QE-1500 Users Manual
Contents
1. To handle situations like this the HUM FILTER base frequency can be tuned 10 via the ADJUST knob In other words for a base frequency of 50 Hz the HUM FILTER can be tuned in the range of 45 to 55 Hz and for a base frequency of 60 Hz a range of 54 to 66 Hz is possible To bypass the HUM FILTER stage so that it has no effect on the audio move the base frequency slider back to the OUT position DECONVOLVER CLEAR ADAPT COMPLEX e E FREEZE E NORMAL QUT SIMPLE Figure 6 DECONVOLVER Module 11 43 DECONVOLVER MODULE The DECONVOLVER processing block See Figure 6 is designed to automatically adjust itself to remove noises that are time correlated from the input signal There are two main classes of time correlated noises that the DECONVOLVER can remove periodic repeating sounds such as tones hums engine idling sounds electrical motors etc and convolutional distortion such as echo reverberation and acoustic resonances caused by reflected sound in the environment the recording was made in There are three user controls in the DECONVOLVER module The CLEAR button is used to flush and re initialize the DECONVOLVER You may wish to do this whenever the signal you are processing has changed significantly and you want the DECONVOLVER to re acquire a fresh solution In very rare instances sudden jumps in the amplitude of the input signal may cause the DECONVOLVER module to become unstable r2. and the RIGHT channel to the RIGHT ear for STEREO listening or the RIGHT channel to both ears You may wish to use this control if you have a monaural signal plugged into only one input channel of the QE 1500 Note The position of the MONITOR switches only affects the HEADPHONES outputs and has no effect whatsoever on the output signals or on the signal that is recorded onto the DESTINATION DRIVE Therefore the user may move these switches as desired without affecting any recording of the processed signal 15 5 2 REPORT BUTTON The REPORT button See Figure 1 is used in conjunction with the PRINTER port on the QE 1500 See Section Error Reference source not found When a printer capable of producing ASCII text printouts is connected to the PRINTER port pressing the REPORT button will cause a plain text formatted REPORT containing the current status of all processor settings to print There is a provision on the printed REPORT for the user to enter the name of the examiner the date and time the case number and other relevant information This REPORT can be used to fully restore a specific configuration of the QE 1500 if needed 5 3 POWER SWITCH Use the POWER switch See Figure 2 to turn the QE 1500 on and off The red LED indicator will illuminate when power is turned on 16 ANALOG Line Inputs Line Outputs Headphones Output Analog Conversion DIGITAL DSP Processors Digital Inputs Outputs Audio Processing P
3. input signal strength can be monitored using the LED bargraph display See Figure 3 This display is calibrated in units of decibels dB below full scale In other words a signal having peaks that illuminate the 18 segment of the bargraph display is 18 decibels below the maximum possible signal level into the QE 1500 A normal processing level will cause the peaks of the input signal to illuminate the yellow segments of the display without illuminating the red overload OL segments If the input signal is too strong causing the OL indicators to illuminate rotate the INPUT LEVEL knobs to the left to attenuate the input signal If the input signal is too weak causing none of the yellow segments to illuminate rotate the INPUT LEVEL knobs to the right slowly to add gain to the input signal Note Be wary of sudden loud sounds in the input signal such as door slams gun shots etc which may cause the input circuitry of the QE 1500 to overload This condition is highly unpleasant to listen to and may cause hearing damage if the listening volume is set too high See Section Error Reference source not found CHAPTER 4 AUDIO ENHANCEMENT MODULES Once the input source has been selected and the correct input level set the signal passes on to the audio enhancement signal processing section of the QuickEnhance QE 1500 The processing modules in the enhancement section provide the main functionality of the QE 1500 Each of the modules is desig
4. 10 10 ADJUST Figure 5 HUM FILTER Module 4 2 HUM FILTER MODULE The HUM FILTER processing module See Figure 5 is useful for removing hum and buzz noises from the audio signal A typical source of hum noise is electrical AC power This hum may be caused by the proximity of the recorder microphone or microphone cables to AC powered electrical sources such as fluorescent lighting power cords motors home electrical wiring etc This noise is generally characterized by a strong energy component at either 50 Hz or 60 Hz depending on the power generation standard of the particular country the recording is made in along with decreasing energy components at integer multiples of the base frequency With the ADJUST knob at the center detent position move the HUM FILTER slide switch from the OUT position to either the 50 Hz or 60 Hz position to activate the HUM FILTER In doing so you may find that the base frequency of the hum does not fall at exactly 50 or 60 Hz resulting in incomplete cancellation of the hum For example if the recording was originally made on a battery powered analog tape recorder and the batteries were approaching the end of their useful life the recorder may have been running too slowly When the recording is played back on a tape player with fresh batteries or an AC power source the recording will appear to be running faster than normal causing the hum component to appear at a higher frequency than 50 or 60 Hz
5. ELECTION SWITCHES There are three possible input sources to the QE 1500 audio processor one analog and two digital See Sections Error Reference source not found and 2 4 Analog Audio Interface The INPUT SELECT and DIGITAL INPUT switches See Figure 3 are used to select which one of these three sources is routed through the QE 1500 s audio processor With the INPUT SELECT switch in the ANALOG position the signal connected to the unbalanced RCA analog inputs is selected When this switch is in the DIGITAL position the DIGITAL INPUT switch determines whether the COAXIAL or TOSLINK digital input is selected This switch has no function when the INPUT SELECT switch is in the ANALOG position Note The INPUT SELECT switches only affect the routing of signals into the QE 1500 All three outputs are always active and available regardless of the position of these switches In this way the QE 1500 can function as an audio patchbay converting any of the three input types to any output 3 2 INPUT LEVELS The two INPUT LEVEL knobs See Figure 3 allow the user to add gain to a low level signal to bring it up to a normal processing level or to attenuate a loud signal that may be overloading the input circuitry of the QE 1500 The center detent position of the knobs indicates the 0 dB point where no gain or attenuation is applied to the input signal These INPUT LEVEL knobs work the same regardless of the type of input selected See Section 3 1 The
6. QuickEnhance QE 1500 Audio Enhancement Fieldkit C B TN dE anes E 1500 prod De prse T AUDIO ENHANCEMENT FIELDKIT cO 0 EE mem E 125 e 8 9 e SI AC POWER 90 2 4 VACA7 OB TOSLINK L MiniDiso INPUTS DECONVOLVER NOISE REDUCTION MONITOR GRAPHIC EQUALIZER AUTO GAIN UU 1 o S N QE1500 AN c E eekleg LR m E 24 m a an IR Uum o Fleiss eelere IEEE FIT 111 C O MADE IN USA BY DIGITAL AUDIO CORPORATION USER S MANUAL Digital Audio Corporation Technology to Make Listening Easier QuickEnhance QE 1500 Audio Enhancement Fieldkit User s Manual Document Number 021217AME July 1 2004 Digital Audio Corporation Digital Audio Corporation 4018 Patriot Drive Suite 300 Phone 919 572 6767 Fax 919 572 6786 Web www dacaudio com Email sales dacaudio com Copyright 2002 by Digital Audio Corporation All rights reserved Table of Contents CHAPTER 1 Introduction sss sss sss sss eene nono sss Eso aaa ee dana ao sassa diae eine d CHAPTER 2 Setup And Connections eere eese esse senses senses D 2 1 AG aU e i cii e de o ea egt ed eade eu eee NE ee e eee ed ea 6 D2 DC POWER EP EE e EE EE Eed ee EE EE 6 2 3 Destination RL eee eae eroi r ee GUIAS E INE e a sss eee ORDER vehe 6 3 1 Input Selection Switches
7. ch as tape hiss the right most sliders may be moved down To reduce low frequency components such as low rumble the 13 left most sliders may be moved down Frequency bands that you do not wish to modify should be left at the top 0 dB position Note Moving the IN OUT slide switch to the IN position causes a fixed 300 Hz high pass filter to be inserted into the signal path This filter will remove any low frequencies which do not contain useful speech information and which may be limiting the intelligibility of speech signals in the recording AUTO GAIN IN 30dB E ES 20dB OUT 10dB Figure 9 AUTOMATIC GAIN Module 4 6 AUTOMATIC GAIN MODULE The AUTOMATIC GAIN module See Figure 9 is a dynamic audio level processor which can be applied to the final output of the processing stage of the QE 1500 The AUTO GAIN automatically increases the level of low amplitude audio signals as needed to maintain a good audio level at the output Move the IN OUT switch to the IN position to enable the AUTO GAIN module The AUTO GAIN module will apply gain as needed to maintain a good audio level up to a maximum amount specified by the Max Gain slide switch Three Max Gain selections are available 10 dB 20 dB and 30 dB If the signal input to the AUTO GAIN is already a good level no gain will be applied This module is useful for restoring the signal level of a heavily processed audio signal Also AUTO GAIN is invaluab
8. d more noise is removed from the audio signal Careful adjustment of this control is necessary to find the optimum position that causes the greatest amount of noise to be removed without removing any desired speech components gt GRAPHIC EQUALIZER 1 2 l mn v v Q e Lem em a IN 12 sal ces s l l ens re m leal m 1 18 sl X es leal emm 18 24 m mn es es e cen mn emm lema 24 DUT 30 s sl le le ces l lel les 21 36 ma Llan lo lma lor hr lor jem 26 500 1000 1500 2000 2600 3300 4000 4800 5650 6500 Hz Figure 8 GRAPHIC EQUALIZER Module 4 5 GRAPHIC EQUALIZER MODULE The GRAPHIC EQUALIZER module See Figure 8 is used to modify the tonal balance of the audio signal The signal is divided in frequency into ten bands spread roughly evenly through the portion of the frequency spectrum that human speech occupies Ten sliders one per band are used to attenuate signal energy in each band independently of the others Slider bars are positioned at 500 1000 1500 2000 2600 3300 4000 4800 5650 and 6500 Hz The lower a particular slider bar is moved the more attenuation is applied Up to 36 dB of attenuation can be applied per band Move the IN OUT slide switch to the IN position to enable the GRAPHIC EQUALIZER module To reduce the high frequency components in the audio signal su
9. eiii ii dia 8 9 2 Input Eevels s eR OE ERREUR UAE EUER 9 CHAPTER 4 Audio Enhancement Modulles cccccccccccccssssssssscsssssssssssssees LO 4 1 Master Switch 10 4 2 Hum Filter Module 11 4 3 Deconvolver Module 12 4 4 Noise Reduction Module 13 4 5 Graphic Equalizer Module 13 4 6 Automatic Gain Module 14 CHAPTER 5 Output SectioN oooocossss LS Sel x A o e e RA 15 RM e Ent 16 5 3 POWER S WICH sis O ON 16 CHAPTER 6 Specifications umi iii dad cacao 7 Table of Figures and Tables Figure 1 QE 1500 Audio Connector Panel 5 Figure 2 Power Connectors sec ec esec eese tse etrr TERRE TERTRE inet EE inet 5 Figure 3 QE 1500 Input Section oce oet OE ERO ODD OUO Eae ts 8 Figure 4 MASTER IN OUT Switch ecieieectte etie re Ecos 10 Figure 5 HUM FILTER Module ici iii 11 Figure 6 DECONVOLVER Module 11 Figure 7 NOISE REDUCTION Module 13 Figure 8 GRAPHIC EQUALIZER Module 13 Figure 9 AUTOMATIC GAIN Module 14 Figure 10 QE 1500 Headphone and Monitor Controls eee 15 Table 1 DECONVOLVER Mode Selections e eeeeeeeeeeeee eee eee eeess LD CHAPTER 1 INTRODUCTION Thank you for purchasing the QuickEnhance QE 1500 Audio Enhancement Fieldkit Please take a few moments to read this User s Guide to familiarize yourself with the main features and functions of the QE 1500 If you are new to audio enhancement pay particular attention to Chapter 4 Aud
10. eo LED bar graph input level indicators 25 pin parallel printer interface connects to most ASCII capable printers for REPORT generation feature 12V BNC connector for 5W gooseneck lamp included EC AC Power connector AC line cord included 2 mm barrel connector positive tip 9 18VDC at 4A 17
11. esulting in static or harsh distortion at the output If this happens simply press the CLEAR button to correct this condition If the module continues to crash in this way it may be necessary to lower the input levels or to move the COMPLEX NORMAL SIMPLE slider to a different position to mitigate the problem This behavior does not represent a defect in the QE 1500 but is an unavoidable side effect of the very powerful signal processing taking place inside the DECONVOLVER module The ADAPT FREEZE OUT switch is used to control whether the DECONVOLVER is actively adapting to the input signal freezing the current solution while ignoring changes in the input signal or not affecting the audio signal at all Depending on the type and nature of the noise problem you are trying to remove and the underlying signal of interest you may wish to allow the DECONVOLVER to continuously ADAPT through the entire recording or you may wish to train the module on a short portion of audio FREEZE the solution and apply that solution to the entire recording On difficult material you may need to try various approaches to see which technique yields the best result The COMPLEX NORMAL SIMPLE mode switch allows the user to modify various parameters in the DECONVOLVER algorithm to better adapt to and remove the current noise problem The table below gives examples of the types of noise problems that are helped by each of the three settings With this in mind however
12. io Enhancement Processors which details the operation and recommended usage of the vast processing resources the QE 1500 has to offer Enjoy using your new QE 1500 CHAPTER 2 SETUP AND CONNECTIONS The QuickEnhance QE 1500 has numerous ways to connect to audio equipment including two digital audio interfaces and one analog audio interface This section details the type and purpose of the various connectors a D T D a 4 o 4007 3m4z au 000000000000 0000000000000 o TOSLINK DIGITAL INTERFACE mPUT Gureur a E o mrur COAXIAL e d DIGITAL INTERFACE h OUTPUT o o 0 00000 0 0000000 o o o o o A A o a o gi o o AMALOG Pure Y ANALOG autruts Y venr Figure 1 QE 1500 Audio Connector Panel 00000000 00000000 00000000 p B POWER DC POWER DH Wes deM OFF Q oN AC POWER 90 2 VRAC AT HZ Figure 2 Power Connectors 2 1 AC POWER A standard AC POWER connector See Figure 2 is provided for connecting the QE 1500 to power mains A line cord appropriate for the destination country will be provided in the case 2 0 DC POWER A 2 1mm barrel type DC POWER connector See Figure 2 with positive tip is provided for supplying power to the unit The unit can accept DC power input at a range of 9 18V and draws a maximum peak current of 4A Note If AC and DC power is connected simultaneously an internal power relay will cause
13. le for correcting the near party far party situation in which the talker closest to the microphone is picked up at a much higher level than the talker furthest from the microphone In fact any signal that has severely fluctuating audio levels can benefit from this module 14 CHAPTER 5 OUTPUT SECTION Once the audio signal is fully processed by the QuickEnhance QE 1500 it will be sent to the audio outputs headphone circuitry and the DESTINATION DRIVE for listening or recording You may also wish to make a permanent record of the settings used to enhance a particular recording HEADPHONES 2 MONITOR m I MEN i Figure 10 QE 1500 Headphone and Monitor Controls 5 1 HEADPHONES The HEADPHONES controls See Figure 10 on the QE 1500 give the user a convenient way to listen to audio signals passing through the device There are two 3 5mm stereo phone jacks on the front panel that pass identical signals and are labeled 1 and 2 This is convenient for two person listening sessions or for training purposes The VOLUME knob controls the volume of signal in both HEADPHONES jacks equally Two MONITOR switches allow the user to select which signal is routed to the HEADPHONES The INPUT OUTPUT switch routes either the currently selected INPUT source See Section 3 1 or the final processed OUTPUT to the HEADPHONES The LEFT STEREO RIGHT switch routes only the LEFT channel signal to both ears the LEFT channel to the LEFT ear
14. ned to remove specific types of noises and the modules can be used in various combinations to enhance audio with multiple noise problems The signal flows through the processing section of the QE 1500 in the same order as the modules appear on the unit reading left to right top to bottom HUM FILTER DECONVOLVER NOISE REDUCTION GRAPHIC EQUALIZER and AUTO GAIN The following sections describe these modules in detail explain the user interface controls for each and provide examples of common noise problems that may be improved by the use of the various modules MASTER E OUT Figure 4 MASTER IN OUT Switch 4 1 MASTER SWITCH The MASTER IN OUT switch See Figure 4 is not a processing module per se but is used to enable or bypass the entire signal processing section of the QE 1500 When the MASTER switch is in the IN position the QE 1500 processes the selected input signal according to the settings of the various processing modules and passes the result to the audio outputs and headphone circuitry Conversely when the MASTER switch is in the OUT position audio from the selected input signal is passed directly through to the audio outputs and headphone circuitry bypassing all processing It is handy to use this switch to quickly compare the processed audio with the original unprocessed audio to determine the effect the QE 1500 is having on speech intelligibility 10 HUM FILTER 0 50Hz Sien OUT
15. or Reference source not found but both digital audio outputs are always active The digital outputs sampling rate is always 44 1kHz regardless of the sample rate of the digital input this is made possible by the high quality real time sample rate conversion in the QE 1500 2 6 LAMP A 12VDC BNC connector is provided for the enclosed gooseneck lamp This lamp uses a commonly available 5W replacement bulb The LAMP connector is energized whenever the main POWER switch is turned on allowing low light operation of the QE 1500 2 7 PRINTER PORT The standard 25 pin parallel PRINTER PORT See Figure 1 is provided to implement the printed REPORT feature for forensic documentation of panel settings See Section Error Reference source not found The PRINTER PORT is suitable for connection to most inkjet dot matrix and laser printers that support ASCII text printing CHAPTER 3 INPUTS The input section of the QuickEnhance QE 1500 is the place where the desired input source is selected and the audio input levels are set and monitored OL OL 3 3 OdB INPUT SELECT 0 zn 0 ANALOG l 3 3 6 6 DIGITAL 12 12 INPUT LEVELS 48 48 DIGITAL INPUT DER 24 24 COAXIAL 36 36 R 48 48 TASAS LEFT RIGHT Figure 3 QE 1500 Input Section 3 1 INPUT S
16. power to be drawn from the AC supply only 2 3 DESTINATION DRIVE The QE 1500 is able to accommodate a MiniDisc or DAT recorder depending on customer specification The recorder is hardwired to receive a direct digital output from the QE 1500 processor making it possible to obtain a recording of the enhanced audio See the additional enclosed documentation for instructions on the operation of the DESTINATION DRIVE 2 4 ANALOG AUDIO INTERFACE Unbalanced stereo ANALOG inputs and outputs See Figure 1 are provided on standard RCA connectors The ANALOG inputs are capable of accepting line level signals up to 3 0Vrms and have an input impedance of 25kO The ANALOG outputs have a maximum level of 3 0Vrms at full scale and the output impedance is 1000 The ANALOG inputs are only active when selected with the INPUT SELECT switches See Section Error Reference source not found but the outputs are always active 2 5 DIGITAL AUDIO INTERFACES There are two types of DIGITAL audio interfaces provided on the QE 1500 S PDIF on coaxial RCA connectors and optical digital on TOSLINK connectors See Figure 1 Both interfaces support input of stereo 24 bit digital audio signals at a maximum sampling rate of 96kHz These digital interfaces are commonly found on professional and some consumer audio equipment such as CD players MiniDisc players DAT machines PC sound cards etc Only one of the digital audio inputs can be active at a time See Section Err
17. rocessing Bandwidth CONSTRUCTION Enclosure User Controls Ports Power CHAPTER 6 SPECIFICATIONS Stereo Panel adjustable 0 1 Vrms to 3 0Vrms e Zin 25kO Ground isolated RCA input jacks Stereo 3 0Vrms at full scale Zout 1000 Unbalanced RCA output jacks Dual 3 5mm stereo headphone jacks Selectable INPUT or OUTPUT monitoring Selectable LEFT channel RIGHT channel or STEREO monitoring VOLUME control 24 bit 128x oversampling stereo A D and D A gt 90dB SINAD Sigma delta conversion technology TMS320F206 20MIPS controller CPU 2 ADSP 2184 at 32 MIPS 14 DSP56200 digital filter processors Optical TOSLINK professional format digital input and output Optical TOSLINK digital output to Destination Drive Coaxial S PDIF professional format digital input and output Supports sample rates of 32 44 1 48 and 96 kHz via asynchronous sample rate conversion Fixed 44 1 kHz sample rate on digital outputs Adjustable stereo 50 60 Hz Hum Filter with 1000 Hz notch limit Stereo 1024 tap 1CH Deconvolver with selectable presets Stereo automatic Noise Reduction filter with adjustable attenuation Stereo 10 band Graphic Equalizer with integral 300 Hz highpass filter Stereo Automatic Gain dynamic level processor 7 0 kHz fixed 16 4 kHz sampling rate 19 1 8 L x 15 7 16 W x 7 9 16 D black Pelican style case 30 front panel switches knobs and slider controls Ster
18. you should always experiment with different settings to determine the optimum position for your particular enhancement situation Mode Example Usage Simple Removal of simple periodic noises such as tones and for the cancellation of minor echo reverberation and resonances in small rooms Normal Removal of more complex periodic noises such as buzzes hums idling engines etc and for the cancellation of echo reverberation and resonances in recordings made in small to medium sized rooms Complex Removal of significant echo reverberation and resonances in recordings made in medium to large sized rooms Table 1 DECONVOLVER Mode Selections 12 NOISE REDUCTION H IN OUT MIN MAX ATTENUATION Figure 7 NOISE REDUCTION Module 4 4 NOISE REDUCTION MODULE The NOISE REDUCTION module See Figure 7 unlike the DECONVOLVER is useful for removing noises that are not time correlated but are more random and unpredictable in nature Examples of this type of noise are air conditioner sounds wind noises radio static tape hiss etc Move the NOISE REDUCTION slide switch to the IN position to enable this module The amount of attenuation the NOISE REDUCTION module applies to the random component in the audio signal is controlled by the ATTENUATION knob When the knob is rotated to the MIN position no noise attenuation is applied to the signal As the knob is rotated toward the MAX position more an
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