Hi-Fi Diary: How to Judge/Describe Sound Quality? A Detailed Explanation of Hi-Fi Testing Dimensions

To better judge the final sound presented by Hi-Fi equipment, we often use various terms to describe our feelings. At a basic level, terms like "sweet highs, accurate mids, deep bass" are used to describe subjective feelings. As we advance, we start using more common, widely understood terms like: resolution, density, three-frequency bands, positioning, etc. Further still, more complex dimensions like airiness, liveness, and layering might be introduced to evaluate music.

As a blog closely related to audio, BLOG owner has conducted many reviews and will likely continue to do so. To help everyone better understand BLOG owner's review logic, and to help us all reach a consensus on certain standards, BLOG owner offers the following explanations:

1. Sound Quality
The most fundamental musical indicator; both Hi-Fi equipment and various real instruments possess this attribute of "sound quality." When using "sound quality" for evaluation, it generally refers to the overall performance capability of the sound-producing system – whether it is sufficiently "pleasant to listen to" and "non-fatiguing" or "listenable for long periods" . To evaluate sound quality, one must combine the impression from the first listen with the feeling from long-term listening for a comprehensive assessment. Being pleasant and non-fatiguing are the absolute measures of sound quality.

2. Timbre/Tone Color
Like sound quality, both Hi-Fi equipment and real instruments have the concept of timbre. Generally, it is determined by loudness and pitch. Every sound-producing system inevitably has a different, unique timbre, which is the system's character and soul. For example, we can clearly distinguish the performance of different instruments playing the same score, relying on timbre.

3. Three-Frequency Bands
This is a highly integrated concept. The three bands include high, mid, and low frequencies. What some enthusiasts refer to as extreme highs and extreme lows should be considered as ultra-high and ultra-low frequencies that the human ear cannot capture. The three bands themselves are not a measurable concept, so we usually add the measurable indicator of "balance." Generally, balance is reflected by the amount and control of sound in each frequency band. In most cases, we can easily judge if high frequencies are excessive (piercing, bright), if low frequencies are uncontrolled (muddy, murky), or if mid-frequencies are disconnected (hollow). Usually, this can be judged more accurately with a spectrum analysis graph, and this aspect is also constantly influenced by the environment, leading to significant differences.

4. Transients/Dynamics
A term that is difficult to explain. Although widely used among Hi-Fi enthusiasts, it should actually be broken down into concepts like: sense of speed, changes in intensity (loudness/softness), etc. An excellent system should have transients that are lively and pleasant, not muddy. Please forgive BLOG owner for not being able to describe this concept with more rational terms; an excellent transient system will definitely make you feel the sound is vivid and full of vitality. We can also summarize this with the term "liveness" .

5. Resolution/Detail
Resolution – this is the first professional term all enthusiasts encounter. A common misconception is that many friends categorize the complexity of vocals or the layering of instruments under resolution; this is actually incorrect. Resolution generally refers specifically to high-frequency resolution and low-frequency resolution. It mainly concerns the ability to present details at high signal levels (the expressiveness of multiple sections during a full orchestral tutti) and low signal levels (subtle changes in instruments like the triangle, shaker, harp, etc.).

6. Density/Weight
These two concepts cannot be represented by data. Subjectively speaking, excellent density and weight can make instruments and vocals more solid, stable, and full-bodied, without that feeling of floating in the air, unable to land. More accurately, BLOG owner believes that excellent density and weight allow listeners not just to hear music with their ears, but to feel it with their bodies. Close your eyes, and you can feel the music's energy transmitted throughout your body. Sometimes enthusiasts also use the term "sense of energy" to describe this feeling.

7. Transparency/Airiness
Another indicator that is almost impossible to quantify with data. BLOG owner is quite sensitive to transparency due to long-term use of electrostatic headphones. Good transparency is necessarily clear and gentle. To use a simple example, it allows you to quickly find the vocal or instrumental line you want to follow in a complex orchestral piece, without being overly affected by other lines. At the same time, excellent airiness will let you feel the real propagation path of sound waves. For example, when we hear experienced enthusiasts talk about hearing a singer's "mouth shape" or silent "sighs," these are influenced by airiness.

8. Soundstage/Positioning/Space/Layering
Soundstage, space, and layering are topics enthusiasts often delight in discussing. Among these, soundstage , also called "audio field" , should be a combination of the latter, encompassing multiple concepts like positioning, space, and layering. Taking a large orchestral piece as an example: good positioning allows you to clearly perceive the location of the piano, timpani, and harp; a good sense of space allows you to clearly grasp your own position, the size of the entire concert hall, and distinguish between the performance area and the audience area (the space in front of and behind the listener); and good layering allows you to clearly perceive the space between the first and second violins, and the gaps between instruments. By combining all of the above, we can arrive at an evaluation of the soundstage/audio field.

9. Character and Proportion
Finally, we discuss character and proportion. In reality, these two concepts complement each other. Proportion refers to the ratio of vocals to instruments in a piece of music. Usually constrained by production, each track's presentation differs. Whether a proportion satisfactory to the listener can be found tests the tuning and matching abilities of the user and the manufacturer. And different proportions, combined with all the review aspects mentioned above, ultimately result in "character," which is also the unique expressive power of an audio system.