Various measurements on audio equipment. by jimmy67music. A classic reprint of the famous Norman Crowhurst book that is a complete compendium of measurement and testing techniques for audio equipment including. AUDIO MEASUREMENTS. by Crowhurst, Norman H. Edition: First Edition; First Printing. Book Description. New York: Gernsback Library, Inc.. First Edition .
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The control for the high-frequency end is called a treble control, for audio purposes, and that for the low-frequency end is called a bass control. Because the current is increasing at the same time, the output cannot possi- bly reach the peak value of the applied a-c because the drain effect willcause dips between the peaks, but the average voltage can rise with a carefully de- signed filter of this kind. With real music, the large number of sum-and-difference terms modulate the noise floor of the musical program, covering up the low-level room reflections the listener uses to analyze the spatial qualities of the performing space.
I’d like to read this book on Kindle Don’t have a Kindle? This can be achieved by using a multiple-wound trans- former. This can be illustrated quite effectively by mounting a loudspeaker in a simple enclosure with three alternatives for the back of the enclosure.
This supply is usually a simple rectifier that takes an alternating voltage from a suitable point such as from a voltage divider connected across the high-voltage secondary of the power transformer and rectifying it with a single diode. Instead, the screen supply is usually derived from the plate supply, using either a series resistor or a voltage divider.
If the feedback starts out being negative at this particular frequency, it will convert into positive feedback. Amazon Renewed Refurbished products with a warranty. Meadurements of The Audio Crtitic can still be found online. What is a cathode follower? One uses an inductor and capaci- tor in parallel to produce a tuned or resonant circuit in which energy passes between the inductor and capacitor at the resonant frequency of the circuit.
The grooves can be cut two ways: The impedance measured across the line between the two transformers is or ohms, and the line is said to work at an impedance of or ohms. If the surface on which charge is induced by a nearby voltage has a high-impedance connection to ground, the charges will not have time to leak away and voltages will appear with them, causing interference.
Under the Musings button you’ll find things related to perception and conciousness which of course are very much applicable to audio! Because of these complexities, only playback re- sponse is specified. If a capacitor is connected across the cathode resistor, the fluctuation due to signal cur- rents is smoothed out, resulting in an almost steady bias that is always higher than that present when no signal passes.
Then came the idea of feedback. These materials are listed in the order of improving efficiency and also their se- quence of development.
This starts a quick feedback action through a couple of tubes that rapidly discharges the capacitor to its original level, from which it starts the charging sequence all over again.
A.R.C. Marketplace: Audio Measurements by Norman Crowhurst
This means the source resistance presented by the amplifier will influence the behavior of the loudspeaker. Usually, with a-c-operated amplifiers, all of the heaters are connected in parallel to a winding on the power transformer.
This is not basically difficult, but it has practical difficulties that are not really audio problems.
What is crossover distortion, and what causes it? This fre- quency can be measjrements by varying either the capacitors or the resistors. This input consists of 10 millivolts original audio minus 9 millivolts fed back from the output, which is introduced into the signal by the amplifier. Motional impedance is the impedance reflected back to the loudspeaker terminals due to the movement of the diaphragm.
This current in the shield sets up its own magnetic field that opposes the original inducing magnetism, and the two fields tend to cancel inside the shield. For radio there are several possibilities: This means that when the current waveform in the tubes falls toward zero for which the bias should aueio at the no-signal levelthe higher bias provided by the capacitor may cause premature cutoff and crossover distortion.
The entire circuit or transformer is surrounded by the shield. For this reason the only way to accentuate some frequencies is to cut down frequencies in the rest of the range.
Not necessarily related to audio, although it often is. Then feedback will be added to get the best possible performance from this com- bination.