Which speaker is the best? This question is not so easy to answer because everyone’s hearing is very different. It is therefore not surprising that, in particular, about the choice of the right loudspeaker, heated discussions are held that are not always fact-based. There is a reason why there is the saying in German “Wat den Eenen sin Uhl, is den Annern sin Nachtigall” (What is an owl for someone is a nightingale for anotherone) – everyone has their own view of the topic. Loudspeakers are not to be excluded from this.
However, there are some technical parameters that are helpful when looking for the right speaker for a specific purpose – and that give the discussions a basis of facts again. For this you need basic knowledge about the different designs. This guide would like to take a closer look at the common speaker chassis in detail.
How does a speaker chassis work?
First of all: The colloquial term “loudspeaker” technically encompasses the entire system of chassis, filter and housing. Chassis is the electromechanical system consisting of membrane, coil, support body and permanent magnet.
The principle of operation is easy to explain: A coil attached to a funnel-shaped membrane is immersed in a permanent magnet. The coil is excited with an alternating voltage of the music signal and the membrane is set in motion via the physical principle of magnetic attraction. However, once the membrane is in motion, it oscillates slightly. This leads to distortion of the music signal, the so-called clink effect, which also affects the listening experience of the song being played. In order to suppress this effect, the chassis are optimized so that they do not oscillate.
The amplifier to which the speaker is connected plays at least as important a role for a flawless music experience. It has to be able to deliver enough energy that the chassis’ natural vibrations are slowed down. This shows how well speakers and amplifiers have to be coordinated with one another.
Ultimately, a loudspeaker chassis is an electric motor with a very poor level of efficiency: only about one percent of the electrical power is converted into sound, the rest into heat. That is also one of the reasons why there are so many different designs and concepts for speaker chassis.
Design of the speaker chassis
The basic function of a loudspeaker chassis to set the membrane vibrating, basically follows the mass principle of physics. The following rule applies: the deeper the tone, the larger the membrane – and thus the moving mass – has to be. After all, the size of the membrane is decisive for the frequency range that a speaker can transmit. It is like the church organs, the lowest notes come from the largest pipes.
This influence of the moving mass on the frequency range has led to loudspeakers being specially developed for certain frequency ranges. The individual chassis categories are explained in the following sections.
Tweeter
exception of the exponential tweeter chassis. The idea behind it was to move into the upper frequency range that could still be heard by humans with as little moving mass as possible. This is 20kHz – the lower limit for the chassis is 3kHz. The problem with this design, however, is also the performance: Due to the small membrane, the radiated sound power is relatively low and must be optimized by structural measures such as exponential funnels. Fine ribbons similar to the human vocal cords are also often used to generate high frequencies.Plasma loudspeakers represent the absolute top class among the high-frequency loudspeakers: Because the sound in this chassis is generated with a modulated plasma flame, the moving mass – and thus the distortion of the sound – is zero. Anyone who has already enjoyed such a high-frequency speaker already knows the brilliance of high-frequency reproduction. As is so often the case, however, quality has its price, and so the plasma loudspeaker also belongs to the luxury category of loudspeakers.
Classical music and jazz songs in particular have high frequencies. That is why we recommend good tweeters, especially to friends of these styles of music. There is a corresponding selection in the reichelt shop.
Midrange
In the mid-range, the chassis are already larger, as the frequency range covers the range from 400Hz to 10,000-15,000Hz. They extend far into the working area of the tweeter and support it in its work. At the same time, the chassis cover the frequency range in which the human ear can hear best, the so-called ear curve range from 500Hz to 4,000Hz.
The characteristics of the midrange loudspeaker often lead to certain frequency ranges being overemphasized during playback. Electronic filters are often used to avoid this effect. You can read exactly how these work in the second part of this guide.
The ear curve area also means that the choice of the right chassis can be decisive for the good sound of a loudspeaker box. In the recording studio, loudspeakers are usually used that have excellent mid-range drivers in order to enable a realistic listening experience when monitoring and leveling the recordings. The price range for mid-range loudspeaker chassis is of course large, but you can get good chassis in the reichelt shop even with a smaller budget.
The speakers from the Italian company LAVOCE deserve special mention. Their midrange chassis have a very high efficiency of over 95db and a relatively low cut-off frequency: At 8kHz, they do not come into the range of the high-frequency chassis as much, which prevents overemphasis on the highs. The chassis are perfect for medium-sized stage speakers and for amplifiers with low output power, such as those found in high-end tube amplifiers. Above all, you have a wide choice between different materials (steel, aluminum, neodymium or ferrite).Truaudio’s loudspeaker chassis are actually complete three-way systems in one loudspeaker chassis. They also cover the midrange frequency range and are designed for use in home theater systems. Their fastening system with clips is unique and cannot be found in this form from other manufacturers – they usually still use screws.
Bass / Woofer
Bass chassis are the largest in a speaker box. In three-way stereo boxes, they are usually installed twice – once per box. However, since the human ear cannot locate bass tones, this is actually not necessary. For this reason, usually only one subwoofer is used in a stereo system, which is sufficient for stereo bass reproduction. This also leads to the fact that the subwoofer in cars is often installed in the trunk or under the seat.High-quality bass chassis must be solidly built to avoid unwanted resonances in the carrier. It depends above all on the materials used, here there is a wide range from aluminum to titanium. Especially for fans of current music such as pop, rock or hip-hop, a good bass reproduction is of great importance. A selection of bass chassis can be found in the reichelt online shop.
Broadband
The first speakers in radios were broadband speakers. Such loudspeakers must cover the entire frequency range from 20Hz to 20,000Hz. It goes without saying that compromises have to be made when it comes to playback; a broadband speaker always weakens in one frequency range. Since their installation is very cost-effective, they are still used quite often today in areas such as sound reinforcement in rooms, industrial plants and train stations.
But there is also the possibility of building very good hi-fi boxes with broadband speakers. This includes the open baffle – as used in guitar amplifiers and portable radios – or the horn loudspeaker. With the horn speaker, an exponential horn is placed in front of the broadband speaker. With the shape of the horn, weaknesses of the speaker can be ironed out. The range of good broadband speakers is huge, just let yourself be inspired.Conclusion
In this first part of the guide on the subject of “loudspeakers”, we introduced you to the basic designs of speaker chassis. Building on this, the second part will explain the most important electronic parameters in a practical way and show how you can choose the best loudspeaker for the respective purpose based on the data provided by the manufacturer.
