-
Thursday, May 16, 2013
Charlie Hughes
05/16/13 05:56 PM,
I’ve heard it argued by that square waves contain DC. How else could they have the flat top and bottom that make it square? Let’s look at a square wave and see what causes it to have its square shape. A complex waveform can be constructed from, or decomposed into, sine (and cosine) waves of various amplitude and phase relationships. This is the basis of Fourier analysis. A square wave consists of a fundamental sine wave (of the same frequency…
View this story
Filed in:
AV •
Feature •
Blog •
Study Hall •
AV •
Measurement •
Processor •
Signal
-
Friday, March 15, 2013
Charlie Hughes
03/15/13 04:29 PM,
We are all familiar (or at least should be) with a low-pass and high-pass filter. As the name implies, they pass one part of the audio spectrum while attenuating the others. They are the basis for loudspeaker crossovers. As with any analog filter there is phase shift associated with the change in output magnitude of these filters. Examples of these are shown in Figure 1 (below) as fourth-order Linkwitz-Riley filters. If we were to add the output of these filters…
View this story
Filed in:
AV •
Feature •
Blog •
Study Hall •
AV •
Line Array •
Loudspeaker •
Measurement •
Processor •
Sound Reinforcement •
System
-
Wednesday, January 16, 2013
Charlie Hughes
01/16/13 09:39 AM,
While it’s nothing new to place a limiter immediately in front of a power amplifier to keep it from clipping, there is more that can be accomplished with a limiter to squeeze a bit more low-frequency performance out of a loudspeaker while keeping it within its safe operating area. Most loudspeaker systems have a limited excursion capability. The voice coil and cone assembly can travel only so far before the motor strength significantly decreases, the suspension (surround and/or spider) reaches…
View this story
Filed in:
AV •
Feature •
Study Hall •
Amplifier •
AV •
Education •
Loudspeaker •
Processor •
Sound Reinforcement
-
Monday, December 10, 2012
Charlie Hughes
12/10/12 08:07 PM,
In a previous article (“Loudspeaker Sensitivity”), I examined the topic of loudspeaker sensitivity and how it may or may not relate to the overall sound pressure level (SPL) produced by a loudspeaker. One of the conclusions of that article is that the SPL produced will be dependent on the spectral content of the signal driving the loudspeaker. Thus, having knowledge of the driving signal (i.e., program material) or being able to make an educated assumption about it may aid in…
View this story
Filed in:
AV •
Feature •
Blog •
Study Hall •
Amplifier •
AV •
Loudspeaker •
Measurement •
Power •
Signal •
Sound Reinforcement
-
Wednesday, December 05, 2012
Charlie Hughes
12/05/12 10:26 AM,
The specification of a loudspeaker’s sensitivity is probably one of the most common, yet perhaps one of the most misunderstood. It’s common to see the magnitude response of a loudspeaker system reduced to a single number as a sensitivity rating. This is perhaps at the heart of the confusion. One would think that this metric should give some indication as to how loud a particular loudspeaker will be when reproducing a signal. One may also think that two loudspeakers with…
View this story
Filed in:
AV •
Feature •
Study Hall •
AV •
Loudspeaker •
Measurement •
Sound Reinforcement
-
Monday, October 08, 2012
Charlie Hughes
10/08/12 03:37 PM,
To determine the input impedance of a device, both the voltage across the device and the current flowing into the device must be known. The impedance is simply the voltage across the device E, divided by the current flowing into it, I. This is given by the following equation: It should be understood that since the voltage, E, and the current, I, are complex quantities the impedance, Z, is also complex. That is to say impedance has a magnitude and…
View this story
Filed in:
AV •
Feature •
Study Hall •
AV •
Loudspeaker •
Measurement •
Signal •
Software •
Sound Reinforcement •
System
-
Thursday, September 27, 2012
Charlie Hughes
09/27/12 08:31 AM,
While sound system operators have come to enjoy the considerable benefits of digital signal processing, it’s important to understand how these devices truly interact with loudspeakers. There’s a lot of cause and effect that sometimes gets overlooked, resulting in less than optimum performance, and leaving the operator scratching his head as to what’s going wrong. One particularly important aspect that is often overlooked is using a DSP to drive loudspeakers with a manufacturer’s prescribed settings (or other target drive function).…
View this story
Filed in:
AV •
Feature •
Blog •
Study Hall •
Loudspeaker •
Measurement •
Processor •
Sound Reinforcement
-
Tuesday, August 07, 2012
Charlie Hughes
08/07/12 05:56 PM,
I have heard the question “How do I align a subwoofer with a full-range loudspeaker system?” asked many times. I thought it might be interesting to delve into this to see if I could come up with an answer. The task of adding a subwoofer to a loudspeaker system to increase the low frequency bandwidth should typically entail three primary items. • The relative bandwidth of the subwoofer and the full-range system (crossover) • The relative output level of the…
View this story
Filed in:
AV •
Feature •
Study Hall •
AV •
Loudspeaker •
Measurement •
Subwoofer
-
Friday, June 03, 2011
Charlie Hughes
06/03/11 10:52 AM,
0 Comments
While sound system operators have come to enjoy the considerable benefits of digital signal processing, it’s important to understand how these devices truly interact with loudspeakers. There’s a lot of cause and effect that sometimes gets overlooked, resulting in less than optimum performance, and leaving the operator scratching his head as to what’s going wrong. One particularly important aspect that is often overlooked is using a DSP to drive loudspeakers with a manufacturer’s prescribed settings (or other target drive function).…
View this story
Filed in:
AV •
Feature •
Poll •
AV •
Digital •
Loudspeaker •
Processor •
Sound Reinforcement
Page 1 of 1 pages
