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Types and characteristics of sound acoustics

Practically no one is able to properly describe the sound of loudspeakers. However it does not sound strange because people in their descriptions often use some delusional descriptions, borrowed from audiophile magazines. Complete information regarding this I mentioned in previous articles so I will not say anything new, but simply group the data available.

Every acoustic system has its own sound type that consists of three caracteristics:

  1. Linearity
  2. Naturalness
  3. detail

Now we can discuss all three caracteristics more in detail.

1) Linear (monitor, flat, neutral sound). By this characteristic means the amplitude linearity of the acoustic sound system, i.e. amplitude-frequency response. Linear acoustic system is a system that in its range has a deviation, no more than 3 dB. So in a room that has no acoustic treatment every acoustic system with such a deviation of the sound will sound timbre identical. In a case of exploitation of acoustics in a room with acoustic treatment, these irregularities can be heard. In this case the deviations of amplitude-frequency characteristics should not exceed 1-2 dB.

2) Natural (natural, live sound). This is a fairly complex characteristic that is not characterized by any particular value, and consists of two sub-items. You can call it natural only if the sound is extensive and phase linear at the same time. Otherwise, you must plug off one of the sub-items.

2.1) Phase linearity. The first sub-item may include phase and time sound distortions (delays). Acoustics, in which the phase characteristic is completely linear, temporal delay between the speakers, is completely absent. Although it is not mandatory requirement. For example, if we consider frequency band of each speaker separately, then they can have linear phase characteristics that may not be compensated for the time between them. For example, this situation is typical for cases where speakers have analog passive phase-linear crossovers (there is not every analog active crossover completely phase-linear), which do not allow temporal alignment of the delay between the drivers. In this case, the graph of phase acoustic system will show the characteristic “step” that consists of equal parts. Correction of the temporal characteristic of acoustic system is possible only with physical retraction of drivers in the front panel of speaker. Therefore, under the phase-linear acoustic is always considered acoustics with linear phase which means that the speakers have linear phase drivers and there are no time delays between them. Correction of any performance in isolation does not provide much tangible effect of sound quality improvement. For phase-linear acoustic system a high localization is typical, good stereo sound effect, less fatigue and a sense of chaos during the listening. But the sound of those acoustic systems is quite specific, so it is necessary to have a personal experience while listening these systems.

2.2) Scale. The scale is mainly characterized by the dimensions, constructs and acoustic design of the drivers.

High magnitudes have highly efficient professional subwoofers and midwoofers with large size membranes and hard suspensions. Thanks to the huge size, they can move with their diaphragms large volumes of air that is usually called the scale and thundering sound, and a hard suspension due to high self dampfing eliminates these drivers from the typical echoing , prolonged sound, which can be seen in everyday home subwoofers. The sound of the drivers whose membranes have hard suspension is usually called speed and dynamical. The speed of sound can be also separated into special sub-item, but usually the driver are no larger than 12-15" are de facto professional and have a hard suspension. Therefore, a large-scale sound in most cases it is also a rapid.

Here we can include also MF and HF compression drivers, which are due to horn design of a specific region of space dense, equable and clear sound image. Inverted version of the above situation can make ribbon drivers that practically do not have direction.

3) Detailed (audio resolution). Unfortunately, detailed sound cannot be measured, but its stage can be determined as better or worse. The easiest way to define the detail is on the mid range and high range frequencies, where the influence of standing waves is not too high, and the human ear has a maximum sensitivity. Example is compared listening of the acoustic systems. If during the reproduction at some speakers you can hear more details of sound recordings and vivid sound picture that means that the speakers are detailed. The main thing is not to mix the details and distortion, but that's another question. High details have MF and HF with rigid metal membranes or totally different sound drivers: compression and ribbon drivers and the Hale drivers.

That is how these three caracteristics form a specific sound type of audio speakers and their division to: home, professional, studio, cinema, etc. And, if you are talking about specific types, we can determine some dominate characteristics of sound that are not present with certain acoustic systems and do not allow assorting of that system to that class.

For example we can use the studio monitor. If its Frequency response exceeds 3 dB, then it is not control acoustics. If distortions do not exceed the limit , then comparison of the studio speakers among themselves by its characteristics of sound of number 1 is almost meaningless: "Well, how important is the location of the distortion, if its value does not exceed the prescribed norms and the AU is operated in a room without acoustic treatment? Therefore, in this case the studio speakers should be compared to two other characteristics: the naturalness and detail. If we're talking about the budget monitor, then it is enough if it has flat frequency response and in this case it is forgivable to be indirect and detailed. But if the monitor needs to be used in a first-class recording studio and its task is the top sound reproduction, than it should not just have an equal sound but also be extremely smooth and have a maximum spontaneity and detail.

Let’s take an ordinary home acoustics with cone midrange driver. Its sound can be described as non-linear, unnatural, and not detailed.

Example of professional speakers with compression drivers: nonlinear, large-scale, high detail.

An example of a three-lane monitor of the company PSI Audio is: amplitude-linear (+ -1.5 dB), phase-linear and medium detail.

Example with monitors TAD and Stage Accompany: amplitude-linear, large-scale, and highly detailed sound.

Example of digital (FIR) three-way studio monitors K+H: perfectly linear, natural and high-detail (dome midrange).

After reading the previous articles on this site, you understood that by using multifunctional digital crossover (DEQX) you can turn any acoustic system into full amplitude phase-linear. Therefore, in our days, these sound characteristics should not be very surprising, and if we speak about construction of high-quality multi-band amplification systems, mentioned characteristics should be a default. The two characteristics that resist the correction are detail and scope. The second characteristic we can secure if we buy the professional acoustics. Unfortunately detail has literally just a few acoustics brands that I have already spoken about.

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