Welcome to part three of the Building Your Own PA blog series. If you missed part one and part two, read them now to learn why a good PA is important for your performance - and see how to choose the right mixer for your needs. Today we’re going to discuss the next important pieces you’ll need for a great personal PA system: speakers and amps.
Honestly, buying speakers and amps for a PA system can be a little daunting. There are so many options on the market, where do you even begin? But don’t worry, the process isn’t as confusing as it might seem. This article will help you analyse your needs - including power, size and features - so you can narrow the field and get the setup that’s right for you.
Size, Power, Features
A major factor in determining what type of PA you’ll need is whether you’re going to be using the system strictly for rehearsing, or whether you’ll be taking it on gigs as well. If it’s the former, you can get by with lower power and smaller speakers. But if you’re going to gig with it, you’ll need a more substantial system.
The type of music you play is also a consideration. If you’re a band with drums, or you’re a DJ, you’ll need a bigger and more powerful system than a solo singer or acoustic group would, because you’ll need to reproduce substantially more low-end information. In that case, you might consider supplementing your main speakers with a subwoofer or two. Subs are the only way to get that chest-thumping bottom-end that makes kick drums and bass notes sound huge.
There are several ways to integrate a subwoofer into your system, but one easy method it is to feed only certain instruments, usually the kick and bass, from an aux output of your mixer. Assuming you have a way to carry them—subs are big and heavy—they can make a major difference in your sound. Plus, you can always leave them home if you’re playing a small venue.
Watch Your Headroom
Venue size is also important. Are you going to play small clubs, large clubs or outdoor shows? Obviously, the bigger the venue, the more power you’ll need. The goal is to have enough power in reserve so that your speakers don’t distort, even when there are loud peaks in the music. This is what is referred to as “headroom.” Having enough headroom is a must for clean, distortion-free sound. To estimate how much power you’ll need for your system, check out these guidelines from Crown.
Active vs. Passive Speakers
Active (aka “powered”) speaker technology has come a long way, and now represents a convenient, affordable and space-saving option for PA systems. Having powered speakers means you don’t have to carry around separate power amps. It also means you have the freedom to upgrade your speakers down the road, without worrying about compatibility with power amps in terms of ohms (which measure electrical resistance) and power handling.
You can purchase a powered speaker with the confidence that the manufacturer has carefully matched the amplifiers and speakers in it.
Active speakers give you as close to a plug-and-play experience as you can have in a PA system. Most are pole-mountable, so it’s easy to put them on speaker stands that raise them high enough to cover the venue. Many active speakers are also designed as wedge-shaped monitors, so you can point them up at you from the floor.
Convenient as active speaker systems are, some will argue that you’ll get better performance and more flexibility from non-powered speakers and separate power amps. If you’re in the market for such a setup, it’s important to work closely with your dealer to make sure you’re getting compatible gear.
The Crown XLi 3500 is an affordable amp that can give you 1000W per channel @ 8 ohms or 2700W @ 8 ohms in bridged mode.
The general rule of thumb is that you want a power amp that can put out about twice as much continuous power as your passive speaker is rated for, at the same ohm rating. For example, a speaker that can handle 500W at 8 ohms should be powered by an amp that puts out 1000W at 8 ohms. This provides enough headroom to cleanly handle peaks. Power amps generally have built-in limiters, which also help with peak management. Most power amps have two channels, but offer the option to be run in “bridged” mode, which allows you to couple those two channels and double the power output.
PA to Go
The quality of your PA system can have a huge impact on your show or rehearsal. It’s as important to the success of your act as your personal instruments and amplifiers. When shopping for a PA, put in the time and energy to research and buy a system that will meet the needs of your group. Make sure you have enough headroom and leave open the potential for expanding your system. You’ll be glad you did.
Don’t miss the next instalment of this series, where we’ll look at how to choose the best microphones for your system.
First published in the HARMAN Insights Blog by Mike Levine, former editor of Electronic Musician. Mike has written numerous articles on music technology and recording.