NTi – XL3 Acoustic Analyzer Functions

NTi Audio XL3 with microphone

The XL3 is a professional sound level meter and acoustic analyzer for noise measurements, room acoustics and building acoustics – optimized for the needs of the acoustician.

Class 1 Sound Level Meter

The XL3 forms a class 1 sound level meter in combination with the measurement microphones M2230 or M2340. All sound pressure levels are measured precisely at the same time and presented in large digits on the color display. Readings exceeding the preset limit turn red indicating non-compliance, while the data is logged in 1 second intervals and the audio is recorded simultaneously. The XL3 is the perfect tool for an easy investigation of noise complaints and long-term noise monitoring. Type approval is pending.

Additionally, the noise spectrum is measured in both octave or one-third-octave resolution, e.g. for tonality investigations, as well as the optional event-marker, back-erase and pre-trigger – all of which extend the sound level meter capabilities for effective attended environmental noise surveys.


At the same time, the XL3 Sound Level Meter is optimized for unattended noise monitoring. The instrument automatically continues the measurement as soon as power resumes in case of an accidental power failure. The long battery life time and the versatile connectivity options allow online control from your preferred web browser from anywhere around the globe including audio streaming for live listening. A weather station may be connected directly to the XL3 and external devices controlled via the accessory I/O-PCB.

All stored measurement data is available in simple text format. Detailed data evaluation and rating level calculations are carried out in the optional Data Explorer PC Software.

Noise Spectrum

The XL3 determines the frequency spectrum with a Class 1 filter bank in octave or one-third octave resolution between 6.3 Hz and 20 kHz. The minimum, maximum and average sound pressure levels of all frequency bands are measured in parallel. The frequency axis can be freely zoomed and scrolled to e.g. 125 Hz – 8 kHz for appliance noise investigations. The summed level of the selected frequency range is shown in the spectrum view at the same time.

Noise Spectrum

Reverberation Time

The XL3 measures the reverberation time in octave bands from 63 Hz – 8 kHz using the standardized T20 or T30. The room may be excited using an impulse source or an interrupted pink noise. The Acoustic Analyzer averages all the recorded decays for each measurement position automatically. Additionally, installing the Extended Room Acoustics Option enables reverberation time measurement in one-third octave resolution, visualizing the decay curve, calculating the spatial average of the room and simultaneous T30/T20/T15/EDT measurement on the XL3 Acoustic Analyzer. Additional quality indicators, such as linearity and curvature, describe the decay curve in accordance with the standard ISO 3382-2. An audio file of the level decay may be recorded for more detailed analysis.

Reverberation Time

Sound Insulation (optional)

The XL3 Acoustic Analyzer enables direct determination of airborne, impact and facade sound insulation on the instrument. Simply measure in the sending and receiving room and see the sound insulation values displayed for immediate compliance confirmation on-site. For additional partitions with the same source or receiving rooms, the XL3 offers time-saving features by re-using of measurement data from previous measurements e.g. reverberation time data or background noise measurements for a common receiving room. In order to prevent any sound absorption from your body, you can leave the room and control the instrument from your mobile phone using Wi-Fi or the 4G/5G network. Generating the final measurement report for sign-off is easy utilizing the optional Sound Insulation Reporter PC Software.

Sound Insulation optional

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