HP RM500SL manual FastFacts 19.5 Speech signal analysis

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19.5 Speech signal analysis

One of the most-used measures of a speech signal is the long-term average speech spectrum (LTASS). This is a 1/3 octave spectrum averaged over a sufficiently long portion of the speech material to provide a stable curve. In practice a 10 second average meets this requirement and, for this reason, all RM500SL passages are at least 10 seconds long.

The dynamic nature of speech is often characterized by the distribution of short- term levels in each 1/3 octave band. These levels are determined by calculating a spectrum for each of a series of short time periods within the passage. Historically, time periods of 120, 125 or 128 ms have been used. The RM500SL uses a 128 ms time period, resulting in 100 levels (or samples) in each 1/3 octave band for a

12.8second passage. The level in each band that is exceeded by 1% of the samples (called either the 1st or 99th percentile) has historically been referred to as the speech peak for that band. The curve for these 1% levels is approximately 12 dB above the LTASS. The level in each band that is exceeded by 70% of the samples (called either the 70th or 30th percentile) has historically been called the valley of speech for that band. The curve for these 70% levels is approximately 18 dB below the LTASS. The region between these two curves is often called the speech region, speech envelope or speech “banana”. The speech envelope, when derived in this way, has significance in terms of both speech detection and speech understanding. Generally, speech will be detectable if the 1 % level is at or near threshold. The Speech Intelligibility Index (SII) is maximized when the entire speech envelope (idealized as a 30 dB range) is above (masked) threshold. This will not be an SII of 100% (or 1) because of loudness distortion factors, but higher SII values will not produce significantly higher scores on most test material. The speech-reception threshold (SRT) is attained when the LTASS is at threshold (approximately - depending on test material and the individual)

FastFacts 19.5: Speech signal analysis

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RM500SL User’s Guide Version 2.8

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Contents USER’S Guide General Operation Table of ContentsGeneral Setup Getting StartedHearing Instrument Tests Setup Ansi S3.22 Hearing Aid TestsOther Hearing Instrument Tests REM Manual Control Speechmap Fitting Procedures TroubleshootingSpeechmap Technical Details About RM500SL Section overviewHelp is available on the following topics by pressing Help FastFacts 1.3 Electronic users guide FastFacts 1.4 Warranty, trademarks, acknowledgements Warranty, Trademarks, AcknowledgementsCispr Electromagnetic Compatability EMCFollowing topics are covered in this section FastFacts 2.1 Getting started Unpacking and connectingFastFacts 2.2 Unpacking and connecting Getting StartedFastFacts 2.3 Microphone connection Microphone connectionProbe microphone FastFacts 2.4 Microphone care Battery pill use and careFastFacts 2.5 Battery pill use and care Microphone care Coupler microphoneFastFacts 2.6 Mouse, keyboard, barcode scanner Mouse, keyboard, barcode scannerSection overview This section covers the following topics General OperationExternal printer, auxiliary audio outputs FastFacts 2.7 External printer, auxiliary audio outputsInput device operation Function KeypadFastFacts 3.2 Input device operation FastFacts 3.3 Barcode data input Barcode data inputFastFacts 3.4 Keypad keys Keypad keys Function ButtonFastFacts 3.5 Menus, lists and buttons Menus, lists and buttons Setup Box List BoxScreen messages FastFacts 3.7 Program memory removal and replacementSoftware updating General SetupFastFacts 4.1 General setup Date and time setup FastFacts 4.2 Date and time setupDisplay settings FastFacts 4.3 Display settings Saving test setupFastFacts 4.4 Saving test setup Networking FastFacts 5.1 Networking Networking requirementsFastFacts 5.2 Networking requirements FastFacts 5.3 Networking setup Networking setupSingle computer connection On the RM500SL, seeFastFacts 5.4 Single computer connection FastFacts 6.1 Printing and storing results Printing and Storing ResultsInternal printer paper loading To load a new roll of paperFastFacts 6.2 Internal printer paper loading Barcodes, headers and comments on printouts FastFacts 6.4 Local printer setupFastFacts 6.5 Printing to a USB memory stick Printing to a USB memory stickFastFacts 6.6 Network printer setup Network printer setupFastFacts 6.8 Data storage to a network file Printing to a network fileFastFacts 7.4 Output or gain scale Hearing Instrument Tests SetupFastFacts 7.2 HIT a or B display Graph or table format FastFacts 7.3 Graph or table format Output or gain scaleHide or Show HIT curves To change the averaging frequenciesFastFacts 7.7 Ansi test frequencies FastFacts 7.8 HIT calibration facts HIT calibration factsFastFacts 7.9 Calibration of HIT reference microphone FastFacts 7.10 Calibration check for coupler microphone Calibration check for coupler microphoneCoupling the hearing instrument FastFacts 7.12 Positioning the hearing instrument Positioning the hearing instrumentFastFacts 8.2 Ansi S3.22-1996 facts Ansi S3.22 Hearing Aid TestsAnsi S3.22-2003 facts Turn the instrument onFastFacts 8.4 Ansi 1996 Linear and AGC tests FastFacts 8.5 Ansi 2003 Linear and AGC tests Ansi 2003 Linear and AGC testsFastFacts 8.6 Ansi test results Ansi test resultsFastFacts 8.7 Ansi input-output curves Ansi input-output curvesFastFacts 8.8 Ansi telecoil terminology Ansi telecoil terminologyFastFacts 8.9 Ansi telephone simulator Tmfs test Ansi telephone simulator Tmfs testFastFacts 8.10 Telecoil test results Telecoil test resultsOther Hearing Instrument Tests Turn the hearing instrument onFastFacts 9.2 Harmonic distortion Multicurve procedure FastFacts 9.3 Multicurve procedure Multicurve resultsFastFacts 9.4 Multicurve results Spectral analysis in Multicurve FastFacts 9.6 Battery drain testFastFacts 9.8 Sound level meter using manual control Manual control procedureFastFacts 10.2 REM calibration facts Real-Ear Measurement SetupFastFacts 10.3 Calibration of REM probe microphone Calibration of REM probe microphoneCalibration check for probe module Max TM SPL setup FastFacts 10.5 Max TM SPL setup 10.6 ABR nHL to eHL setupFastFacts 10.6 ABR nHL to eHL setup FastFacts 10.8 Positioning the probe tube Positioning the clientFastFacts 11.3 Graph, table or 2cc target format REM Screen SetupFastFacts 11.5 Hide or show REM curves REM Manual ControlSPL or HL scale FastFacts 11.4 SPL or HL scale Hide or show REM curvesManual control measurements FastFacts 12.3 Sound level meter using REM probeSensory Loss Simulator Sensory loss simulator descriptionFastFacts 13.2 Sensory loss simulator operation FastFacts 14.1 Occlusion effect measurement Occlusion Effect TestOcclussion effect measurement Turn the hearing aid OFFFastFacts 15.2 Recd facts Recd real-ear to coupler differenceFastFacts 15.3 Recd coupler response Recd coupler responseRecd real-ear response Allow the foam tip to fully expand in the earFastFacts 15.4 Recd real-ear response FastFacts 15.5 Recd results Recd resultsInsertion Gain FastFacts 16.1 Insertion gain Insertion gain in SPLFastFacts 16.2 Insertion gain in SPL FastFacts 16.3 Insertion gain in HL Insertion gain in HLFastFacts 16.4 Audiometric data entry Audiometric data entryTo enter data from a barcode see 3.3 Barcode data input To enter assessment data and parameters manuallyFastFacts 16.5 Reur measurement procedure Reur measurement procedureFastFacts 16.6 Rear measurement procedure Rear measurement procedureFastFacts 16.7 SII calculation in Insertion gain SII calculation in Insertion gainSpeechmap FastFacts 17.1 Speechmap 17.2 Speechmap factsFastFacts 17.2 Speechmap facts FastFacts 17.3 DSL 5.0 in Speechmap DSL 5.0 in SpeechmapDSL 5.0 changes FastFacts 17.4 DSL 5.0 changes NAL-NL1 in SpeechmapFastFacts 17.5 NAL-NL1 in Speechmap Using Speechmap FastFacts 17.6 Using SpeechmapTo enter audiometric data, see 18.2 Assessment data entry 0611 RM500SL User’s Guide Version FastFacts 17.9 REM or S-REM mode REM or S-REM modeFastFacts 17.10 SII calculation in Speechmap 17.10SII calculation in SpeechmapSpeechmap Fitting Procedures To enter assessment data manuallyFastFacts 18.2 Assessment data entry FastFacts 18.3 Assessment data choices Assessment data choicesFastFacts 18.4 Assessment data choices From 18.3 Assessment data choicesFastFacts 18.5 Fitting to targets for soft speech Fitting to targets for soft speechFastFacts 18.6 Fitting to targets for loud sounds Fitting to targets for loud soundsFastFacts 18.8 Open fittings in Speechmap Fitting to targets for mid-level speechFastFacts 18.9 FM fitting and verification FM fitting and verificationFastFacts 19.2 Speechmap stimuli Speechmap Technical DetailsFastFacts 19.3 Stimulus levels Stimulus levelsFastFacts 19.4 Microphone location effects Microphone location effects Microphone Location EffectsFastFacts 19.5 Speech signal analysis Speech signal analysisTroubleshooting FastFacts 20.1 Troubleshooting Self test failuresFastFacts 20.2 Self test failures FastFacts 20.4 HIT curves inconsistent FastFacts 20.7 No HIT reference mic. detected No HIT reference mic. detectedFastFacts 20.10 Invalid REM calibration Invalid HIT calibration Invalid HIT CalibrationFastFacts 20.12 Barcode scanner malfunction 20.11REM speaker overdrivenHIT Chamber Technical SpecificationsStorage & Transportation GeneralGlossary Page Page Page References Page Page 0611 RM500SL User’s Guide Version Verifit and RM500SL Test Signals and Analysis Test signalsIntroduction Broad-band signals Loud Vocal Effort Effect re nominal band SPL Pink noise signal analysis Analysis of broad-band signalsVerifit / RM500SL Speechmap 07/05/06 Example of speech envelope and Ltass 07/05/06 Ltass for Speechmap speech signals at average vocal effort Ltass Dynamic