Howling microphones and speakers are common in family karaoke, conferences or stage performances. Howling is not only annoying but also reduces vocal quality, making the music experience less comfortable. The cause may come from the location of the microphone - speaker, incorrect amplifier adjustment, the room has not been soundproofed, or simply the equipment is not compatible.

According to Phuc Truong Audio's survey of 500 karaoke systems in Ho Chi Minh City (2024), 87% of howling cases come from basic causes that can be completely fixed.

The following article from Phuc Truong Audio will analyze the main causes of howling and 6 effective treatment methods from speaker arrangement, sound absorption treatment, microphone cleaning to how to hold the microphone and choose the right equipment. At the same time, we also guide 6 detailed steps to adjust the amplifier and digital echo to completely eliminate howling. Let's take a look.

Why do microphones and speakers howl? 

According to Phuc Truong Audio's experience, microphones and speakers howl due to 7 main technical reasons: incorrect placement (45%), resonance space (20%), dirty microphone (10%), incorrect holding (8%), weak equipment (7%), overloaded amplifier (5%) and incorrect adjustment (5%). Below is a detailed analysis of each cause.

Microphones placed too close or pointed directly at the speaker cause continuous feedback.

This is the number one cause of microphone feedback. When you place the microphone in front of the speaker, the sound coming from the speaker is picked up by the microphone, amplified and then played back. This loop continues, the sound is resonated exponentially and produces a piercing howling sound.

The most obvious example is in home karaoke: if the singer stands right in front of the speaker (under 1,5 meters) or holds the microphone towards the speaker, a hissing sound will immediately be heard. This is a very common cause but can be completely limited by arranging the speaker properly and keeping the microphone in a safe position.

Room space and sound resonance causing microphone echo and howling

Sound not only depends on the equipment but also on the space. In singing rooms that have not been soundproofed, there are many reflective surfaces such as ceramic tiles, glass, smooth walls, etc., so the sound is easily reflected and resonated. When the resonant frequency coincides with the microphone's frequency, it will create a long-lasting howling sound.

This is the reason why professional karaoke rooms or recording studios must be acoustically treated with sound-absorbing foam, sound-absorbing wood or thick curtains to limit the resonance phenomenon that causes microphone howling.

Microphone vent is clogged due to dirt, sweat or moisture over time

Inside the microphone, behind the diaphragm, there are vent holes used to equalize pressure. When the microphone is used for a long time without cleaning, dirt and sweat will stick to and clog these holes. At that time, air cannot circulate, creating internal resonance in the microphone, causing sound distortion and howling.

Incorrect way of holding and using the microphone leads to frequent howling.

Many people when singing karaoke or performing often make the mistake of holding the microphone incorrectly. For example:

• Hold the microphone so that it covers the receiver (for wireless microphones).
• Holding the microphone too close to your mouth causes the volume to be too loud.
• Turn the microphone directly towards the speaker, accidentally creating feedback.

These are seemingly small errors but are major causes of microphone howling. 

Weak microphone power, not compatible with sound system causing howling and distortion

Some cheap microphones or those that are not compatible with the amplifier/speaker in the system are prone to underpowering. The signal is distorted, exceeding the headroom and leading to clipping. The sound is not only distorted but also prone to howling when the volume is increased.

Weak or overloaded amplifiers make the system easily howl when operating.

Not only microphones, amplifiers are also an important cause of speaker howling. If the amplifier does not have enough power to pull the speaker, the output signal will be weak, the sound will be unclear, distorted and howling will easily appear when increasing the volume.

In addition, if the amplifier is overloaded for a long time, the components will heat up, making the signal unstable, making the system more prone to howling.

Adjusting the amplifier, digital echo or mixer incorrectly can cause the microphone to howl.

The way the amplifier and digital echo are adjusted directly affects the howling condition. Some common adjustment errors are:

• To Mic Volume, Echo, Treble too high
• Unbalanced frequency range, making the microphone too sensitive in some ranges.
• Using old karaoke amplifier without automatic anti-howling function.

If not properly adjusted, the microphone will easily howl, especially in small or crowded spaces. 

How to adjust the microphone to avoid howling in detail from A to Z

After understanding the 7 causes, below are the 6 most effective methods to handle howling noise, applicable to all systems from home to professional.

Place the microphone and speaker properly to minimize audio loops.

You need to rearrange the system: the speakers should be placed above the singer’s head, facing out at the audience instead of facing the microphone. For the monitor speakers, place them at a 45–60° angle from the singer so that they can still be heard clearly but do not cause feedback. In addition, the minimum safe distance between the microphone and the speakers is 2–3 meters, which helps to minimize the possibility of howling.

At Phuc Truong Audio, the team of technicians always advises and supports setting up sound systems according to technical standards, ensuring the microphone sings well, does not howl, and brings a smooth karaoke experience for both families and businesses.

Soundproofing the karaoke room to avoid resonance and echo

You can use sound-absorbing foam, soundproof foam to stick on the walls and corners of the room to reduce echoes. In addition, hanging thick fabric curtains, carpeting or arranging wooden furniture will also help absorb sound better. 

For tea rooms or business karaoke rooms, investing in specialized sound-absorbing walls will bring clear results, both reducing microphone howling and improving overall music quality.

Clean and check the microphone vent to keep the sound clean.

You should periodically clean the microphone with a soft dry cloth, clean the filter head and check the vent. If the microphone has not been maintained for a long time, bring it to a technician to disassemble and check the inside. In addition, when choosing to buy a microphone, you should prioritize genuine products, durable design and good dust resistance, to limit the situation of clogged vents in the long run.

Hold and use the microphone properly to reduce howling when singing karaoke

Keep the microphone 5–10 cm away from your mouth to ensure clear vocals and minimize wind noise. 

With a wireless microphone, never cover the antenna with your hand as this will weaken the signal. When singing, hold the microphone slightly to one side and avoid pointing it directly at the speaker. This is a simple habit but it will significantly improve the sound quality and reduce howling.

Choose the right microphone and power amplifier to avoid distortion and howling.

You need to ensure synchronization: choose a microphone with good sensitivity, an amplifier with a capacity compatible with the speaker. For large systems or business karaoke rooms, you should add a power amplifier to support the amplifier. In addition, you can equip a frequency shifter or phase regulator to stabilize the signal and reduce frequency conflicts that cause howling.

Adjust the amplifier, digital echo or mixer properly to eliminate howling.

At Phuc Truong Audio, when customers buy amplifiers or digital echoes, the team of technicians will guide them in detail on how to calibrate properly, helping the microphone operate stably and minimizing howling. The basic solution is to reduce Mic Volume and Echo to a moderate level, keeping Treble, Mid, and Bass balanced. 

For professional systems, you should use a digital echo or digital mixer with an integrated automatic feedback suppressor. If you are still using an old karaoke amplifier, consider upgrading to a new digital amplifier to both sing better and limit howling.

Tips for adjusting your sound system to fix microphone feedback

Below are 6 steps to adjust the sound system to fix howling microphones, applicable for family karaoke, tea rooms or business karaoke rooms.

Step 1: Plug the microphone into the correct position and reduce the background music volume to the lowest level.

The first step is to check the microphone connection. The microphone must be plugged into the correct port on the amplifier or digital echo. If the port is wrong or the jack is loose, the signal will be unstable and easily create howling. After making sure the microphone is properly connected, reduce the Music volume to the lowest level.

Reason: When adjusting the microphone, if the background music is too loud, it will cover up the vocals, making it difficult to tell if the microphone is really howling or if it is the music. Reducing the music to 0 will help you focus on handling the microphone first, then gradually adjust the music later.

Step 2: Bring the total volume and potentiometers to the middle position to create balance.

In this step, you need to adjust the Master Volume, along with the basic potentiometers such as Mic Volume, Echo, Balance, Mid to the middle position (average level). This is considered the "balanced starting point".

When all potentiometers are brought to this level, you can easily adjust up/down gradually according to your needs, instead of adjusting randomly, causing the system to deviate from a certain frequency range, causing howling. This is a basic principle but many people ignore it.

Step 3: Test the microphone sound and adjust the Echo to suit the room space

After adjusting the potentiometers to the balance level, turn on the system and try speaking or singing with the microphone. At this time, pay special attention to the Echo, Rpt (Repeat), and Dly (Delay) buttons. This is a group of echo effects that largely determines whether the microphone will howl or not.

• If Echo is too loud: The voice will reverberate many times, easily resonate → howling.
• If Delay is too short: The voice will repeat thick and screechy.
• If Repeat too much: overlapping echoes, the microphone picks up the echo itself → howling.

How to handle: from the middle position, gently turn Echo/Rpt/Dly to the left or right about 10–15°. Continue testing until you achieve a moderate level of resonance: the voice is thick but not too echoey, not creating a howling feeling.

Step 4: Adjust Bass - Mid - Treble according to voice quality to avoid howling

Not everyone has the same voice, so the way you adjust the microphone should also depend on your voice quality:

• People with low, bass-heavy voices should reduce bass (turn left 10–90°) so that the voice does not sound muffled.
• People with high voices, leaning towards Treble: should reduce Mid or Treble (Hi) by 10–45° to reduce harshness.
• Medium voice: just keep it balanced, don't overdo it with the max boost.

Note: If Treble (Hi) and Mid are adjusted too high, the microphone will be abnormally sensitive in the high range → prone to howling. Therefore, the principle is to adjust so that the vocals sound natural, clear, not too bass-heavy or too treble-heavy.

Step 5: Gradually increase the music volume, balancing with the adjusted microphone sound

Once the microphone is stable, you can start increasing the Music Volume. Increase the music gradually, so that the music and the vocals are in harmony, but absolutely do not let the music overwhelm the microphone. 

In case you are not familiar with the operation, Phuc Truong Audio technicians are always ready to support on-site calibration, ensuring the sound system operates stably and without howling. 

If howling occurs while increasing the music, immediately reduce the Treble (Hi) in the Master Volume section from 10–90° to the left. This is the fastest way to handle it, helping the music not to “override” the microphone, and at the same time reduce the resonance that causes howling.

Step 6: Control the Hi frequency of the microphone and Echo at a safe level

This is the “key” step to prevent feedback. Normally, the Hi frequency of the microphone and Echo, if set beyond the average position, will cause the voice to be shrill and howling. Check again, gradually move the Hi to the left until the feedback stops.

The amount of rotation depends on the room and system, and can be anywhere from 10–90°. The goal is to keep vocals clear, not boomy, but not howling at high volumes.

Which unit provides, maintains and repairs karaoke systems with prestige and professionalism in HCM?

In Ho Chi Minh City, Phuc Truong Audio is a leading prestigious unit specializing in providing, maintaining and repairing karaoke systems for families and businesses. With many years of experience, a team of highly skilled technicians and on-site installation and calibration services, we are committed to providing 100% genuine sound systems, diverse from speakers, amplifiers, digital echo, microphones to accessories, accompanied by a long-term warranty and after-sales policy. 

Customers coming to Phuc Truong Audio are always advised to choose the optimal configuration according to the space, ensuring good singing, no howling, durable operation, worthy of being the trusted choice of thousands of families, tea rooms and karaoke bars in HCM.

Frequently asked questions about karaoke microphones and speakers 

I want to replace the microphone and karaoke speakers. Can I exchange the old for a new one at Phuc Truong Audio?

Yes. Phuc Truong Audio have a program Trade in old for new karaoke system, helping you save costs when upgrading equipment. You can change karaoke speakers, karaoke microphones or the entire system. karaoke system to experience the new, more modern system.

I want to buy a good anti-howling karaoke microphone, which one should I choose?

You can refer to the samples wireless karaoke microphone anti-howling or wired microphone for tea room is very popular now. 

Is regular karaoke system maintenance important?

Yes. Regular maintenance helps the device operate durably and limits damage. During maintenance, the technician will clean the microphone, check the amplifier, retest the speakers and adjust the digital echo. You can refer to the article for more information. Tips for maintaining karaoke systems to always sing well on Phuc Truong Audio blog.

Besides repair, does Phuc Truong Audio provide separate karaoke equipment?

Yes. You can purchase each device individually as karaoke speakers genuine, karaoke amplifier, digital echo Anti-feedback, wireless or wired microphone. All are 100% new, fully warranted and consulted to choose the right one for the space.

To own a karaoke system that sings well, does not howl, has genuine equipment and is calibrated to technical standards, come to Phuc Truong Audio to experience and get direct advice.