How to measure sound or audio quality?
I’ve met quite a few audio engineers and sound engineers in my life, and the best of them had one thing in common: they had great ears.
They knew what a good sound was. The field of their opponents is occupied by engineers who rely solely on measurements to “prove” that “their” sound is better. In my opinion, people in the second group rarely create good-sounding products. Audio is too complex to be analyzed by numbers alone.
Today I see more and more digital audio engineers specializing in designing programs to correct for speaker characteristics and room acoustics. They are generally very nice people, and their diagrams and tests look pretty impressive when displayed from a laptop, but this all fades into the background, once I hear real sound. Results often range from good to really scary – your hard work is the least likely to succeed.
Obviously, they were so focused on measuring the characteristics of the sound that they forgot to listen to the result, or at least hire assistants who understood what good sound is. If the goal of these people was to achieve the best possible performance, I would congratulate them on their successful implementation. But they strive for something different, and understanding exactly what kinds of measures characterize improvement in sound quality is an art. Art in which only a few have succeeded.
There are several reasons why the measurements do not correlate with subjective evaluations of sound quality. First, measuring the characteristics of electronics and speakers has little to do with how the music sounds. The test tones are too simple and predictable; the music is much more complex and varied. Reproducing the sound of a violin or drums is extremely challenging, and since the real purpose of any hi-fi system is to play music, not test tones, the most important task for an engineer should be to develop a product that sounds “good.” . to the target audience. For example, if he is designing DJ headphones, he is not trying to reproduce the bass as accurately as possible. Amplifier designers shouldn’t waste time trying to design an amplifier that delivers maximum performance during test loads. They must create amplifiers that can handle the complexities of playing music with real speakers. Amp designers don’t know which speakers their product will ultimately work with. Each type of speaker places a different “load” on the amplifier.
In the 1970s, a new generation of amplifiers emerged that had much lower “harmonic distortion” than their predecessors; It was believed that if this value could be measured more accurately, the amplifiers would produce a better sound. But they did not measure what was really needed. Blindfolded perception, expressed in “bespoke” design, is unlikely to take sound reproduction to a qualitatively new level. This does not mean that metric values are useless; They are a great help to talented engineers, but measurements cannot replace listening to music.
I know the sound of the latest audio adjustment and calibration systems installed in receivers from Denon, Onkyo, Pioneer, Sony and Yamaha, and I can say that the result of their work is difficult to predict in advance. Of course, these systems can improve the sound, but most of the time, processing the sound just changes it. In these cases, I get the best results by listening to music and manually tuning in parallel. Processed audio may have better numerical characteristics, but again, this does not necessarily correlate with improved audio quality.
I recently talked about this with a friend of mine, writer Brent Butterworth, who believes that quantification is a useful tool, but we never reached a compromise. However, according to him, the measurements of the value of the indicators that characterize flaws in the speaker’s sound may go unnoticed by the human ear, which means that some speakers, characterized by not having the most optimal performance, from a point of view subjective, they can produce high quality sound. So find out.
Therefore, even if experienced engineers are faced with the problem of separating useful information from unnecessary quantitative indicators, it is difficult to imagine how a buyer looking at the wavy lines on a graph can use it to decide which amplifier or speakers to buy.
