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The Acoustilyser is based on the NTI Audio (formerly part of Neutrik) Minilyser, offering a calibrated, portable, acoustic measurement instrument, to Class 1 or Class 2 standard when used with an appropriate microphone, at an extremely attractive price. Supplied with software which connects the instrument to a PC to transfer data or log data it is an all-in-one tool aimed at sound contractors, installers, and acoustics specialists; there are even functions useful for touring sound engineers and recordists. Available as a stand- alone test instrument or as a cross-grade package for existing Minilyser users to allow them to switch between the functions of the two instruments. Accessories and options include a Class 2 microphone and a package to add reliable measurement of STI, speech transmission index.

AL1 Acoustilyzer

The instrument is mechanically the same as the Minilyser, featuring an LCD display screen showing menu options and measured values. It offers over 16 hours use from three AA batteries. There is a balanced XLR input for making electrical measurements of balanced signals and for the connection of a measuring microphone such as the MiniSPL. An RCA (phono) socket takes unbalanced signals. A 3.5mm headphone socket provides for monitoring the incoming signal. A microphone is built-in, which may be used for polarity and delay measurements.

The addition of the MiniSPL microphone makes it possible to make acoustic measurements to Class 2 standard. The M2010 microphone may be used to make measurements to Class 1, but this and most other Class 1 standard microphones will require a suitable external power supply and appropriate calibration equipment.
The AL1 functionality may also be made available to existing Minilysers. Please see ML1-AL1 Cross-grade below. The same cross-grade option can be used to install the Minilyser functions on the AL1 to enable alternative electrical test functions. The included AL1 test CD has various useful audio test signals, such as delay-time test chirp and gated pink noise for RT60 measurements.

The AL1 is supplied with a copy of the Minilink PC software. This enables the transfer of stored measurements from the Acoustilyzer to a PC. Additionally online data logging from the AL1 directly to the PC is supported. The graphical display provides remote control of the instrument from the PC. Minilink supports Windows 98SE, 2000, ME and XP. When used with the software, power is supplied by the USB.


Sound pressure level: Leq, short-time Leq, Lmin, Lmax acc., IEC 61672. Timer for single and repeated measurements. Dynamic range: Using MiniSPL, 30-130dB SPL; using M2010 24-150dB SPL. Filters: Flat, A, C, inverse X-Curve, RLB (Broadcast Loudness). Logging of SPL/RTA results into AL1 memory. Wideband and RTA values available simultaneously.
Real time analyser: Third or octave-band resolution, Class 0 filters. SPL, Leq and Max-Min display per band.
Zoom FFT: Real-time Zoom FFT with 50% overlapping, 93 bins. Frequency range: 10Hz-20kHz. Resolution: 187.5-0.73Hz.
Reverberation time: Octave-band resolution, based on T20 results, according to ISO3382. Automatic averaging with individual result readout and storage. Source signal: Gated pink noise, included on CD.
Delay time: Propagation delay between electrical and acoustical signal input using built-in microphone. Resolution less than 0.1milliseconds. Dedicated test signal: NTI chirp included on the AL1 test CD.
Frequency: Range 10Hz-20kHz. Resolution 4 digits. Accuracy better than 0.1%.
Signal level: V RMS, dBu, dBV; resolution 3 digits (dB scale) or 4 digits (V scale). Accuracy 0.5% at1kHz. Bandwidth 20Hz-20kHz. Flatness +/- 0.1dB
Distortion: THD+N (total harmonic distortion +noise), measurement bandwidth 10Hz-20kHz. Resolution 3 digits (dB scale) or 4 digits (% scale). Residual THD+N; less than -85dB, from -10dBu to +20dBu, balanced or -74dB from 0dBu to +14dBu, unbalanced.
Polarity test: Requires a test signal generated by an NTI Audio Minirator. Positive or negative detection through internal microphone, balanced or unbalanced inputs. Checks polarity of midrange and low frequency speakers and cables, subject to a minimum 10dB S/N ratio of input signal.
Filters: Available on balanced and unbalanced input signals when measuring audio: Flat, A weighting, C weighting, high-pass 400Hz, inverted X-Curve, high-pass 19kHz.

Technical Specification:
Input impedance: 40kohms balanced, 20 kohms unbalanced
Maximum input level: +20dBu balanced, +14dBu unbalanced, audio,RMS (Adapter -20dB must be used for balanced input levels higher than +20dBu, to extend the range up to +40dBu).
Maximum input level: +/- 50V DC
Residual noise: Less than 12 microvolts, XLR input short circuited
Temperature: 0 to +45 degrees C
Humidity: Less than 90% RH, non condensing
Power source: 3 x AA batteries, alkaline, not rechargeable types, or USB.
Dimensions: 163 x 86 x 42 mm, (w) x (d) x (h)
Weight: 300g, including batteries

Included accessories: Minilink CD, Minilink USB cable, Acoustilyzer test CD, manual.
Optional accessories: STI-PA, MiniSpl, M2010 microphones, soft pouch, -20dB adapter, ML1- AL1 cross-grade package to load Minilyser functionality on the Acoustilyzer.

ML1-AL1 Cross-grade

This loads the Acoustilyser firmware onto an existing Minlyser, provided that this has been fitted with the Minilink upgrade, so the Minlyser effectively becomes an Acoustilyzer. It can also be used to load the Minilyzer firmware onto an Acoustilyser, providing electrical test functions such as level (measured RMS, Peak, in VU or as a PPM or oscilliscope), balance, THD, frequency. For more details please see NTI Audio ML1 Minilyser. A copy of the Minilink PC software is included, see description above.

Included accessories: MiniLink CD, Acoustilyzer test CD, license number for cross-grade, Acoustilyzer manual, Minilyzer manual.
Optional accessories: STI-PA, MiniSpl, M2010 measurement microphones, soft pouch, system case, -20dB adapter.


This option allows the reliable measurement of the speech transmission index according to IEC standards within 15 seconds. Besides the single value STI or CIS test result, a detailed view of the modulation indices and individual band level results is provided. Error indicator. Fulfills the IEC 60268-16 release 2003 standard (including amplitude weighting), TNO verified algorithm.

Included accessories: STI-PA test CD (STI-PA test signal), Acoustilyzer manual.


This is used with the Acoustilyzer to make a comprehensive integrating sound-level meter. A self-contained omni-directional half-inch measuring microphone with built-in impedance converter, pre-amplifier and power supply. It is battery powered and the XLR-output is balanced. The MiniSPL is classified as Class 2 in accordance with IEC 61672 and is factory adjusted to a sensitivity of 20 mV/Pa. The MiniSPL may also be used with the Minilyser.

Technical Specification:
Microphone type: 0.5-inch, omni-directional, pre-polarized condenser.
Sensitivity: 20(+/-2) mV/Pa, -34(+/-1) dBV/Pa at 1kHz
Frequency response: 100-1250Hz +/- 1.5dB
20Hz-20kHz +/-3dB
Peak acoustic input: 130dB SPL at 1kHz
Noise: 30dB SPL, A weighted
Output impedance: 200 ohms, XLR, balanced
Power source: 1 x AA size 1.5V battery, lifetime typically 300 hours, no phantom power required, phantom power resistant
Dimensions: 22mm diameter x 180mm
Weight: 100g including battery


A very compact and accurate measurement microphone providing Class 1 accuracy. It has a balanced XLR output and requires an external 10V - 48V DC phantom power supply. Supplied with microphone clamp, wind protection, case and individual calibration certificate.

Technical Specification:
Microphone type: 0.5-inch omni-directional pressure microphone
Sensitivity: 35 mV/Pa (-29 dBV/Pa), 1kHz, typical
Frequency response: Class 1, temperature -10 to +50 degrees C
Peak acoustic input: 150dB SPL (A-weighted)
Noise: less than 24dB SPL, A weighted

Adapter -20dB

A passive device in an XLR ‘barrel’, used when making electrical measurements on the balanced input where levels are higher than +20 dBu, to extend the range up to +40dBu. A fuse is incorporated for safe operation when connecting via USB.

Soft Pouch

This has a convenient belt clip and fits an Acoustilyzer or a Minilyser or Digilyser.

Minstruments System Case

A moulded case with foam cut-out inside. It will store a test system consisting of a Minirator plus Minilyzer or Acoustilyzer and a MiniSPL. Room is provided for cables, connectors and test CDs, for use in the field.

Acoustilyser Test Sets

Two acoustic test kits are offered. Both contain an Acoustilyser, an NTI Audio MR-Pro Minirator signal generator, MiniSpl microphone, the AL1 test CD, and a system case. The ‘Test kit with STI-PA’ contains the STI-PA option in addition.

Ordering Note

Unless otherwise stated, all products are exclusive of calibration certificate(s). NTi AL1 Acoustilyzer calibration certificates can be purchased optionally along with the product. Please ensure you add multiple calibration certificates if the system you are purchasing includes multiple products.

  Description Price (£) Add to basket
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NTI AL1 ACOUSTILYZER AUDIO ANALYSER Without calibration certificate   Stock code: 25-396
No longer manufactured. See the product page for suggested alternatives.
NTI AL1 ACOUSTILYZER STI-PA Option firmware   Stock code: 25-397
No longer manufactured. Unfortunately we are not currently able to offer an alternative.
NTI AL1 ACOUSTILYZER AL1/ML1 Crossgrade firmware   Stock code: 25-398
Please login for stock availability and lead times.
NTI MINISPL MEASUREMENT MICROPHONE Without calibration certificate   Stock code: 25-424
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NTI M2010 MEASUREMENT MICROPHONE Without calibration certificate   Stock code: 25-402
Please login for stock availability and lead times.
NTI ADAPTER, -20dB   Stock code: 25-395
Please login for stock availability and lead times.
NTI SOFT POUCH For ML1, DL1 or AL1   Stock code: 25-423
No longer manufactured. Unfortunately we are not currently able to offer an alternative.
NTI MINSTRUMENTS System case, holds 2 minstruments, mic and cables   Stock code: 25-426
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NTI ACOUSTIC TEST KIT PRO AL1, MR-Pro, MiniSpl, CD, case, without calibration certificates   Stock code: 25-388
No longer manufactured. See the product page for suggested alternatives.
NTI ACOUSTIC TEST KIT PRO STI-PA AL1, MR-Pro, MiniSpl, CD, case, without calibration certificates   Stock code: 25-389
No longer manufactured. Unfortunately we are not currently able to offer an alternative.
NTI MR2 MINIRATOR SIGNAL GENERATOR Analogue audio, without calibration certificate   Stock code: 25-421
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Please login for stock availability and lead times.