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The Narrowband Absorber Company Limited
bass absorption testing
Thorough Sound Absorption Testing
Sound absorption tests were undertaken on the product with guidance taken from BS EN ISO354:2003 Acoustics - Measurements of sound absorption in a reverberation room. The boxes were absorption tested in a reverberation chamber as per guidance provided in the standard. These tests are benchmark tests conducted in an acoustically treated room at the University of Salford.

Further absorption tests were conducted in a studio control room at Sound Hub, Denmark by Schacoustics. The studio control room had built in acoustic treatment. The measured absorption results did correlate with the earlier University of Salford absorption tests.
Listen to the sound differences produced by the Portable Variable Acoustics Device in the audio clips below. Remember to play one clip at a time and use headphones for accurate representation.

No P:VAD Boxes
2x P:VAD Boxes
4x P:VAD Boxes
with or without sheeps wool test
Testing with and without sheep’s wool insulation
Initial tests were conducted with reference to BS EN ISO 354:2003 - Measurements of sound absorption in a reverberation room in the small reverberation chamber at the University of Salford on six boxes arranged across the floor of the chamber. This showed absorption at 80Hz, with and without 50mm thick sheep’s wool placed in the box cavity.

The absorption coefficient was improved with sheep’s wool in the cavity. The overall absorption class for the product with sheep’s wool placed in the cavity was Class C. Without sheep’s wool in the cavity, the product behaved overall as a Class D absorber. The product is subsequently manufactured with sheeps wool in the cavity.
2x2 config test
2x2 configuration in the centre of the wall
Further acoustic tests were conducted on the boxes at alternate locations in the reverberation chamber to replicate a real-world scenario. With four boxes arranged in a 2 x 2 formation along the back wall, the fundamental frequency absorption was 63Hz.
1x1 config test in the corner
1x1 configuration in the corner
With one box arranged diagonally facing into the room in one corner. The fundamental frequency absorption was 63Hz with further second harmonic absorption at 125Hz.
4x1 config test in corner
4x1 configuration in the corner
Four boxes arranged in the corner of the room in a column formation facing into the room. Absorption was evident in the frequency bands 63Hz, 125Hz and 160Hz.
6x boxes in centre test
6x boxes across the floor in the centre of the room
The initial tests with six boxes arranged in the centre of the floor were later repeated with the plastic plug-in inserts placed into the central funnels of the boxes. This was found to lower the frequency absorption down to 50Hz.
isa award winner
The P:VAD absorbs down to 63Hz/80Hz, and with multiple devices (x3) the use of the plug-in will take the absorption down to 40Hz/50Hz. The larger the space, the more devices are required for effective sound control, so where 2 or 3 will suffice for a small to medium size control room, proportionately more devices will be required for larger spaces.
Send Anthony a message using our online form to ask a question or for retail outlets where you can purchase P:VAD. REQUEST INFO