DOCSLIB.ORG

Implement a Chorus Effect in a Real-Time Embedded System

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Implement a Chorus Effect in a Real-Time Embedded System Universitat Polit`ecnicade Catalunya (UPC) Escola T`ecnicaSuperior d'Enginyeria de Telecomunicaci´ode Barcelona (ETSETB) Implement a chorus effect in a real-time embedded system by Gerard Amposta Boquera Advisor: Asunci´onMoreno Bilbao Barcelona, September 2016 \I was left with an urge to make the guitar sound like things it shouldn't be able to sound like." Adrian Belew (1949 - ) Universitat Polit`ecnicade Catalunya (UPC) Abstract Escola T`ecnicaSuperior d'Enginyeria de Telecomunicaci´ode Barcelona (ETSETB) Departament de Teoria del Senyal i Comunicacions by Gerard Amposta Boquera An implementation of a chorus effect in an embedded device has been devised. Some objective and subjective qualities of this implementation have been analyzed, with the purpose of being tested for their adequacy for usage in the music industry. These qualities include, but are not limited to: maximum delay, number of delayed copies of the original signal, waveshape of the signal modulating the delay, dependency of parameters of the modulating signal from parameters from the input signal, adaptability of the architecture to accommodate further effects without increasing significantly resources usage. It is encountered that a scientific approach to this study has either not been taken, or the results of this research are privately held, therefore being adequate to start this research for the public interest. The system has been implemented in a dsPIC33FJ256GP506 digital signal controller using a standard development board, and results show that this is a promising approach that could be industrializable using audio-grade components for the analog stages and a slightly more powerful DSC. Acknowledgements When my family and friends finally managed to overcome my stubbornness and con- vinced me to put it together and write this thesis, I knew what I was heading into was though. What I happily ignored at that moment was how though. This last year has been a challenging tour de force on juggling with my time: time for work, time for the thesis, time for resting, when feasible, and all while trying (and failing) to avoid losing contact with the same family and friends that talked me into writing my thesis. It's been some difficult times, but I also learnt a lot, so I am grateful that I actually did it. None of this would have been possible without the help of a lot of people. First and foremost, I would like to thank my advisor, Asunci´onMoreno, for her time, her patience, her wise advice, her kindness, and specially for stepping up at crucial times, steering the ship in the right direction when it was necessary. For the very same reasons, I would also like to thank Antonio Bonafonte, whose early insights about the project were incredibly helpful. A large share of the gratitude that I owe for being able to finish this thesis is due to the sole person that has been with me every single day during this period: thanks Montse for your kindness, patience, love and understanding. I also need to thank all my family, specially Mom and Dad, for their unconditional support. Is difficult to go through this without your peers comprehension, so is lovely to be able to count upon friends who have gone through the same as you to for some morale boosting. Thanks Marc, Jordi, Marc, V´ıctor,Miquel, Dani, Jes´us,Albert, and all of you guys, for being there during the last 10 years, and for the years to come. Since this is, in the end, about music, I would also like to thank my \road family", for allowing me to skip rehearsals and such. Thanks Manel, Esteve, Josep and Maurici for making me laugh like crazy during that last year every single time we met. Being now a quite experienced engineer, I have had the opportunity to observe in others how determinant is the influence of senior engineers in juniors, and the importance of blossoming in the right environment, and picking the right role models. For this reason, although they have not been linked to this project whatsoever, I would not feel right finishing this acknowledgements section without thanking Sergio Casanova and Oriol Sol`a.I feel fortunate to have had the opportunity to grow up with them both personally and professionally, and I hope I can keep learning from them for the years being. And, well. the little furry dudes can't actually read, but their unparalleled comforting abilities have helped me to keep my sanity during those very stressful times, so thanks Neko and Pam. iii This page is intentionally left blank Contents Abstract ii List of Figures vii List of Tables viii Acronyms ix 1 Introduction1 1.1 Motivation...................................1 1.2 A brief introduction to music effects.....................3 1.2.1 A brief history of music effects....................4 1.2.2 Modulation effects explained.....................5 1.3 State of the art.................................6 1.4 Objectives....................................6 2 Technical description8 2.1 System design..................................8 2.1.1 Features................................. 10 2.2 System description............................... 12 2.3 Modules..................................... 15 2.3.1 Filters.................................. 16 2.3.2 RNG................................... 20 2.3.3 Envelope follower............................ 20 2.3.4 Pitch change detector......................... 21 2.3.5 Oscillators................................ 22 3 Implementation 24 3.1 MCU choice................................... 24 3.2 CPU architecture and peripherals....................... 27 3.3 Module implementation & technical details................. 29 3.3.1 Audio path............................... 29 3.3.2 Trigonometric functions........................ 29 3.3.3 Filters.................................. 30 3.3.4 Oscillators................................ 31 v Contents vi 3.3.5 RNG................................... 33 3.3.6 Envelope follower............................ 34 3.3.7 Pitch change detector......................... 34 4 Results 36 4.1 Results obtained................................ 36 4.1.1 Objective quality............................ 36 4.1.2 Subjective quality........................... 38 4.1.3 Comparison with similar products.................. 39 5 Conclusions and future work 41 5.1 Conclusions................................... 41 5.2 Future work................................... 41 A Project source code 43 B Test subjects demographics 44 Bibliography 46 List of Figures 2.1 Basic chorus architecture...........................9 2.2 Leaky integrator................................ 16 2.3 Low-pass filter frequency response for N = 2, 4, 8 and 16 (dB)...... 17 2.4 High-pass filter................................. 17 2.5 High-pass filter frequency response for N = 2, 4, 8 and 16 (dB)...... 18 2.6 Band-pass resonator.............................. 19 2.7 Band-pass resonator frequency response for fc = 4KHz, 8KHz, 12KHz and 16KHz (dB)................................ 20 2.8 Envelope follower................................ 21 2.9 Pitch change detector............................. 21 3.1 Low-pass and high-pass filter topology.................... 31 4.1 Square wave output signal as received by the oscilloscope (mV)...... 37 4.2 Sinusoidal wave output signal as received by the oscilloscope (mV).... 37 vii List of Tables 2.1 Fixed system parameters............................ 11 2.2 Reconfigurable parameters and their default values............. 12 2.3 Configurable options.............................. 12 2.4 Band-pass filter central frequencies fm(Hz)................. 22 B.1 Subject relationship with music industry................... 44 B.2 Subject primary instrument.......................... 44 B.3 Subject musical education........................... 44 B.4 Subject musical interests............................ 45 viii Acronyms AGC Automatic Gain Compensation. 23 CLT Central Limit Theorem. 33 CPU Central Processing Unit.v,6, 26, 27, 34 DAW Digital Audio Workstation.3 DCI Data Converter Interface. 28, 29 DF1 Direct Form 1. 25, 41 DSC Digital Signal Controller. ii, 29, 30, 41 DSP Digital Signal Processor. 25, 26, 27, 28, 29, 30, 32 FFT Fast Fourier Transform. 25 FIR Finite Impulse Response. 16 FPU Floating Point Unit. 25, 26, 28, 29, 30 HAL Hardware Abstraction Layer.6 HW Hardware. 25, 26, 27, 28, 29, 32, 41 I2C Inter-Integrated Circuit. 28 IDE Integrated Development Environment. 25, 26 IEEE Institute of Electrical and Electronics Engineers. 46 IIR Infinite Impulse Response. 16, 18, 21, 25, 30, 31, 34, 41 LFO Low Frequency Oscillator.5, 10, 11, 13 LPF Low Pass Filter. 20 ix List of Acronyms x LSb Least Significant Bit. 33 LUT Least Significant Bit. 29, 30 MAC Multiply-and-Accumulate. 25, 26, 28 MCU MicroController Unit.v,2, 24, 25, 26, 27, 28, 29, 30, 33, 34 PC Personal Computer. 39 RNG Random Number Generator.v, 11, 13, 15, 19, 33 SIMD Single Instruction, Multiple Data. 26 SW Software. 28, 29, 33, 34 TI Texas Instruments. 26 TRS Tip, Ring, Sleeve. 25, 29 VST Virtual Studio Technology.2,3, 39 Dedicated to Montse, for her support, dedication and patience during this journey. xi Chapter 1 Introduction 1.1 Motivation Short and clear, the motivation for this project is to conjugate my passion for embedded systems programming and digital signal processing with my passion for music. I am myself a regular user of chorus and other effects units. When using them, I often wonder about the design choices taken on their design. Why the range of this parameter is constrained to those values? Why did not they include a low-pass filter in this side-chain? Why there isn't any
Load more

Recommended publications
  • Gemini Chorus User's Guide
    Gemini Chorus User’s Guide Welcome Thank you for purchasing the Gemini Chorus. This powerful stereo effects pedal features a collection of meticulously crafted chorus sounds ranging from classic dual-voice sounds to lush quad-voice ensembles. With a simple control set, the Gemini can work in a wide variety of musical settings, and the powerful MIDI and Neuro control options under the hood provide access to a vast array of additional tonal possibilities. The Gemini is housed in a durable, lightweight aluminum housing, packing rack mount power and flexibility into a compact, easy-to-use stompbox. SA242 Gemini Chorus User’s Guide 1 The USB and Neuro ports transform the Gemini from a simple chorus pedal into a powerful multi- effects unit. Using the free Neuro App (iOS and Android), a wide range of additional control parameters and effect types (phaser, flanger, resonator) are accessible. When used together with the Neuro Hub, the Gemini is fully MIDI-controllable and 128 multi-pedal presets, or “scenes,” can be saved for instant recall on the stage or in the studio. The Gemini can also connect directly to a passive expression pedal or the Hot Hand for expressive control of any parameter. The Quick Start guide will help you with the basics. For more in-depth information about the Gemini Chorus, move on to the following sections, starting with Connections. Enjoy! - The Source Audio Team Overview Diverse Chorus Sounds – Choose from traditional chorus tones such as Dual, Classic, and Quad, or delve deeper into unique sounds cooked up in the Source Audio lab.
    [Show full text]
  • Frank Zappa and His Conception of Civilization Phaze Iii
    University of Kentucky UKnowledge Theses and Dissertations--Music Music 2018 FRANK ZAPPA AND HIS CONCEPTION OF CIVILIZATION PHAZE III Jeffrey Daniel Jones University of Kentucky, [email protected] Digital Object Identifier: https://doi.org/10.13023/ETD.2018.031 Right click to open a feedback form in a new tab to let us know how this document benefits ou.y Recommended Citation Jones, Jeffrey Daniel, "FRANK ZAPPA AND HIS CONCEPTION OF CIVILIZATION PHAZE III" (2018). Theses and Dissertations--Music. 108. https://uknowledge.uky.edu/music_etds/108 This Doctoral Dissertation is brought to you for free and open access by the Music at UKnowledge. It has been accepted for inclusion in Theses and Dissertations--Music by an authorized administrator of UKnowledge. For more information, please contact [email protected]. STUDENT AGREEMENT: I represent that my thesis or dissertation and abstract are my original work. Proper attribution has been given to all outside sources. I understand that I am solely responsible for obtaining any needed copyright permissions. I have obtained needed written permission statement(s) from the owner(s) of each third-party copyrighted matter to be included in my work, allowing electronic distribution (if such use is not permitted by the fair use doctrine) which will be submitted to UKnowledge as Additional File. I hereby grant to The University of Kentucky and its agents the irrevocable, non-exclusive, and royalty-free license to archive and make accessible my work in whole or in part in all forms of media, now or hereafter known. I agree that the document mentioned above may be made available immediately for worldwide access unless an embargo applies.
    [Show full text]
  • Metaflanger Table of Contents
    MetaFlanger Table of Contents Chapter 1 Introduction 2 Chapter 2 Quick Start 3 Flanger effects 5 Chorus effects 5 Producing a phaser effect 5 Chapter 3 More About Flanging 7 Chapter 4 Controls & Displa ys 11 Section 1: Mix, Feedback and Filter controls 11 Section 2: Delay, Rate and Depth controls 14 Section 3: Waveform, Modulation Display and Stereo controls 16 Section 4: Output level 18 Chapter 5 Frequently Asked Questions 19 Chapter 6 Block Diagram 20 Chapter 7.........................................................Tempo Sync in V5.0.............22 MetaFlanger Manual 1 Chapter 1 - Introduction Thanks for buying Waves processors. MetaFlanger is an audio plug-in that can be used to produce a variety of classic tape flanging, vintage phas- er emulation, chorusing, and some unexpected effects. It can emulate traditional analog flangers,fill out a simple sound, create intricate harmonic textures and even generate small rough reverbs and effects. The following pages explain how to use MetaFlanger. MetaFlanger’s Graphic Interface 2 MetaFlanger Manual Chapter 2 - Quick Start For mixing, you can use MetaFlanger as a direct insert and control the amount of flanging with the Mix control. Some applications also offer sends and returns; either way works quite well. 1 When you insert MetaFlanger, it will open with the default settings (click on the Reset button to reload these!). These settings produce a basic classic flanging effect that’s easily tweaked. 2 Preview your audio signal by clicking the Preview button. If you are using a real-time system (such as TDM, VST, or MAS), press ‘play’. You’ll hear the flanged signal.
    [Show full text]
  • Neural Modelling of Periodically Modulated Time-Varying Effects
    Proceedings of the 23rd International Conference on Digital Audio Effects (DAFx2020),(DAFx-20), Vienna, Vienna, Austria, Austria, September September 8–12, 2020-21 2020 NEURAL MODELLING OF PERIODICALLY MODULATED TIME-VARYING EFFECTS Alec Wright and Vesa Välimäki ∗ Acoustics Lab, Dept. of Signal Processing and Acoustics Aalto University Espoo, Finland [email protected] ABSTRACT In recent years, numerous studies on virtual analog modelling of guitar amplifiers [11, 12, 13, 14, 4, 15] and other nonlinear sys- This paper proposes a grey-box neural network based approach tems [16, 17] using neural networks have been published. Neural to modelling LFO modulated time-varying effects. The neural network modelling of time-varying audio effects has received less network model receives both the unprocessed audio, as well as attention, with the first publications being published over the past the LFO signal, as input. This allows complete control over the year [18, 3]. Whilst Martínez et al. report that accurate emulations model’s LFO frequency and shape. The neural networks are trained of several time-varying effects were achieved, the model utilises using guitar audio, which has to be processed by the target effect bi-directional Long Short Term Memory (LSTM) and is therefore and also annotated with the predicted LFO signal before training. non-causal and unsuitable for real-time applications. A measurement signal based on regularly spaced chirps was used In this paper we present a general approach for real-time mod- to accurately predict the LFO signal. The model architecture has elling of audio effects with parameters that are modulated by a been previously shown to be capable of running in real-time on a Low Frequency Oscillator (LFO) signal.
    [Show full text]
  • Metaflanger User Manual
    MetaFlanger Table of Contents Chapter 1 Introduction 2 Chapter 2 Quick Start 3 Flanger effects 5 Chorus effects 5 Producing a phaser effect 5 Chapter 3 More About Flanging 7 Chapter 4 Controls & Displa ys 11 Section 1: Mix, Feedback and Filter controls 11 Section 2: Delay, Rate and Depth controls 14 Section 3: Waveform, Modulation Display and Stereo controls 16 Section 4: Output level 18 Section 5: WaveSystem Toolbar 18 Chapter 5 Frequently Asked Questions 19 Chapter 6 Block Diagram 20 Chapter 7.........................................................Tempo Sync in V5.0.............22 MetaFlanger Manual 1 Chapter 1 - Introduction Thanks for buying Waves processors. Thank you for choosing Waves! In order to get the most out of your new Waves plugin, please take a moment to read this user guide. To install software and manage your licenses, you need to have a free Waves account. Sign up at www.waves.com. With a Waves account you can keep track of your products, renew your Waves Update Plan, participate in bonus programs, and keep up to date with important information. We suggest that you become familiar with the Waves Support pages: www.waves.com/support. There are technical articles about installation, troubleshooting, specifications, and more. Plus, you’ll find company contact information and Waves Support news. The following pages explain how to use MetaFlanger. MetaFlanger’s Graphic Interface 2 MetaFlanger Manual Chapter 2 - Quick Start For mixing, you can use MetaFlanger as a direct insert and control the amount of flanging with the Mix control. Some applications also offer sends and returns; either way works quite well.
    [Show full text]
  • Magpick: an Augmented Guitar Pick for Nuanced Control
    Magpick: an Augmented Guitar Pick for Nuanced Control Fabio Morreale Andrea Guidi Andrew McPherson Creative Arts and Industries Centre For Digital Music Centre For Digital Music University of Auckland, Queen Mary University of Queen Mary University of New Zealand London, UK London, UK [email protected] [email protected] [email protected] ABSTRACT This paper introduces the Magpick, an augmented pick for electric guitar that uses electromagnetic induction to sense the motion of the pick with respect to the permanent mag- nets in the guitar pickup. The Magpick provides the gui- tarist with nuanced control of the sound that coexists with traditional plucking-hand technique. The paper presents three ways that the signal from the pick can modulate the guitar sound, followed by a case study of its use in which 11 guitarists tested the Magpick for five days and composed a piece with it. Reflecting on their comments and experi- Figure 1: The Magpick is composed of two parts: a ences, we outline the innovative features of this technology hollow body (black) and a cap (brass). from the point of view of performance practice. In partic- ular, compared to other augmentations, the high tempo- ral resolution, low latency, and large dynamic range of the The challenge is to find ways to sense the movement of Magpick support a highly nuanced control over the sound. the pick with respect to the guitar with high resolution, Our discussion highlights the utility of having the locus of high dynamic range, and low latency, then use the resulting augmentation coincide with the locus of interaction.
    [Show full text]
  • Guitar Resonator GR-Junior II
    Guitar Resonator GR-Junior II User Manual Copyright © by Vibesware, all rights reserved. www.vibesware.com Rev. 1.0 Contents 1 Introduction ...............................................................................................1 1.1 How does it work ? ...............................................................................1 1.2 Differences to the EBow and well known Sustainers ............................2 2 Fields of application .................................................................................3 2.1 Feedback playing everywhere / composing / recording ........................3 2.2 On stage ...............................................................................................3 2.3 New ways of playing .............................................................................4 3 Start-Up of the GR-Junior .........................................................................5 4 Playing techniques ...................................................................................5 4.1 Basics ...................................................................................................5 4.2 Harmonics control by positioning the Resonator ...................................6 4.3 Changing harmonics by phase shifting .................................................6 4.4 Some string vibration basics .................................................................6 4.5 Feedback of multiple strings .................................................................9 4.6 Limits of playing, pickup selection,
    [Show full text]
  • 506 Operation Manual
    Operation Manual Thank you for selecting the ZOOM 506 (hereafter simply called the "506"). Please take the time to read this manual carefully so as to get the most out of your 506 and to ensure optimum performance and reliability. Retain this manual for future reference. ZOOM CORPORATION NOAH Bldg., 2-10-2, Miyanishi-cho, Fuchu-shi, Tokyo 183, Japan PHONE: 0423-69-7111 FAX: 0423-69-7115 Printed in Japan 506-5000 1 Major Features • 24 individual built-in effects provide maximum flexibility. Up to 8 effects can be used simultaneously in any combination. • Memory capacity for up to 24 user-programmable patches. • Integrated auto-chromatic bass guitar tuner for simple and precise tuning anywhere. • Optional foot controller FP01 can be used for pedal wah or pedal pitch, and volume control is also possible. • Optional foot switch FS01 can be used for bank switching, resulting in enhanced playability. • Dual power supply principle allows the unit to be powered from an alkaline battery or an AC adapter. • New DSP (digital signal processor) ZFx-2 developed by Zoom produces high-quality effects from an amazingly compact package. 2 Safety Precautions USAGE AND SAFETY PRECAUTIONS Usage precautions In this manual, symbols are used to highlight warnings and cautions for you to read so that accidents can be prevented. The Electrical interference meanings of these symbols are as follows: This symbol indicates explanations about extremely For safety considerations, the 506 has been designed to provide dangerous matters. If users ignore this symbol and maximum protection against the emission of electromagnetic ！� handle the device the wrong way, serious injury or radiation from inside the device, and from external death could result.
    [Show full text]
  • Strymon El Capistan Manual
    Strymon El Capistan Manual Renado ceded repressively while fluctuant Geoff outstare obnoxiously or swans songfully. Maynord plunge utterly? Plano-convex and translative Giorgio still connects his ski sulkily. This page contains information about the User Manual search the El Capistan from Strymon. At strymon el capistan manual that is no compromises in this is valid in no fui a fight each with others was quiet about the hell. Returning to the wake one had time, screaming and hurling insults at each shift like fastballs. USER MANUAL Strymon Volante Magnetic Echo Machine pg 3 Front Panel. Strymon El Capistan dTape Echo Whammy Bar. Manual Akai E2 Head and Delay Looper Pedal Demonstration Part together by. OPERATING INSTRUCTIONS USER GUIDE USER MANUAL OWNER GUIDE OWNER. See how is. Or manual strymon merchandise is possible make a different. There are always read! Adios: pronto quedaremos desocupados para serviros. Possessions have strymon el capistan manual из СШЕ ѕвлѕютѕѕ отличным приобретением в любое времѕ. When purchased from strymon el capistan? Jhs milkman was once you already know is always active. Pedal Parts Ltd is not associated with and makes no claims to these trademarks. Its warmth whispered against infant skin food if it said trying to tell is something. Normally Open Normally Closed TRS configuration used by most Strymon pedals and dig DIG it for the Strymon DIG. So tonight I wanted nor have distortion I turn an audio signal the the Epsilon and distortion is secure I got.
    [Show full text]
  • Recording and Amplifying of the Accordion in Practice of Other Accordion Players, and Two Recordings: D
    CA1004 Degree Project, Master, Classical Music, 30 credits 2019 Degree of Master in Music Department of Classical music Supervisor: Erik Lanninger Examiner: Jan-Olof Gullö Milan Řehák Recording and amplifying of the accordion What is the best way to capture the sound of the acoustic accordion? SOUNDING PART.zip - Sounding part of the thesis: D. Scarlatti - Sonata D minor K 141, V. Trojan - The Collapsed Cathedral SOUND SAMPLES.zip – Sound samples Declaration I declare that this thesis has been solely the result of my own work. Milan Řehák 2 Abstract In this thesis I discuss, analyse and intend to answer the question: What is the best way to capture the sound of the acoustic accordion? It was my desire to explore this theme that led me to this research, and I believe that this question is important to many other accordionists as well. From the very beginning, I wanted the thesis to be not only an academic material but also that it can be used as an instruction manual, which could serve accordionists and others who are interested in this subject, to delve deeper into it, understand it and hopefully get answers to their questions about this subject. The thesis contains five main chapters: Amplifying of the accordion at live events, Processing of the accordion sound, Recording of the accordion in a studio - the specifics of recording of the accordion, Specific recording solutions and Examples of recording and amplifying of the accordion in practice of other accordion players, and two recordings: D. Scarlatti - Sonata D minor K 141, V. Trojan - The Collasped Cathedral.
    [Show full text]
  • Contents About the Author
    2 THE SERIOUS GUITARIST | EsseNtiaL BOOK OF Gear CONTENTS About the Author ..................................................... 3 2000 and Beyond ............................................38 Part 3: The Technical Stuff ..................................82 Introduction .............................................................. 4 Amp Modeling ...............................................39 The Science of Sound .....................................82 Guitar Apps ...................................................39 Vibrations........................................................82 Part 1: The History of Guitar Gear ...................... 5 8- and 9-String Guitars ...............................39 Amplitude and Types of Waves .................82 The1930s ............................................................. 5 Guitar-Based Video Games ......................40 Overtones (Harmonics) ..............................82 The First Electric Guitars .............................. 5 Look, Ma, No Amp! ......................................40 Modulation .....................................................83 The First Amplifiers ........................................ 6 Fractal Audio Systems Axe-FX II ..............40 The Order of Effects ....................................83 Early 7-String Guitar ...................................... 8 Looking Ahead ..............................................41 Understanding Guitar Amps ..........................84 Early Talk Box .................................................. 8 Tube Amps .....................................................84
    [Show full text]
  • User's Manual
    USER’S MANUAL G-Force GUITAR EFFECTS PROCESSOR IMPORTANT SAFETY INSTRUCTIONS The lightning flash with an arrowhead symbol The exclamation point within an equilateral triangle within an equilateral triangle, is intended to alert is intended to alert the user to the presence of the user to the presence of uninsulated "dan- important operating and maintenance (servicing) gerous voltage" within the product's enclosure that may instructions in the literature accompanying the product. be of sufficient magnitude to constitute a risk of electric shock to persons. 1 Read these instructions. Warning! 2 Keep these instructions. • To reduce the risk of fire or electrical shock, do not 3 Heed all warnings. expose this equipment to dripping or splashing and 4 Follow all instructions. ensure that no objects filled with liquids, such as vases, 5 Do not use this apparatus near water. are placed on the equipment. 6 Clean only with dry cloth. • This apparatus must be earthed. 7 Do not block any ventilation openings. Install in • Use a three wire grounding type line cord like the one accordance with the manufacturer's instructions. supplied with the product. 8 Do not install near any heat sources such • Be advised that different operating voltages require the as radiators, heat registers, stoves, or other use of different types of line cord and attachment plugs. apparatus (including amplifiers) that produce heat. • Check the voltage in your area and use the 9 Do not defeat the safety purpose of the polarized correct type. See table below: or grounding-type plug. A polarized plug has two blades with one wider than the other.
    [Show full text]