Rule 1 - Hearing AND LISTENING
The ability to hear the audible spectrum and
apply critical listening
Identifying any personal hearing disability and learning the art of critical listening is your first step toward the creation of a high-resolution audio system
Before you start 'upgrading' to achieve better sound, it would be wise for you to ascertain if you can indeed hear the full audible spectrum of music in all its glory. Our ears are sensitive to hearing damage. Unfortunately, once damage it cannot be reinstated. Continuous listening to loud sounds because of occupational requirements such as being a disc jockey, a musician in a rock band, a construction worker using a pneumatic hammer or operating the piling machine or working in the airport apron without proper protection, etc., may have already caused you some hearing damage. Old age, certain forms of illness, hereditary circumstances, and even some types of medications such as loop diuretics, nonsteroidal anti-inflammatory drugs, antibiotics, chemotherapeutic agents, quinine, and acetaminophen including Aspirin (8 to 12 pills a day) are said to contribute to hearing loss.
Hearing begins with the presence of sound waves, which are changes in pressure generated by vibrating molecules. The inner ear contains thousands of hair cells that pick up different frequencies and send information to the brain to be processed. As you age the continued exposure to noise and loud sounds can break, bend and destroy these cells. The high frequencies would usually go first as the hair cells that are tuned to high pitches are first to encounter soundwaves and as a result, they experience more stress and degenerate earlier which is why the older you are the harder it is to hear the high-pitch. Sometimes it may be due to a birth defect or an accident if you have not already succumbed to such occupational hazards. Even if one side of the ear is affected, this would seriously handicap your ability to listen to stereo and review audio systems critically.
The maximum range of human hearing includes sound frequencies from about 15Hz to about 18Khz per second and for young people is from 20Hz to 20kHz. It is pertinent to know that the ear's natural frequency response is non-linear (Fletcher-Munson curve). The hearing curves show a significant dip in the range 2000-5000 Hz with peak sensitivity around 3500-4000 Hz. This is associated with the resonance of the auditory canal. That means, our ears are more sensitive to mid-range sounds than to frequencies at both extremes of the audible spectrum. We generally don’t notice this phenomenon, therefore; our brains take the mid-range bias into account. Generally, audiophiles tend to focus on the importance of the software, equipment, and the listening environment and unwittingly forget about the sound that has made its way into our internal hearing mechanism. We take for granted as our ears and brains process the sound and determine how that sound will be perceived. Therefore, any physical hearing defect may affect how we perceived loudness, imaging, and high frequencies during music playback. Suffice it to say that everyone hears differently from birth to death.
Understand the characteristics of sound
The physical characteristics of sound waves influence music reproduction in areas of loudness, pitch (aka dynamics), timbre (aka tonal balance), and spatial coherence (soundstage). The loudness of sound is measured in decibels (dB). This is a measure of intensity, which relates to how much energy the pressure wave has to the standard pressure. Decibels are a relative measurement that differs between individuals. It essentially means how strong or intense an auditory noise is to an individual. The noise level will seem too loud for some and too low for others. The middle ear muscles involuntarily contract, which decreases the amount of vibrational energy being transferred to the sensitive cochlea (the bit that converts the sonic vibrations into electrical impulses for processing by the brain). The muscles clam up to protect the more sensitive bits. Loud volumes are generally not good for creating an accurate tonal balance which also saves your ears from unnecessary listener fatigue. This may cause irreparable damage if listening over 100db for prolonged periods because the ears cannot regenerate. It is instructive to note that pitch and frequency are not the same things. Objects that vibrate slowly produce a low-frequency sound that we hear as low-pitched. Things that vibrate more quickly make sounds of a higher frequency that our ears hear as high-pitch.
Audiogram testing
Audiophiles are encouraged to go for a hearing test. An audiologist will discover your listening history (lifestyle) and your main hearing concerns during the interview. You will likely take an otoscopy test – this visual test will ascertain that the ear's canals are free of damage and that they are free of wax or other debris to proceed with the next test. Next, would be an audiometry test (Tympanometry) to check middle ear disorders, (how your eardrums are moving) the mobility of the middle ear system is measured while varying the air pressure in a sealed ear canal.
The final test would be an audiogram test – the use of headphones or insert earbuds. This air conduction testing uses pure tone stimuli (beeps) to one ear at a time. If you hear anything, you are required to press the response button. The test establishes the clients' threshold of hearing for each of the frequencies that are important for understanding speech. The auditory test typically ranges from 500hz to 8KHz with an easily audible intensity level (30db) to the client, the level is then decreased in intensity by increments of 10db making sure the tones are not presented in a predictable rhythm or pattern until the client no longer responds. Thereafter intensity level is increased in 5db increments until a response is obtained. This is repeated until the client has responded to 2 out of 3 ascending presentations. The threshold is recorded for both ears. If hearing loss is detected, then further testing may be conducted using the bone conduction (cochlea) testing method. The audiologist integrates the data across each of the different tests and presents the findings to the client. The audiologist may provide some counseling on hearing and balance difficulties or may recommend further assessments. Audiophiles or sound engineers may opt for an increased frequency bandwidth test on demand.
A hearing threshold chart example
Studies suggest that the safe exposure limit is 85 decibels (dB) for no more than eight hours a day.
The illustration offers some perspective on loudness levels:
How audiophiles develop 'golden' ears
The art of critical listening
Critical listening is conducted when evaluating new recordings or an entire audio system, individual system components, or ancillary equipment. This activity requires the audiophile to focus on the musical performance, unlike the casual listener. Casual listening focuses on letting the music do what it was intended by its creators, it is an exercise of connecting more closely to the music as a whole, appreciating its creativity, lyrical content, and the musician's prowess.
Critical listening instead dissects music into parts and evaluates its portions while ignoring the whole. The quality of the system components is not the primary focus but the quality of attachment to the musical soundstage; how many musicians, what instruments are they using, and their location within the soundstage. The quality of attention is what's important; an absolute focus will enable the audiophile to better discern the musical performance which must not relegate to becoming background. Nevertheless, a high-quality recording will draw the listener in, intimately connecting with the music. The critical listener has an objective in mind, listening for the following sonic properties and intuitively identifying any coloring of the music.
Identify the general sonic properties of a musical performance
The following 4 sonic properties describe the perceived sound quality of a recording and define the resolution of an audio system:
What is a soundstage?
On audiophile-quality recordings and if the system is set up according to audiophile practices, you should be able to ‘see’ a soundstage which is the overall presentation of space in which the musicians are arrayed from left to right and from front to back. The images should be layered approximately and their width spread to the far extensions of the loudspeaker edges and even beyond on relevant recordings. You should also be able to perceive subtle details and clues as to the “depth of image” as having a formation that is deep of at least three layers (rows) with relevant recordings. The layering gap between these images should have distance in between layers. The images of musical instruments should also have a sense of height and not float on the same plane but staggered with some height variation. For instance, cymbals are often heard as higher and the same is true with the soloist in the middle and kick drums on the floor. A three-dimensional soundstage is an important sonic characteristic because it provides a sense of reality – as though musicians are performing in front of you. On quality recordings, the soundstage should not appear congested and shallow as it is in mono recordings.
What is imaging?
Imaging has to do with the presentation of individual musicians and vocalists as they are located within the soundstage also known as “image specificity”. They should have a “palpable presence”, be well-delineated and not diffused, be stable and not wavering unless it’s a live recording, and not be bunched and indistinct. There is actual space between these images conjuring from a dark space – the darker the better, i.e., more black than grey. The apparent size of images (musicians/instruments) should have a correct perspective corresponding to their relative size and not be bloated, small, or blurred into a mass. The main lead vocalist or lead instrument (if instrumental music) should be centered between your loudspeakers which all good mixing engineers would endeavor to achieve. Imaging is important musically because it allows one to distinguish the weight of individual instruments and therefore hear the individual lines that are being played. It also contributes to the illusion of 'reality' allowing your loudspeakers to ‘disappear’ entirely.
What is the tonal balance?
Music has tonal properties which are described in frequencies that make up the audible spectrum (20Hz to 20Khz). A quality audio system should ideally be able to handle frequency ranges within the audible spectrum. The frequency response should ideally be flat, meaning that there is no unnatural emphasis in the bass, mid-range, or treble areas. These frequency ranges will maintain the timbre integrity for a variety of musical instruments on relevant recordings. Any glaring spikes or dips in these frequencies will affect the tonal balance of an audio system. A relative flat frequency response curved (plus or minus 3 dB) as measured at the listening seat is desirable in this respect. For critical listening, the genre of recordings would impact the evaluation process. Ideally, music for evaluation should mostly be created by organic musical instruments instead of electronics such as synthesizers, drum machines, and computer-generated special effects much like the type of progressive techno-pop that the younger generation has come to appreciate. It makes it difficult to evaluate something if there is no reference. However, these progressive-styled techno recordings would not have any phase issues, are less susceptible to room modes, and have no miking issues during the recording process.
The tonal balance may perhaps be articulated by three fundamental frequency groups; Bass, Midrange, and Treble. The 3 groups are explained in the following paragraphs and should appear ‘seamless’ working together as a whole instead of the sum of its parts.
Bass should not be heavy but controlled and tight (immediacy) without causing an 'overhang' where it lingers on interfering with the next preceding note. It should be well-defined and not muddy. Bass ranges around 250Hz extending down to 20Hz. The mid-bass region operates from 40Hz to 80Hz. This area should be rich and warm not appear lean (lacking). Rich mid-bass reinforces the bass with a sense of impact and slam.
The midrange is best judged by good vocals. Voices unlike musical instruments should be ‘articulate’ i.e., life-like, and not excessively ‘sibilant’ in an annoying way. It should not be ‘chesty’ or ‘nasal’ but natural. Female voices, in general, should sound lush, smooth, breathy, and not raspy, grainy, or gritty. Although all aspects of tonal reproduction are important, it is usually the midrange that is crucial to the music which may explain why certain audiophiles swear by tubes. Tube equipment usually described as ‘warm’ sounding tends to excel in the midrange where our ears are most sensitive, and where most of the music is. A poor midrange tends to make everything sound harsh (bright) or lean (dark). Midrange frequencies operate around 315Hz to 3KHz.
Treble should be “coherent” integrating with the midrange and not standing out to be “strident” or “glaring”. It should be detailed, airy, and extended with a texture that is best described as being “silky or smooth” as opposed to being 'glassy', ‘shrill’ or 'rolled off' after 16KHz. Harshness in the treble is annoying and contributes to the listener’s fatigue. On the other hand, a rolled-off treble tends to make the whole presentation sound a little flat, dark, and uninvolving. The character of the treble should be 'delicate' i.e., gentle on the ears not piercing, or 'peaky' on transient attacks. Nor should the 'treble' be closed-in without any sense of bite or sting. Treble extends from 3KHz to 20KHz.
What are dynamics?
Music is essentially dynamic that has contrasting soft and loud passages (“pppp” and “ffff”) from the first attack, the sustain and the final decay should all be coherent in a good system setup. The more ‘obvious’ the contrast, the better is said to be the dynamics of the system. The soft passages are known as “micro-dynamics” and the loud ones are “macro-dynamics”.
Micro-dynamics - You should be able to hear soft detailing from late wall reflections. On relevant recordings, there would be hints of the recording environment and peripheral noise such as the room ambiance report, breathing of performers, foot movement, whispers, etc.
Macro-dynamics - You should be able to ‘feel’ the majesty of loud crescendos (climaxes) without causing images within the soundstage to collapse into a bunch or blur. ‘Transient’ (start and stop) should be ‘articulated' in its speed to begin and end a musical note. It should not appear 'tentative'. Its leading edge' at transients should be 'crisp' where brasses have their bite and kick drum their slam. You should not only hear the bass but also feel (haptics) the punch and the low end touching and moving through your body.
Pace and Rhythm - This is another characteristic of dynamics which in essence is the music’s timing or tempo. It should be ‘coherent’ or ‘lively’ that may initiate involuntary foot-tapping or head bobbing from relevant music. You should be able to follow the bass line which should be ‘catchy’ and pronounced and not ‘sluggish’ (slow) or “mechanical” (monotonous).
The music and voice reproduction chart (Center frequency (Hz) @ 1/3 octave bandwidth)
The following table is adapted from the equipment operating manual of the Behringer ULTRAGRAPH PRO FBQ3102HD 31-Band Stereo Graphic Equalizer. The table maps out the operating frequencies of various instruments as well as the cause and effect of fundamental frequency ranges in music reproduction.
The 10 action steps to critical listening – a pathway to develop your “Golden Ears” (not for the casual listener)
1. Establish a conducive listening environment
Firstly, you must be in the mood to listen – be in the best mental state
Ensure the listening space has a low noise floor of no more than 30dB as measured from the sweet spot
There should not be any intermittent or noise disturbances from within or outside the listening space. Turn off any noise-making electrical devices e.g., dehumidifier, fan, dimmers, etc., or place them as far as possible from the sweet spot.
An ideal listening time is usually at night when human activity in the environment is at its lowest.
No bright lights inside the listening room but dimly lit to create warm (yellow) instead of cool (white) bulbs, and a pleasant setting to get you into a relaxing mood.
The center stage in between loudspeakers should have soft lighting with an object (plant or figurine, image, painting, poster, audio equipment, etc.) to help focus and provide perspective on the center image within the soundstage.
The listening space should ideally be airconditioned; the blower as far away as possible from the sweet spot for noise reduction, ideally use the central cassette design type aircon which has a quieter blower.
2. Prepare to listen
Wax out ears (outer ear) and ‘blowout’ pressure (inner ear) if any that may be trapped inside your ears for better high frequencies and imaging. It is pertinent to note that accumulated wax may contribute to hearing and some medical experts say even memory loss in the long term.
Remove loudspeaker grills and any furniture in between the loudspeakers and the sweet spot for best high frequencies and imaging
Set playback volume level between 75 to 80db as measured from the sweet spot. Use pink noise played through the audio system and select A-weighting and ‘slow’ on a portable ‘SPL’ measuring device placed at the sweet spot at the ear level when seated. Similarly for subwoofers if any, if you have not already gain-match them against the sweet spot. You can pre-set this playback level by marking a reference point next to the volume control knob at the preamp side. Ensure that it is also gain-matched to the same volume output between channels.
3. Prepare the sweet spot
Check the listening chair to ensure that it is correctly positioned in the sweet spot. Pre-set a reference point by marking a spot on the floor against the 2 front legs of the listening seat.
Adopt a ‘Head-in-a-vice’ seating position. Every head movement will shift the center image accordingly if your system is well-tuned. If your head is locked, you would better appreciate and evaluate the soundstage and imaging. Sit with your back straight on a comfortable chair with an armrest. The backrest should not be higher than your neck to avoid time-smear reflections.
4. Prepare your music source
Use only audiophile-quality recordings and music you are familiar with
Select a range of genres to evaluate aspects of music such as voice, soundstage, imaging, tonal balance, rhythm, and dynamics or for a particular area that you would want to evaluate
Familiarity with the source is key when evaluating equipment or systems
5. Focus on the soundstage
Identify image locality - how wide from left to right
Identify the depth of field - how many layers from front to back
Identify the height contrast of the musical instruments
6. Focus on the voice
Is it cantered?
Is it life-size?
Any background singers or duets, trios, etc., if any, how many and where are they
7. Focus on one instrument at a time
Its relative position
Its timbre
How it contributes to the rest of the music
8. Follow the musical beat
The bass line
The rhythm guitar
The drums
9. Feel the dynamics
Soft to loud passages; identify the attack, sustain, and decay
Identify any ambient noises; foot movements, breathing, whispers, room size, etc.
You should be able to feel the punch and low-end bass hitting your body on relevant recordings
10. Evaluator’s ethics (for evaluation purposes only)
Personal biases, such as third-party recommendations, brand popularity, and high prices should not be soaked into your consideration, only how it sounds matters. Leave your biases at the door to reach a fair value judgment.
No flash evaluation, allow for component 'break-in' if new and for at least 2 weeks or better 4 weeks to stabilize the electronic parts or moving parts in case of loudspeakers. A break-in tool such as pink noise or other digital files may be used and run 24/7 at low volume to get to the settle-in point quickly.
Ensure only one variable is in play unless it’s a whole system appraisal. Otherwise, you won’t know which product or tweak is making the difference. The volume level must remain constant in all cases.
It is best to be familiar with the target item for at least a month to get used to the 'new' sound.
Use the A/B/A comparison method to solidify your impressions. This will recap and support retention and recency memory efforts. Swap the products quickly; get the necessary tools ready to execute the change. Try to keep the image on top of your mind without distractions and unnecessary conversations. Take notes or use a structured checklist. Always evaluate the reference component first before switching to the target item. Make judgments only when the target is removed from the system to identify any sins of commission or omission impacting the music. There is an old principle that suggests that 'You will not know what you are missing until it's gone".
Use the blind test method (if there is assistance). This will avoid observational bias. Make at least 16 swaps for reliable sampling for a credible binary judgment.
Conclusion
A well-setup and finely tuned system will help maintain the timbre integrity for organic musical instruments without omission and or commission. Music will have that sense of Pace and Rhythm that would be involving or alluring which we have all come to appreciate. It appeals to our sense of 'feel' allowing the creative processes in music to develop. Macro and micro-dynamics will provide the much-needed foundation that is the lifeblood of music. The creation of a soundstage with image specificity would provide a better appreciation of individual performers as if it were a live event. Some people may argue that audiophiles are not listening to music, but I believe this is a straw-man argument. An audiophile who has a high-resolution setup and with audiophile quality recordings who is schooled in the art of critical listening would be hearing all the musicians perform much like a live event and the nuance that exists. A high-resolution audio system will draw the audiophile much closer to the music. Take the time to learn the language and terminology from the lexicon provided in the Resource section to help you understand what audiophiles and audio reviewers are saying. Thereby, you can identify your system’s strengths and weaknesses to steer you in the right direction. Remember, your ears are the sharpest tool in the shed.
Note: A training video link "How to identify frequencies by ear" is provided in the Resource section for further enrichment.