NTi Audio AL1 User Manual

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ACOUSTILYZER

User Manual

AL1

Contact details:

NTi Audio AG Im alten Riet 102 9494 Schaan

Liechtenstein, Europe

Tel.	+423 - 239 6060
Fax	+423 - 239 6089
E-mail	info@nti-audio.com
Web	www.nti-audio.com

NTi Audio is an ISO 9001:2008 certified company.

Subject to change without notice.

Release April 2014 / Firmware A1.32 or higher

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

Made in

Switzerland

Contents

1. Introduction		4
	Registration	5
	CE Declaration of Conformity	6
	International Warranty and Repair	7
	Warnings	8
	Test & Calibration Certificate	8

2. Overview		9
	Acoustilyzer Functions	10
	Easy Operation	10
	Connectors	11

3.	Basic Operation	13
	Start-up Screen	14
	Menu Bar	14
4.	Measurement Functions	23
	SPL/RTA - Sound Level Meter	24
	SPL/RTA - Real Time Analyzer RTA	28
	Reverberation Time RT60	37
	FFT Analysis	43
	Polarity Test	47
	Delay Time	49
	Electrical Measurements - RMS/THD	52
	Speech Intelligibility STI-PA (optional)	54
	Calibration	62
5.	MiniLINK PC Software	65
	Installation	65
	Start the MiniLINK PC Software	66
	Free Registration of your Test Instrument	67
	Readout of Stored Test Results	68
	Visualizing the Test Results	69
	Test Result Logging at the PC	73
	Remote Test Instrument Control with the PC	75
	MiniLINK Tools	76
	Activate Options	82
6.	Troubleshooting	83
7.	Accessories	84
8.	Technical Specification	86
9.	Appendix: Introduction to STI-PA	89

1. Introduction

Congratulations and thank you for buying NTi Audio’s Acoustilyzer AL1, a product specially suited for professional acoustical test applications. The Acoustilyzer offers advanced acoustic functions including an optional speech intelligibility STI-PAmeasurement 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.nti-audio.com.

The Acoustilyzer AL1 is available as a stand-alone test instrument or as a 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 include 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	1x STI-PA Test CD (STI-PA test signal)
Option	1x License Number STI-PA
	1x	Acoustilyzer User Manual

Registration

•Keep your products up-to-date

Access free firmware and software updates.

•Activate options

Enable additional functions for your products.

•Access premium content

Access downloads, information and specific support for your products.

•Receive application and product news Sign in for the NTi Audio Newsletter.

•Get fast worldwide support

•Confirm your ownership

Allows us to contact you with important product notifications and provides a product record in case of loss or theft.

How to Register

•Open the web page http://my.nti-audio.com.

•You are prompted to login or create the My NTi Audio Account.

•The web page “My NTi Audio Products” opens.

•Select the product type and enter the serial number.

•Confirm with “Register”.

•Now your product is listed in the table “My NTi Audio Products“.

CE Declaration of Conformity

We, the manufacturer

NTi Audio 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 Audio.

Date:

1. September 2004

Signature:

Position of signatory: Technical Director

International Warranty and Repair

International Warranty

NTi Audio 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 specified 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 Audio service center or if the instrument has been opened in a manner other than specified in this manual.

No other warranty, written or verbal, is authorized by NTi Audio. Except as otherwise stated in this warranty, NTi Audio makes no representation or warranty of any kind, expressed or implied in law or in fact, including, without limitation, merchandising or fitting 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 Audio Acoustilyzer AL1 packed in the original box, to the authorized NTi Audio representative in your country. For contact details see the NTi Audio web page www.nti-audio.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 guidelines listed below:

•Use the instrument for the intended purpose only.

•Never connect the instrument to a high voltage output such as a power amplifier, 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 flat or if it is not intended to use the instrument for an extended period of time.

Test & Calibration Certificate

This is to certify the Acoustilyzer AL1 is fully tested to the manufacturer’s specifications. NTi Audio recommends calibration of this test instrument one (1) year after purchase, and every subsequent one (1) year thereafter.

2. Overview

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

TheAL1 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 acoustical analyzer

NTi Audio offers the class 1 frequency responsemicrophoneM2010(anexternal phantom power supply is required). The Acoustilyzer in combination with the M2010 measurement microphone forms a highly accurate class 1 acoustical analyzer.

Class 2 acoustical analyzer

The Acoustilyzer in combination with the MiniSPL forms a comprehensive class 2 acoustical 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 (SPL) & time-averaged sound
	pressure level (Leq) measurements of wideband values.
	Real Time Analysis (RTA) of octave or ⅓ octave values
• RT60:	Reverberation time with 1/1 octave band resolution
• FFT:	Real-time zoom Fast Fourier Transform (FFT)
• POLARITY:	Polarity measurement of speakers and line signals
• DELAY:	Delay time measurements between speakers
• RMS/THD:	Root Mean Square (RMS) level and Total Harmonic
	Distortion (THD) measurements
• STI-PA:	Speech intelligibility measurement is visible after
	Speech Transmission Index for Public Address systems
	(STI-PA) license key has been activated
• 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 required value.

•Alternatively, for longer selection lists, the chosen field flashes. Now select the required value with the cursor keys.

Confirm 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 a signal to be fed into the AL1. We recommend using the XLR input for best performance (minimum noise floor and best dynamic range). In case a measurement microphone with unbalanced output is used, connect to the XLRinput between pin 2 and 3.

•A 3.5 mm (1/8“) jack headphone monitor output is used to monitor the 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	Monitor	Internal
Inputs	Output	Microphone

Note: Never connect the XLRand the RCA input at the same time!

Battery Replacement

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

Notes:

•We do not recommend the use of rechargeable NiCdor NiMHbatteries.

•Do not insert batteries of different types.

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

•Ensure the correct polarities of the inserted batteries.

•Removethebatteriesassoonastheyareflator if it is not intended to use the instrument for an extended period of time.

3. Basic Operation

Despite the wide range of availability of measurement functions and optional setups, the operation of the Acoustilyzer is almost self-explanatory.

Menu Bar

Test Result

Escape button

Power On/Off-

Backlight

Enter / Cursor

Keys

The LCD is divided into 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 (numeric or graphic display)

Start-up Screen

The start-up screen remains displayed by pressing and holding any button during the start up of the unit. This allows you, for example, to read the instrument serial number of your device. The serial number starts with three letters (e.g. ANK675A2A2).

After the successful registration (See details in “Free Registration of your Test Instrument“ later in this user manual) of your AL1 the start-up screen may be customized (See details in “Customizing the Start-up Screen” later in this user manual).

Menu Bar

Use the menu bar to select the basic test configurations.

Measurement	Screen	Input	Setup	Memory Menu
Functions	Selector	Filters	Screen	& Battery Status
				Indication

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 SPL/RTA, RT60 and STI-PA measurement functions can be viewed in two test result screens.

For example, the SPL/RTA “123” selector displays the sound level meter screen while the bargraph symbol selector displays the real time spectrum analyzer.

Short-cut

Hold the ESC button down and simultaneously press the left or right arrow key to switch between the two display screens within the same measurement function.

Input Filters

Depending on the selected measurement function the following sets of filters are available:

SPL/RTA function:

Filters	Applications
FLAT	Overall sound		pressure level; all
Flat frequency response	sound signal components are included
(no filtering)	without weighting - required for special
	applications.

A-WTD	Applicable to most common sound
A-weighting filter in	pressure levels if level weighting
accordance with IEC 61672	compensation		for	human		loudness
	perception	is required.

C-WTD	Applicable to higher sound levels if level
C-weighting filter in	weighting	compensation			for	human
accordance with IEC 61672	loudness perception			is required.

X-CRV-1	Required for cinema installations
Inverted X-Curve filter in
accordance with ISO 2969

RLB (Revised Low-	Applicable	for	loudness		measurement
frequency B-curve)	of broadcast		material.		The	revised
Broadcast Loudness	B-weighted Leq measurement (RLB)
filter in accordance with	has the best correlation to the subjective
AES Paper “Loudness	experience of humans.
Assessment of Music and
Speech” 2004

RMS/THD function:

Filters	Applications
FLAT	Overall	sound	pressure		level;		all
Flat frequency response	sound signal components are included
(no filtering)	without weighting - required for special
	applications.

A-WTD	Applicable to most common sound
A-weighting filter in	pressure levels if level weighting
accordance with IEC 61672	compensation		for	human		loudness
	perception is		required. For			example,
	measuring residual noise of a device in
	sound broadcasting applications.

C-WTD	Applicable to higher sound levels if level
C-weighting filter in	weighting	compensation			for	human
accordance with IEC 61672	loudness	perception		is required -			for
	special applications.

HP400	Removes any mains frequency (50/60Hz)
Highpass 400 Hz in	components from the test signal.
accordance with DIN 45045,
-120dB/dec.

HP19k	Removes any low frequency components
Highpass 19 kHz	from the test signal, e.g. to measure
	critical public announcements					systems
	with no audible change to the signal
	(using a 20kHz pilot tone level)

Setup Screen

The setup screen allows customization of basic settings of the Acoustilyzer AL1:

•Move the cursor to the corresponding field and press the enter key.

•Select the required status using the arrow keys.

•Press the enter key to confirm.

AUTO POWER OFF defines the time period, after the last keypress, after which the AL1 is switched OFF automatically. The available settings are 3 MIN, 10 MIN, 30 MIN, 60 MIN and DISABLE. If DISABLE is selected, the user has to turn the unit off manually or it will run until the batteries are discharged.

AUTO LIGHT OFF defines how long the backlight stays on after any key stroke. Possible selections are 3 SEC, 10 SEC, 60 SEC and DISABLE. If DISABLE is selected, the backlight will stay on until the unit is switched off. Note that the backlight reduces the lifetime of the batteries.

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 “Auto Power Off” and “Auto Light Off” power-saving functions are disabled. After the PC software MiniLINK is closed, and until the USB cable is disconnected, the Acoustilyzer continues to be powered from the PC but these power-saving features are again enabled.

LCD CONTRAST adjusts the contrast of the display. Alternatively, hold the ESC button down and simultaneously press the up/down arrow key while in any measurement function.

MULTIPLE SETUP allows storage of up to four individual settings. To enable the multiple setup mode, set the corresponding entry to ENABLE and confirm. The next time the Acoustilyzer is switched on, the user will be prompted to select the individual setup-ID (1, 2, 3 or 4) in the startup screen. All parameter settings in all measurement functions 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 file name consisting of the test mode and a continuous running number from 000 - 999, such as “A001_RMS_THD” or “A002_RT60”. After 999 the running number starts again with 000.

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 only, thus occupying less memory space.

•VIEW + DELETE

The stored measurement results are listed in decending order, so the latest recorded measurement is always on top of the list. The remaining memory space is displayed in the right-upper 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 with the shaded square on the left. You can recall the marked record at any time later by holding down the ESC button and simultaneously pressing the enter key.

Delete individual memory records

Individually stored results can be deleted from the memory.

•Select the DEL field beside the memory location to be deleted.

•Select 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 field “DELALL“.

LOAD

Various Acoustilyzer functions support test result data loading from the internal AL1 memory. This feature is useful for reviewing test results of measurements previously stored 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 viewing of a previous test result.

Application example using SPL/RTA:

•Select LOAD in the memory menu and press enter.

•The data available for loading is displayed.

•Select the test result of interest.

•Confirm the selection with the enter key → the square symbol on the left of the selection is shaded.

•Press the ESC button (cursor jumps to OK) and confirm with enter.

The loaded test result is displayed on the active AL1 screen and the abbreviation LOD flashes in the status bar memory field.

The individual band levels can be viewed, the Y-axis altered or even the Leq or min/ max test result shown.

Return 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” field of the menu bar when a change of batteries is required.

4. Measurement Functions

Overview

	Test
Function	Result		Test Features
	Screens
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 acoustic speaker or electrical line signals
DELAY		Delay Time
		Propagation	delay measurement between
		electrical reference and acoustic signal
RMS/THD		Electrical Measurements
		Level RMS, THD+N, Frequency
STI-PA		Speech intelligibility
		with STI or CIS values. Visible after STI-PA
		license key has been activated
		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 Audio 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 review.

The measurements displayed on the big and small result position may be chosen among

•	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 Timer can be configured to

•Stop the Leq, LCpeak and MAX/MIN SPL measurements after a user-defined time period

•Reset the Leq, LCpeak and MAX/MIN SPL measurements after a user-defined time period in order to start a new measurement

Timer	Pause	Reset	Test Cycle	Measurement
Status			Period	Timer, Clock

Big Result

Small

Result

Input Range	SPL Bargraph and range	Time Weighting
indicator arrows	indication	indicator / selector

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-defined time setting.

•Set the required test cycle period.

•The clock counts back to zero. After the defined test time is completed, the clock flashes ”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 repeat measurements with user-defined test time interval.

•Set the required test cycle period.

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

•The previously measured Leq is displayed as PreLeq (useful for Leq monitoring at live 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 flashes.

•The actual SPL value is continuously measured and displayed.

•Select the pause symbol and press the enter key to continue the measurement; the clock continues to count.

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 previously-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) flashes if the input voltage exceeds the selected input range of the instrument. As long as the OVL is flashing the displayed Leq and LCpeak results are not accurate.

Input Range Selector & Bargraph

In the SPL/RTA Mode the AL1 has three measurement ranges (RNGE). The span of each range depends on the sensitivity of the microphone used. 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, called the “primary indicator range”, must be selected. Correct setting avoids overflow indications and lowers the influence 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 that 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.

When exceeding the primary indicator range, three overload arrows replace 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 1/3rd or full octave band test results using class 0 filters. 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.

Set	Pause Reset	Cursor
Menu		Readout

Audio

Spectrum

Input Range	X-Axis with manual	Y-Axis
indicator arrows	range selection

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 filter 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 anAweighted filter. Please note that only various filter combinations are possible.

Note: Changing filter settings re-starts the ongoing measurement.

Set Menu

The SET menu provides access to 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 filled bars.

The Leq spectrum is displayed with framed bars.

The MAX/MIN SPL range is displayed with filled bars. The cursor readout 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

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