What is sound? What should you know about sound?

Sound is not just something we hear, but a physical phenomenon that is closely linked to our lives, emotions and health. From communication, learning, entertainment to art, sound is always present and has a direct impact on our daily experiences.

 In the field of karaoke and music, understanding basic concepts such as frequency, intensity, duration, pitch, reverberation or resonance... will help users choose and install a more standard sound system. 

Not only are the equipment such as speakers, amplifiers, digital echo, mixers or microphones important, but the source and the listening room environment also determine the quality of the singing. Therefore, mastering the basic knowledge of sound is the key to having a karaoke experience that is "pleasing to the ears, pleasing to the voice" and durable over time.

What is sound?

Sound is a physical phenomenon created by the vibration of an object, propagating through a medium such as air, liquid or solid, and perceived through human hearing. 

When sound waves reach the eardrum, they vibrate the eardrum to the rhythm of the source, so we can hear. The special thing is that sound cannot be transmitted in a vacuum, but only exists when there is a transmission medium.

The role of sound in life

Sound is involved in every daily activity – from verbal communication, enjoying music, alarm signals, to the natural sounds around us. In modern life, sound also plays many special roles:

• Sound in communication: 80% of the information people exchange every day comes from sound (according to research by Journal of Communication.
  
• Sound in entertainment and arts: A piece of music can have a powerful effect on emotions; for example, classical music has the ability to reduce average heart rate from 60–80 beats/minute down to 50–65 beats/minute (Oxford University study, 2016).
  
• Sound in education: Music and sound effects are proven to increase the ability to remember information. 17% compared to learning in a quiet environment (as reported by Harvard Medical School.
  
• Sound and health: Research at the University of Southampton (UK) in 2014 showed that exposure to natural sounds at levels below 40 dB significantly reduces stress levels and improves mood. In contrast, exposure to continuous noise over 85 dB may cause hearing damage if prolonged.
  

Sound is therefore not only a means of communication, but also a factor that directly affects emotions, health and quality of lifeIn the field of music and karaoke, understanding the principles of sound helps users easily choose, install and optimize the system to bring the best listening and singing experience.

Sound knowledge you should know

Sound is not simply what the ear sees, but physical phenomenon complex created by the vibrations of an object, transmitted through a medium such as air, liquid or solid. According to American Speech-Language-Hearing Association (ASHA), the normal human ear can perceive sound ranges in the range of 20 Hz – 20.000 Hz, and this is the foundation for us to listen to music, chat or enjoy karaoke. Understanding basic concepts such as frequency, velocity, intensity, duration, pitch, resonance, reflection and resonance of sound will help users choose, install and maximize the effectiveness of karaoke systems, thereby bringing a more complete singing experience.

What is audio frequency?

Sound frequency is the number of oscillations of sound waves in one second, the unit of measurement is Hertz (Hz). The human ear can hear from 20 Hz (deep bass) come 20.000 Hz (high-pitched sound). For example, bass drums typically range around 60–100 Hz, while violins can reach 2.000–3.000 Hz. For karaoke, speakers with a wide frequency range will reproduce both vocals and background music more evenly.

What is the speed of sound?

Sound travels at different speeds depending on the medium. In air at 20°C, speed is 343 m / s, in water about 1.480 m / s, and in steel up to 5.960 m / s (Engineering Toolbox). This is the reason why the knocking sound spreads very quickly through the iron bar, and in the karaoke room, the surface of the wall - glass - curtain also greatly affects the quality of sound transmission.

What is sound intensity?

Sound intensity reflects loudness, measured in decibels (dB). According to WHO, the safe sound level is ≤ 85 dB for 8 hours/day. Above 120 dB can cause immediate ear pain. In home karaoke, the ideal sound level is maintained at 70-85dB, just enough to "float" without damaging hearing.

What is sound intensity?

Duration represents the length of a sound. A short, sharp drum beat is different from a long, lingering organ sound. In karaoke, duration helps create a harmonious rhythm and keeps the vocals in sync with the music.

What is pitch?

Pitch depends on frequency. High-pitched sounds (high frequencies) sound bright and clear; low-pitched sounds (low frequencies) sound deep and warm. In a karaoke system, combining tweeter (for high pitch) and woofer (for low pitch) speakers is a key factor in creating a full sound quality.

What is sound reverberation?

Reverberation is the phenomenon of sound remaining audible after the source stops. According to the standard ISO 3382, in a small karaoke room, the ideal reverberation time is 0,5–1 second. Too little reverb makes the sound dry and lacking in emotion; too much reverb makes it dull and difficult to hear.

What are sound reflection, refraction and resonance?

• Reflex: Sound waves bounce back when they encounter obstacles, for example echoes in a cave. In karaoke, sound absorption is needed to reduce excess reflections.
  
• Refraction: Sound changes direction when passing through different media (air → water), causing the listener to perceive the wrong source location.
  
• Resonance: When a sound wave matches the frequency of an object, it vibrates more strongly, amplifying the sound. For example, the body of a guitar naturally resonates. In karaoke, uncontrolled resonance can easily cause buzzing and howling.
  

What is sound power?

Sound power is the energy emitted in one second, measured in Watts (W). A karaoke speaker with power 300W can cover a 20 m² room, while a 30 m² room needs at least 500W to ensure the bass is not lacking. According to the installation experience of Phuc Truong AudioChoosing speakers - amplifiers - power amplifiers with synchronous power is the deciding factor for the quality of singing and durability of the karaoke system.

Factors affecting sound quality

Good or bad sound does not only depend on the speaker or amplifier, but is the combination of many factors: from the source, the equipment to the listening room environment. According to practical experience of Phuc Truong Audio, if just one link in this chain is not standard, the whole system will be affected.

Sound source

The sound source is the “input material” of the entire system. A high-quality source will produce a clean, clear signal, while a poor source will cause distortion and noise, no matter how good the equipment is.

• In karaoke, the sound source comes from the microphone, karaoke player or musical instrument. A good microphone helps the voice to be clear, honest, and limits howling. On the contrary, poor quality microphones often cause noise, interference or quick damage.
  
• With karaoke players, the new online version often integrates a high-quality music store, supports HDMI, Optical or Bluetooth 5.0, ensuring that the signal is not degraded during transmission.

Research by AES (Audio Engineering Society) shows that the source determines up to 40% of the perceived sound quality, emphasizing the important role of the microphone and karaoke player in a home theater system.

Audio equipment

If the sound source is the raw material, then the audio equipment is the “kitchen” that prepares the dish. A basic karaoke system includes speakers, amplifiers (or power amplifiers + digital echo), mixers, and microphones. Proper equipment combination determines 70% of the overall sound quality.

• LoA: Power, sensitivity, frequency range must be compatible with the room area. For example: 300W speakers are suitable for rooms under 20 m², 500–600W speakers are suitable for rooms 25–30 m².
  
• Amplifier/digital reverb/power amplifier: Choose the power corresponding to the speaker. If the speaker is 300W, the amplifier should be ≥ 350W/channel to overload, sing for a long time without distortion. Modern digital echo lines such as E3 Audio S7, EUDAC KM600 3-level anti-feedback, helps vocals to be clear and microphone to sing softer.
  
• Mixer: Increased flexibility when connecting instruments or adjusting effect details.
  
• Microphone: Wireless microphone with anti-feedback, strong signal, durable battery is the optimal choice for family karaoke.

According to a survey by Phuc Truong Audio in 2024, 80% of customers who encountered howling and distorted sound were due to improperly matched equipment, not due to poor speaker or amplifier quality.

Listening environment

The listening environment – ​​the space of the singing room – has a huge impact on the experience. Even if the equipment is expensive, if the room is not treated well, the sound will still be reverberant, buzzing or harsh.

• Room not soundproofed: Sound reflected from walls, ceilings, and floors creates echoes, causing discomfort.
  
• Standard treatment room: Equip with sound-absorbing foam, thick curtains, floor carpets, or sound-absorbing wood to help moderate the reverberation (ideal reverberation time is about 0,5–1 second according to standard ISO 3382).
  
• Equipment layout: Place the speaker at the correct height (1,5–2 m), ≥ 30 cm from the wall to spread the sound evenly and avoid bass hum.

A study of Institute of Acoustics, UK (2018) shows that 60% of the music experience depends on the room space, only the remaining 40% comes from the equipment. This explains why the same set of speakers, but in the showroom sounds good, when you get home it is not as "happy".

Which unit specializes in installing reputable sound systems in HCM? 

If you are looking for a reputable sound system installation unit in Ho Chi Minh City, the answer is Phuc Truong AudioWith many years of experience in the field of karaoke sound, halls, stages and tea rooms, Phuc Truong Audio has become the first choice of thousands of customers. 

Our strengths are providing 100% genuine equipment, consulting on suitable solutions for each space, a team of professional technicians directly installing and adjusting, ensuring the system operates stably, with good sound - clear - no howling. 

Besides, Phuc Truong Audio We also commit to competitive prices, genuine warranty and dedicated after-sales service, helping customers feel absolutely secure when investing in a complete sound system.

Audio FAQ

1. How does sound frequency affect karaoke quality?

Frequency is the factor that determines whether the voice sounds deep or clear. For example, bass (20–200 Hz) creates a feeling of warmth and richness, while mid and high tones (500 Hz – 10 kHz) determine the brightness and clarity of the voice. A karaoke speaker with a wide frequency range will help the voice and background music to be reproduced in balance, without lacking the frequency range.
Read more: Technical specifications you need to know when buying cheap high quality karaoke speakers

2. Why do high-power karaoke speakers not necessarily sound good in small rooms?

Many people think that the higher the power, the better the sound, but in fact, it is not. If you use 500-600W speakers in a room of only 15-20m², the bass will be reflected and easily cause buzzing and ear-piercing. Therefore, the speaker power must be suitable for the area and properly calibrated.
See details: What is Speaker Power? Does the Higher the Power, the Better the Speaker?

3. Karaoke microphones often howl, what is the cause?

Howling usually occurs when the microphone picks up sound waves from the speaker, creating a feedback loop. In addition, placing the speaker too close to the microphone, or using a poor quality microphone, can also make this situation worse. An effective solution is to use digital echo with anti-feedback, or high-end wireless microphones with built-in noise filtering technology.
Refer: Experience in choosing anti-feedback microphone equipment for home karaoke systems

4. How does room reverberation affect the karaoke experience?

Reverberation is the sound that remains after the source has stopped. If there is too little reverberation, the voice will sound dry; on the contrary, too much reverberation will cause buzzing, mixed sounds, which is very unpleasant. In a family karaoke room, the ideal reverberation according to ISO 3382 standard is about 0,5–1 second. To achieve this, you should treat the acoustics with sound-absorbing foam, curtains, sound-absorbing wood or carpet.
See more: Professional karaoke room design standards

Contact now Phuc Truong Audio for quick consultation and installation!