It's one of the first things you look at when you step into a venue. It's also a large part of feedback problems in the front of house speakers. It's amazing what a difference proper speaker placement can make in the sound of your system.
Speaker placement is probably one of the most important yet overlooked areas of setting up a system. It doesn't matter if you have a small, bare bones system or a huge line array system. If the placement of the speakers is "off" not only could your coverage suffer, but a variety of other problems could arise.
It's funny, I'll go into a venue and drop my bag around my FOH position and walk right up to the stage and stand in one spot on the stage and just look out into the seating area. Then I'll move to another area. Oh, the looks I get.
Let's start at the beginning though. Get to know your speakers. READ THE MANUALS!!!! Then read them again. You need to know what their dispersion patterns are. 90 x 40, 90 x 60, etc. The manuals should show dispersion for various frequencies. Knowing these facts will let you know how wide and tall your speaker throws and if your horn aims down at all.
Once you know your speakers, and you're ready to set up, stand in different spots near the performing area and look out at the listening area. Think about how high they need to be. How wide is the room? How long is the room? Are there hard, flat reflective surfaces on the sides or the back wall (behind the listeners)? If there are hard surfaces on the sides consider moving your speakers a little wider than normal and turn your speakers in some. This will allow you to cover the same area but aim the horns away from that reflective surface and get more "direct" sound to the listeners.
If the wall behind the listeners is also flat and hard and you can't tilt your speakers down at all keep the height of the speaker's horn just above the listners' heads as if they were standing up. This allows more sound to get absorbed by the listeners. However if it's a deep room by any definition get those speakers up.
This is another experimental thing. The more you do it, the better idea you'll have of what to do from room to room. And for the first time, I'm about to give you the name of a book anyone who has anything to do with running sound should own. It's called "The Sound Reinforcement Handbook." It's by Yamaha and is written by Gary Davis and Ralph Jones. Some of things in this book may be a bit too much for a very new engineer, but I would still recommend it. I still read it myself from time to time. If you have a chance to study mathematics, you can become extremely exact in speaker placement.
Well, get the book, try things out, and read, read, read. Read manuals, books, magazines, articles, etc. I will also, next month, be listing some workshops that are very good for church and similar sound technicians.
Josh Hoevelmann
Author: .(JavaScript must be enabled to view this email address)
Written: 10/01/2003
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Category: Monthly ArticlesSound Advice
Comments: 6
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Another important and overlooked aspect of speaker placement is driver alignment between subs and top cabinets. A misaligned sub can severely impact your sound. If you’re running a crossover or speaker management system then most are already adjusting delay settings. With the introduction of powered subs, people are now able to add these cabinets without running crossovers and without delay settings. Keeping your sub’s face perpendicular with the top cabinet or even slightly behind the top cabinet face will keep your sound tighter. If the sub is in front and not delayed, the sub will affect the audience before your vocals. If the room is subject to low frequency standing waves, your vocals will struggle to cut through cleanly.
I've often wondered if using subs isn't overkill in many situations. I've certainly heard them over-power the rest of the mix at enough concerts. On the other hand, I miss hearing some of the low end when I go to NQC.
Does anyone know of any good books for beginners on sound boards? If so please shoot me an e-mail. .(JavaScript must be enabled to view this email address)
Our quartet just recently purchased a Powered Mackie System with SUBS. Everywhere we go people can't get over how GOOD it sounds. They are right. It's the best portable sound I have ever heard. (Didn't mean this to sound like a commercial for Mackie, just wanted to pass along what my ears are telling me.)
Setting the angle of your house speakers so that you avoid a direct "hit" on those huge wood beams protruding out into the typical church, can be a big issue. Setting time offset for subs and main speakers is more than adjusting the time delay. At the -6 0r -3 db location of where the sub(s) croosover into the mains, you should have both time and PHASE adjusted the same at crossover. Many people do not take into account that there is both a phase rotation and a time domain offset that should be aligned. Failing to know where this is at can render the subs worthless. Also, you need to know the normal rolloff of your cabinets for this "normal" rolloff is part of your crossover as well. I am not a big fan of seperate subs simply because this is a hard issue for most non-tech types to handle. We use a custom designed biamped system that has two 15" woofers and a horn/driver in each cabinet. The low frequency corner on these cabinets is about 28 Hz, which is lower than many seperate sub cabinets can handle. It is also easier to setup for it requires 2 cabinets be hauled in rather than 4. Less power amplifiers too.
Ben, when you consider that every setup a traveling group makes must be done without the luxury of a lot of time, I think you've made an excellent point.
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