Many exceptional speaker systems are available nowadays. Unfortunately, they often sound like crap because of how they’re used!
The most common symptoms I’ve seen are;
- Speech which is unintelligible (not understandable)
- Simultaneously too loud at the front of the audience and too quiet at the back of the audience
By understanding & applying a few basic principles of speaker design, you can reduce these problems substantially, thereby leaving the audience to focus their attention on your show.
By the way, when I refer to a ‘speaker’, I mean a speaker cabinet (sometimes called an enclosure or a box), and not the actual components (woofer, tweeter, horn, etc…).
Speaker Coverage Principles
- Speakers have a ‘coverage’ pattern, expressed in degrees (ie, 65º x 45º). For the speakers magicians use, the higher value almost always refers to horizontal coverage, that being the left-to-right coverage of the audience area. Basically, this means that audience members within this area will hear intelligible speech, and those outside will experience reduced intelligibility.
- High frequencies, being those that include, among other things, sibilant and hard consonant sounds, are the part of a sound which aid intelligibility. Low frequency sounds, being those that include, among other things, vowels, don’t have as much to do with intelligibility.
Front-To-Back Loudness Principles
- High frequency sounds travel in a straight line, and are not good at traveling through or around things. Low frequency sounds ARE good at traveling around & through things. That’s why, when you’re in another room from a PA or stereo, everything sounds ‘boomy’.
- Each speaker is designed with a particular ‘throw’ in mind. That’s the distance to which it can be considered to be effective, and really refers to the high frequencies, since that’s the contributor to intelligibility. Until you get to the point at which you’re touring with a dedicated PA and a dedicated audio crew, you can be quite sure that your speakers have a short throw, and I guess that their maximum effectiveness would be limited to about 35 metres (35 yards), although every speaker model will be different.
- Stated in a suitably simplified manner, feedback occurs as the result of the relationship between the speaker, the room, and the mic.
- As you raise the volume of your PA, the likelihood of feedback increases.
- As the mic moves closer to the speakers, the likelihood of feedback increases.
- As the mic moves out into the audience, the likelihood of feedback increases.
- In a room with exposed surfaces (walls, ceiling and sometimes floors) which are reflective (glass, brick, metal, etc…), the likelihood of feedback increases.
- The type of mic you use can have a HUGE impact on the likelihood of feedback. For more info on this, see “Pick A Mic, Any Mic“.
How do you apply all of this knowledge?
- Place your speakers such that everyone in the audience is within the speakers’ coverage area. In a smaller venue, if the people in the front would be able to hear you just fine without speakers, you don’t need to worry about their being within the speakers’ coverage area.
- Since the intelligibility-contributing high frequencies do a poor job at go through things, make sure the speakers are placed such that everyone in the audience can see the speakers’ horns/tweeters. If their eyes can see them, then so can their ears! Since having the speakers up high makes it easier for the folks at the back to hear, it means you can turn things down, making it less painful for the folks in the front and reducing the likelihood of feedback! This is one of the reasons that speakers at most large concerts are now ‘flown’ high above the stage.
- In order to achieve this, you’ll likely need to place the speakers on tripod stands. Be sure to use speaker stands safely! Place sandbags on the inside support bars of the stand to lower the stand’s centre of gravity, thereby making it less likely to tip over if bumped. (By the way, the horn/tweeter is the top component in the speaker, usually round & relatively small, or rectangular and flared.)
- Don’t expect your speakers to ‘throw’ 100 metres (100 yards).
- Place your speakers such that, when you’re using your mic, you can’t see any portion of the front of the speakers. This will ensure that you’re well outside the speaker’s coverage area.
- Use a mic which is appropriate for your needs. For more info on this, see “Pick A Mic, Any Mic“.
Poor Speaker Placement
Pointing inward & placed too close to the ground. The sound is too loud for the people near the speakers, not loud enough for the people at the back, unintelligible for the people on the sides, and too likely to cause feedback with your mic.
Good Speaker Placement
High enough so that the people at the back can fully see the horns of the speakers. This makes it possible to have the sound level comfortable at the front at back of the room. The people in the front-centre have the advantage of hearing your voice directly from you.
Spread the stand’s legs as far as they will go, and place sandbag(s) on the inside support bars of the stand to lower the stand’s centre of gravity. Notice that they’re not touching the ground.
So many users spread the stand’s legs very little, making it MUCH more likely that the speaker will fall over, hurting someone and/or damaging the speaker.
- If you use recorded music in your show, but not a mic, then all of this becomes less important, and the bits about feedback make almost no difference whatsoever. Remember that the principles concerning coverage & throw will still apply: It’s just that they won’t be as crucial.
- If you use a mic and recorded music, it likely means that your mic will need to be louder than it would for someone who doesn’t use music, so feedback will be more of a concern.
- The room will sound different at sound check than it will during the show. The two main differences will be that;
- Since the addition a soft, absorptive audience will reduce the amount of reflective sound in the room, feedback will reduce, and you’ll be able to raise the volume of the PA a little.
- The addition of the aforementioned soft, absorptive audience will also decrease the effective ‘throw’ of the speakers, since high frequencies will be soaked up as the sound travels past each person on its way to the back of the room.
- Outdoors, with soft, absorptive floors (grass), and no walls or ceilings, your PA won’t cover as much area as it will indoors. The fact that there is usually more ambient noise outdoors (crowd noise, traffic, etc…), is another contributor to your PAs not covering as much area as it will indoors.
- In order to allow for the best possible audience ‘sightlines’, you may need to compromise speaker placement. Just do your best.