Sound optimization starts with acoustic measurements. Even the best sound equipment won't reach its full potential if the room's acoustics aren't properly tuned. Here's what you need to know:
- Measurements: Frequency response, reverberation time (RT60) , room resonances , noise levels.
- Equipment: Calibrated microphone (from €80), audio interface (from €50), software ( Room EQ Wizard – free).
- Standards: LST EN ISO 16283-1:2014 ensures accuracy.
- Practical tips: Prepare the room properly (close windows, doors), place speakers, use acoustic panels and bass traps.
Accurate acoustic measurements allow you to not only solve problems , but also achieve the best sound quality in your home theater system . Below we will discuss how to do this step by step.
Preparing for Acoustic Measurements
In order to perform accurate acoustic measurements, proper preparation is necessary. Even the slightest inconsistencies in the room or equipment can distort the results and confuse further optimization steps. All measurements must be performed in accordance with the LST EN ISO 16283-1:2014 standard [2] .
Required Equipment for Measurements
Professional measurements require reliable and specialized equipment. AUTOGARSAS.LT offers everything you need, as well as advice on choosing the right equipment.
The main device is a calibrated microphone . It ensures accurate measurements because it has a known frequency response and high technical characteristics. Microphones such as the Behringer ECM8000 or Dayton Audio UMM-6 cost from 80 to 200 €, and their accuracy reaches ±1 dB.
In addition to a microphone, you need an audio interface that allows you to transmit the microphone signal to your computer. Popular models, such as the Focusrite Scarlett Solo or the PreSonus AudioBox USB 96 , cost €50–120 and provide high sound quality.
Finally, you need measurement software that helps you analyze the collected data. One of the most popular programs is REW (Room EQ Wizard) . It is free and allows you to analyze frequency response, room resonances, and reverberation time (RT60) [2] .
| Equipment | Price (EUR) | Advantages | Disadvantages |
|---|---|---|---|
| Calibrated microphone | 80–200 | Accurate measurements, versatility | Additional equipment required |
| Simple microphone | 20–50 | Cheaper, more accessible | Lower accuracy |
| Professional services | 300–800 | Highest accuracy, expert advice | Higher price, longer term |
In addition to the basic equipment, AUTOGARSAS.LT also offers additional accessories, such as microphone stands or calibration equipment. Regular calibration and maintenance of the equipment according to the manufacturers' recommendations helps maintain the reliability of the results.
Preparing the Room for Testing
Room preparation is no less important than the right equipment. In order to ensure accurate measurements, it is necessary to document the arrangement of furniture, carpets and curtains. This makes it easier to recreate the same conditions during each measurement session. AUTOGARSAS.LT specialists recommend taking photos of the room layout before each test.
Windows and doors should be closed to prevent outside noise from affecting the measurements. The listening position should also be selected based on the size of the room and the placement of the speakers to achieve a natural sound field.
In addition, attention should be paid to environmental conditions - temperature (18–24 °C) and humidity (40–60%) can affect the accuracy of the results.
Preparation of acoustic measurement documents in Lithuania usually takes 5–10 working days. Therefore, careful preparation not only saves time, but also ensures high-quality results. Such a responsible approach is necessary in order to optimize sound, for example, in home cinema systems.
Performing Acoustic Measurements
Once the preparatory work is complete, we move on to the crucial stage – the acoustic measurements themselves. This process is extremely important, as accurate results depend on properly performed actions.
Equipment Connection and Calibration
First, connect your microphone to your audio interface using a balanced XLR cable to ensure a clean signal. Then, connect your audio interface to your computer using a USB or Thunderbolt cable.
AUTOGARSAS.LT experts often choose Swiss NTI equipment, known for its high accuracy [3] . However, simpler equipment can also be used at home, such as Focusrite Scarlett series audio interfaces.
Load a microphone calibration file into the REW program (Preferences → Mic/Meter → Calibration file) to compensate for frequency response inaccuracies.
It is very important to set the input gain of your audio interface correctly. If the gain is too high, the signal will be distorted, and if it is too low, the measurement accuracy will decrease. Make sure that the level indicator does not go beyond the red zone.
You can check the calibration by playing a 1 kHz reference tone and observing whether the program's readings match the actual volume level. Professionals use calibrated sound level meters for this.
Once everything is ready, you can start generating test signals and taking measurements.
Taking Measurements
Measurements begin with the generation of test signals . REW software typically uses sine sweeps or pulsed signals. These signals allow the analysis of the room response over the entire frequency range, from 20 Hz to 20 kHz [3] .
It is important that the test signals are played at a moderate volume – 75–85 dB SPL . This helps to reduce the influence of background noise, but does not pose the risk of nonlinear distortion or dissatisfaction with neighbors.
Place the microphone at the main listening point , where the listener is most likely to be. The microphone should be at least 1 meter away from the walls and at a height of about ear level, about 1.2 meters from the floor.
Record the impulse response to analyze RT60, reflections, and room resonances [2] .
It is recommended to measure at multiple locations (5-9 points) covering the entire listening area. This will help optimize the sound quality not just for one location, but for the entire room [3] .
Don't forget to save your measurements with clear names, for example "Measurement_01_Center_2025-10-25". This will be very useful when analyzing and comparing results later.
Also, ensure that the microphone is not too close to reflective surfaces, as this can distort the measurement results [3] .
All measurements performed in Lithuania must comply with the LST EN ISO 16283-1:2014 standard. This standard defines uniform measurement methods and data interpretation rules [2] . This is especially important if the measurement results will be used for professional projects or certification.
Reading and understanding measurement data
Before you start optimizing your sound, it's essential to properly analyze your measurement data. This helps you pinpoint sound issues and find solutions that will improve the performance of your home theater system. By understanding the results, you can make informed decisions and achieve better sound quality.
Frequency response and RT60 readings
The frequency response graph shows how frequencies are reproduced (20 Hz–20 kHz). It allows you to notice sharp peaks that indicate frequencies that are reproduced too strongly, and dips that signal weak reproduction. This data is the basis for further adjustment.
The RT60 measurement indicates how long it takes for the sound to drop by 60 dB after the signal has been interrupted. [2] [3] The ideal RT60 time creates a natural sound balance, avoiding echo or overly dry acoustics. It is important to observe how the RT60 changes between different frequencies, as this can help identify specific acoustic challenges that require targeted solutions.
Room resonances and reflections
Room resonances are calculated using the formula f = 172 / L , where L is the length of the room in meters. In measurement graphs, resonances usually appear as sharp peaks or deep slopes that need to be corrected to achieve a balanced sound.
Early reflections are visible in the impulse response graph as distinct "spikes" after the main signal. They, especially from side walls or ceilings, can distort the stereo image and reduce the overall sound quality. It is also worth paying attention to periodic reflections (flutter echo), which affect stereo accuracy.
AUTOGARSAS.LT experts emphasize that special attention should be paid to the mid-frequency range (approximately 200–2000 Hz). This range is where essential elements of speech and music are formed, so their correct analysis can significantly improve the listening experience.
All measurements and their interpretation must comply with the LST EN ISO 16283-1:2014 standard. This ensures that the analysis is carried out in accordance with international acoustic measurement requirements [2] . These results provide the basis for further sound optimization, which we will discuss in the next section.
Sound improvement based on measurements
After analyzing the collected data, the next step is to optimize the sound based on the results of the measurements. This process involves a systematic approach, from speaker placement changes to digital equalization adjustments . After each step, it is important to perform control measurements to assess the impact of the changes.
Adjusting speaker placement and settings
Changing the position of your speakers is often one of the easiest and most effective ways to improve sound quality. If your measurements show significant frequency deviations or peaks, it may be a sign that your speakers are not properly positioned in the room.
Subwoofer phase correction becomes particularly important when the measurement graph shows a dip around 80 Hz. Phase inversion can help eliminate this deficiency and improve bass reproduction. Most modern amplifiers have a phase correction function that allows you to fine-tune the settings according to the measurements.
Setting the crossover frequency is another critical step. This setting ensures a smooth transition between the main speakers and the subwoofer. While a crossover frequency of 80 Hz is commonly recommended, your system measurements may indicate that 60 Hz or 100 Hz is more appropriate. A properly tuned crossover helps achieve a smoother, more balanced sound.
"They sincerely advised how and what wires to run, where and what speakers to place or connect. They put everything together on the project, and later installed the equipment. A true team of professionals!!!" – Daiva, AUTOGARSAS.LT client [1] .
Once you've made all the physical adjustments, it's time to move on to digital equalization, a tool that allows you to precisely balance frequencies.
Using digital equalization
Parametric equalization allows you to precisely adjust specific frequency ranges that show problematic deviations in measurements. It is important to focus only on the most pronounced deviations exceeding ±3 dB. Smaller deviations are often natural and adjusting them can reduce the naturalness of the sound.
The choice of Q factor is also very important. If you see a narrow peak, for example at 125 Hz, use a higher Q (10-15) to correct only that specific range. For wider deviations, a lower Q (2-5) is better, which covers a wider frequency range.
Adjusting gradually is a good rule of thumb. Instead of making drastic changes, it's better to lower the problematic frequency by 3 dB and re-measure. Making too much change can cause distortion and degrade the overall sound quality.
Frequency gain limitations – experts advise avoiding gain of more than 6 dB. If necessary, it is better to reduce other frequencies or improve the speaker position. Too much gain requires more power and can strain the speakers.
"Our goal is not just to sell equipment, but to help the customer create a sound that inspires every day" - AUTOGARSAS.LT team [1] .
It is recommended to perform the adjustment process in stages: first focus on the low frequencies (20-200 Hz), then move on to the mid-range (200-2000 Hz), and finally to the high frequencies (2000-20000 Hz). After each change, perform a control measurement to ensure that the corrections have been effective and the system is operating optimally.
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Implementation of acoustic solutions
After digital equalization, it is worth taking physical measures that will further improve the sound quality. Such solutions not only enhance the sound, but also create a comfortable listening environment, adapted to the settings already made.
Installation of acoustic panels and bass traps
Based on previous measurements, acoustic panels (500–5000 Hz) reduce reverberation, bass traps (50–200 Hz) regulate low frequencies, and diffusers (1000–4000 Hz) help disperse sound. It is recommended to cover 15–25% of the wall area, depending on the size of the room and the desired acoustic parameters [4] . Studies show that properly installed panels can reduce reverberation time (RT60) by up to 40–60% [4] .
It is best to install the panels at the points of first reflection - on the side walls, approximately half the distance between the speaker and the listener. If measurements show reverberation at high frequencies, it is also useful to install the panels in the ceiling.
Bass traps work best in the corners of a room, as this is where low frequencies tend to accumulate. It is recommended that the diffuser be mounted on the back wall behind the main listening position to allow the sound to spread naturally and create a sense of space.
| Measure | Frequency range | Main function | Installation location |
|---|---|---|---|
| Acoustic panels | 500-5000Hz | Reverb reduction | Walls, ceilings |
| Bass traps | 50-200Hz | Bass control | Room corners |
| Diffusers | 1000-4000Hz | Sound dispersion | Back wall, ceiling |
"Professional advice and impeccably done work! Recommended to improve the soundproofing (the result was particularly impressive), audio equipment, and rear camera. Super good and strong sound!" – Emilis S., Review from Google
When installing these devices, it is important to take into account the specifics of Lithuanian residential premises. For example, most apartments and houses have ceilings of 2.5–3.0 m high, so the installation height of bass traps should be adapted to these conditions. In addition, radiators or other elements may limit the possibilities of installing panels on the side walls.
After completing the installation, it is necessary to check how these solutions affected the sound quality.
Verifying improvements with repeated measurements
To ensure that the solutions you have implemented have achieved their intended purpose, repeat measurements should be performed. Use the same primary listening position and the same tools – a calibrated USB microphone, an audio interface and the Room EQ Wizard (REW) software.
Compare the new results with the original measurements and note:
- Balanced frequency response changes, reduced peaks and slopes
- Shortened RT60 duration indicating better sound control
- Balanced low frequencies (80 Hz, 125 Hz), reduced problematic peaks
If the results do not meet expectations, additional solutions may be needed, such as rearranging the acoustic panels or adding additional elements. AUTOGARSAS.LT specialists can help assess the situation and offer solutions that allow for even better results.
Acoustic solutions should work in conjunction with properly positioned speakers and finely tuned equalization settings to ensure the highest sound quality.
Final checks and best practices
Checking optimization results
Once the optimization is complete, it is necessary to perform final checks. This ensures that all changes work as intended. Use the REW program and a calibrated USB microphone to compare the new measurements with the original ones.
It is important to take measurements not only at the main listening position, but also at several other locations in the room. This will help to verify that the sound quality is consistent throughout the listening area. Pay particular attention to bass balance and reverberation time ( RT60 ) to ensure that these parameters meet the optimization goals.
Please note the following aspects:
- Frequency response stability – are there no pronounced peaks or dips;
- RT60 duration – whether the reverberation control has reached the desired level;
- Bass control – makes sure bass frequencies are not too concentrated in the corners.
If you notice discrepancies, you may need to make minor adjustments, such as slightly adjusting the speaker position or adjusting the equalization settings.
Maintaining sound quality over the long term
To maintain high sound quality, it is necessary to adapt to environmental changes. Acoustic parameters can change due to temperature and humidity fluctuations, which affect air density and sound propagation. In Lithuania, where the seasons vary greatly, it is recommended to check the system at least once a year.
Watch for the following signs that indicate the need for repeat measurements:
- The sound has become too "bottom-up" or too sharp;
- An unusual echo appeared;
- Bass frequencies sound unnaturally strong or weak;
- There are noticeable changes in quality when changing the sound level.
Save your REW files and equalization settings – this will allow you to quickly restore optimal settings if necessary. It is also worth documenting the acoustic solution diagrams to make it easier to track changes in the future.
If you notice that the sound quality has deteriorated, or you are planning to change the layout of the room, furniture or equipment, contact AUTOGARSAS.LT specialists. They can perform a professional system assessment and provide solutions that help maintain excellent sound quality.
"Our goal is not just to sell equipment, but to help the customer create a sound that inspires every day." – AUTOGARSAS.LT [1]
Regular maintenance and inspections are essential if you want to ensure that your system works flawlessly for many years. A professional approach allows you to avoid costly mistakes and maintain the best possible result.
Conclusions
Acoustic measurements are an indispensable tool for achieving the highest sound quality in your home theater. They allow you to objectively assess the acoustics of a room and determine exactly what actions are needed to optimize the sound. Subjective listening alone would not achieve such a result.
The entire process, from equipment preparation to final testing, helps reveal areas that need improvement. This includes frequency response analysis, RT60 measurements, and room mode identification. This data allows for precise adjustments to the sound parameters using digital equalization, proper speaker placement, and other acoustic solutions based on the results of the measurements.
In Lithuania, acoustic measurements are carried out in accordance with recognized standards. In residential premises, the recommended reverberation time is between 0.3 and 0.6 seconds [4] . This interval helps ensure excellent speech intelligibility and sound detail, which is especially important for home theater systems .
It is important to remember that acoustic optimization is not a one-time job. It is a long-term process that requires periodic checks. Changes in temperature and humidity can affect sound quality, so regular measurements are essential to maintain the best results.
AUTOGARSAS.LT specialists, based on this data, can offer solutions that best meet your needs. We offer high-quality equipment, consultations and optimization services tailored to the characteristics of your premises and local standards.
If you want to ensure professional sound in your home theater system, acoustic measurements are essential. Visit the AUTOGARSAS.LT store in Kaunas or contact our experts - we will help you achieve the best results in your space.
FAQs
How often should acoustic measurements be performed to ensure the best sound quality?
Acoustic measurements are worth performing whenever there are significant changes to your space. This could be rearranging furniture, purchasing new audio equipment, or renovating the interior of the room. Such changes can affect sound propagation and its overall quality, so it is important to assess how they have affected the acoustic environment.
If your sound system is operating stably and the room environment remains unchanged, periodic measurements – for example, once a year – can help maintain optimal sound quality. To achieve the most accurate results, it is worth using professional equipment or contacting specialists, such as AUTOGARSAS.LT , who ensure high-quality and precise work.
What is the difference between acoustic panels and bass traps, and how do you choose the right solution for your room?
Acoustic panels and bass traps serve different functions, but both are designed to improve the acoustic environment of a room. Acoustic panels help absorb mid- and high-frequency sounds, reducing echoes and reflections, which results in clearer and cleaner sound. Bass traps, on the other hand, are specifically designed to control low frequencies. They absorb low-frequency waves, especially those that tend to accumulate in the corners of a room, thus eliminating the problem of excess “bass”.
To choose the right solution, it is necessary to take into account the size, shape and existing acoustic problems of the room. In smaller spaces, acoustic panels are usually sufficient, but in larger rooms or when facing significant low frequency problems, it is worth considering the installation of bass traps. If you are not sure what solution you need, AUTOGARSAS.LT specialists are ready to help - they will assess your needs and offer the optimal solution so that the sound in your room sounds perfect.
Is it possible to achieve high-quality audio optimization using only free software like REW, or is professional help required?
Yes, free software such as REW (Room EQ Wizard) can be very useful for measuring room acoustics and improving sound quality. It allows you to analyze acoustics, identify problems such as reverberation or frequency distortion, and make adjustments to sound settings.
However, professional help has its advantages. Specialists not only have more experience, but also use advanced equipment, allowing them to offer individually tailored solutions that ensure the best result. If your goal is impeccable sound quality, it is worth contacting experts, for example, the AUTOGARSAS.LT team, who will help you implement your project from start to finish.
