Certainly, the speakers are among the most difficult choice HiFi components.
We will try to understand some basic concepts in the meantime, then go into the consideration of some possible criteria of choice.
The speakers (speakers, loudspeakers or speaker systems you want) have the delicate task of transforming the electrical signal from the amplifier into a perceived acoustic signal from our ear.
Depending on the method used to implement such transduction, they are divided into several categories. It is not my intention to do here a list of transduction techniques that can be complicated to understand for those who come close to High Loyalty for the first time and have no technical background behind them.
For the sake of simplicity, we will only deal here with dynamic speakers that then account for 90-95% of the market.
The working principle
The principle according to which dynamic speakers work is the following:
a coil, integral with the loudspeaker membrane, is immersed in a magnetic field generated by a magnet …. (yes, the magnet that is there Behind the loudspeakers). The passage of the alternating current (the musical signal) produced by the amplifier generates in the coil an electromotive force which moves it forward and back within the magnetic field. Consequently, since the loudspeaker diaphragm is integral with the coil, the loudspeaker itself is set in motion thus generating an air movement, i.e. sound waves.
I hope this very simple explanation has not hurt the industry experts so much .
The audible sound of the human ear extends (optimistically) from 20 to 20,000 Hz (frequency unit of measurement). 20 Hz represent a very low tone and 20,000 Hz a very sharp tone.
For a variety of physical reasons, it is extremely difficult for a single speaker to reproduce the entire frequency range from 20 to 20.0000 Hz. That is why in the speakers you will often find at least two loudspeakers. In essence, the task is divided between two or more specific speakers for a certain range of frequencies. The number of these divisions is counted in ways , so if you divide the audio signal into two portions, high frequencies and low frequencies, it will be said that the chassis is two-way and this regardless of how many speakers it has.
For example, a two-way case can have three speakers for high frequencies and four for low frequencies.
Low frequency loudspeakers are called woofers , those for high tweeters, and those for midrange midrange frequencies .
The division of the audio range into portions (or ways ) is performed by a passive electrical circuit inside the casing said crossover filter or more simply crossover .
This filter splits the audio signal coming from the amplifier in more ways and can also perform other more complex functions such as regularize the impedance or the combination of the different speakers. Normally it consists of capacitors, resistors and inductances.
Simply, we can divide the dynamic boxes into three large families, depending on whether the cabinet is completely closed or open outdoors: Pneumatic suspension (closed case), bass reflex (open case by tube) and transmission line (open case via An acoustic labyrinth).
As with all other HiFi objects, there are no inherently better building principles than others. Each approach has pros and cons.
A simple way to check the goodness and quality of the cashier’s construction is to check how much this is deaf . Basically, the mobile phone does not have to resonate when it is urged by the loudspeakers. Try to beat the walls of the furniture with the knuckles and make sure they do not resonate too much. The strength and weight of the case are already a good presentation card.
In the pneumatic suspension system (closed case without hole ) the frequencies emitted from the back of the woofer are in practice eliminated. Closed air inside makes it an elastic element for controlling the movement of the loudspeaker.
In bass reflex systems (or similar), the rear woofer output is tuned at a certain frequency through a tube so that it also contributes to the bass response on the chassis.