EASERA Tutorial

EASERA 1.1 EASERA Tutorial By Software Design Ahnert GmbH, Berlin. 11/01/2006 EASERA Tutorial - Contents Contents EASERA TUTORIAL........................................................................................................................................................1 CONTENTS.........................................2 OVERVIEW........................................6 Preface6 EASERA vs. EASERA Pro............6 LESSON 1: EVALUATING A MEASUREMENT .........................................................................................................9 THE VIEW & CALC PAGE.................11 THE IMPULSE RESPONSE..................13 Zooming in.................................13 FREQUENCY RESPONSE....................14 Overlay......................................................................................................................................................................16 REVERBERATION TIME.....................17 SPEECH INTELLIGIBILITY.................18 LESSON 2: LIVE..............................19 SELECTING THE SOUNDCARD...........20 THE LIVE PAGE................................22 Channel selection.......................22 Diagram selection......................23 Bandwidth..................................23 Frequency weighting..................24 Presentation...............................24 Mouse Cursor.............................24 LESSON 3: PERFORMING A MEASUREMENT.......................................................................................................25 SELECTING AND CALIBRATING A CHANNEL ....................................................................................................................26 Calibrating the microphone ......................................................................................................................................29 STIMULATING SIGNAL......................31 CHECKING THE LEVEL.....................33 Calibrating the faders................34 STARTING THE MEASUREMENT........34 Averaging...................................35 LESSON 4: WHAT IS AN IMPULSE RESPONSE? ....................................................................................................36 WHAT IS A DIRAC?..........................37 What is the Dirac impulse good for? ........................................................................................................................39 THE IMPULSE RESPONSE IN ROOM ACOUSTICS.................................................................................................................40 IMPULSE RESPONSE OF LOUDSPEAKERS ..........................................................................................................................44 Adding up signals......................................................................................................................................................47 Crossover frequency at 1kHz.....48 The impulse response in practice..............................................................................................................................49 LESSON 5: AVERAGING AND ADDING MEASUREMENTS.................................................................................52 ADDING DATA.................................53 Frequency resolution and phase behavior ................................................................................................................54 Page 2 EASERA Tutorial - Contents Complex Vector.........................................................................................................................................................54 When do we use which option....56 DATA AVERAGING...........................56 Speech intelligibility...................56 Other acoustical quantities........57 Frequency response57 LESSON 6: FILTERING AND WINDOWING ............................................................................................................58 OCTAVE AND ONE-THIRD OCTAVE SPECTRA ...................................................................................................................59 One-third octave spectra............61 WINDOWING....................................62 Time-shifting a curve.................62 Setting the window.....................63 Filtering.....................................65 WINDOWING THE DISPLAY..............................................................................................................................................65 Window types.............................66 LESSON 7: DISPLAYING RESULTS...........................................................................................................................68 CREATING OVERLAYS......................69 The Overlay navigator page.......70 Select Overlay............................71 Add To Overlay..........................72 Display Active Only...................72 CURSORS.........................................73 The List of Cursors.....................74 DIAGRAM REGION............................75 Full.............................................75 Zooming ....................................................................................................................................................................76 View Limits.................................76 EXPORTING DIAGRAMS....................78 CHANGE LEGEND............................78 LESSON 8: PROCESSING..............80 MATHEMATICAL OPERATIONS.........81 Relative calculation values .......................................................................................................................................82 Remove DC................................84 DISPLACEMENTS..............................84 Move Arrival to Zero..................87 EDITING SEQUENCE.........................88 Processing for any new measurement.......................................................................................................................89 LESSON 9: MEASUREMENTS AT DIVERSE ROOM POSITIONS........................................................................91 FRAUENKIRCHE DRESDEN ..............................................................................................................................................92 Realization of the measurements92 EVALUATION OF THE MEASUREMENTS............................................................................................................................93 The reflections............................93 Echo criterion94 The reverberation time...............94 Frequency response...................96 Some acoustical values..............97 Speech intelligibility97 THE SOUND REINFORCEMENT SYSTEM98 Averaging curves........................99 LESSON 10: WATERFALL DIAGRAMS ..................................................................................................................101 CREATING A WATERFALL DIAGRAM..............................................................................................................................102 Page 3 EASERA Tutorial - Contents Positioning of the diagram......................................................................................................................................102 Level peaks at the end of the diagram.....................................................................................................................103 Two-dimensional view..............103 FINE ADJUSTMENT OF THE PRESENTATION....................................................................................................................104 Frequency range and smoothing.............................................................................................................................104 Time range...............................104 Level range105 Slices or grid............................105 DETAIL EXAMINATIONS WITH WATERFALL DISPLAY.....................................................................................................107 SPECTROGRAM..............................109 LESSON 11: SPEECH INTELLIGIBILITY ...............................................................................................................110 THE MODULATION TRANSFER FUNCTIONS111 THE REGISTER PAGE RESULTS.......112 CONSIDERING AMBIENT NOISE......................................................................................................................................113 Considering masking effects....114 CUSTOM FREQUENCY WEIGHTING..114 THE MODULATION TRANSFER INDEX (MTI)..................................................................................................................115 LESSON 12: EXPLANATION OF FURTHER MEASURING QUANTITIES .......................................................116 DIAGRAMS OF THE TIME DOMAIN..117 Impulse response......................117 ETC (log-squared and envelope) ............................................................................................................................117 Schroeder Integral...................118 Step Response...........................118 Energy Sum..............................119 Weighted Energy......................119 Echogram................................................................................................................................................................120 Echo (Speech and Music).........120 DIAGRAMS OF THE FREQUENCY DOMAIN ......................................................................................................................122 Magnitude................................122 Smoothed..................................122 Phase........................................123 Sum and average......................124 Group delay .................................................................................................................................................