Back to Basics: Amplifier Technology

Back to Basics: Amplifier Technology

Like every other element in the professional AV sphere, digital audio has continued to advance at a rapid pace...but the signal path hasn’t changed. Sure, we don’t have to run heavy 100-foot snakes anymore to route our signals, but it’s still the same path, just different cabling. Instead of big snakes, we’re now running Cat-5 so our sources can communicate with one another. Audio consoles continue to draw attention at audio shows like NAMM and AES as they incorporate ever-sleeker LED lights and interactive touchscreens. But if you’ve ever installed or managed a sound system, or worked FOH, you know that amplifiers are key players for reliable audio performance. This might seem obvious—Live Audio Class 101—but sometimes it’s useful to go back to the basics to get a clearer picture of where amplifier technology is today and where it is headed.

Not Often Seen but Always Heard

Amplifiers are a critical piece of the audio puzzle that boost electric current to your loudspeakers. If you’re not the one installing the system or the engineer who will be operating audio during a show, you’ll more than likely never see the amps. Though they go unseen, they’re still critically important in the signal path. Over the years we have seen many manufacturers working on making their amps smaller in size and a lot lighter in weight as technology advances. This is good news for installers, but not all compact amps are created equal.

Head of the Class (D)

The design behind a more compact deployment and better performance of new amplifiers is called a Class D amplifier. Class D amplifiers work as pulse-width modulated switching devices. Basically, the signal is converted into a stream of pulses that switches MOSFET (metal-oxide semiconductor field-effect transistor) on and off, presenting new design options to the manufacturer. The greatest benefit of Class D is that it produces less heat and less heat means less stress on the amplifier. The Class D design also saves on circuit board space.

Yamaha believes Class D amplifiers offer incredible efficiency resulting in lower power usage and less heat emission that, in turn, reduce the requirement for HVAC cooling which equates to lower expenses in energy costs for a facility’s installation. According to Marc Lopez, director of marketing, Yamaha Professional Audio, “Class D contributes to the Yamaha goal of producing products with a lower environmental impact.”

Crown’s multi-channel power amplifier with Dante.

Crown by Harman is devoted to innovating in the amplifier category. The company has obtained a significant number of patents to continue drive amplifier technology forward. The first time I installed a system within a church, I worked with Crown amps. As I grew into my career, Crown became a reliable choice; we installed them in most of the worship facilities in which I worked. The company’s latest technology, DriveCore, is a new technology that has been added to their amplifiers. The engineers at Crown found a way to incorporate 500-plus parts into a tiny chip. The modulator stage, controls, and other functions all went into this chip. It reduced a lot of cost on their part, but the focus was the technology and how it would boost the sound quality that could now be compacted into smaller housing units. DriveCore integrated circuits are established on Gerald Stanley’s discoveries of five different patents that engaged modulation, feedback, and output stage technologies. DriveCore technology pulls on the ability of Class D output stages to produce their well-known products that have been in the market for years.

Making the Connection

Along with Class D switching, another prominent feature of amplifiers is integrated audio networking. Why? Because everything is on the network, right? Audio consoles, speakers, and amps must be included—not just to follow along with this industry-wide trend, but because audio networking creates a better experience for the end user, audio engineers, and integrators. As I mentioned, most of the time the amps can go unseen. Depending on the size of a venue, they might be placed in the ceiling, up on a catwalk, or in a different control room in a rack—the placement can vary. So can speaker systems: They might be suspended in the air on truss, or in ceilings as well. You cannot always easily access these pieces of gear. Networked audio helps get the job done, with managed and controlled network features.

Lopez said Yamaha has been a long-term supporter of networked audio, and an early adopter of Dante technology. “Our XMV Series multichannel power amplifiers are available with Dante built in for applications requiring network distribution to simplify infrastructure and create flexibility. Dante provides sound designers the broadest choice for applications and incredible ease and flexibility in implementation.”

Ashly Audio is another manufacturer committed to advancing the amplifier category. “At Ashly Audio, we believe power amplifiers should integrate seamlessly into an environment and sustain a long life,” said Anthony Errigo, Ashly’s director of marketing communications. “Our NX Multi-Mode Amplifiers are built in the USA to the highest standard and designed to be flexible with selectable output modes, remote control and DSP options.”

Ashly’s NX Multi-Mode Power Amplifiers are Class-D, 2 and 4 amplifiers now offered in 150 and 75 Watt per channel models.

Ashly’s nX amp series comes loaded with options, but the nX(e) is the company’s amplifier that comes equipped with network cards. The nX(e) series has Ethernet control where you can set up, manage, and control your amplifiers with their Protea network-enabled software. There is also an option to use Dante or CobraNet for audio integration.

The nX series showcases Multi-Mode, which is another feature of selectable outputs on each channel to allow you to connect to virtually any speaker. Networking has changed how all of our devices talk, and many manufacturers are taking advantage of it by incorporating networking cards into the amplifiers like Ashly Audio. This is a technology we will continue to see grow as our entire industry moves toward more networked devices. Every AV pro should stay up to date with networking developments via AES67, AVB/TSN, CobraNet, Dante, and Q-SYS, to name a few, as we see more interest in auto-discovery, remote management, and remote diagnostics for IP-enabled audio systems.

And Ashly’s in the game for the long-haul. “Ashly’s customer is an audio professional with a trained ear and an understanding that a piece of audio gear is a long-term investment,” Errigo concluded.

Compact Amps that Punch Above Their Weight

Creating amplifiers that are lightweight is another popular request in the field. We carry our UC and computational devices in our hands as smartphones. A lot of end users are looking for a similar experience with professional AV; though not as small as Apple Watches, most pro AV stakeholders appreciate when gear can be lighter and more compact without compromising quality. More compact equipment means better portability, and lends itself to more simplified installations.

Yamaha’s XMV8140-D Power Amplifier combines Class-D efficiency with features designed specifically to benefit commercial installation sound systems.

To that end, Creston is expanding its audio solutions by incorporating a few new amplifiers in its enterprise solutions line. With its modular amplifiers, its slogan is “Professional performance meets compact, efficient design.” The space-saving design is 1/4 and 1/2-rack form that allows end users to use multiple units in a single rack space. This frees up more space without losing power, making the most of available real estate when installing AV system racks. Though this isn’t a trend that is fully technology driven, it too plays a role in how and where amplifiers are being installed.

Class D amplifiers provide efficiency along with networked audio in compact housing units. Again, these technologies and trends are not implemented in all amplifiers yet, but we will see this confluence as more integrators and end users demand next-gen features.

Alesia Hendley is a young AV professional who is determined to leave her mark by making an impact, not just an impression. She can be reached on Twitter @thesmoothfactor.