NTI NEU-AL1 User Manual

ACOUSTILYZER

User Manual

AL1

MiniLINK, Minilyzer, Digilyzer, Acoustilyzer, Minirator, MiniSPL and Minstruments are trademarks of NTI.

NTI contact details:

NTI AG Im alten Riet 102 9494 Schaan Liechtenstein, Europe Tel. +423 - 239 6060 Fax +423 - 239 6089 E-mail info@nt-instruments.com Web www.nt-instruments.com

Index:

1. Introduction 4

CE Declaration of Conformity 5 International Warranty and Repair 6 Warnings 7 Test & Calibration Certicate 7

2. Overview 8

Acoustilyzer Functions 9 Easy Operation 9 Connectors 10

3. Basic Operation 12

Start-up Screen 13 Menu Bar 13

4. Measurement Functions 22

SPL/RTA - Sound Level Meter 23 SPL/RTA - Real Time Analyzer RTA 27 Reverberation Time RT60 36 FFT Analysis 42 Polarity Test 46 Delay Time 48 Electrical Measurements - RMS/THD 51 Speech Intelligibility STI-PA (optional) 53 Calibration 61

5. MiniLINK PC Software 64

Installation 64 Start the MiniLINK PC Software 65 Free Registration of your Test Instrument 66 Read Out of Stored Test Results 67 Visualizing the Test Results 68 Test Result Logging at the PC 72 Remote Test Instrument Control with the PC 74 MiniLINK Tools 75 Activate Options 81

6. Troubleshooting 82

7. Accessories 83

8. Technical Specication 85

9. Appendix: Introduction to STI-PA 88

1. Introduction

Congratulations and thank you for buying NTI’s Acoustilyzer AL1, a product specially suited for professional acoustical test applications. The Acoustilyzer offers advanced acoustics functions including an optional speech intelligibility STI-PA measurement module and further basic electrical features. We are convinced you will enjoy using it!

This manual describes the Acoustilyzer AL1 functions and measurements in detail. Further application information about the acoustical and electrical measurements can be found on the web site “www.nt-instruments.com”.

The Acoustilyzer AL1 is available as stand alone test instrument or as crossgrade package for existing Minilyzer ML1 users. The same crossgrade option can be used to install the Minilyzer functionalities on the AL1. The STI-PA measurement feature is optional.

The product packages includes the following items:

Acoustilyzer AL1 1x Acoustilyzer AL1

1x MiniLINK CD (PC software)

1x MiniLINK USB Cable

1x Acoustilyzer Test CD

1x Acoustilyzer User Manual

ML1-AL1 Crossgrade 1x MiniLINK CD (PC software)

1x Acoustilyzer Test CD (audio samples)

1x License Number Crossgrade

1x Acoustilyzer User Manual

1x Minilyzer User Manual

STI-PA Measurement Option

1x STI-PA Test CD (STI-PA test signal)

1x License Number STI-PA

1x Acoustilyzer User Manual

CE Declaration of Conformity

We, the manufacturer

NTI AG Im alten Riet 102 9494 Schaan Liechtenstein, Europe

hereby declare that the product Acoustilyzer AL1, released in 2004, conforms to the following standards or other normative documents.

EMC-Directives: 89/336, 92/31, 93/68 Harmonized Standards: EN 61326-1

This declaration becomes void in case of any changes on the product without written authorization by NTI.

Date: 1. September 2004

Signature:

Position of signatory: Technical Director

International Warranty and Repair

International Warranty

NTI guarantees the functionality of Acoustilyzer AL1 against defects in material or workmanship for a period of one year from the date of original purchase, and agrees to repair or to replace at its discretion any defective unit at no cost for either parts or labor during this period.

Restrictions

This warranty does not cover damages caused through accidents, misuse, lack of care, the attachment or installation of any components that were not provided with the product, loss of parts, connecting the instrument to a power supply, input signal voltage or connector type other than specied or wrongly polarized batteries. In particular, no responsibility is granted for special, incidental or consequential damages. This warranty becomes void if servicing or repairs of the product are performed by any party other than an authorized NTI service center or if the instrument has been opened in a manner other than specied in this manual. No other warranty, written or verbal, is authorized by NTI. Except as otherwise stated in this warranty, NTI makes no representation or warranty of any kind, expressed or implied in law or in fact, including, without limitation, merchandising or tting for any particular purpose and assumes no liability, either in tort, strict liability, contract or warranty for products.

Repair

In case of malfunction, take - or ship prepaid - your NTI Acoustilyzer AL1 packed in the original box, to the authorized NTI representative in your country. For contact details see the NTI web page “www.nt-instruments.com”.

Make sure to include a copy of your sales invoice as proof of purchase date. Transit damages are not covered by this warranty.

Warnings

In order to avoid any problems during the operation of the instrument, follow the rules listed below:

• Use the instrument for the intended purpose only.

• Never connect the instrument to a high voltage output such as a power amplier, mains power plug, etc.

• Do not disassemble the instrument.

• Never use the instrument in a damp environment.

• Remove the batteries as soon as they are at or if the instrument is not intended to be used for a longer period of time.

Test & Calibration Certicate

This is to certify the Acoustilyzer AL1 is fully tested to the manufacturer’s specications. NTI recommends to calibrate this test instrument one (1) year after purchase. Thereafter the calibration- and adjustment interval is subsequently one (1) year.

2. Overview

The Acoustilyzer AL1 is a sophisticated tool used to analyze acoustical signals. It is designed for easy and quick detailed analysis of the acoustic environment and to carry out the most important electrical measurements. An accurate overview of the actual acoustical signal is displayed on a large LCD.

The AL1 is a class 1 accuracy instrument and available with the measurement microphones MiniSPL (class 2) or M2010 (class 1 frequency response). Alternatively other measurement microphones can be used.

Class 1 acoustics analyzer

NTI offers the class 1 frequency response microphone M2010 (an external phantom power supply is required). The Acoustilyzer in combination with the M2010 measurement microphone forms a highly accurate class 1 acoustics analyzer.

Class 2 acoustics analyzer

The Acoustilyzer in combination with the MiniSPL forms a comprehensive class 2 acoustics analyzer. MiniSPL is a battery powered measurement microphone. It is the ideal accessory for the Acoustilyzer.

Acoustilyzer Functions

The Acoustilyzer AL1 features many measurement functions, which are accessible through a drop down menu bar.

The base element is the cursor (inverted area), which may be navigated through the various functions by using the cursor keys.

• SPL/RTA: Sound pressure level & time-averaged sound pressure

level (LEQ) measurements of wideband, octave or 1/3 octave values

• RT60: Reverberation time with 1/1 octave band resolution

• FFT: Real time zoom FFT

• POLARITY: Polarity measurement of speakers and line signals

• DELAY: Delay time measurements between speakers

• RMS/THD: Level and distortion measurements

• STI-PA: Speech intelligibility measurement (only visible after

received STI-PA license activation key)

• CALIBRTE: Calibration of connected measurement microphone

Easy Operation

Unit selected with cursor to change setting

All selectable settings may be adjusted simply by

• Pressing the enter key to select the

requested value.

• Alternatively at longer selection lists the

chosen eld is ashing. Now select the requested value with the cursor keys. Conrm the setting by pressing the enter key again.

Connectors

On top of the AL1, three connectors as well as the internal microphone are located:

• The XLR and RCA inputs allow to feed a signal to the AL1.

• A 3.5 mm (1/8“) jack monitor output allows the connection of a headphone. Thus, the user may hear any electrical input signal.

• The internal microphone is used to test the polarity of loudspeakers and for delay time measurements. SPL measurements are not supported with this internal microphone.

XLR & RCA Inputs

Monitor Output

Internal Microphone

Note: Never connect the XLR- and the RCA input at the same time!

Battery Replacement

After unpacking, insert three (3) pcs. 1.5 V alkaline batteries, type AA, LR6, AM3 into the AL1 battery compartment as shown below. The typical lifetime for a set of alkaline batteries is 16 hours.

Notes:

• We do not recommend to use rechargeable NiCd- or NiMHbatteries.

• Do not insert batteries of different types.

• Replace all batteries at the same time - never mix old and new batteries.

• Note the correct polarities of the inserted batteries.

• Remove the batteries as soon as they are at and change all batteries at the same time.

3. Basic Operation

In spite of the wide range of available measurement functions and optional setups, the operation of the Acoustilyzer is almost self-explanatory.

Menu Bar

Test Result

Power On/OffBacklight

Escape button

Enter / Cursor Keys

The LCD is divided in the menu bar on top and the measurement results displayed below.

The cursor keys and the escape button allow straightforward navigation through the available features

• Actual settings (measurement function, filters)

• Measurement results (numerical or graphical display)

Start-up Screen

The start up screen remains displayed by pressing and holding any button during the start up of the unit. This supports e.g. the read out of the instrument serial number from your device. The serial number starts with three letters (such as e.g. ANK675A2A2).

After the successful registration of the AL1 the start-up screen may be customized. See details in “Customizing start-up screen” later in this user manual.

Menu Bar

The menu bar allows the selection of the basic test congurations.

Measurement Functions

Screen Selector

Memory Menu & Battery Status Indication

Input Filters

Setup Screen

Measurement Functions

• SPL/RTA: SPL & RTA measurement

• RT60: Reverberation Time

• FFT: Real time zoom FFT

• Polarity: Speaker polarity

• Delay: Delay time

• RMS/THD: RMS level and distortion

• STI-PA: Speech intelligibility

• Calibrte: Calibration menu

Screen Selector

The Acoustilyzer features the SPL/RTA, RT60 and STI-PA function with two different test result screens.

e.g. the SPL/RTA “123” is showing the sound level meter screen and the marked graphical symbol shows the real time spectrum analyzer.

Short-cut

Hold the ESC button down and additionally press the left or right arrow key to switch inbetween the two display screens within the same measurement menu.

Input Filters

Depending on the slelected measurement functions the following sets of lters are available:

SPL/RTA function:

Filters Applications

FLAT

Flat frequency response (no ltering)

Overall sound pressure level, all sound signal components are included without weighting, required for special applications;

A-WTD A-weighting lter acc. IEC 61672

Applicable for most common sound pressure levels if level weighting following the human ear is required.

C-WTD

C-weighting lter acc. IEC 61672

Applicable for high sound levels if level weighting following the human ear is required. Verify the lter setting with the test specications.

X-CRV

-1

Inverted X-Curve lter acc. ISO 2969

Required for cinema installations

RLB (=Revised Low frequency B-curve)

Broadcast Loudness lter acc. AES Paper “Loudness Assessment of Music and Speech” 2004

Applicable for loudness measurement of broadcast material. The revised Bweighted Leq measurement (=RLB) correlates the best to the subjective experience by humans.

RMS/THD function:

Filters Applications

FLAT

Flat frequency response (no ltering)

Default measurement setting.

A-WTD A-weighting lter

Measuring residual noise of the unit under test acc. IEC 61672 e.g. in sound broadcasting applications.

C-WTD

C-weighting lter acc. IEC 61672

Special applications.

HP400

Highpass 400 Hz acc. DIN 45045, -120dB/dec.

Removes any mains frequency (50/60Hz) components from the test signal.

HP19k

Highpass 19 kHz

Removes any low frequency components from the test signal, e.g. to measure any 20kHz pilot tone level of critical public announcements systems.

Setup Screen

The setup screen allows to customize basic settings of the Acoustilyzer AL1 by the following procedure:

• Move the cursor to the corresponding eld and press the enter key.

• Select the required status by using the arrow keys.

• Press the enter key to conrm.

AUTO POWER OFF denes the time the AL1 is switched OFF automatically

after the last key-press. The available settings are 3 MIN, 10 MIN, 30 MIN, 60 MIN and DISABLE. In case DISABLE is selected, the user has to turn the unit off manually or it will run until the batteries are discharged.

Acoustilyzer operation with MiniLINK PC Software

During the operation of the AL1 with the MiniLINK PC software, the AL1 is powered from the PC and the following power saving functions are disabled:- Auto Power Off - Auto Light Off. After the PC software MiniLINK is switched off the Acoustilyzer is continuously further powered from the PC but the power saving features are enabled again.

AUTO LIGHT OFF denes how long the backlight stays on after any key

stroke. Possible selections are 3 SEC, 10 SEC., 60 SEC. and DISABLE. In the latter case, the backlight will stay on, until the unit is switched off. The longer the backlight is turned on, the shorter lifetime of the batteries will be.

LCD CONTRAST adjusts the contrast of the display. Alternatively, hold the

ESC button down and press the up/down arrow key simultaneously in any measurement panel.

MULTIPLE SETUP allows to store up to four individual settings. To enable

the multiple setup mode, set the corresponding entry to ENABLE and conrm. At the next time the Acoustilyzer is switched on, the user will have to select the individual setup-ID (1, 2, 3 or 4) in the startup screen. All parameter settings in all measurement modes are now stored under this ID at switch off.

Memory Menu & Battery Status Indication

All measurements can be stored into the internal instrument memory. Each record is saved with a le name consisting of the test mode and a continuous running number from 000 - 999, such as “A001_RMS_THD” or “A002_RT60”. The running number starts after 999 with 000 again. You can store the test results as follows:

• STORE+BMP

Saves the numeric test results including the graphical screenshot, indicated by BMP (=bitmap) in the memory overview.

• STORE

Saves the numeric test result, so occupying less memory space.

• VIEW + DELETE

The stored measurement results are listed in ascending order from bottom to top, so the latest recorded measurement is always on top of the list. The remaining memory space is displayed in the rightupper corner of the screen.

All screenshots marked with BMP can be reviewed directly on the instrument.

• Select any record in the list using the cursor.

• Press and hold the enter key.

• The recorded measurement is displayed on the instrument screen

• The selected record is marked in the memory menu by the full square in the front. You can recall the marked record at any time later by holding down the ESC button and pressing the enter key simultaneously.

Delete individual memory records

Each stored result can be deleted individually from the memory.

• Select the DEL eld beside the memory location to be deleted.

• Conrm OK within the pop up window and press the enter key.

• The memory location is deleted from the device memory.

Delete all memory records

The complete memory can be deleted by selecting the eld “DEL ALL“.

LOAD

Various Acoustilyzer functions support the test result data loading from the internal AL1 memory. This features is very useful for detailed test result read out of previously stored measurements on the test instrument.

The following measurements support this feature:

• SPL/RTA

• RT60

• FFT

• STI-PA

Note: Any ongoing measurement is

continuing during loading and reading a memorized test result.

Application example using SPL/RTA:

• Select LOAD in the memory menu and press enter.

• The possible memorized data for loading are displayed.

• Select the test result of interest.

• Conrm the selection with the enter key → the square symbol in front of the selection is lled up.

• Press the ESC button (cursor jumps to OK) and conrm with enter.

The loaded test result is displayed on the active AL1 screen and the abbreviation LOD is ashing in the status bar memory eld.

The individual band levels can be read out, the Y-axis altered or even the Leq or min/max. test result shown. Non-available functionalities are not selectable.

Return back to the live mode by selecting LIVE MODE in the memory menu of the upper menu bar.

Low battery indication

A low battery symbol is displayed in the “MEM” eld of the menu bar to indicate that a change of batteries is required.

4. Measurement Functions

Overview

Function

Test

Result

Screens

Test Features

SPL/RTA Sound Level Meter

Sound pressure level SPL, MAX/MIN SPL, LEQ, LcPEAK

Real Time Analyzer

1/1 and 1/3 octave real time spectrum analyzer showing SPL, MAX/MIN SPL & LEQ per band

RT60 Reverberation Time

in octave band resolution based on T20 results

Reverberation Time

detailed test results listed in seconds including correlation factor

FFT Real-time Zoom FFT

POLARITY Polarity Test

of acoustical speaker or electrical line signals

DELAY Delay Time

Propagation delay measurement between electrical reference and acoustical signal

RMS/THD Electrical Measurements

Level RMS, THD+N, Frequency

STI-PA Speech intelligibility

of public announcement systems in STI or CIS test results (only visible after received STI-PA license activation key)

Speech intelligibility

Individual LEQ and STI-PA modulation indices of test frequency bands

CALIBRTE Calibration Menu

for external measurement microphones, sensitivity set by default to NTI MiniSPL

SPL/RTA - Sound Level Meter

The Acoustilyzer features a comprehensive, integrating sound level meter with timer for single or repeated measurements. All results may be logged into the internal memory for further investigations.

The measurements displayed on the big and small result position may be altered between

• SPL Actual sound pressure level

• MIN SPL Minimum sound pressure level

• MAX SPL Maximum sound pressure level

• LEQ time-averaged sound pressure level

• PreLEQ LEQ of the previous timer period (only available when timer is in repeat mode

• LcPEAK: C-weighted peak sound pressure level

The included Timer allows automatically to

• Stop the LEQ, LcPEAK and MAX/MIN SPL measurements after a user dened time

• Reset the LEQ, LcPEAK and MAX/MIN SPL measurements after a user dened time to start a new measurement.

Time Weighting indicator / selector

Timer Status

Pause Measurement

Timer, Clock

Reset Test Cycle

Period

SPL Bargraph and range indication

Input Range indicator arrows

Big Result

Small Result

Test Applications: “Timer Status” Setting

TIMER OFF

(applicable for standard measurements) All values are recorded and monitored continuously. The measurement timer shows the actual testing period length. Pressing the RESET icon sets the clock and the test results back to zero.

TIMER SINGLE

Sound pressure level measurement with user dened time setting.

• Set the required test cycle period.

• The clock counts back to zero. After the dened test time is completed the clock is ashing as”00.00.00”.

• The test results LEQ, LcPEAK and MAX/MIN SPL are frozen.

• Changing the test cycle period setting or pressing the RESET icon restarts the measurement.

TIMER REPEAT

Automatically repeating measurements with user-dened test time interval.

• Set the required test cycle period.

• The measurement timer counts back to zero. When the test time is elapsed the clock and the test results are reset and a new measurement is started.

• The previously measured LEQ is displayed as PreLEQ (very useful for LEQ monitoring at concerts)

• Changing the test cycle period or pressing the RESET icon restarts the measurement.

Pause: The LEQ, LcPEAK and MAX/MIN measurements can be paused

• Select the PAUSE symbol and press the enter key.

• The PAUSE symbol is ashing.

• The actual SPL value is continuously measured and displayed.

• Select the pause symbol and press the enter key to continue the measurement, visible by the continuing counting clock.

Reset: Pressing the RESET icon restarts the measurement. The timer and

test results are reset.

Test Cycle Period: Applicable in SINGLE and REPEAT timer status only.

• SINGLE: Set to 10 min by default

• REPEAT: Set to 10 sec by default

Measurement Timer: Actual measurement in hours:minutes:seconds.

Big and Small Result: Two of the previous listed measurements may be

display at the same time.

Time Weighting: All SPL measurements (SPL and MAX/MIN SPL)

are time weighted measurements. Changes in the SPL level are smoothed resulting in quicker or slower change of the displayed value. Available time weightings, corresponding to IEC 61672, are

• SLOW (long attack- and release response time, t = 1s)

• FAST (short attack- and release response time, t = 125ms)

The time weighting for the broad band values ( ) and the RTA ( ) are always the same.

Overload

The OVL (Overload) is ashing if the input voltage exceeded the selected input range of the instrument. As long as the OVL is ashing the displayed LEQ and LcPEAK result is not accurate.

Input Range Selector & Bargraph

In the SPL/RTA Mode the AL1 has three measurement ranges. The span of each range depends on the sensitivity of the used microphone. For a MiniSPL with a sensitivity of 20mV/Pa the measurement ranges are:

20 to 100 dB 40 to 120 dB 60 to 140 dB

The selected input range is displayed at the bottom of the bargraph and may be changed by operating the range indicator arrows. The bargraph provides an analog display of the actual sound pressure level.

Primary Indicator Range

To achieve best measurement accuracy the appropriate range

must be selected, called “primary indicator range”. Correct setting avoids overow indications and lowers the inuence of noise on the measurement result.

The two range indicator arrows assist the user to set the optimal range.

As soon as the indicated bargraph value is found lower than the primary indicator range, the down arrow symbol below RNGE will start to move, symbolizing the actual SPL measurements are inaccurate. The bargraph range needs to be changed manually by selecting the moving left arrow symbol and pressing the enter key.

Note: Changing the ranging resets all ongoing measurements.

By exceeding the primary indicator range three overload arrows replacing the big result reading.

• Select the right arrow below RNGE and press enter to change to the next higher bargraph range.

SPL/RTA - Real Time Analyzer RTA

The Acoustilyzer sound level meter features the individual 1/3rd or full octave band test results using class 0 lters. The SPL, MAX / MIN and LEQ values are displayed per band.

Stored spectra may be averaged by using the available mathematical functions. The MAX-MIN display is particularly helpful for characterizations of listening areas.

Input Range indicator arrows

Audio Spectrum

Set Menu

Pause Reset Cursor

Readout

X-Axis with manual range selection

Y-Axis

The audio spectrum is displayed without interrupting any ongoing sound level measurements, so e.g. changing from to screen will not interrupt the ongoing sound level measurements.

Input Filter

The SPL/RTA input lter for the broad band values ( ) and the RTA ( ) may be selected independently - so e.g. a FLAT RTA is available while the broad band values are acquired using an A weighted lter. Please note that only various lter combinations are possible.

Note: Changing lter settings re-starts the ongoing measurement.

Set Menu

The SET menu allows for particular measurement settings and display options as listed below:

RES - Resolution

Select 1/3rd octave or full (1/1) octave band resolution by pressing the enter key.

SHOW - Test Result

The actual SPL, MAX/MIN SPL and LEQ can be displayed per band.

The actual SPL is displayed with lled bars.

The LEQ spectrum is displayed with framed bars.

The MAX/MIN SPL range is displayed with lled bars. The cursor read out shows either the maximum, the max-min difference or the minimum sound pressure level of the selected band.

Simply toggle through these results with upper & lower arrow keys:

- max. SPL

- min. SPL

- max. - min. SPL

TWTD - Time Weighting

Applicable for the actual sound pressure level measurement. The available response times, corresponding to IEC 61672, are

• SLOW (long attack- and release time)

• FAST (short attack- and release time)

The time weighting for the broad band values ( ) and the RTA view ( ) are always the same.

HOLD - Cursor Hold

The cursors indicates the band of highest sound pressure level. For simple read out and traceability the cursor can remain for 1 - 9 seconds at the frequency band with the highest level. This may e.g. support nding of feedback frequencies.

Cursor Readout: Actual level result in the indicated frequency band.

The cursor readout displays the center frequency and the level of the band pointed to by the arrow. The cursor automatically jumps to the highest level band in the spectrum.

Alternatively the cursor readout may be controlled manually:

• Select the read out data eld and press the enter key.

• A frame is ashing around the data readout.

• Move the cursor and read the corresponding test results.

Pause / Reset / Input Range Indicator / TWTD - Time Weighting:

These controls are exactly the same as found on the sound level

meter screen and also effect both, the RTA and the sound level meter measurement (e.g. pressing PAUSE in the RTA screen also pauses the broad band LEQ, LcPEAK and MAX/MIN SPL measurements).

+ 67 hidden pages

NTI NEU-AL1 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual