The café had an acoustic issue where sound reflections were building up inside the room. In simple terms, the space had too much sound bouncing around, especially in certain frequency areas. This can make a café feel noisy, uncomfortable, and tiring, especially when people are talking, music is playing, or the sound system is in use.

The main concern was not just volume, but how long the sound remained in the room after it was produced.

Gelombang Audio measured the room using acoustic measurement tools and software. The main parameters assessed were:

• Reverberation Time, also known as RT60
• Frequency response
• Sound behaviour across several listening positions inside the café

Measurements were taken at four areas: the corner left, the centre front, the corner right, and the centre middle near the sliding door entrance. The assessment showed that several low-to-mid frequency bands below 1 kHz had decay times exceeding 1 second. This indicates that sound energy in these frequency ranges remained in the room longer than desired, contributing to a build-up of reverberant energy, reduced speech clarity, and a higher perceived noise level inside the café

The high-frequency range was also observed, with decay time reaching around 2.0 to 2.2 seconds before treatment. This indicated that acoustic absorption was required to reduce excessive reflection and improve room control.

Based on the measurement result, the direction was to use acoustic treatment panels to reduce sound energy, control reflections, and improve decay time across the room.

The recommendation was not to simply add more materials blindly, but to treat the room based on measured acoustic behaviour. After the result, bass traps were not recommended because the lower frequency decay was already within an acceptable range after treatment, and the café did not use a subwoofer setup.

The next recommended step was to configure and calibrate the venue loudspeakers so the sound system could perform properly within the improved room conditions.

Gelombang Audio carried out acoustic measurement and verification before and after the acoustic treatment installation. The service included:

• Room acoustic measurement
• RT60 assessment
• Frequency response assessment
• Multi-point measurement inside the café
• Analysis of room behaviour before treatment
• Post-installation measurement after the acoustic panels were installed
• Practical recommendation for the next stage of loudspeaker configuration

Measurement tools included REW acoustic measurement software, a dbx RTA-M measurement microphone, and a Focusrite Solo audio interface.

After the acoustic panels were installed, the café showed a significant improvement in acoustic control.

The target reverberation time was around 1.1 seconds, and the longest decay point after treatment was around 1.2 seconds. The high-frequency decay also improved significantly, reducing from around 2.2 seconds to approximately 780 ms to 600 ms.

In practical terms, the room became more controlled, less echoey, and more suitable for a restaurant or meeting venue environment. The treated space was no longer expected to create major issues related to excessive noise build-up or uncomfortable echo. The remaining improvement would depend on proper loudspeaker configuration and calibration.

Based on typical setups found in many surau and masjid, the system usually has these problems:

1. Mixed and non-standard equipment Different amplifiers, mixers, microphones, and wireless systems are added over time without proper system planning.
2. Low-quality or imitation products Some products may look like professional equipment, but the internal quality, RF stability, output reliability, and protection circuit may not be suitable for daily mosque use.
3. Amplifier load not properly calculated More speakers are added without checking the actual amplifier capacity, speaker line load, impedance, or 100V line calculation. Over time, the amplifier works beyond its safe operating range.
4. Frequent microphone feedback Feedback is usually caused by poor speaker placement, excessive microphone gain, poor EQ control, reflective room surfaces, and unstable wireless microphones. A 100V/high-impedance system itself is not the main cause of feedback, but poor system design and wrong loading can make the system harder to control.
5. Poor coverage Some areas are too loud, some areas cannot hear clearly. This usually happens when speaker placement is based on convenience, not coverage design.
6. Improper mixer and effect setting Excessive reverb, wrong EQ, high gain, and uncontrolled microphone channels make speech unclear.
7. No proper commissioning The system is installed, switched on, and left as it is. There is no tuning, no measurement, no documentation, and no proper handover setting.

The main problem is not only that the equipment is cheap. The bigger problem is that the system was never treated as a complete audio system.

A proper surau or masjid audio system should consider:

• Room size and shape
• Ceiling height
• Speaker coverage angle
• Microphone position
• Imam and Bilal usage
• Indoor and outdoor zone requirements
• Amplifier loading
• Cable routing and termination
• Speech clarity
• Feedback control
• Long-term maintenance

Without these considerations, the system will continue to face the same issues even if the committee keeps replacing amplifiers or microphones.

This is why many surau and masjid keep spending money, but the problem never really goes away.

At Gelombang Audio, we do not approach mosque audio by simply asking: “What speaker do you want to buy?”

We start with a better question: “What problem must the system solve, and what level of performance must the jemaah receive?”

For worship spaces, the objective is clear:

• The imam’s voice must be natural and clear.
• The khutbah must be intelligible.
• The bilal and announcer must be heard without shouting.
• The system must be stable without constant feedback.
• The coverage must be even across the prayer area.
• The equipment must be reliable for daily use.
• The committee must understand how to operate the system correctly.

This distinction highlights the difference between merely purchasing audio gear and making an investment in a thoughtfully engineered audio system.

Before recommending any equipment, Gelombang Audio carries out a structured assessment.

1. Existing System Inspection

This helps us identify whether the problem comes from equipment failure, wrong setup, poor design, or operational misuse.

2. Load & Amplifier Capacity Review: For 100V line or distributed speaker systems, we calculate the total speaker load against the amplifier capacity. This is important because many systems fail when additional speakers are added without recalculating the load.

3. Microphone & Feedback Analysis: We identify why the microphone feeds back. Feedback is not solved by simply changing the microphone. It must be solved through gain structure, speaker placement, EQ control, and system tuning.

4. Coverage Review: We review whether the speaker system covers the prayer area properly. A good system should not be loud only at the front and weak at the back. It should deliver clear speech evenly across the space.

5. Operation & User Behaviour Review: Many mosque audio problems happen because the system is too complicated or poorly labelled. A good mosque system must be easy to operate but professionally controlled.

Our recommendation is not always to replace everything immediately.

We normally propose a practical, staged approach.

Option 1: System Recovery & Stabilisation

Suitable when the existing system can still be improved. This option helps reduce common problems without a full replacement.

Option 2: Proper System Upgrade

Suitable when the existing system is too unstable or underpowered. This option gives the surau or masjid a more stable and professional system.

Option 3: Full Audio System Redesign

Suitable for masjid, main halls, multipurpose spaces, or venues with serious recurring complaints. This is the most complete and long-term solution.

Gelombang Audio uses a consultant-driven and engineering-driven approach.

• Step 1: Site Visit & Problem Discovery
• Step 2: Technical Inspection
• Step 3: Design Direction
• Step 4: Professional Installation or Rectification
• Step 5: Commissioning & Tuning
• Step 6: Handover & User Training