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Tuesday, March 15, 2011
Chuck McGregor 03/15/11 02:55 PM, 0 CommentsPolarity and Phase - two terms are often used as if they mean the same thing. They are not. POLARITY: In electricity this is a simple reversal of the plus and minus voltage. It doesn’t matter whether it is DC or AC voltage. For DC, Turn a battery around in a flashlight and you have inverted or, more commonly stated, reversed the polarity of the voltage going to the light bulb. For AC, interchange the two wires at the input… View this story
Filed in: AV • Feature • Poll • Study Hall • AV • Audio • Education • Loudspeaker • Signal -
Thursday, December 16, 2010
Joan La Roda 12/16/10 03:41 PM, 0 CommentsThis is the third in a multi-part series. Additional segments are available here. Previously we examined the basics of cardioid subwoofer systems. These examples continue that series. Example 2. “Measurements on a real system: two facing forward and one backward” In this example our cardioid configuration uses three stacked DAS LX218A subwoofers. The top and bottom ones are facing forward while the centre one is firing backward. The DAS LX218A subwoofer is a self-powered system incorporating signal processing (crossover and… View this story
Filed in: Live Sound • Feature • Poll • Audio • Line Array • Loudspeaker • Software • Sound Reinforcement • Subwoofer • System -
Friday, December 10, 2010
Chuck McGregor 12/10/10 03:55 PM,Polarity and Phase - these terms are often used as if they mean the same thing. They are not. POLARITY: In electricity this is a simple reversal of the plus and minus voltage. It doesn’t matter whether it is DC or AC voltage. For DC, Turn a battery around in a flashlight and you have inverted or, more commonly stated, reversed the polarity of the voltage going to the light bulb. For AC, interchange the two wires at the input… View this story
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Filed in: AV • Feature • Poll • AV • Education • Installation • Measurement • Processor • Signal • Technician -
Monday, December 06, 2010Joan La Roda 12/06/10 04:55 PM, 0 CommentsThis is the second in a multi-part series. Additional segments are available here. Previously we examined the basics of cardioid subwoofer systems. This example continues that series. Example 1. “Scaled down measurements: one cabinet in front and one cabinet behind” Before trying to do these adjustments for the first time in a real- life situation, where one may not always have enough time and where conditions are far from ideal, scaled down measurements can be handy to get some practice… View this story
Filed in: Live Sound • Feature • Poll • Audio • Loudspeaker • Signal • Sound Reinforcement • Subwoofer • System -
Friday, December 03, 2010Joan La Roda 12/03/10 10:59 AM, 2 CommentsThis is the first in a multi-part series. Additional segments are available here. In general, we say that a speaker, or a group of speakers, radiates with a cardioid pattern when it radiates more energy forward than it does backward. Strictly speaking, however, a cardioid pattern is heart shaped (hence the name) and is represented mathematically by the equation ρ = (1 + cos σ), where σ represents the horizontal angle. Setting up subwoofers such that they radiate this way… View this story
Filed in: Live Sound • Feature • Poll • Audio • Loudspeaker • Signal • Sound Reinforcement • Subwoofer • System -
Friday, October 01, 2010
Joan La Roda 10/01/10 01:30 PM, 0 CommentsIn the previous two segments of this series we discussed phase and polarity, what causes phase to vary, what is meant by phase alignment, coherence curves, and we took a look at the first of three illustrative examples. If you haven’t yet read the first two articles in the series, which are available here, I’d urge you to do so. If you’re up to speed and ready to continue, let’s take a look at the rest of our examples Example… View this story
Filed in: Live Sound • Feature • Poll • Audio • Line Array • Loudspeaker • Mixer • Sound Reinforcement • System -
Monday, September 27, 2010
Joan La Roda 09/27/10 03:15 PM, 0 CommentsIn the first part of our series, we took a look at what exactly phase and polarity are, what causes phase to vary, and what is meant by phase alignment. Coherence Curve The coherence curve that Fast Fourier Transform based measurement systems provides indicates the probability that the measurement is reliable. It’s very common to find a coherence curve (ranging from 0 to 1, or from 0% to 100%, depending on the measurement system) with low values in part of… View this story
Filed in: Live Sound • Feature • Poll • Audio • Loudspeaker • Mixer • Signal • Sound Reinforcement • System -
Tuesday, September 21, 2010Joan La Roda 09/21/10 03:25 PM, 0 CommentsThis is the first in a three-part series on phase alignment. Additional segments of the series are available here. FFT based field measurement systems have made it possible for us to do phase alignment at fixed installations as well as at live events, where every venue demands a different approach. This is particularly important these days, since mid-high boxes are often flown and subwoofers remain on the ground, meaning that phase differences at the listener location can be very significant.… View this story
Filed in: Live Sound • Feature • Poll • Audio • Loudspeaker • Manufacturer • Signal • Sound Reinforcement • System -
Thursday, April 15, 2010
PSW Staff 04/15/10 12:35 PM, 0 CommentsProvided by Sweetwater. Q: Are there any potential phase issues when placing multiple microphones on a single instrument? A: During a recent recording session, we were reminded of just that: you have to be careful of what you’re measuring and lining up when you’re aligning microphones for proper phase. This became clear when we were miking guitar cabinets. We had a Sennheiser MD 421, a Mojave MA-100, and a Royer R-122 set on a single speaker in a cabinet.… View this story
Filed in: Recording • Feature • Study Hall • Education • Microphone • Sound Reinforcement • Stage -
Tuesday, August 25, 2009
PSW Staff 08/25/09 03:24 PM, 0 CommentsThe Christian Life Assembly (CLA) Church in Langley, British Columbia is a tech-savvy multi-campus congregation that offers both media streaming and podcast downloads of its services from its website. When the church began an extensive upgrade of its facilities last year, a new sound reinforcement system for its 1,500-seat sanctuary was high on its list of priorities. The new system is headed by three EAW KF730 compact line arrays, SB730 compact line array subwoofers and SB1000z large-format subwoofers supporting program… View this story
Filed in: Live Sound • Church Sound • News • Audio • Installation • Line Array • Loudspeaker • Processor • Sound Reinforcement • Subwoofer • System
Articles Tagged Phase
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