If you are looking for a pair of headphones that can deliver a clear and balanced sound, you might want to pay attention to their mid frequency response accuracy. This is a measure of how well the headphones reproduce the mid-range frequencies, which are crucial for vocals, instruments, and harmonics.
In this article, we will explain what mid frequency response accuracy is, why it matters for headphones, and how we measure it. We will also show you how we score headphones based on their mid frequency response accuracy, using a scale from 1 to 10. Finally, we will describe how we test headphones for mid frequency response accuracy, including the steps we follow and the challenges we face.
What is Mid Frequency Response Accuracy?
Mid frequency response accuracy is the degree to which the headphones reproduce the mid-range frequencies without distortion or deviation from the original sound source. The mid-range frequencies are typically defined as the range from 250 Hz to 4 kHz, and they contain most of the information that makes up the sound quality of audio content. For example, human voices, guitars, pianos, and most other instruments have their fundamental frequencies and harmonics in the mid-range. Therefore, having accurate mid frequency reproduction is essential for clarity, comprehensibility, and naturalness of sound.
The mid frequency response accuracy of headphones can be measured by comparing their frequency response curve with a reference or target curve. A frequency response curve is a graph that shows how the headphones respond to different frequencies, from low to high. A reference or target curve is a graph that shows how an ideal pair of headphones should respond to different frequencies, based on a certain sound profile or preference. The closer the frequency response curve of the headphones is to the target curve, the more accurate their mid frequency response is.
Why is Mid Frequency Response Accuracy Important?
Mid frequency response accuracy is important because it affects the sound quality of different types of audio content, such as music, podcasts, audiobooks, movies, etc. Depending on your personal preference and listening habits, you may want to have more or less emphasis on certain mid-range frequencies. For example, if you listen to a lot of music genres that feature vocals and acoustic instruments, such as pop, rock, folk, jazz, etc., you may want to have a neutral or slightly boosted mid-range to bring out the details and nuances of these sounds. On the other hand, if you listen to a lot of podcasts or audiobooks that mainly consist of spoken words, you may want to have a slightly cut mid-range to reduce the nasal or muddy sound that some voices may have.
Having accurate mid frequency reproduction also helps you enjoy a more realistic and immersive sound experience. For example, if you watch movies or play video games with headphones, having accurate mid frequency reproduction can help you hear the dialogues clearly and locate the sound sources accurately in the virtual space. Moreover, having accurate mid frequency reproduction can also enhance your emotional connection with the audio content. For example, if you listen to music with headphones, having accurate mid frequency reproduction can help you feel the emotions and expressions of the singers and musicians more vividly.
How to Measure Mid Frequency Response Accuracy?
To measure the mid frequency response accuracy of headphones, we use a combination of tools and methods that allow us to capture and analyze the sound output of the headphones across different frequencies. Here are some of the tools and methods we use:
Frequency response graphs: These are graphs that show how the headphones respond to different frequencies, from low to high. We use a software called REW (Room EQ Wizard) to generate these graphs based on the measurements we take with a microphone.
Standard error: This is a statistical measure that quantifies how much the frequency response curve of the headphones deviates from the target curve. The lower the standard error value, the more accurate the mid frequency response is. We use an Excel formula to calculate this value based on the data points from the frequency response graphs.
Target curves: These are graphs that show how an ideal pair of headphones should respond to different frequencies, based on a certain sound profile or preference. We use different target curves for different types of headphones and sound profiles. For example, we use the Harman target curve for over-ear and on-ear headphones with a neutral sound profile, and we use the Diffuse Field target curve for in-ear monitors with a bright sound profile.
How We Score Headphones for Mid Frequency Response Accuracy
Based on our measurements and analysis of the mid frequency response accuracy of headphones, we assign them a score from 1 to 10. The score reflects how well the headphones reproduce the mid-range frequencies without distortion or deviation from the original sound source. Here are some of the criteria we use to determine the score:
What are the Criteria for a Good Score?
A good score for mid frequency response accuracy means that the headphones have:
Low standard error: This means that the frequency response curve of the headphones is close to the target curve, indicating that the headphones reproduce the mid-range frequencies accurately. We consider a standard error value of less than 1 dB to be excellent, and a value of less than 2 dB to be good.
Balanced tonal balance: This means that the headphones have a balanced and natural sound across the mid-range frequencies, without over or under-emphasizing any particular frequency. We consider a tonal balance that matches the target curve to be ideal, and a tonal balance that deviates slightly from the target curve to be acceptable.
Consistent performance: This means that the headphones perform consistently across different users, devices, and audio content. We consider a consistent performance to be one that does not vary significantly depending on the fit and seal of the headphones, the shape and size of the head and ears of the user, the source and volume of the audio content, and the ambient noise level.
What are the Criteria for a Bad Score?
A bad score for mid frequency response accuracy means that the headphones have:
High standard error: This means that the frequency response curve of the headphones is far from the target curve, indicating that the headphones reproduce the mid-range frequencies inaccurately. We consider a standard error value of more than 4 dB to be poor, and a value of more than 3 dB to be mediocre.
Over or under-emphasized frequencies: This means that the headphones have a skewed or unnatural sound across the mid-range frequencies, with some frequencies being too loud or too quiet compared to others. We consider an over or under-emphasis of more than 3 dB to be noticeable, and an over or under-emphasis of more than 6 dB to be extreme.
Inconsistent performance: This means that the headphones perform differently across different users, devices, and audio content. We consider an inconsistent performance to be one that varies significantly depending on the fit and seal of the headphones, the shape and size of the head and ears of the user, the source and volume of the audio content, and the ambient noise level.
How We Compare Headphones with Different Sound Profiles
We understand that different users may have different preferences and expectations when it comes to the sound profile of their headphones. Some users may prefer a neutral sound profile that reproduces all frequencies equally, while others may prefer a bass-heavy, bright, warm, or v-shaped sound profile that boosts certain frequencies over others.
Therefore, we do not compare headphones with different sound profiles based on their absolute scores, but rather on their relative scores. This means that we adjust our scoring according to how well the headphones match their intended sound profile. For example, we do not penalize a bass-heavy pair of headphones for having a low score in the mid-range frequencies, as long as they have a high score in the low frequencies. Similarly, we do not penalize a bright pair of headphones for having a high score in the high frequencies, as long as they have a low score in the low frequencies.
How We Test Headphones for Mid Frequency Response Accuracy
To test headphones for mid frequency response accuracy, we follow a rigorous and standardized procedure that involves several steps and challenges. Here are some of the details of how we conduct our tests:
The Testing Environment
The testing environment we use is a dedicated room that is designed to minimize external noise and reflections. Acoustic panels cover the walls and ceiling of the space, while carpet covers the floor. The windows are covered with drapes. During testing, the room’s fan and air conditioner are both switched off. On average, 22°C is kept as the room temperature.
The testing equipment we use consists of a laptop computer, an audio interface, a microphone stand, a measurement microphone, and a pair of reference headphones. The laptop computer runs REW (Room EQ Wizard) software, which generates test signals and records measurements. The audio interface connects
The testing equipment we use consists of a laptop computer, an audio interface, a microphone stand, a measurement microphone, and a pair of reference headphones.
The laptop computer runs REW (Room EQ Wizard) software, which generates test signals and records measurements. The audio interface connects the laptop to the microphone and the headphones, and allows us to adjust the volume and the output channels. The microphone stand holds the microphone in a fixed position, at the same height and distance from the headphones as a human ear. The measurement microphone is a calibrated omnidirectional microphone that captures the sound output of the headphones. The reference headphones are a pair of headphones that have a known and accurate frequency response, which we use to verify the accuracy of our measurements.
The testing software we use is REW (Room EQ Wizard), which is a free and powerful software that allows us to generate test signals, record measurements, analyse data, and generate graphs.
To generate sine sweeps—test signals that range in frequency from low to high—we use REW. We assess the frequency response of the headphones using these sine sweeps, as well as other characteristics like distortion, impulse response, and phase response. Additionally, we employ REW to apply perceptual weighting filters, like A-weighting and ITU-R 468-weighting, that modify the frequency response in accordance with how people hear sound at various volumes. The frequency response curves of several headphones are also compared using REW, and the standard error values are computed.
The Testing Procedure
The testing procedure we follow is as follows:
We set up the testing equipment in the testing room, and make sure that everything is connected and working properly.
We calibrate the microphone using the reference headphones and a calibration file that matches the microphone model. This ensures that the microphone captures the sound output of the headphones accurately and consistently.
We position the headphones on our heads, making sure that they are aligned with our ears and that they have a good fit and seal. We adjust the headband and the ear cups as needed to achieve a comfortable and stable fit.
We select the audio interface as the output device in REW, and set the volume to a comfortable level. We also select the appropriate output channel for each headphone, depending on whether they are mono or stereo.
We select the sine sweep option in REW, and set the parameters for the test signal. We typically use a sweep length of 10 seconds, a start frequency of 20 Hz, an end frequency of 20 kHz, and a level of -12 dBFS.
We start the measurement in REW, and wait for the sine sweep to finish. We repeat this step three times for each headphone, to account for any variations in fit and seal.
We save the measurements in REW, and label them accordingly. We also take notes of any observations or issues we encounter during the testing process.
The Testing Challenges
The testing process for mid frequency response accuracy is not without challenges. There are many factors that can affect the accuracy and consistency of our measurements, such as:
Variations in fit and seal:
The fit and seal of the headphones can affect how they reproduce sound, especially in the low and high frequencies. Different users may have different head and ear shapes and sizes, which can result in different levels of fit and seal. Moreover, the fit and seal of the headphones can change over time, due to factors such as sweat, movement, or wear and tear. Therefore, we try to achieve a consistent and optimal fit and seal for each headphone, by adjusting the headband and the ear cups as needed, and by taking multiple measurements to account for any variations.
Variations in ambient noise:
The ambient noise level in the testing room can affect how we perceive the sound output of the headphones, as well as how the microphone captures it. Even though we use a dedicated room that is designed to minimize external noise and reflections, there may still be some residual noise from sources such as the air conditioner, the fan, or the outside traffic. Therefore, we try to eliminate or reduce any ambient noise as much as possible, by turning off any unnecessary devices, closing the windows and doors, and using acoustic panels and curtains. We also use a perceptual weighting filter in REW, which adjusts the frequency response according to how humans perceive sound at different levels.
Variations in source and volume:
The source and volume of the audio content can affect how the headphones reproduce sound, as well as how we perceive it. Different sources may have different encoding formats, sampling rates, bit depths, or compression levels, which can result in different levels of quality and fidelity. Moreover, different volumes may have different effects on the dynamics, distortion, or loudness of the sound. Therefore, we try to use a consistent and high-quality source and volume for each headphone, by using a laptop computer with an audio interface as the output device, by using sine sweeps as the test signal, and by setting the volume to a comfortable level. We also use a level meter in REW, which shows us the peak and RMS levels of the test signal.
How We Analyse and Interpret the Test Results
After we finish testing headphones for mid frequency response accuracy, we analyse and interpret the test results using various tools and methods that allow us to process the data and generate graphs and scores. Here are some of the tools and methods we use:
The Analysis Tools
The analysis tools we use are:
Excel formulas:
We use Excel formulas to calculate the standard error values for each headphone, based on the data points from the frequency response graphs. We use the following formula: =STDEV.S(range)/SQRT(COUNT(range)), where range is the range of cells that contain the data points for each frequency from 250 Hz to 4 kHz. We then average the standard error values for each headphone across three measurements to get a final value.
Perceptual weighting filters:
We use perceptual weighting filters in REW to adjust the frequency response according to how humans perceive sound at different levels. We use two types of filters: A-weighting and ITU-R 468-weighting. A-weighting is a filter that mimics how humans hear sound at low levels (around 40 dB SPL), by attenuating low and high frequencies more than mid frequencies. ITU-R 468-weighting is a filter that mimics how humans hear sound at high levels (around 90 dB SPL), by attenuating low frequencies more than high frequencies. We apply these filters to both the frequency response curve of the headphones and the target curve before comparing them.
Target curves:
We use target curves in REW to compare the frequency response curve of the headphones with an ideal curve that represents a certain sound profile or preference. We use different target curves for different types of headphones and sound profiles. For example, we use
Target curves:
We use target curves in REW to compare the frequency response curve of the headphones with an ideal curve that represents a certain sound profile or preference. We use different target curves for different types of headphones and sound profiles. For example, we use the Harman target curve for over-ear and on-ear headphones with a neutral sound profile, which is based on extensive research and surveys by Harman International. We use the Diffuse Field target curve for in-ear monitors with a bright sound profile, which is based on the average frequency response of a sound field that is equally distributed in all directions. We use these target curves as references to evaluate how well the headphones match their intended sound profile.
The Analysis Methods
The analysis methods we use are:
Calculating standard error: We use the standard error values that we calculated using Excel formulas to quantify how much the frequency response curve of the headphones deviates from the target curve. The lower the standard error value, the more accurate the mid frequency response is. We use these values to assign scores to the headphones, using a scale from 1 to 10. We also use these values to compare different headphones and rank them according to their mid frequency response accuracy.
Comparing frequency response curves: We use REW to compare the frequency response curves of different headphones, as well as with the target curves. We use REW to overlay the curves on the same graph, and to zoom in and out on different frequency ranges. We use these graphs to visually inspect how well the headphones reproduce the mid-range frequencies, and to identify any peaks or dips that may affect the sound quality. We also use these graphs to explain our scoring and ranking of the headphones, using examples and screenshots.
Identifying peaks and dips: We use REW to identify any peaks or dips in the frequency response curve of the headphones, which are points where the curve deviates significantly from the target curve. We use REW to measure the magnitude and width of these peaks or dips, and to locate their frequency positions. We use these measurements to determine how noticeable and problematic these peaks or dips are, and how they affect the sound quality of the headphones. We also use these measurements to suggest possible ways to correct or compensate for these peaks or dips, such as using equalizers or filters.
The Interpretation Guidelines
The interpretation guidelines we use are:
How to read frequency response graphs:
We use frequency response graphs to show how the headphones respond to different frequencies, from low to high. The horizontal axis represents the frequency range, from 20 Hz to 20 kHz, which covers the human hearing range. The vertical axis represents the sound level, in decibels (dB), which measures how loud or quiet the sound is. A flat line on the graph means that the headphones reproduce all frequencies equally, without boosting or cutting any frequency. A curved line on the graph means that the headphones reproduce some frequencies more or less than others, creating a certain sound profile or character.
How to understand standard error values:
We use standard error values to quantify how much the frequency response curve of the headphones deviates from the target curve. The lower the standard error value, the more accurate the mid frequency response is. We use a scale from 1 to 10 to assign scores to the headphones based on their standard error values. A score of 10 means that the headphones have a standard error value of less than 1 dB, which is excellent. A score of 1 means that the headphones have a standard error value of more than 4 dB, which is poor. A score of 5 means that the headphones have a standard error value of around 2 dB, which is average.
How to compare different headphones:
We use REW to compare the frequency response curves and the standard error values of different headphones, as well as with the target curves. We use these comparisons to rank the headphones according to their mid frequency response accuracy, and to highlight their strengths and weaknesses. We also use these comparisons to recommend the best headphones for different types of users and audio content, based on their preferences and expectations.
Evolution of mid frequency response accuracy testing
How Our Score and Test for Mid Frequency Response Accuracy on Headphones Has Evolved from Previous Models or Releases.
Our score and test for mid frequency response accuracy on headphones is not a static or fixed method, but rather a dynamic and evolving one. We constantly strive to improve our score and test by incorporating the latest research, technology, and feedback from our users and experts. Here are some of the ways that our score and test for mid frequency response accuracy on headphones has evolved from previous models or releases:
We have updated our target curves to reflect the most recent and reliable studies on human hearing preferences and sound quality.Â
For example, we have adopted the Harman target curve for over-ear and on-ear headphones with a neutral sound profile, which is based on extensive research and surveys by Harman International. We have also adopted the Diffuse Field target curve for in-ear monitors with a bright sound profile, which is based on the average frequency response of a sound field that is equally distributed in all directions.
We have improved our testing equipment and software to ensure more accurate and consistent measurements.
For example, we have upgraded our measurement microphone to a calibrated omnidirectional microphone that captures the sound output of the headphones more precisely. We have also upgraded our REW software to the latest version, which offers more features and functions for generating test signals, recording measurements, analysing data, and generating graphs and scores.
We have refined our testing procedure and analysis methods to account for more factors and variables that can affect the mid frequency response accuracy of headphones.
For example, we have added perceptual weighting filters, such as A-weighting and ITU-R 468-weighting, which adjust the frequency response according to how humans perceive sound at different levels. We have also added more criteria and guidelines for interpreting the test results, such as how to identify peaks and dips, how to compare different headphones, and how to suggest possible corrections or compensations.
We have expanded our testing scope and coverage to include more types and models of headphones with different sound profiles and features.
For example, we have tested more wireless headphones, noise cancelling headphones, earbuds, in-ear monitors, etc., with different sound profiles such as neutral, bass-heavy, bright, warm, or v-shaped. We have also tested more audio content with different genres and formats, such as music, podcasts, audiobooks, movies, etc.
By evolving our score and test for mid frequency response accuracy on headphones, we aim to provide more reliable, relevant, and useful information for our users who are looking for a pair of headphones that can deliver a clear and balanced sound. We also aim to help our users make informed and confident purchase decisions based on their personal preference and listening habits.
Conclusion
In conclusion, mid frequency response accuracy is a measure of how well the headphones reproduce the mid-range frequencies, which are crucial for vocals, instruments, and harmonics. Having accurate mid frequency reproduction is important for sound quality, realism, and immersion. To measure and score the mid frequency response accuracy of headphones, we use a combination of tools and methods that involve generating test signals, recording measurements, analysing data, and generating graphs and scores.
We also face some challenges in the testing process, such as variations in fit and seal, ambient noise, and source and volume. We hope that this article has helped you understand how we score and test for mid frequency response accuracy on headphones, and that you will check out our reviews and ratings of headphones based on this criterion.
Frequently Asked Questions
Here are some frequently asked questions about mid frequency response accuracy on headphones and their answers:
What are some examples of headphones that have a good score for mid frequency response accuracy?
Some examples of headphones that have a good score for mid frequency response accuracy are the Sennheiser HD 800 S, the Beyerdynamic DT 1990 Pro, and the Sony WH-1000XM4.
What are some examples of headphones that have a bad score for mid frequency response accuracy?
Some examples of headphones that have a bad score for mid frequency response accuracy are the Beats Solo3 Wireless, the Skullcandy Crusher Wireless, and the Bose QuietComfort Earbuds.
How can I improve the mid frequency response accuracy of my headphones?
You can improve the mid frequency response accuracy of your headphones by using an equalizer or a filter to adjust the sound output according to your preference or the target curve. You can also try different ear tips or pads to improve the fit and seal of your headphones.
How can I find out the mid frequency response accuracy score of my headphones?
You can find out the mid frequency response accuracy score of your headphones by visiting our website and searching for your headphone model. You can also read our detailed reviews and ratings of different headphones based on their mid frequency response accuracy.
How can I measure the mid frequency response accuracy of my headphones myself?
By using a similar process as we use, you can assess the correctness of your headphones’ mid-frequency response on your own. A laptop computer, an audio interface, a microphone stand, a measurement microphone, some target curves, a pair of reference headphones, REW software, Excel software, and software for both will be required. Our website and other internet resources both have more instructions on how to achieve this.
What are the advantages and disadvantages of using perceptual weighting filters in measuring mid frequency response accuracy?
The advantages of using perceptual weighting filters are that they account for how humans perceive sound at different levels, and that they make the frequency response curves more comparable and meaningful. The disadvantages of using perceptual weighting filters are that they may introduce some errors or biases in the measurements, and that they may not reflect the actual sound output of the headphones.
What are some of the best target curves for different types of headphones and sound profiles?
Some of the best target curves for different types of headphones and sound profiles are:
The Harman target curve for over-ear and on-ear headphones with a neutral sound profile, which is based on extensive research and surveys by Harman International.
The Diffuse Field target curve for in-ear monitors with a bright sound profile, which is based on the average frequency response of a sound field that is equally distributed in all directions.
The Bass Extension target curve for headphones with a bass-heavy sound profile, which is based on the Harman target curve with an additional boost in the low frequencies.
The Consumer Preference target curve for headphones with a v-shaped sound profile, which is based on the Harman target curve with an additional boost in the low and high frequencies.
How can I tell if my headphones have a peak or a dip in the mid-range frequencies?
You can tell if your headphones have a peak or a dip in the mid-range frequencies by looking at their frequency response graph. A peak is a point where the curve rises above the target curve, indicating that the headphones reproduce that frequency louder than expected.
A dip is a point where the curve falls below the target curve, indicating that the headphones reproduce that frequency quieter than expected. You can also tell if your headphones have a peak or a dip in the mid-range frequencies by listening to them. A peak may make the sound harsh, shrill, or sibilant, while a dip may make the sound dull, muffled, or hollow.
How can I choose the best headphones for mid frequency response accuracy?
Check out our reviews and rankings of various headphones based on this criterion to determine which ones are the best for mid frequency response accuracy. Additionally, you can choose headphones that fit the sound profile and audio content you enjoy by taking into account your listening preferences and behaviours. Additionally, you can evaluate the sound quality and functionality of various headphones by trying them out for yourself.
