Environmental Noise Monitoring

The XL2 Sound Level Meter provides the dedicated solution for environmental noise monitoring in industry and communities. It measures levels and detailed spectral information in parallel and stores the data on an SD card for post-processing and reporting. A linear audio file (wav-file) may be recorded for detailed simultaneous analysis.


  • Noise annoyance assessment
  • Rating level calculation
  • Verifying boundary noise level emission


The XL2 is a type approved class 1 sound level meter and offers a flexible handheld instrument with accurate and reliable measurements. Data recording can be scheduled to occur at pre-determined times or automatically triggered when pre-determined levels are exceeded. The Data Explorer software automatically marks periods containing tones or impulse and calculates the rating level Lr for comparison with the applicable limits.

XL2 測定ファンクション

XL2 with M4260 Measurement Microphone

XL2 サウンドレベルメータ

音圧レベル SPL

XL2 monitors the noise pollution to verify any annoying or excessive noise. All sound levels such as actual, Lmin, Lmax, Leq and the sound exposure level LAE are simultaneously measured and logged with frequency weighting A, C, Z and time weightings Fast, Slow and the optional Impulse.

The event recorder functionality triggers the measurement by programmable level thresholds or manually by the external input key pad. (optional with Extended Acoustic Pack).

Rating Level Lr

The XL2 Sound Level Meter measures environmental noise according to the ISO 1996 standard. The Rating Level Lr is used as a measure to evaluate long-term annoyance of noise. This is calculated from the A-weighted equivalent continuous sound level LAeq with various adjustments:

Lr = LAeq + KI + KT + KR + KS
KI Adjustment for impulsiveness
KT Adjustment for tones and information content (survey and engineering method)
KR Adjustment for the time of the day
KS Adjustment for special situations and noise sources

These adjustments are standardized and differ between countries. The Data Explorer software automatically determines periods with impulsive or tonal noise and calculates the rating level Lr. 

Percentiles (optional)

Measures statistic sound levels in wideband and the real time spectrum 0,1% - 99,9%.

Application Examples:
  • Road Traffic Noise
  • Industrial Noise
  • Noise Pollution Level LNP = Leq + (L10 - L90)

Remote Measurement (optional)

Allows querying the XL2 measurement data online via the USB interface. Thus customers may integrate the XL2 into their noise monitoring application.

屋外測定用マイクロホン M2230-WP

Outdoor Measurement Microphone

The Outdoor Measurement Microphones offer a weather-protected measurement solution for the Sound Level Meter allowing acquisition of environmental noise data in outdoor applications. 耐食性に優れたポリマーハウジング、ウィンドスクリーン、撥水ボディ、バードスパイクが、雨、風、塵、鳥から強力に保護します。

The Outdoor Measurement Microphones M2230-WP and M2340-WP fulfill the Class 1 requirements according to IEC 61672 and ANSI S1.4 for horizontal and vertical sound incidence. For compliance with horizontal sound incidence a spectral correction is employed in the associated Sound Level Meter. The Outdoor Measurement Microphone M4261-WP fulfills the Class 2 requirements accordingly.

The outdoor microphones consist of a measurement microphone and the applicable weather protection:

  • M2230-WP: M2230 + WP30-90 / -150 ウェザープロテクション
  • M2340-WP: M2340 + WP30-90 / -150 ウェザープロテクション
  • M4261-WP: M4261 + WP61 ウェザープロテクション


  • Class 1 and Class 2 Outdoor Measurement Microphones for vertical and horizontal sound incidence according IEC 61672 and ANSI S1.4 (with XL2)
  • 雨と塵(IP54)、風、鳥から強力に保護
  • 腐食に強い材質
  • 上部パーツを外し、簡単にマイクロホンの校正が可能
  • Standard tripod mount, optional pole mount


The 90 mm or 150 mm wind screen protects the measurement microphone from rain and dust while reducing wind-induced noise. The seamless design of the water-repellent membrane under the wind screen ensures perfect protection from rain and dust.


The Outdoor Measurement Microphone M2340-WP is system self-test (CIC) enabled. Automated self-tests may be performed by NoiseScout, the unattended noise monitoring solution, in combination with the Sound Level Meter. This ensures reliable operation and precise measurements.




Basic Outdoor Case

NTi Audio #:
  • IP43: 600 000 471
  • IP63: 600 000 473


XL2 Outdoor Case


NTi Audio #:
  • IP43: 600 000 476
  • IP65: 600 000 477


Noise Monitoring Terminal


NTi Audio #:

  • Enclosure Large, IP55: 600 000 480
  • Enclosure Large, IP66: 600 000 486
  • Enclosure Compact, IP66: 600 000 485




PTB型式承認オプションをXL2にインストールすると、XL2-TAへアップグレードします。M2230をXL2-TAに接続しシュラウドジャケットを組み合わせると、IEC 61672:2014、IEC 61260:2014、ANSI S1.4:2014、ANSI S1.11:2014規格に準拠したclass 1サウンドレベルメータとして使用できます。


  • XL2-TA サウンドレベルメータ (XL2 に型式承認オプションをインストール済み)
    • ファームウェア V3.11
    • オプション:拡張アコースティックパック
    • オプション:XL2入力キーパッド
  • M2230測定用マイクロホン
  • Shroud MXA01


XL2 Type Approval Certificates:

Local Noise Monitoring Network


XL2 Noise Monitoring Network

Individual Solution programmed by Customer




Exel Set for Environmental Noise Monitoring


  • XL2 サウンドレベルメータ
  • エクステンデッド・アコースティックパック
  • Data Explorer 365
  • M2230 測定用マイクロホン
  • ASD ケーブル
  • XL2用ACアダプタ
  • Exel システムケース



for outdoor noise assessments


for type approved measurements and certification


for accurate noise measurements


for querying measurement data online from the PC


for visual (pre-) warning indication