KIRCHNER ATB 805 Handbook

Audio analyzer

Hide thumbs

Table Of Contents

Table of Contents

Quick Links

Download this manual

____________________________________________________________________________________

Kirchner elektronik, Brunnenweg 10, D - 38118 Braunschweig, Germany

Audio Analyzer

ATB 805

HANDBOOK

Table of Contents

Need help?

Do you have a question about the ATB 805 and is the answer not in the manual?

Questions and answers

Summary of Contents for KIRCHNER ATB 805

Page 1 ____________________________________________________________________________________ Kirchner elektronik, Brunnenweg 10, D - 38118 Braunschweig, Germany Audio Analyzer ATB 805 HANDBOOK...
Page 2 H A N D B OOK ATB 805 Project Manager Dipl.-Ing. Leo Kirchner Program development Dipl.-Inf. Elmar Meyer-Carlstädt Joachim Metzner © Copyright 2008 by Kirchner elektronik Brunnenweg 10 38118 Braunschweig Germany Telefon +49(531)46412 Fax +49(531)2407434 Email: Kirchner-elektronik@t-online.de...
Page 3: Table Of Contents
THE ATB 805 UNITE............................8 GETTING STARTED FOR WINDOWS WINDOWS 7, 8.1, 10 ..............10 INSTALLATION OF THE USB DONGLE....................10 INSTALATION OF THE ATB 805 BOX .......................14 INSTALLATION OF THE SOFTWARE .......................14 SETTING UP THE INPUT AND OUTPUT W 7, 8.1, 10..............15 INDOWS CALIBRATION ..............................18...
Page 4 PRINTING ..............................45 14.1 ADJUSTMENT...............................45 14.2 PRINT START ..............................46 WORKING WITH THE WINDOWS CLIPBOARD ................47 15.1 COPYING ...............................47 15.2 COPYING SINGLE MEASUREMENTS .......................47 DIAGRAM ..............................48 16.1 DIAGRAM INSCRIPTION ..........................48 MEASUREMENT PROGRAM ........................49 17.1 PARAMETERS...............................49 17.2 SIGNAL ................................50 17.3 MEASURING WITH CD, DVD ........................50 17.4 THE MEASUREMENTS ..........................50 16.5...
Page 5 24.2 THE THD MEASUREMENT.........................75 24.3 THEK2, K3, K4 UND K5 DISPLAY ......................76 DISTORTION SPECTRUM........................78 25.1 SETTINGS..............................78 25.2 THE IMD MEASUREMENT .........................78 25.3 THE DISTORTION MEASUREMENT ......................79 MEASURING CAR INTERIORS WITH THE CD ..................81 26.1 ROOM CORRECTION...........................81 26.2 NEAR FIELD MEASUREMENTS ........................81 SOUND SYSTEM CALIBRATION USING THE DVD ................83 27.1 AMPLIFIER..............................83...
Page 6: An Introduction To The System
AN INTRODUCTION TO THE SYSTEM GENERAL DESCRIPTION The ATB 805 PC Measuring program combined with the ATB 805 USB box forms an exact and extensive Audio Analyser. The ATB 508 is a 2-channel analyser. The 2-channel is for the new coming ATB program and for other 2-channel measurement programs.
Page 7: Safety Information
SAFETY INFORMATION The guarantee/warranty will expire if damage is incurred resulting from non- compliance with these operating instructions. We do not assume liability for any consequential damage. Nor do we assume any liability for damage to property or personal injury caused by improper use or failure to observe the safety information.
Page 8: The Atb 805 Unite
THE ATB 805 UNITE Speaker out function selector output volume calibration switch channel 2 input selector For the function Calibration and impedance the volume is disabled. For the impedance measurement it is set automatically corresponding to to the calibration measurement.
Page 9 Microphone input, MC1 and MC2 audio out 1 = left, 2 = right USB scket digital out electrical, optitical...
Page 10: Getting Started For Windows Windows 7, 8.1, 10
GETTING STARTED FOR WINDOWS WINDOWS 7, 8.1, 10 3.1 INSTALLATION OF THE USB DONGLE The ATB PC Pro 64 program is protected with an USB dongle. Insert the ATB program CD into your CD-ROM drive. In the workplace menu the driver can be found.
Page 11 Select drive: "Next" 9. Windows 7, 8.1, 10: With "Browse" select the DVD drive  "OK" to complete 9. Windows 7, 8.1, 10: In "Windows Security"  "install driver software anyway" 10. Windows 7, 8.1, 10: The driver has been installed  "Close" The dongle installation is shown in the folloing The ATB PC Pro 64 program is protected with an USB dongle.
Page 12 Driver software update In the menu set the drive with the installation CD ROM...
Page 13 Ready! If you want to check the correct installation of the dongle then open CONTROL PANEL in the START menu then open SETTINGS choose SYSTEM from the list then HARDWARE and then DEVICE MANAGER where you will find a list containing various devices including the BUS controllers :...
Page 14: Instalation Of The Atb 805 Box
INSTALATION OF THE ATB 805 BOX After connecting the ATB 805 via USB there will start an automatic installation. Installation of the device driver The device is ready to use. INSTALLATION OF THE SOFTWARE Place the DC „ATB-PC Pro Software“ in the CD ROM drive of your computer.
Page 15: Setting Up The Input And Output Windows 7, 8.1, 10
With double click “SETUP.EXE“ the installation will start. Follow the instruction. SETTING UP THE INPUT AND OUTPUT Windows 7, 8.1, 10 Open the program with a double click at the icon. 1. INPUT First you have to select LINE (USB AUDIO) or (2 channel USB AUDIO) in the INPUT menu. There is no win-mixer in the Vista, 8.1, 10 program.
Page 16 In the OUTPUT menu you have to select SPEAKER (USB AUDIO) or (2 channel USB AUDIO) In the main menu the correct setting is shown The menu Win-mixer shows the setting of the output. The menu can be found at SYSTEMCONTROL –...
Page 17 In the SOUND menu SPEAKER will be selected.
Page 18: Calibration
Before you can do any measurement, the USB box will be tested and a correction file will be generated. In the System-correction, a correction curve will be generated for the input and output of the ATB 805 box. The box is set to CALIBRATION. For the function Calibration and impedance the volume is disabled.
Page 19 Attention: There is the message “signal too strong”. This comes from a other setup and had no meaning for the ATB 805. For this and the next klick at OK. After the first measurement switch the ATB 801 Device to Correction 2 and start the second measurement.
Page 20: System-Correction For The Signal From Cd / Dvd Player
SYSTEM-CORRECTION FOR THE SIGNAL FROM CD / DVD PLAYER There are measurements which can be done with an external signal of a CD or a DVD player. For the test of the car sound and the HiFi sound system there is the Auto-Test CD. For the Surround equipment there is the Surround Test DVD.
Page 21: Error Message For The System-Correction
ERROR MESSAGE FOR THE SYSTEM-CORRECTION Whilst CORRECTION is taking place, the following error indication messages may appear: “Missing/weak signal” or “no signal” The ATB 805 is broken. “signal too strong” The message was programmed for another unit. Please klick to OK “insufficient record level”...
Page 22: Microphone
MICROPHONE MICROPHONE CORRECTION The ATB PC microphone MC 1 corresponds in precision of frequency response to the professional electret measuring microphones and does not need to be adjusted. The ATB PC measurement program makes the adjustment of as many microphones as desired possible.
Page 23: Microphone Sensitivity
MICROPHONE SENSITIVITY MICROPHONE SENSITIVITY is necessary for SPL measurements. Because of the differing sensitivity of microphones a correction factor is used. The correction factor is to set in MIC.- CORRECTION and is a part of the microphone adjustment. A frequency characteristic correction is not necessary when using the delivered microphone MC1.
Page 24: Program
PROGRAM INPUT AND OUTPUT CONTROLLER The OUTPUT level The OUTPUT level can be set with the OUTPUT controller. The displayed dB level is for the sin-Signals in dBV. 0db = 1V The INPUT level The INPUT level can be set with the INPUT controller.
Page 25: The Measurements
THE MEASUREMENTS Frequency response of amplidude Sound pressure Impedance Amplitude Frequency response of phase Step response Measurement with analysis Quality Thiele-Small Distortion...
Page 26: The Measurering
THE MEASURERING Measurering Single measurement Duration measurement Averanged Current DISPLAY ANG HANDLING Display, handling Plot management Combine Parameter...
Page 27: Carring Out The Measurement
Put the microphone 1m away and in front of the left front loudspeaker and connect the microphone to the microphone socket of the ATB 805 box. The microphone should be positioned at “ear height”. Usually it is about 80-90 cm above the floor, as music is usually...
Page 28 Following menu is shown In the SPL active menu you can set: The impedance of the speaker. The program set the output power to 1W. The distance between speaker and microphone. For a distance smaller than 1m the program shows the SPL for 1W/1m. Choose “parameter”...
Page 29 The modulation display indicates microphone-level. With the slide controller (record) you can adjust the microphone sensitivity. The green bar should fill 1/3 of the display window. The bar turns red if the microphone input is overload (set to a too sensitive position). The frequency response curvature of the left hand loudspeaker should appear on the screen.
Page 30: Measurement Signal
MEASUREMENT SIGNAL SETTING Before carrying out a test the measurement signal must be adjusted. Signal: BMH BassMidHigh, full range noise for SPL and Impedance measurement It is the M-PN signal. It is equal to the PCM signal Bass, bass noise for woofer testing MidHigh, noise for testing tweeter RB low Rub&Buss signal for testing woofer, frequencies 180Hz, 234Hz...
Page 31: The Bmh, B And Mh Signal
CD-Plus is the usual test signal used in most measurement processes. It corresponds to the DVD signal in relation to its frequency distribution. The signal is a x 4 over sampling and it is almost analog. This signal is also the internal generator signal. The signal CD-Normal is a measurement period of 1/3 s allows extremely fast results to be acquired.
Page 32: The Rblow, Rbmid And Rbhigh Signal
The measurement with these signals has a problem with the surrounding noise. Therefore, the Signal 13 was developed from the Kirchner elektronik company. The signal consisting of the heterodyne of two sine waves with the ratio of 1:1,3. This...
Page 33: The Sin Signal
gives a non-static signal. The signal 13 is for testing distortion like THD, IMD und nonlinear distortion. The time domain of the Signal 13 The frequency spectrum of the Signal 13 The time domain of the signal shows an always-varying wave. The signal excited all resonances of the unit under test.
Page 34: Plot Management
PLOT MANAGEMENT HANDLING SINGLE MEASUREMENTS Up to 32 single measurements can be handled with the window in the program or the menu PLOTS. With a right mouse click at the plot name there is to activate the menu. The menu performs following tasks: 1.
Page 35 The menu is opened with The PLOT menu performs following tasks: 1. To select a colour for the plot: Click the colour in the colour window. 2. Selecting PLOT line type: In front of the field for plot name the colour and line type are displayed. After selecting the plot to be changed with the cursor the colour/style menu is opened with a right mouse click.
Page 36: Cursor
This function allows the different lines to be identified when printing in black and white. Important! This only functions with a Print-line width of 1. 3. To name the plot: Enter the name of the graph in the NAME window. 4.
Page 37 A zoom function is contained in the main menu. After clicking ZOOM with the left mouse button it is possible to (the left mouse button is held pressed) mark the area intended for closer inspection. The area selected will then automatically be enlarged. The frequency range remains unchanged for further measuring.
Page 38: General Parameters
GENERAL PARAMETERS RESOLUTION The resolution gives the scale of the Y-axis. Its upper limit is fixed at 0dB, which automatically gives the lower limit a negative value. Reduction of the shown can thus be compared to a zooming in to an existing diagram. ’Zooming’ presupposes, however, adequate transformer level control.
Page 39: Windows - Program
WINDOWS - PROGRAM 10.1 STARTING ATB PC Pro If the program group ATB for Windows is shown as a symbol, it must be opened with a double click on the symbol. After this the ATB is opened. 10.2 THE CONFIG FILE The complete settings of the program are written in the config file C:\WINDOWS\ATB_Prec.ini.
Page 40: Opening Data Files
OPENING DATA FILES With the command FILE  OPEN you can open a file saved on the disk drive. The following pop up window will appear: The pop up window shows the data in a file. Disk drive and files can be changed with SEARCH IN: Click on the desired data, the name will appear in the box FILE NAME.
Page 41 The buttons in the menu have the following functions: OPEN Clicking on OPEN jumps back to the menu OPEN to enable a new data selection. LOAD ALL loads all plots in the file list (previous plots will be deleted). LOAD SELECTED loads a selected plot into the diagram.
Page 42: Saving Data
SAVING DATA After creating or changing a file, the file should be saved. This enables you to retrieve and work with the file later. When saving for the first time the following pop up window will appear: The name of the data to be saved should be written in the box data name. It is suggested that the file extension .xft be used.
Page 43: Exporting Data
EXPORTING DATA The ATB program has many export formats so that data can be exported to other programs. It is an ASCII text format. This allows the data to be read by many programs. A lot of CAD programs need a special format to read loudspeaker data for example. To be compatible with nearly all known programs the ATB PC Pro has the function to export data in several formats.
Page 44 When saving data in the ATB export format it is important to differentiate between saving measurements with multiple curves and singular measurements. 1. Saving measurements. Open EXPORT in the menu FILE. The pop up window SAVE AS will appear and the measurements saved. 2.
Page 45: Printing
PRINTING Of course you wish to see your documents in black and white, to do this they have to be printed. A printer must be connected to your PC to enable the printing of a diagram. The printer must be installed properly, power on and switched to »On Line«.
Page 46: Print Start
14.2 PRINT START The button prints the whole document. If PRINT is activated in the menu FILE a similar print menu will appear In COPIES you can choose the amount of copies to be printed.
Page 47: Working With The Windows Clipboard
WORKING WITH THE WINDOWS CLIPBOARD The Windows clipboard is available to any application. It is an outstanding tool when exchanging data between different applications. 15.1 COPYING To copy the diagram produced from all the measurements made into the clipboard press: 15.2 COPYING SINGLE MEASUREMENTS Single measurements can also be copied into the clipboard.
Page 48: Diagram
DIAGRAM 16.1 DIAGRAM INSCRIPTION The diagram can be marked in the window PLOTS. PLOTS is opened with Measurement diagrams can be marked in the PLOT window. The diagram elements, HEADLINE, LEFT, RIGHT and OPTION, are those above each diagram. Options are also available for marking the diagram axes and the required units.
Page 49: Measurement Program
MEASUREMENT PROGRAM 17.1 PARAMETERS SMOOTHING Smoothing radius in octaves, 1/24, 1/12, 1/6, 1/3 = Terz, ½, 1 SCALE (RESOLUTION) Field of scale from 5 to 60dB In this window there is to set the lowest dB level for the dB scale. LARGE IMP-SCALE This Function is for the Thiele-Small parameter testing.
Page 50: Signal
17.2 SIGNAL The program has the capability to task various assignments. Before the measurement the signal has to be selected. For the measurement with the CD or DVD select the EXTERNAL SIGNAL It is possible to use either the CD or the DVD as a signal source for measuring. The CD is used for car interiors (most cars lacking a DVD Player).
Page 51: Combine
The Measurements mean average M and M+ are activated with the buttons shown above. The number of mean averages, for the test duration, is unlimited. Another function of the Optitest is the M D und M+D continuous measurement. This test is a constant measurement where the actual measurement is shown.
Page 52: Measurement Description
With the field can the distribution of near field and distance (SPL) plots are changed. The next step is to set the cut frequency between distance (SPL) and near field plots with the low/high connector. Low/high-connector can be adjusted to make room resonance vanish. To make both plots into a single line the near field plot is to be set with the low-frequency level connection.
Page 53: Magnitude Measurement
ATB 805. For the Mag measurement the ATB 805 selctor is switched to Magnitude. The Audio Out level is set in the programme. The volume is disabled for the Audio Out.
Page 54: Amplitude-Frequency Response, Spl
AMPLITUDE-FREQUENCY RESPONSE, SPL 19.1 SET-UP FOR THE MEASUREMENT SPL frequency response measurements are carried out in conjunction with the MICROPHONE IN socket. The speaker is connected to the speaker out. The selector is switched to SPL and the volume to 9dB (SPL). The picture do not show the right selector position.
Page 55: Nearfield Measurement
19.3 NEARFIELD MEASUREMENT How to carry out acoustic measurements with loudspeakers and rooms are described in the following chapters. By the near field measurement, the physical property of sound getting weaker over the distance is made of use. A measurement microphone is placed 10cm away from the woofer. This way the direct sound is many times greater than reflected sound, so that only the direct sound is measured.
Page 56 blended out by a time window. Because of the small time delay difference it lies within the time window. Fig.19.2 Fig. 19.3 Fig. 19.2 shows the measurement of the bass reflex opening at different distances. The follow up of distance to the rim of the bassreflex opening is green, light blue brown and blue. The measurement was carried out with near field correction.
Page 57: The Boarder Area Measurement
19.4 THE BOARDER AREA MEASUREMENT By the boarder area measurement the measurement microphone is operated as boarder area microphone. The microphone lies flat on the floor and has that way a half ball characteristic. picture shows positioning loudspeaker and microphone. The sound waves of the loudspeaker hit the floor at an angle and reflect into the room.
Page 58: Impedance Measurement
IMPEDANCE MEASUREMENT 20.1 THEORY Impedance is the frequency dependent resistance of alternative currents. It consists of the value Z in  and the phase  =  . The measurement displays both values above the frequency range. The phase  displays the values of reactive and active resistance which together result in the value Z.
Page 59: Impedance Measurement From 12Hz
after changing over the usual buttons are available. The constant measurement using averages is not necessary for impedance measurements and is deactivated. The measurement is started with: The result is displayed in  on the right-hand axis of the diagram created. The two buttons at the left are for a single measurement.
Page 60: Phase Measurement
PHASE MEASUREMENT 21.1 BASICS The phase is used when describing sinus shaped processes such as mechanical oscillation, alternate currents, radio waves and sound waves. t  U(t) = Us cos (t+) t Time, U(t) Instantaneous value of voltage, Us peak value (max. Amplitude), f Frequency, T = 1/f Period duration, ...
Page 61 Examples of how the angle  effects the waves :  = 180 => blanked out t   = 0, 360 => maximum amplitude t  = 90, 270 => partly amplified, or also partly blanked out t The phase and loudspeakers...
Page 62 Loudspeakers also have to comply with the basics of physics. Amplitude and phase are essential for a correct description of the sound pressure emitted. The common theory that the phase can be determined in the frequency response is not true. This only complies to simple electronic circuits.
Page 63: Electrical Phase Measurement
21.2 ELECTRICAL PHASE MEASUREMENT The electrical phase measurement is carry out in the Mag measure. 21.2 IMPEDANCE PHASE MEASUREMENT With the electrical phase measurement we can measure for example loudspeakers impedance. This measurement is essential for a fault free operation of loudspeakers. Large phase angles show a capacitive and inductive behaviour of the loudspeaker impedance.
Page 64 The correct range has been found when the phase curvature remains the same. When the curvature is intact in the high amplitude range then a correct result has been attained. When measuring loudspeakers separately it is only possible to compare the phase behaviour. Phase differences of 180...
Page 65: Step Response
STEP RESPONSE 22.1 THEORY The step response shows the amplitude and the phase simultaneously. It is calculated using both measurements. The first thing done is to calculate the impulse of the sinus oscillation through a complicated addition, with value and phase. Because the impulse is a mathematical factor, ideally the amplitude is infinite;...
Page 66: The Measurement
The signal ascends steeply and falls in correspondence with the e – function. The descent is caused by the differentiating function of the air. The picture shows an ideal loudspeaker. The steep ascent of the step response displays a high top frequency border.
Page 67: Setting Of The Delay With The Step
22.3 SETTING OF THE DELAY WITH THE STEP The following plots show a speaker combination from midrange and tweeter. Between the speakers is a delay, the sound of the speaker doing not reach the microphone at the same time. The plot shows the sound pressure of a combination with the tweeter behind the midrange. The plot shows the sound pressure of a combination with the tweeter before the midrange.
Page 68 The plot shows at the start of the signal the sound pressure of the tweeter. After there is the signal of the midrange. Between the two signals there is a small drop. This comes from the crossover. The crossover is not right. The plot shows the step function of a time right speaker.
Page 69: Hiele-Small Paramerter
By the first start of the Thiele-Small measurement there is following message For the adjustment the ATB 805 device selctor is switched to calibration switch to 1. The volume is disabled. After the adjustment is to start with a click at the ADJUST button The bar get blue and there is to seen the plot below for a short time.
Page 70 THE MEASUREMENT The speaker free air measurement is implemented through FREE AIR MEASUREMENT. During this measurement, the driver must be in a vertical position, which would be the normal as- installed position, and the nearest large surfaces must be at least 1 m away. The entire set of parameters, i.e.
Page 71: The Method
23.2 THE METHOD The Thiele-Small method determines the parameters in compliance with the conventional three- point method. The diagram shows the impedance curve for the free air and the weight options (low resonance frequency). The values the program uses for calculation are also plotted. The program searches these automatically;...
Page 72: The Voice Coil Inductance
For the Thiele-Small method, the ATB uses a sinus sweep. Reference can be made to up to 500 measured values at a frequency spacing of 0.01Hz. Since the frequency deviation remains below 1%, the ATB is one of the most precise Thiele-Small measuring units. 22.3 THE VOICE COIL INDUCTANCE For the development of a crossover there is to know the voice coil inductance.
Page 73 3.14 = F; r = membrane radius + 0.5 x bead 4. Check Range The range for the calculation. The ATB 805 selector is switched to IMP. The volume is disabled. The picture does not show the right selector position. It is IMP.
Page 74 Measuring always commences with the free air option Measurement having been completed, the parameters Fs, Qe, QM and Qt are shown below the diagram. Before proceeding with the measurement, the values should be checked for plausibility. Any value of 1.00, for instance, implies that no evaluation was possible. The shape of the impedance curve has to be such that the amplitude values for F1, Fs and F2 appear in the diagram (cf.
Page 75: Distortion Measurement
DISTORTION MEASUREMENT 24.1 THE SETTING IN THE MAIN MENU The setting for the Distortion measurement is carry out in the main menu. In the SPL measure is to make a test measurement. The microphone is to place in a distance of 1 m to the speaker. In the SPL active menu is to select free Output control.
Page 76: Thek2, K3, K4 Und K5 Display
The Total Harmonic Distortion measurement used the sine-sweep as test signal. The frequency range is 20Hz – 7kHz. The harmonics are measured up to K8. It is to set under point the number of the test frequencies and the Frequency range. Scale is fort the resolution of the plot.
Page 77 For the analysis of the THD there could be shown the harmonics K2, K3, K4 and K5. To get the plot click at...
Page 78: Distortion Spectrum
DISTORTION SPECTRUM 25.1 SETTINGS The setting for the Distortion measurement is carry out in the main menu. In the SPL measure is to make a test measurement. It is described in the THD measurement. For the max. precision the OUTPUT controller is in the +15dB range. The measurement is called up with the button To leave the menu, to come back to the main menu, there is the...
Page 79: The Distortion Measurement
The measurement is a frequency analyser and shows the intermodulation and harmonics. (Plot from the Mag measure) To get the distortion there is to calculate the amplitude for following frequencies. Signal Fundamental IMD2 IMD3 IMD4 f2-f1 f2+f1 f2+2f1 f2+3f1 RB low RB mid 1,0k 1,5k...
Page 80 The distortion measurement uses the sin signal. he harmonics are measured up to K8. After selected sin the Sin-frequency is set. In the display the THD is showing in %. In the plot the harmonics are shown.
Page 81: Measuring Car Interiors With The Cd
MEASURING CAR INTERIORS WITH THE CD Before testing, the system-correction is to be measured once. The system-correction is for comparison of the USB box. Thus any CD/DVD Player can be used. For comparison, the left audio output of the CD/DVD player is connected (through the measuring adapter) to the microphone input on the soundcard.
Page 82 Near field measure: blue = Bass, green = Middle, = room corrected Middle- High tone, light green = Bass reflex, black = Bass mean average, Middle and Bass reflex The room correction for the low frequency range cannot be carried out as described. To suppress room resonance the low frequencies are measured in near field.
Page 83: Sound System Calibration Using The Dvd
SOUND SYSTEM CALIBRATION USING THE DVD For a real cinema feeling in your living room, as well as the proper picture, sufficient sound is necessary. For good sound first of all you need good loudspeakers. Sound differences between high quality DVD players and amplifiers are present but are not as important for attaining the cinema sound.
Page 84: Microphone
27.2 MICROPHONE The microphone is connected to the MIC INPUT. Microphone positioning: First of all the seating places for the audience are decided. The microphone is positioned on the back of the sofa or armchair, so that the head of the microphone is in the same position as the head of the spectator.
Page 85 positioning the loudspeaker obliquely in the direction of the seating position. Elevation or drops in the Middle tone range can be compensated through a greater distance to the bordering walls. A super elevation in the low frequency range shows a corner position. Enlarging the distance to the back lowers the elevation.
Page 86 Surround Loudspeaker Special rules are needed for the positioning of surround sound loudspeakers. The Home Cinema owner should be aware of the fact that films are not made for the living room but for the cinema. Just as the picture format is not suitable for a television screen so has the sound been mixed for the cinema.
Page 87 The picture shows plots for the SW in different positions. The difference to each position is 20cm. The red curve is the FL loudspeaker. Simultaneously it is an advantage to place the subwoofer between the FL and FR loudspeakers. Through multiple tests with M+ and repositioning of the Subwoofer it is possible to find the ideal position quite quickly.
Page 88: Cumulative Signals
The volume complies with the height of the sound pressure curve. After this FR is measured with M+ and the adjustments in the amplifier menu are changed so that the plots lie over each other. The same is done with the centre and the surround sound loudspeakers. The room influence should be considered when adjusting the volume of the Subwoofer.
Page 89: Cumulative Signals And Bass
The Equalizer Some instruments have an equalizer to adjust the loudspeakers to the room. Cumulative signals prove best for adjusting equalizers because the acoustic properties of the room are shown. To adjust the equalizer properly a few rules should be followed. The problem with equalizers is that when linearising the frequency characteristics, the Impulse- and phase behaviour changes simultaneously.
Page 90 The picture shows the plots for the front loudspeaker and SW Whilst the test is running the controller of the subwoofer (for the splitting frequency) is to be operated until the plot for the front loudspeaker and the bass plot are symmetrically mirrored with one another.
Page 91: The Audio Test
The plots show the cooperation of front loudspeakers and subwoofer and the influence of the phase controller. Light green, green and brown show the influence of the phase controller. Die brown curve is the adjustment without deletion in the low frequency range. The inconsistency of the middle and high tone ranges are brought forth through persons moving in the room.
Page 92: Calibrating The Hifi Stereo System
CALIBRATING THE HIFI STEREO SYSTEM 28.1 MICROPHONE This chapter is for the loudspeaker developers out there! The ATB PC program offers the function continuous measurement with averages, a tool that no developer can miss. When using a DVD player the measurement signal used is the PCM signal on the surround test DVD. If a CD player is the signal source then the CD plus signal is used on the auto test CD.
Page 93 Chapter 17.4 has already dealt with the positioning of the loudspeakers. A stereo sound system demands a higher sound quality and special balance. First of all the relationship between the distance to the walls and loudspeakers should be investigated. The curvatures display the frequency characteristics of a loudspeaker in relation to the distance from a lateral (side) wall.
Page 94 The figure displays the influence of the back wall in relation to the seating position. The waves in blue curve are caused by the interference of direct sound and reflected sound from the back wall. The sound reflected from the wall is delayed and creates an interfering reverberation. The curve displays the results when acoustic mats are placed on the back wall, the sound becomes more satisfying.
Page 95: Room Acoustic Measurement
28.3 ROOM ACOUSTIC MEASUREMENT Room acoustic describes the sound waves in a room. When a sound wave is created in a room then speckles are formed. Speckles are points on a sound wave that have either the greatest or the smallest amount of energy. This is especially important when working in the low frequency ranges.
Page 96: Surround-Test Dvd
Surround-Test DVD The test signals The curves shown are from test signals played back from a DVD Player and measured with ATB precision USB. The Signals: Blue above = single signals FL, C, FR, SL, SR Light green = single signal SW, with Surround amplifier output +10dB Brown = cumulative signals FL+FR, SL+SR Green...
Page 97: Technical Data
TECHNICAL DATA Technical data of the ATB 805 Microphone input: Frequency range 20Hz – 20kHz, +0.1dB Input range 50mV – 0,7V, noise < -50dB, Distortion < 0.05% Input impedance 2.2kΩ, 9V microphone-power ATB 805 XLR Imput impedance 6.8kΩ, 48V microphone power LINE output Frequency range 20Hz –...