|
 |
 |
 |
|
 |
|
 |
|
|
Last Updated
03/31/2019
Sitemap
|
|||||||||
Detailed entries for one subject from the INDEX TO HOW TO DO IT INFORMATION. |
|||||||||
|
LOUDSPEAKER TESTING sa LOUDSPEAKER IMPEDANCE & IMPEDANCE TESTING xx LOUDSPEAKER Speaker evaluation using ear or machine. Understanding your own behavior as you listen, as well as understanding of the various measurements you can make on a speaker system. Part 1. Speaker evaluation using ear or machine. Part 2. The warbler (a tone oscillator that periodically sweeps through 1/3 octave bands). A clever test technique for speakers in rooms uses an audio signal generator and a sound level meter. Microphones for measuring a loudspeaker's response. Includes an equalized preamp circuit for the Sony ECM-170. Using a plastic soda straw to locate physical causes of diffraction. Includes tips on smoothing various profiles to correct the diffraction noise. Digital measurement of the Thiele/Small parameters for speaker design. The unobtrusive stage. Advice on the end result we seek using loudspeakers. Some simple tests for loudspeakers. A quick opening, variable volume test box for use when measuring the Thiele-Small parameters on a lot of drivers. Cheap calibrated L-pads for speaker testing. Finding fp (resonant frequency) for passive radiator speakers. An audio pulse generator useful for speaker design and testing and for sound reinforcement. Modular test instruments. Part 1. Build your own voltmeter boards and power supply boards which will be incorporated into other instruments. Modular test instruments. Part 2. How to build a dual-channel wattmeter for speaker testing. Modular test instruments. Part 3. Direct-reading phase meter. Step response of loudspeakers. Speaker testing method utilizes a microcomputer and a Fast Fourier Transformation algorithm to extract the frequency response from the time response of the signal produced by the speaker under test. Tuning bass reflex speaker systems. How to design, build and tune a port (vent) for a bass reflex speaker system. Testing the amplifier/loudspeaker interface. Build a special waveform generating circuit which drives the amplifier's protection circuits into current limiting. The result is displayed on an oscilloscope. Switcher. Heavy-duty loudspeaker switcher allows independent switching of left and right channels to facilitate comparison testing of loudspeakers. Loudspeaker measurement methods. An introduction to the 1/3-octave warble method. Wheatstone bridge to measure voice coil resistance. Measuring sensitivity and power ratings for raw drivers and complete speaker systems. How to achieve Heyser's measurements without an anechoic chamber. An explanation of TDS (time delay spectrometry), one of several loudspeaker measuring techniques. Measuring resistance and inductance of voice coils. Designing and using Zobel networks to make the impedance of a woofer look like a resistor. Mitey Mike. Build a good free-field microphone with a frequency response of 20Hz to 20kHz for testing loudspeakers. Est. cost: $50. Measuring drivers with radar. Using an X band microwave transceiver to measure if a finished enclosure is functioning as intended. Modifying a personal computer to generate the audio frequencies needed to test loudspeaker drivers. A tutorial on methodology compares MLSSA broad band excitation with sine wave excitation when testing loudspeaker drivers. A 1/3-octave noise source with a constant average power output and a sound level monitor. Used to measure loudspeaker response. Circuit for a precision current source delivers 50mA AC constant current for testing loudspeakers. The IMP (Impulse response Measurement and Processing). A circuit board and software complement which makes a PC into a sophisticated FFT (fast Fourier Transform) analyzer for loudspeaker and audio equipment evaluation and development. Allows collection and analysis of 12-bit analog data up to 4,095 samples in length. Sample rates are selectable at either 61.441kHz or 1.92kHz which, along with internal filtering, allows measurements from several hertz to 20kHz. Est. cost: $250 (kit). Part 1. Hardware construction. Loudspeaker power rating and power handling specifications explained. The IMP. Part 2. Functions and operations of the software. The IMP. Part 3. Step-by-step examples of measurement procedures. The IMP. Part 4. Measuring Thiele/Small parameters. Matching driver efficiencies. How loudspeaker manufacturers calculate driver sensitivity ratings. How to successfully match driver efficiencies in multi-driver systems. The IMP. Part 5. Noise stimulus, maximum length sequence (MLS) test signal, constructing an IMP/MLS satellite board, and the new version M software with all its bells and whistles. Tip on using an older oscilloscope that doesn't do Lissajous traces to locate the resonant frequency. Oscilloscope method for taking the accurate measurements necessary for vented-box design. Requires the use of an audio signal generator. Converting Radio Shack's sound level meter to also function as a millivolt (mV) testmeter to measure loudspeaker response. Acoustic distortion and balanced speakers. Results of testing supposedly idential speakers by energizing them with the same inputs. Microphone response correction with IMP. How to introduce corrections for an inexpensive microphone into the IMP (Impulse response Measurement and Processing) computer software used to measure speaker output. Build a sealed enclosure to measure a woofer's shift in resonant frequency and electrical Q. This dual-volume test box can be adjusted for either 1- or 2-cubic feet depending on the size of the driver. IMPcycling. Using the IMP (Impulse response Measurement and Processing) module and computer software to view your loudspeaker measurements in real time (for example, to watch the frequency response while you make adjustments on the crossover). Absolute SPL (sound pressure level) sensitivity measuring with IMP computer software. The damping factor. An explanation of this complex topic plus a technique to calculate a loudspeaker's true damping value. AIRR. Anechoic and in-room response measurement. Using the "SoundBlaster" computer card and available software to measure both loudspeaker and amplifier response as a function of frequency. Computer programs for the IMP Audio Analyzer (a speaker testing device from Liberty Instruments) help you establish the proper test setup and allow IMP files to be used by other computer programs. A mike/probe preamp for sound-card measurements. This accessory for a high-performance PC-based multimedia sound card facilitates using your computer as a sophisticated loudspeaker/audio testing device. How to generate and read waterfall plots for loudspeaker measurements. Measuring driver flux density. How driver characteristics are interrelated and techniques that allow you to determine the salient characteristics of drivers. Impact of surface texture when making speaker measurements using the ground plane method. Reflecting on echoes and the cepstrum. Cepstral analysis. What it means, how it relates to horn measurements, and more about the hearing process. Time, frequency, phase, and delay. A simple treatment of these subjects, with emphasis on their importance in loudspeaker design and testing. Waveform phase distortion (also called group-delay distortion). A look at the causes and the audible results. Using the merge function in the IMP analyzer. Includes a step-by-step example. Measuring a loudspeaker's resonance (resonant frequency) by various methods. Mitey Mike II. An upgraded version of the popular high-performance, low-cost mike system for loudspeaker and acoutic measurements can also be used for recording and performance. This new version is smaller, lighter, quieter, costs less, and uses less power. Troubleshooting the appearance of an abnormal "dip" in the frequency measurement when using the IMP loudspeaker measurement system on a flat electrostatic speaker. Procedure for measuring the frequency response of individual drivers using IMP and the program IMPRoom. Tips on testing a driver with the Woofer Tester from Peak Instruments Company. Interface for LAUD measurement system. Provide protection for your sound boards when making audio measurements using this computer-based product. Plotting one-third-octave frequency-response curves without using semilogarithmic ruled paper. Review of the Loudspeaker Parameter Meter tester available in kit form from Audio Specialities Company. Used to determine T/S parameters. Est. cost: $89. Dual-driver confusion. Determining the response of parallel dual drivers directly coupled to the air. | |||||||||
Copyright © by Norman Lathrop Enterprises. All Rights Reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted, in any form or by any means (electronic, mechanical, print photocopying, recording or otherwise) without the prior expressed permission of Norman Lathrop Enterprises, except as permitted by law. |
|||||||||