We happen to live in the golden era of live reinforcement speakers. Thanks to market demand, competition and ever evolving technological advancements, there are some really great and inexpensive speaker options on the market. Thanks to speakers that use neodymium magnets and switching power amps, we’ve seen the weight of speakers drop and an explosion of self powered speaker options.
While line arrays aren’t the perfect tool for every situation, they have revolutionized the large touring sound industry. Less weight means less transportation costs, less infrastructure , less set up time, etc…
Things can only get better from here too. That’s good news for us all.
How do you choose the right speaker for a certain job with so many options?
The fundamental rule hasn’t changed. “Put sound where the ears are and not anywhere else!” That concept rules the decision making process in my book.
Put another way, the goal is to pick speakers that provide even cover to the audience area but don’t blow all over the ceiling, walls and empty floor.
How do you know whether you’ve been successful or not?
Once you have looked at and understood what an impulse response reveals, you will have a whole new perspective on things.
Here is an example of a good impulse response:
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Here is an example of a really band impulse response:
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The difference between these two traces are reflections. One has lots of secondary reflections and one has minimal reflections.
Which one will sound better? The one without any reflections.
Which one will be more intelligible? The one with minimal reflections.
If you choose the wrong speakers (too wide a pattern or too narrow) and then you place those wrong speakers in the wrong positions and then you don’t time align and EQ them correctly, you have lost. No amount of tweaking at the console will put you back in the game.
I have learned this lesson the hard way and it’s a lesson that many people don’t even know needs to be learned.
Unlike a toaster which has the simple purpose of heating bread until it browns, speakers are all unique. Every design and every model is a compromise driven by market forces and cost analysis. Even the best speakers in the world are a compromise. There is no perfect speaker for every acoustic environment and there is no perfect acoustic space.
How then are we to know where to start?
One obvious answer is “modeling”. Any install project of any importance should be modeled in my opinion. Knowing which speakers to use and where to put them takes all the guess work out of the equation and eliminates the risk. A space modeled correctly and a PA system designed by someone that understands the basic principles and knows how to the tools can nail a design every time. Some day the tools required to model spaces and speakers will a tool commonly used by all of us but until then most of us are left to work without these tools.
How do you pick appropriate speakers for a venue and then locate and aim them correctly?
I tend to purchased speakers with more narrow dispersion patterns because they are more versatile. If I don’t know what I’m going to use a speaker for, having a warehouse full of the same speaker isn’t going to serve my clients very well.
I personally won’t purchase a speaker that doesn’t come with factory rated rigging options. Speakers as a general rule need to be located overhead to avoid excessive volume for those up close and to allow significant SPL to reach the further audience members.
So let’s set some basic requirements.
1. MUST BE ABLE TO BE HUNG FROM RATED RIGGING POINTS
If you’re purchased floor monitors, obviously rigging points aren’t required but I have purposely chosen to purchase speakers that can act as floor monitors but also have rigging points.
I want a speaker that in free air (not on the floor, not right next to the ceiling nor up against a wall or in a corner) that are as flat as possible. This way I know what to expect from a single box.
Speaking of floor monitors, if you don’t already know this, understand it now.
If you put a speaker that measures flat in free space on the floor it won’t be flat any more. It will have more low and low mid content.
If you raise a speaker off the floor that measures flat on the floor it will no longer measure flat. It will be deficient in low and low mid content.
The inverse of each other. If you put that same speaker into a corner, you will gain more low and low mid content than you had with the same speaker sitting on the floor. This is due to the physics of how sound works.
How do you deal with these situations? The best way is to have the measurement tools it takes to see what you’re frequency response is in the specific location of that specific speaker and use your EQ and possibly delay to correct whatever imbalance there is.
Meaning there is no one speaker that can be used in every possible situation without correcting for whatever the local conditions are.
If you put two speakers that measure flat on the floor by themselves side by side and don’t change anything else, you’re going to have extra low and low mid content. There is no way around it. Being able to adjust the eq for that speaker combination is the key.
Some modern self powered speakers actually provide switches that let you select the low end response of the speaker cabinet.