50–5000; the published measurement sheet does not provide that term.

Standard Norge · acoustic classes ↗
CEDIA / CTA-RP22 · PRIVATE CINEMA ISOLATIONApproaching RP22 Isolation Level 4.

RP22 describes DnT,w field results as typically 4–6 dB below Rw and gives STC/Rw 80 as the typical Isolation Level 4 benchmark. Against that broad guidance, Holmenkollen's DnT,w 72 dB approaches this benchmark, alongside R′w 67 dB. This is an indicative comparison; neither field rating converts directly to Rw or STC. Full RP22 classification also involves construction, services and other performance criteria.

RP22 isolation guidance, pages 92–93 ↗

These comparisons concern measured airborne sound insulation. They provide residential and cinema design context, rather than a complete acoustic classification of either building.

View frequency data and measurement notes

Frequency-by-frequency performance

Third-octave apparent sound reduction index, R′. A value marked ≥ is a measured lower bound: the isolation at that frequency is at least the value shown, within the measurement method's reporting limits.

The original measurement sheet marks all 20 numerical R′ values with ≥. It does not provide a numerical R′ result at 50 Hz; this is shown as — in the table.

Airborne measurement export, 14 October 2025: R′w (C; Ctr) = 67 (−5; −13) dB and DnT,w = 72 dB. The frequency table reproduces the R′ values in the published measurement report.

Extended low-frequency rating: C50–5000 is not stated in the published measurement sheet. The Norwegian comparison therefore uses the same uncorrected R′w baseline shown for Kolbotn. The ordinary C value is a different correction and is not substituted for C50–5000.

Measurement setting: from the apartment bedroom to the main house's living room/kitchen. The residential installation includes windows, doors and ventilation. The receiving room was almost unfurnished and unusually reverberant.

Both ratings already account for reverberation. Their approximately 5 dB difference primarily reflects their different normalizations and the room/partition geometry. Furnishing can reduce reverberation and the perceived transmitted sound level in use.

Revised full measurement report · English PDF · 10 pages ↗
Holmenkollen · field sound insulation
Frequency / HzR′ / dB
50—
63≥28.4
80≥24.5
100≥34.4
125≥46.8
160≥56.8
200≥52.8
250≥58.1
315≥63.0
400≥63.7
500≥66.3
630≥71.1
800≥74.3
1,000≥77.3
1,250≥75.9
1,600≥79.6
2,000≥80.2
2,500≥82.5
3,150≥86.6
4,000≥89.6
5,000≥88.5
Select a reference using the tabs or arrowsPROJECT-SPECIFIC FIELD MEASUREMENTS

03 The core of the system

Three roles.
One system approach.

Explore the components at the heart of ProSilence, then build the supporting layers around them. The System Planner connects both in one practical project schedule.

FluxCore Clip for wall and ceiling decoupling

Walls + ceilings / Decouple

FluxCore Clip

Connect the lining to the structure through the isolation system, with ProSilence channels carrying the board layers.

Explore the component ↗
FluxCore U-boat floor support

Floating floors / Support

FluxCore U-boat

Bring decoupling into the floor build-up. Plan the support layout and specify the floor structure for the project load.

Explore the component ↗
FluxCore Compound Red damping compound

Between rigid layers / Damp

FluxCore Compound Red

Viscoelastic damping between board layers, used alongside mechanical decoupling as part of the selected build-up.

Explore the component ↗

Walls, ceilings and floating floors need their own construction details and relevant test evidence. Airborne wall insulation and floor impact insulation are different measurements.

04 From component to complete room

Plan the system.
Share the specification.

A working room planner, not a product list. Enter your dimensions, choose the treated surfaces and see calculated component quantities — ready for a discussion with your installer, consultant or local partner.

Preparing the system planner…

05 See it in practice

The principle.
The components. The project.

Explore the technology and see it in practice. Press Play to watch each film here on ProSilence. The embedded YouTube player loads only on request.

Meet the FluxCore principle.

Start with the technology at the centre of the system.

Make vibration visible.

A practical demonstration of floor decoupling, not a substitute for a laboratory impact-sound rating.

Universal Music, Norway.

Explore a studio project using ProSilence and CineVent.

06 European partner development

Bring FluxCore
to your market.

We are building the European ProSilence partner network. Connect the technology with your local expertise — from specifying the construction to supplying the components and supporting installation.

Distributors & specialist dealers

A focused product family supported by an explanation of the system, technical content and a practical planning tool. Discuss territory, supply and local requirements.

Installers & system integrators

Turn a client's room into an initial component schedule. Share it with the project team and resolve the installation details before ordering.

Architects, consultants & project owners

Review the build-up, examine the low-frequency data and discuss how the system fits your project constraints.