WFGUI User Ation
User Manual: WFGUI User ation
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WFGUI User Documentation Index 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. Preface by Matthias Klumpp........................................................................................................... 2 What is WFGUI ? ............................................................................................................................ 2 Communities & discussions............................................................................................................ 2 Download ........................................................................................................................................ 2 Further improvements..................................................................................................................... 2 System requirements ...................................................................................................................... 2 Accuracy ......................................................................................................................................... 3 GUI overview .................................................................................................................................. 4 Signal (sound card) input................................................................................................................ 4 Start / Stop button ........................................................................................................................... 5 Center frequency ............................................................................................................................ 5 Signal quality indicator .................................................................................................................... 5 Signal level meter ........................................................................................................................... 5 Frequency counter .......................................................................................................................... 6 Display range .................................................................................................................................. 6 RMS% value ................................................................................................................................... 6 W&F evaluation method ................................................................................................................. 6 Peak value (needle instrument + numeric display)......................................................................... 8 Maximum value............................................................................................................................... 8 Oscilloscope.................................................................................................................................... 8 Version history ................................................................................................................................ 8 Internet links with additional technical information ......................................................................... 9 Author Contributors Alex Freed Matthias Klumpp Alex Nikitin Software development, technical realization Testing, accuracy check, documentation Testing, accuracy check 1/9 WFGUI User Documentation 1. Preface by Matthias Klumpp We, the contributors, want to thank the author for his excellent work he has spent on developing and improving this tool. It provides a very good base for all the analog audio enthusiasts, especially those working on vintage equipment, to keep their units in good working shape 2. What is WFGUI ? WFGUI (Wow & Flutter Graphical User Interface) is a tool that provides possibilities to adjust speed and measure speed fluctuations real-time by software means that in former times needed to be done by hardware Wow & Flutter meters. It can be used for turntables, audio cassette decks or open reel tape decks by playing a reference disk or tape with either a 3000Hz or 3150Hz tone. The output signal of the audio device is then input to the PC's soundcard and evaluated by WFGUI. Note: This software is provided in good faith, but supplied "as is" without any warranty of any kind. 3. Communities & discussions WFGUI was presented in several internet forums. English: Tapeheads: http://www.tapeheads.net/showthread.php?t=32287 DiyAudio: http://www.diyaudio.com/forums/analogue-source/254453-software-wf-meter.html German: 4. New-Hifi-Classic: http://new-hifi-classic.de/forum/index.php?topic=7328.0 Bandmschinenforum: http://forum2.magnetofon.de/board7-digitale-audiotechnik/board84anwendung-und-praxis/15584-wfgui-wow-flutter-echtzeitmessung-persoftware/ - post166946 Download WFGUI can be downloaded from the following sites: 5. Alex Nikitin's page: http://www.ant-audio.co.uk/index.php?cat=post&qry=library New-Hifi-Classic Server: http://uebergabe-daten.hificlassic.at/httpdocs/kuni/WFGUI/WFGUI_Test_WAV_Files.zip Further improvements The author is spending his spare time on developing this tool without charging anything. Please be aware that he has no obligation for anything, but hopefully will continue to work on further suggestions and improvements. The a.m. communities can be used to report problems and suggestions. 6. System requirements WFGUI was tested with Win XP / 7 / 8 and should flawlessly run on these platforms. The PC system should have at least a 1,6GHz dual core processor and - of course - a sound card. 2/9 WFGUI User Documentation 7. Accuracy WFGUI's accuracy was initially tested with several WAV files taken from audio cassette decks. The results were compared to hardware W&F meters. Sony WM-D6C Sony TC-D5M Tandberg TCD-310 ASC AS-3001 Tandberg TCD-3014 Speed -0,01% -0,65% -0,02% +0,09% -0,06% (3149,7Hz) (3129,6Hz) (3149,5Hz) (3152,8Hz) (3148,0Hz) -0,02% 0% -0,70% -0,60% -0,04% 0% 1) 1) 1) +0,08% - -0,08% - W&F (DIN) WFGUI (peak) Woelke ME106 Philips PM6307 Kenwood FL140 0,11% 0,12% 0,10% 0,08% 0,08% 0,06% 0,29% 0,30% 0,26% 1) 1) 1) 0,28% 0,30% - 0,08% 0,09% - W&F (unweighted) WFGUI (peak) Woelke ME106 Philips PM6307 Kenwood FL140 0,36% 0,44% 0,40% 0,18% 0,30% 0,10% 0,37% 0,38% 0,35% 1) 1) 1) 0,52% 0,50% - 0,13% 0,20% - WFGUI Woelke ME106 Philips PM6307 Kenwood FL140 1) Just little or no difference (<5% of the value measured) found in reading between WFGUI and the Kenwood FL-140 in all modes except in non-weighted peak measurements (still less than 10% of the value measured). 3/9 WFGUI User Documentation 8. GUI overview 9 13 12 10 19 14 15 11 17 16 20 9. 18 Signal (sound card) input The sound card device for input signal capturing can be selected here (drop down box shows one entry per detected sound card). WFGUI only shows the primary recording channel (as selected in the control panel) of each device. A selection of the various input/recording channels of a sound card (e.g. microphone, line etc.) can't be done directly from within WFGUI. Win XP: Input/recording channel selection can be done with the sound mixer control. Win 7 / 8: Win 7 / 8 doesn't offer a sound mixer with selection of the recording channel anymore. Instead, this needs to be done in the sound settings of the control panel. Note: - Just setting the wanted recording channel to "default" might sometimes not be recognized correctly by WFGUI. This seems to depend on the hardware. - In such cases, all unwanted recording channels need to be deactivated instead. By selecting "Stereomix" for recording, this provides a way to analyze also WAV files while playing them e.g. with Audacity. Note: Data capturing is done with standard 44.1kHz / 16 bits. WFGUI applies a general input filter with 600Hz bandwidth to the incoming signal. 4/9 WFGUI User Documentation 10. Start / Stop button By these buttons the measurement can be started, stopped and re-started. 11. Center frequency Defines the center frequency WFGUI is using for its analysis. The setting can be changed during a running measurement. 3000Hz setting: Frequencies <2850Hz or >3150Hz are ignored (valid range: ±5%) 3150Hz setting: Frequencies <2992,5Hz or >3307,5Hz are ignored (valid range: ±5%) The accuracy of the test frequency (3000 / 3150Hz) will have no effect at all on W&F measurements within the ±5% valid range. 12. Signal quality indicator If the signal quality is good for WFGUI to analyze W&F, then the "lamp" is green. Level needs to be higher ~ 24mV / -30dBm Frequency must be in valid range Otherwise the "lamp" is grey and a message is shown in the box. The indicator only works when the measurement is started. 13. Signal level meter Shows the applied signal level. With sound mixer level sliders all set to 100%, full range is ~ 170mV / -13dBm (absolute value may depend on the hardware). The signal level doesn't have any impact on the calculation accuracy as far as the level is high enough for data capturing. The level meter only works when the measurement is started. Note: There are intentionally no voltage levels given on the level meter. WFGUI doesn't control the mixer gain, it therefore has no way to determine the absolute level. Read samples are internally within a range of ±32767 (16 bit sampling resolution). If they are < 50 WFGUI simply declares the level being too low. 5/9 WFGUI User Documentation 14. Frequency counter Currently measured frequency. For speed adjustment the measured frequency should equal the reference frequency specified for the played reference tape or disk. Frequency outside the valid range (±5%) of the center frequency: - Frequency display is still updated, but then rounded down to 5Hz - This mode is useful to adjust speed deviations near to ±0% - The speed of the audio device needs to be adjusted prior to do any W&F measurement in order to get into the valid range again for further analysis of W&F. Frequency inside the valid range (±5%) of the center frequency: - Accuracy is a lot more precise as indicated by the format with a decimal point. - This is mode is required to reliably measure W&F. Note: WFGUI's frequency counter relies upon the sound card oscillator Some sound cards may give very accurate results, but some may give an error. It's therefore recommended to test the used sound card in this respect. Anyway the accuracy of the reference crystal in the sound card will have no effect at all on W&F measurements within the ±5% valid range. 15. Display range Display range for scope and needle instrument. The setting can be changed during a running measurement. 16. RMS% value RMS (root mean square) value in % of the currently evaluated Wow & Flutter. The result depends on the selected W&F evaluation method. 17. W&F evaluation method Specifies according to which standard the W&F shall be evaluated. The setting can't be changed anymore if the measurement was started. If it is to be changed, WFGUI needs to be stopped, closed and re-opened. For details about the filters, refer to the diagrams below. DIN (weighted): Applies a weighting filter according to the German Industry Standard (Deutsche IndustrieNorm) Unweighted: th Applies a Bessel bandpass filter, 4 order, -3dB frequencies: 0,3 - 200Hz Wow: th Applies a Bessel bandpass filter, 4 order, -3dB frequencies: 0,3 - 6Hz Flutter: th Applies a Bessel bandpass filter, 4 order, -3dB frequencies: 6 - 200Hz 6/9 WFGUI User Documentation Weighting filters used by WFGUI: General characteristics of different weighting filters: In detail the weighting filter according DIN 45507 with allowed tolerances: st nd Bessel filter (0,2Hz to 200Hz) consisting of a 1 order low pass and 2 order high pass filter. 7/9 WFGUI User Documentation 18. Peak value (needle instrument + numeric display) Peak (current) value in % of the currently evaluated Wow & Flutter. The result depends on the selected W&F evaluation method. The dynamics of the needle instrument are adjusted to simulate attack and decay of a real analog hardware instrument. 19. Maximum value Maximum value of RMS and (quasi) peak in % during the evaluation period of the last 10s. Re-calculation of these values starts newly, if WFGUI is stopped and re-started. Note: If the signal is not steady (i.e. turned off and on while capturing), the first 20s will not show reliable values. These values should therefore be discarded. 20. Oscilloscope The scope screen shows ~200ms of the demodulated signal (period of the last 125 samples). E.g. when testing with an artificial 2Hz sine modulated 3150 Hz you can clearly see the sine wave going between ±0.5 for 0.5% Wow. This therefore not only shows the real peaks but also gives a good idea of the nature of the Wow & Flutter. The result depends on the selected W&F evaluation method. 21. Version history wfgui_4_60.exe First public beta version with capability of signal real-time processing directly from sound card. wfgui_6_00.exe Changed ranges to 0,1%, 0,4%, 1% and 4% Changed the meter color to light yellow Added saving of raw "demodulated" data in a file "WF_out.dat" in the current directory: - The program mimics the structure of a hardware tool. - The input filter applied to the raw 3 (or 3.15) KHz data is always present but is pretty flat around the center frequency and should not affect the demodulated signal's spectrum much. - Then the signal is frequency demodulated by calculating time between consecutive zero crossings and subtracting the "perfect" interval. - This demodulated signal is optionally saved before being processed by the next filter. 8/9 WFGUI User Documentation 22. Internet links with additional technical information Measuring method for W&F as per DIN 45507 (German): http://www.theimann.com/Analog/Misc_Tech/Mess_TB/Teil2.html Schematic for a W&F meter (German): http://www.theimann.com/Analog/Misc_Tech/TonSchwMess/index.html Article "Speed, pitch and timing errors in tape recording and reproducing" by John McKnight (English): http://home.comcast.net/~mrltapes/mcknight_speed.pdf 9/9
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