In addition to being a state-of-the-art sound level meter, the XL2 measures high-resolution RTA and FFT spectra, reverberation time, polarity, delay, and THD+N total distortion and noise levels. Optional features include STIPA speech intelligibility, advanced acoustic functions, noise curves, film calibration, pass/fail analysis, and remote measurement acquisition. With type approval, the instrument can be upgraded to the XL2-TA.

Sound Level Meter - The Flexible Solution

The XL2 is a powerful sound level meter for events and environmental noise monitoring. Numerous measurement variations are available. Actual level, Lmin, Lmax and Leq may be measured in combination with frequency weighting A, C or Z and time weightings fast, slow and optional impulse. All results are simultaneously available.

XL2 Sound Level Meter

Customers may log all acquired level information onto a removable SD card. Additionally the XL2 offers wav-file recording for a complete documentation of the measured sound pressure levels. Voice notes may also be added to each measurement.


  • Standards
    • IEC 61672, IEC 60651, IEC 60804, IEC 61260
    • China: GB/T 3785:2010, GB/T 3241, GB 3096-2008, GB 50526, GB-T_4959-1995
    • Germany: DIN 15905-5, DIN 45645-2, optional: DIN 45645-1
    • Japan: JIS C1509-1:2005, JIS C 1513 class 1, JIS C 1514 class 0
    • Switzerland: SLV
    • UK: BS6698, BS5969
    • US: ANSI S1.4:2014, ANSI S1.43, ANSI S1.11:2014
    • SMPTE ST 202:2010, ISO 2969:2015
  • Sound levels
    • SPL actual, Lmin, Lmax, Lpeak, Leq, gliding Leq
    • Frequency weighting: A, C, Z (=flat) simultaneously
    • Time weighting: Fast, slow and optional impulse simultaneously
    • Correction values k1, k2
    • Indicators show when sound level limits are exceeded
    • Digital I/O interface for the control of external peripherals
    • Sound Exposure Level LAE (optional)
    • Percentile statistics for Lxy (x= A, C or Z, y= F, S or EQ1"): 1 - 99% (optional)
    • Calculated levels: LCeq - LAeq, LAIeq - LAeq, LAFT5eq -LAeq (optional)
    • Clock-impulse maximum level "TaktMax" in accordance with DIN 45645-1 (optional)
  • Logging and Reporting
    • All levels simultaneously
    • Short-time levels including spectrum for 1 second or longer
    • Wav-file for listening (compressed)
    • Data logging in 100 ms intervals (optional)
    • Linear wav-files with 24 bit, 48 kHz resolution (optional)
  • Remote measurement acquisition (optional)

Real Time Analyzer RTA

The RTA perfectly suits tasks such as optimization of sound systems and rooms. The XL2 measures and logs wideband values and the real time spectrum in 1/1 or 1/3 octave-band resolution according to IEC 61260 class 0. The sound level meter results of the wideband and RTA spectrum are simultaneously available.

XL2 Sound Level Meter


  • 1/3 octave, 1/1 octave
  • Frequency weighting: A, C, Z (=flat)
  • Time weighting: Fast, slow and optional impulse
  • Percentile statistics for Lxy (x= A, C or Z, y= F or S ): 1 - 99% (optional)

Acoustic Analyzer

FFT Analysis

XL2 FFT AnalyseThe real-time FFT is the ideal tool for visualization of comb filters and narrow band effects. It measures the actual level and the averaged level Leq in three ranges over the entire audio band. The optional Extended Acoustic Pack offers an additional high-resolution Zoom-FFT up to 0.4 Hz steps in the frequency range 5 Hz - 20 kHz and adds the linear audio recording (24 Bit, 48 kHz). The Spectral Limits Option extends the FFT Analysis with trace capturing, relative curve display and comprehensive tolerance handling.

Reverberation Time RT60

XL2 RT60 NachhallzeitmessungThe XL2 measures the energy decay in the range from 63 Hz to 8 kHz by the Schroeder method in 1/1 octave bands. Automatic triggering and averaging of multiple measurements simplifies the operation and minimizes the measurement time. Use either an impulse source or an interrupted pink noise as the test signal. The optional Extended Acoustic Pack extends the reverberation time measurement to a 1/3 octave resolution.


XL2 PolaritätFor a stereo sound image, it is important to match the polarities of the left and right speakers. The XL2 measures the polarity of cables, single speakers and speaker cabinets. The detailed result page displays the measured polarity as octave bands from 125 Hz to 8 kHz. This allows in-depth verification of the polarity - frequency relation. The polarity test signal is provided by the NTi Audio Test CD or the Minirator test signal generator.

Delay Time

XL2 LaufzeitThe delay function supports the accurate setup of delay lines and thus the optimization of the directionality of the signal source. The XL2 measures the delay time between the electrical reference signal and the acoustic signal from the speaker. The required delay settings are displayed automatically, allowing the audio engineer to set the measured delay time directly into the delay device in the rack.

Speech Intelligibility STIPA (optional)

XL2 Sprachverständlichkeit STIPAThe XL2 Analyzer measures speech intelligibility according to the latest revision of standard IEC 60268-16:2020 (edition 5) as well as older revisions. It offers ambient noise correction and automated averaging for consecutive measurements. The XL2 displays the measurement results as STI or CIS, accompanied by the individual levels and modulation indices of the seven octave bands.

The measurement results are acquired from the dedicated STIPA test signal source:

  • NTi Audio TalkBox
    Acoustic signal generator, required for audio systems that include voice microphones, allows the entire signal chain to be measured.
  • Minirator MR-PRO
    Test signal generator, required for audio systems with line inputs
  • USB Flash Drive
    (included with XL2)

1/12 Octave Band Analysis (optional)

XL2 Oktavband AnalyseIf you are looking for more detailed spectral resolution, the Spectral Limits Option adds a 1/6th and 1/12th octave RTA analyzer to the XL2. Further, with this option, the XL2 can compare spectral measurements against a tolerance band and show exceptions in every frequency band as well as a passed/failed result. This result can be shown in color on the built-in LED limit button and is easily integrated into existing automated test systems or shown on the Stack Light via the XL2 I/O interface.

Fast Frequency Response (optional)

Measuring the frequency response of an acoustic or audio component is often required. The NTi Audio FastPink1” and FastPink4” test signals are particularly well-suited if you need to save time, as these signals settle within 1 or 4 seconds, respectively, which is much faster than traditional pink noise. These FastPink signals are available on the MR-PRO signal generator. The Spectral Limits Option must be installed on the XL2 for this fast frequency response analysis.

AppNote Fast Frequence Response Measurements

Noise Curves (optional)

XL2 Noise CurvesThe noise curve measurement provides an objective rating of the background noise level in a room or environment. The noise curve rating of a spectrum is designated as the value of the highest noise curve “touched” by the measured octave-band spectrum. The speech interference level (SIL) and the noise curve rating are calculated in parallel. The Noise Curve function is offered with the Spectral Limits Option.

The XL2 Acoustic Analyzer measures the following Noise Curves:

  • Noise Criteria NC (ANSI/ASA S12.2-2019)
  • Room Noise Criterion RNC (ANSI/ASA S12.2-2019)
  • Room Criteria RC (ANSI/ASA S12.2-2019)
  • Noise Rating NR (ISO/R 1996-1971)
  • PNC Rating (ASA 1971)

Analog Audio Analyzer

Level RMS / THD+N

XL2 Effektivwertpegel RMS / THD+NThe XL2 with balanced XLR and unbalanced RCA inputs offers a comprehensive, high performance audio analyzer. It simultaneously measures balance, level, distortion (THD+N) and frequency. The internal loudspeaker or headphone output offers audible monitoring of either the input signal or just the residual distortion. The optimized low distortion and low noise design enable level measurements down to -112 dBu and residual distortions typically lower than -100 dB, which is unmatched in handheld instruments.

Audio Spectrum

XL2 Spektrale AudiomessungSpectral audio measurements are offered in the units Volt, dBu and dBV within the following measurement functions:

  • Sound Level Meter (1/3 and 1/1 Octave)
  • FFT
  • 1/12 Octave (optional)


XL2 OszilloskopThe scope function visualizes the waveform of the electrical input signal. It triggers to the fundamental frequency and selects the scaling of the X-axis (time) and Y-axis (level) automatically. The fundamental or most dominant frequency is displayed above the scope screen.