In this article, we will talk about the differences in the design of active and passive speaker systems, analyze common misconceptions about them, and give recommendations on choosing one or another option for a home stereo system.
This is a type of acoustic systems familiar to all Hi-Fi lovers, where filters consisting of passive elements – capacitors, resistors, inductors are used to separate the audio signal into separate frequency bands. Their task is to extract individual frequency sections from the broadband signal, each of which will be reproduced by a special emitter – high-frequency, mid-frequency or low-frequency.
The main feature of passive acoustic systems is that the filters installed in them work with a high-amplitude signal received from the output stage of the power amplifier. This means that the accuracy of the operation of such filters critically depends on both the correctness of the calculations and the quality of the passive elements in the crossover circuit. Factors such as additional impedances, capacitor capacitance, potential phase distortion, contact reliability and much more affect sound quality. And the amplifier itself receives not only a reactive load in the form of speaker drivers, but also has to additionally “break through” the filter components, especially when it comes to complex crossovers with compensating chains or additional smooth control circuits in the form of attenuators.
All this together reduces the efficiency of both the dynamic heads and the output stages of the amplifier, as a result of which the maximum achievable sound pressure level is also reduced. Nevertheless, passive loudspeakers have significant advantages, primarily from a practical point of view.
1 , the buyer gets the opportunity to further smoothly upgrade both the amplifying part of his system and the cable one.
2 , if components of equal quality are used, a passive circuit is usually cheaper than an active circuit.
3 , DIY enthusiasts are much more likely to make good-sounding passive speakers at home than active ones.
First of all, let’s understand the definitions. Very often, under the words “active acoustics” users understand any speakers, inside which amplifiers are built. This is not entirely correct, since in such speakers the amplifiers can be connected to the dynamic heads through passive filters, that is, in fact, such models are structurally no different from passive ones. The main condition for classifying acoustic systems as “active” is not the fact of embedding amplifiers inside the speaker cabinet, but the use of low-level crossover filters that divide the audio signal into separate frequency bands before it enters the output stages of power amplifiers, separate for each band. However, amplifiers can often be housed in their own separate enclosures.
How an active speaker system works
From the source, the digital or analog signal is fed to the processor / active filter, where it is split into the desired number of bands. These can be two, three or more frequency sections intended for reproduction by dedicated emitters. Next, separate amplifiers come into play, connected directly to the speakers, each of which operates in its own frequency band.
This solution allows not only to make the most efficient use of the amplifier’s capabilities, but also to flexibly configure the entire system. So, for example, to get a clean and deep bass for the low-frequency band, it is logical to use a powerful amplifier, for example, working in class D, while the middle and high frequencies are best assigned to a less powerful, but more “singing” transistor device in class A or even a tube amplifier. Many manufacturers of professional active monitors generally develop special versions of amplifiers that operate in a narrow frequency band. In addition, digital or analog processors are significantly superior to passive solutions in tuning accuracy. So, modern high-end professional active crossovers make it possible to “stitch” almost any type of emitter by introducing signal time delays, smooth adjustment of level, phase, cutoff frequency and slope for each emitter, as well as adding equalization curves. As a result, each of the amplifiers receives a previously “prepared” signal, which is further amplified and sent directly to its own dynamic head or other emitter.
What are the advantages of active speakers over passive ones?
First , a significantly higher sound pressure level with minimal nonlinear, phase and intermodulation distortion.
Secondly , such a scheme ensures the most efficient operation of amplifiers and emitters in the frequency band allocated to them.
Thirdly , the ability at the level of the crossover filter (if such functionality is available) to adjust the sound in a particular room, taking into account its characteristics.
What active speakers are on the market today
Most off-the-shelf band-amplified loudspeakers are found on the professional market in the form of near, mid and far field active monitors. Despite the existing myths and legends, there are no obstacles to their successful use in high-end home systems. Moreover, in terms of price and quality ratio, such speakers are often very profitable due to the fact that the finishing of their cases is quite utilitarian – among studio monitors you will not find models covered with fine wood veneer or triple varnish from Ferrari. In addition, their price does not include a serious margin of distributors and dealers of High End equipment, who have been working with acoustics for a long time on the same principles as sellers of any luxury goods.
There is also a proposal for active speaker systems in the home acoustics market; similar solutions are offered by many companies that produce Hi-Fi and High End speaker systems. Especially popular in recent years have become digital active wireless speakers designed to work both in a conventional stereo system and as part of multi-room installations. Moreover, many companies simultaneously produce both professional and household high-end speaker systems – JBL, Dynaudio, Tannoy, Focal, and top-class studio acoustic manufacturers are actively promoting their solutions in the household market – Genelec, Westlake Audio, Backes & Muller, Ocean Way.
The main types of active speakers
Near and midfield monitors
Typically, they are compact 2-way active monitors with a 5 “to 8” main speaker with all the electronics inside the cabinet. They are intended for listening to phonograms at a distance of 1 to 3 meters, that is, where the level of the direct signal is greater than or equal to the reflected one. As a rule, the operation of such monitors implies a 2.1 scheme, in which active subwoofers are used in separate enclosures, but this is not true in all situations.
Far field monitors
Usually, their role is played by three- or four-way systems, which can either have their own enclosures or be built into special niches. All electronics are often placed in a separate rack. The far field – usually more than 3 meters – means the position of the listener in which the ratio between the direct and reflected sound in the signal perceived by him is either 1 to 1, or the reflected sound begins to prevail.
Household active speakers
They are broadly similar in class and purpose to studio speakers, with the exception that all large far-field speakers have their own enclosures.
Who Should Buy Home Active Studio Monitors?
Musicians and DJsIf you are recording at home, then professional active speakers will be the natural choice, this is quite obvious.
For lovers of heavy and electronic musicMusical genres that require high sound pressure levels with minimal nonlinear and intermodulation distortion are best reproduced by powered speakers. To get the same sound level from a passive home system, you have to pay significantly more.
For fans of even and neutral soundDespite the fact that studio monitors, like hi-fi acoustics, also sound different, they are united by a common requirement to obtain the most flat frequency response at the listening point and minimum sound coloration. This means that on any phonogram the result will be more predictable.
Who doesn’t need to buy active studio monitors at home
Upgrade loversIf regular replacement of components, wires and accessories is an integral part of your passion for sound, then an active system, especially a studio system, is not your choice. It offers less room for experimentation and less responsiveness to cable changes.
For fans of “live” soundThose who are looking for the most mobile and plastic sound with rich timbres and a tender attitude to the intended intention of the composer will hardly like the workhorses in the form of modern active monitors. Their design places much more emphasis on overload capacity and reliability than on sublime matters.
Design fansActive studio monitors most often have a fairly utilitarian look, so if you care about maintaining a sophisticated design of your interior, then they are unlikely to suit you. If you still need active acoustics, then your choice is products intended for the household market, since there is already a good selection of such speakers on the market today.