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Certificate – booth noise reduction SPB33S (NIC 25)
The SPB33S soundproof booth (single-layer version, 100 × 100 × 200 cm) was measured in the accredited laboratory Riverbank Acoustical Laboratories. On this page you will find the result, the table of measured values, our sheet with the conversion and an excerpt from the original report.
Download: booth noise reduction sheet (1 page) · detailed sheet with an excerpt from the report
What was measured
The complete assembled booth was measured, including the door and the transparent window, not an individual panel. The booth stood in a reverberation room where a loudspeaker played, and the laboratory measured the noise level outside the booth and inside it. The method is called ASTM E596 and its result is the noise reduction (NR) in one-third octave bands. The measurement took place on 13 November 2019, report RAL-NR19-002.
Result: NIC 25
From the measured values the laboratory determined the single-number rating NIC 25 (Noise Isolation Class) according to ASTM E413. The number is intended for enclosed booths and cabinets, whereas STC and Rw are used for materials and partitions.
| Band | 125–160 Hz | 200–315 Hz | 400–630 Hz | 800–1,250 Hz | 1,600–2,500 Hz | 3,150–5,000 Hz |
|---|---|---|---|---|---|---|
| Noise reduction | 7 dB | 16 dB | 21 dB | 25 dB | 32 dB | 37 dB |
Measured values by band
The table shows the noise reduction of the booth in all one-third octave bands from the report. The higher the value, the more noise the booth stops in that band.
| Frequency [Hz] | Noise reduction [dB] |
|---|---|
| 100 | 3 |
| 125 | 12 |
| 160 | 10 |
| 200 | 14 |
| 250 | 16 |
| 315 | 19 |
| 400 | 19 |
| 500 | 21 |
| 630 | 22 |
| 800 | 24 |
| 1,000 | 25 |
| 1,250 | 28 |
| 1,600 | 31 |
| 2,000 | 33 |
| 2,500 | 35 |
| 3,150 | 36 |
| 4,000 | 37 |
| 5,000 | 40 |
Conversion according to EN ISO 717-1
To make the result comparable with European ratings, we applied the EN ISO 717-1 procedure to the measured values in the 100–3,150 Hz bands. The result is a weighted rating of 25 dB (C = −1; Ctr = −6). It is a calculation from values measured by the ASTM E596 method, not a measurement according to EN ISO 11957, so we give it only as a supplement to the NIC value.
How to read NIC, STC, Rw and αw
NIC describes how much noise the whole enclosed booth stops. STC and Rw describe the sound insulation of a material or partition, without doors and gaps. αw describes how much sound a material absorbs, that is, how much it reduces echo. Numbers for different quantities therefore cannot be compared with one another.
Interior panels: αw 0.75
The interior panels of the booth are made of deNoise 1300 acoustic material in a single layer. Its laboratory measurement (Riverbank A12-119, EN ISO 11654) gave αw = 0.75. They absorb sound inside the booth, which reduces echo. You can find the full report in the article Certificate αw deNoise 1300.
Sizes SPB63 and SPB66
The SPB33 booth was measured. The SPB63 and SPB66 booths have the same wall construction and the same interior panels. The actual sound reduction also depends on how the booth is assembled and how well the door is sealed.
Original report
The annex contains pages 6 and 8 of 9 of report RAL-NR19-002 unchanged (table and chart of the noise reduction). You will find it in the detailed sheet.
