Manufacturer

Whisperwool

Tante Lotte Design GmbH from Innsbruck manufactures sound absorbers made of sheep wool under the Whisperwool brand. The material consists of virgin sheep wool, mostly from Tyrol and the rest of the Alpine region, recycled wool and recycled Whisperwool residues, bonded with a biodegradable binding fibre. The base board has a two-layer structure: a top layer of colour-sorted sheep wool over a hard, air-permeable core. It is the basis for acoustic boards for wall and ceiling, ceiling rafts, wall, window, hanging, floor-standing and desk panels, baffles, room dividers, acoustic curtains, self-adhesive panels and acoustic wallpapers. Standard colours are natural white, silver grey and anthracite; custom dyeing, embossing and cutting to size are possible. Production takes place in Austria. Tante Lotte is a certified Common Good company.

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Test report on request

Whisperwool smooth acoustic panel

Name: Whisperwool smooth acoustic panel
Brand: Whisperwool

Smooth acoustic panel

WallCeilingIntegrated

Description

The smooth acoustic panel is the base panel of the Whisperwool range, two-layered with a hard, air-permeable core. Installation with joints or jointless, nailed or glued onto a timber substructure; the nail heads remain invisible. Cutting, drilling and bending are possible with simple tools. The manufacturer offers custom sizes, colouring, printing, folding, 3D forming and CAD cutting.

Technical data

Material: Virgin sheep wool, recycled wool and recycled Whisperwool residues, bonded with biodegradable binding fibre; facing layer of colour-sorted sheep wool (wool felt)

Surface: smooth

Up to fire class: EN 13501-1 F

Certifications: CE per ÖNORM EN 13964 and ÖNORM EN 15102; emissions test ISO 16000 (OETI), AgBB-compliant

Colours: natural white, silver grey, anthracite; special colours on request

Measurement data

Sound absorption

Reverberation chamber (ASTM C423 / ISO 354)· 4 variants

NRC

0.90

Frequency values

α_p per octave band

f (Hz)	125	250	500	1k	2k	4k
α_p	0.60	0.80	0.90	0.85	0.95	0.95

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Compare		Value
	2 in cavity, fully damped with 2 in glass wool	NRC0.90
	9.8 in cavity, undamped	NRC0.75
	2 in cavity, undamped	NRC0.75
	no cavity, laid directly	NRC0.45

Test report: P-1430-2016/08-1

NRC: 0.90 (derived from ISO 354 lab data)

Institute: Quiring Consultants, Dipl.-Ing. Dr. techn. Karl Bernd Quiring, state-authorised and sworn civil engineer for building construction, Aldrans (AT)

Measurement date: 2016-08-10

Room volume: 7,063 cu ft

Object area: 131 sq ft

Dimensions: 900 × 900 × 0.5 in

Measured values as a table (4 measurements)

Whisperwool smooth acoustic panel: sound absorption coefficient αs per ISO 354 by frequency and test build-up
Build-up	NRC	100 Hz	125 Hz	160 Hz	200 Hz	250 Hz	315 Hz	400 Hz	500 Hz	630 Hz	800 Hz	1000 Hz	1250 Hz	1600 Hz	2000 Hz	2500 Hz	3150 Hz	4000 Hz	5000 Hz
12 mm · no cavity, laid directly · glatt, Deckschicht Nadelfilz	0.45	0.07	0.05	0.03	0.10	0.10	0.14	0.22	0.28	0.38	0.49	0.57	0.68	0.76	0.80	0.87	0.93	0.89	0.86
12 mm · 50 mm cavity, undamped · glatt, Deckschicht Nadelfilz	0.75	0.15	0.15	0.20	0.23	0.51	0.59	0.70	0.77	0.79	0.83	0.86	0.88	0.85	0.85	0.86	0.86	0.83	0.83
12 mm · 50 mm cavity, fully damped with 50 mm glass wool · glatt, Deckschicht Nadelfilz	0.90	0.60	0.66	0.53	0.72	0.87	0.87	0.88	0.95	0.91	0.88	0.86	0.88	0.90	0.92	0.96	0.97	0.94	0.88
12 mm · 250 mm cavity, undamped · glatt, Deckschicht Nadelfilz	0.75	0.64	0.49	0.58	0.67	0.67	0.69	0.79	0.75	0.71	0.69	0.75	0.79	0.85	0.86	0.89	0.89	0.90	0.84

Measured values as a table (4 measurements)

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Last updated: 09/16/2026