I really do not know where this old rule came from, but many old sound persons used to budget a “number” of watts per persons in the audience as a way to size a sound system. Now this could be useful if the rig offered is fixed in size and dispersion so that multiple rigs splayed together could get close to a “watts per person” criteria. But imagine a 2-watt per head system in an outdoor festival gig with ground stack speakers.
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One of my rules I have held fast on is the “no 2-ohm” loading of power amplifier outputs. But back when I was buying my first real power amplifiers, the thought of 2-ohm loading capability was a godsend. This was because I had limited funds for power amplifiers, and the two Peavey M-3000 power amplifiers I bought for around $300 each was carefully thought through.
Read More »This time every year, the summer outdoor gig season becomes upon us, and our attention is distracted by the “extra” things we have to drag along to do outdoor gigs. For the new local sound companies who have been used to club and hotel indoor gigs, all it takes is one or two nightmare outdoor gigs before lessons are learned.
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Every once in a while, we need to tell the experienced sound guys to take a break and re-introduce a basic topic that does not get discussed much. Power distribution (distro) connectors are such a topic. It’s as good a time as any to now go over the common types and discuss their usage.
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In the early days of audio, the “power matching” technique of creating 600-ohm source impedances to drive 600-ohm load impedances was a standard design practice. The topic of impedance matching used to be a prime teaching topic in decades past. The reason for learning impedance matching was that many sound sources, signal processors, consoles, and amplifiers were borrowed from fields other than sound reinforcement, and the necessity of knowing the input and output impedances was critical to get the system to play nicely together.
Read More »We at Front Of House Magazine have not harped about the usage of Sound Pressure Level (SPL) meters for a while. But that doesn’t mean the SPL police have stopped lurking around at your gigs. All they may do is give you a polite reminder to turn it down. But in a worst-case scenario you could be facing litigation and fines by violating the rules against excessive noise.
Read More »Occasionally, I get a chance to provide the sound system and let other band engineers take over once I have the system settled. This gives me the wonderful experience of kicking back from the pressure of mixing to mentally critiquing the band engineer mixing in front of me. But not all band engineers are experienced, so I find not much delight in their lesser skills, but a learning lesson of what I would do to improve the show in their shoes. From this experience, here are some of my mixing tips that everyone should review.
Read More »A couple of Decembers ago, I remember loading in for a club gig. The club manager was not happy with the necessary evil of loading in the production gear through a side door, not because of the choice of entrance, but because it took a half hour to complete the task.
Read More »When forced with the option to use portable generators for live production, there are aspects that most sound engineers do not understand. While install power connections are reasonably lightly loaded for the audio watts provided, the nature of the current demands will vary with the music intensity of the performance and needs to be considered with portable power.
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Getting into line-array speakers is a nice additional tool to have when deciding what gigs get what kinds of speakers. In fact, line-array speaker cabinets have been popping up in unconventional applications, such as being stacked two high for medium- to long-throw spot reinforcement in nightclubs. In this piece, I want to run through the typical line array application, determine the amplifier/speaker processor settings and take another look at when more compact arrays are used.
Read More »Color-coding of cabling, road cases, speakers, etc. is one of those “how do you know that?” questions I get all the time. In all honesty, I have to blame my eighth grade industrial arts teacher (in electronics shop) for the lifelong passion into all my esoteric electronics knowledge. But, of course, it was 1974, and my first project was a one-tube AM radio. I remember a lot of both the good and bad habits of electronics from that class; bad things like how to toss molten solder from the iron-tip toward other classmates, and good things like the color code.
Read More »Zeroing out a console — the methodical process of bringing all the live audio mixing console knobs, faders and switches to a benign state of usage. This way the future engineer using the console will not have to be observant of every last detail before connecting the system to the console and fear immediate mayhem. But zeroing out a console is more than a courtesy after the gig; it should also be a practice before the gig.
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