What Are Active Speaker Systems
With our upcoming Kudos Active Roadshow we thought it might be a good idea to explain a little more about active systems.
WHAT IS AN ACTIVE SYSTEM
A traditional HiFi system will consist of a number of components, although these may be combined together in fewer “boxes” to simplify cabling or for convenience.
A typical system would have a source (eg. a turntable), an amplifier and loudspeakers. Built into the loudspeakers will be a crossover, which divides the incoming signal into frequency bands to suit the drive cones of the loudspeaker.
Various manufacturers have different solutions for their systems, some may combine the source in the same box as the amplifier, some may split the amplifier into a pre amplifier, which will switch between multiple sources and provide the volume control, and a power amplifier to drive the speakers.
How does an active system differ from a traditional passive system?
The simplest answer is that the crossover is placed in the system before the power amplifier(s), the result is that the signal is split before it reaches the amplifier stage so each amplifier only deals with part of the signal. In its simplest form a 2 way loudspeaker design has a high frequency driver and a low frequency driver, so these speakers in active configuration would require 2 amplifiers, one to drive the high frequency drivers in both left and right speakers and one to drive the low frequency drivers.
Are powered speakers active?
Not always. Some speakers include the amplifier within the loudspeaker but whether they are active depends where the crossover is arranged in the signal path.
Can all loudspeakers be run active?
No, only ones where the manufacturer has designed them with internal wiring or some other solution to bypass the passive crossover.
Manufacturers have found different solutions to create active systems, some include amplifiers within their loudspeakers, some rely on external amplifiers and a box to house the external crossovers (Linn Tunebox, Naim Snaxo), or house the crossovers within the amplifiers themselves.
As many sources in todays systems are digital sources, digital files from a CD player, streamed from a local NAS or via the Internet, there has been a move towards digital crossovers, which accommodates more control of the signal or digital signal processing (DSP) before converting to analogue signal to be amplified for the loudspeakers. Traditionally a digital source eg. A CD player would convert to analogue before being fed to the pre amplifier of a system.
In many of todays active systems, the signal is split by a crossover in the digital domain (Linn Exaktbox, Devialet Expert Pro), then converted to analogue, and then amplified, in many cases all of these elements being incorporated in the loudspeaker (Linn Exakt speakers, Meridian Digital active speakers), which has the advantage of reducing cabling (usually an Ethernet type cable is all that is required) and it also makes for a reduced box count, which for something like a 5 way loudspeaker design would be quite considerable.