Measurement's report Dexp BT212 Bluetooth test and graphs

About this report

This is a headphone report for professionals.
You can see a simple report for "dummies" with explanations of the main characteristics for Dexp BT212 Bluetooth

Test report - general data of Dexp BT212 Bluetooth headphone

Frequency response

Graphics setting view

Range, dB:

90 50 24

Perception of headphone frequency response curves of equal loudness ISO 226-2009

General results

General results Dexp BT212 Bluetooth

Channel

Summary (Right + Left)

Variation in frequency response in band from 100 Hz to 0,01 kHz, dB

-17,70, 7,06

The table shows a most important technical characteristics of Dexp BT212 Bluetooth

*Center channel headphone is received by averaging between left and right channels

*impedance value in the table for channel

Test conditions

Type of headphones: On-ear
Measurements were performed on the stand:

with on the simulator of human head with ears HDM-X with natural acoustic damping

Headphone's impedance has not been tested

The model use internal headphone amplifier
Can be used only with special AMP
By other reason

The tags (specifications) for this report are:

Type of device : Headphones Internal sound cards USB-DAC DACs Combines with USB Smartphones Players External sound cards Headphone Amplifiers with Line In Laptops & Tablets Combines with SPDIF Motherboards Displays Bluetooth-in
Headphones tested in (measure) : normal frequency range wide frequency range (HD)
Headphones tested on (measure) : stands of the old generation modern stands
Type of headphones (device) : In-Ear or Tablet On-ear Over-ear
The type of acoustic design (measure) : Closed Open Semi-open

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Frequency response of Dexp BT212 Bluetooth headphone

Graphics setting view

Range, dB:

90 50 24

Channel:

Center Left Right Left Right

Brief information

Graph of frequency response ^F.A.Q. the shows the balance of the frequency of the headphones (reproduced frequency spectrum) in dB. 0 dB is the average of the amplitude.

The frequency response of the headphones can be represented as the selected equalizer setting in the player, applicable to headphones with a flat sound. Subjective "flatness" is perceived differently from external conditions: the volume level ^F.A.Q. of the external noise and noise isolation headphones. When connected to an amplifier, the frequency response can change ^F.A.Q..

The frequency response in RAA is obtained through the reproduction and analysis of a special noise signal with the subsequent generation of an impulse response. The frequency response plot is constructed from the spectrum of the impulse response.

According to the frequency response curve, it is possible to calculate the width of the frequency range ^F.A.Q..

The difference in amplitudes of 6 dB is equivalent to a twofold ratio of signal levels.

Original text in Russian report. You can help with translation via the feedback or select text and press Ctrl+Enter (anonymously).

Table of measured characteristics

Frequency response Dexp BT212 Bluetooth

Channel

Left

Right

Variation in frequency response in band from 100 Hz to 10 kHz, dB

-20,51, 6,99

-16,79, 8,64

Perception of headphone frequency response curves of equal loudness ISO 226-2009 of Dexp BT212 Bluetooth headphone

Graphics setting view

Channel:

Center Left Right Left Right

Brief information

The graph shows the change in the perception of the frequency response^F.A.Q. of the headphones when listening to music with a different loudness relative to the natural level. When listening to headphones at a low volume, the perception of recoil in the low frequency range decreases, and when you listen to it at a high volume, it increases.

According to this graph, you can estimate at what volume the headphones will be perceived more flat.

The perception of the number of low frequencies depends on the volume according to the curves of equal loudness. (ISO 226-2009 Acoustics. Normal equal-loudness-level contours). For the base level, 72 dB SPL (live performance of several instruments with vocals without amplifiers with acoustics) is selected.When you select another base level, the dependence varies slightly and is suitable for almost all levels.

Examples of graphics application in practice ^F.A.Q..

Original text in Russian report. You can help with translation via the feedback or select text and press Ctrl+Enter (anonymously).

Table of measured characteristics

Perception of headphone frequency response curves of equal loudness ISO 226-2009 from Dexp BT212 Bluetooth

Channel

Summary (Right + Left)

From level 48 dB at 72 dB SPL in band 100 Hz to 10 kHz, dB

-18,8, +17,0

From level 36 dB at 72 dB SPL in band 100 Hz to 10 kHz, dB

-18,6, +13,9

From level 24 dB at 72 dB SPL in band 100 Hz to 10 kHz, dB

-18,3, +10,8

From level 12 dB at 72 dB SPL in band 100 Hz to 10 kHz, dB

-18,0, +7,8

From level 0 dB at 72 dB SPL in band 100 Hz to 10 kHz, dB

-17,7, +7,1

From level -12 dB at 72 dB SPL in band 100 Hz to 10 kHz, dB

-17,4, +7,8

From level -24 dB at 72 dB SPL in band 100 Hz to 10 kHz, dB

-17,2, +8,5

From level -36 dB at 72 dB SPL in band 100 Hz to 10 kHz, dB

-17,0, +9,1

*Center channel is received by data averaging between the left and right channels

Impulse response of Dexp BT212 Bluetooth headphone

Graphics setting view

Time, ms:

2ms 5ms 10ms

Channel:

Left Right Left Right

Brief information

Impulse response is a reaction to the pulse of the minimum possible duration. From the impulse response, most of the parameters under study are calculated: frequency response ^F.A.Q., phase-frequency response, group delay, waterfall, step response and square wave. The impulse response is visually not informative and for obtaining the majority of characteristics a fast Fourier transform and other mathematical algorithms with the analysis of the total pulse length are used. The total pulse length is about 5 seconds, while only the beginning of a pulse of 2-4 milliseconds is visually visible. Vertically, the visual detail does not exceed 40-45 dB.

The impulse response is able to show visually only the same or different polarity of the drivers and possible high-frequency resonance.

The waveform of the impulse response of the Dexp BT212 depends on the Dexp BT212 frequency response and the damped resonances and reverberations of the Astrotec AX-60 and the reverberation in the stand chamber. The visual clarity of the parameters on the impulse response is very low. Visual determination of quality by impulse response was actual in "pre-computer" years.

The frequency response in RAA is obtained through the reproduction and analysis of a special noise signal with the subsequent generation of an impulse response. The impulse response is displayed as is, without compensation of the frequency response for the microphone or smoothing. It is RAW data. The reduction in the frequency response of the microphone starts at 20 kHz^F.A.Q.. When reproducing the test signal via the E-MU 1616m , the original impulse response does not contain any pre-ringing ^F.A.Q.. Translation of the description is not yet ready

Original text in Russian report. You can help with translation via the feedback or select text and press Ctrl+Enter (anonymously).

Impulse Response Envelope (ETC - Energy Time Curve) of Dexp BT212 Bluetooth headphone

Graphics setting view

Time, ms:

2ms 5ms 10ms

Range, dB:

120 90

Channel:

Left Right Left Right

Brief information

The envelope of the impulse response is the sum of the half-wave moduli of the impulse response, constructed on a logarithmic scale.

In speaker tests, the envelope of the impulse response tracks the reverberation of the room. For headphones that operate on a small volume, this feature does not carry any useful information. The envelope of the impulse response is given for general educational purposes - to show that the impulse response is not a short burst of 2-4 ms, but a long-term attenuation within a few seconds. The widespread opinion "on the impulse characteristic all at once it is visible" incorrectly.

Original text in Russian report. You can help with translation via the feedback or select text and press Ctrl+Enter (anonymously).

Step response of Dexp BT212 Bluetooth headphone

Graphics setting view

Time, ms:

2ms 5ms 10ms

Channel:

Left Right Left Right

Brief information

The step response is a playback on a step (front square) signal. It is built on the derivative impulse response .The response to the step represents the beginning of the meander front with zero frequency.

In the audiophile community on the square wave it is customary to determine the "speed" of the headphones, however this characteristic is applicable only to amplifiers having a flat frequency response with no reverberation and completely not applicable to headphones.

The waveform of the response to the step depends on the frequency response and the resonances of the headphones. In ancient times, before the wide spread of digital technologies, in the form of a meander, a rough estimate was made on the frequency response ^F.A.Q. and F.A.Q.. Today, the analysis of acoustic parameters on the meander is hopelessly outdated and the graphs of the final frequency response and waferballs with resonances are looked at separately.

Original text in Russian report. You can help with translation via the feedback or select text and press Ctrl+Enter (anonymously).

QSD / Watterfall of Dexp BT212 Bluetooth headphone

Graphics setting view

Channel:

Left Right

Brief information

The cumulative spectrum of the signal attenuation shows resonances and reverberations after the headphones cease to reproduce the signal.

The cumulative spectrum ^F.A.Q. of signal attenuation is constructed by impulse response .The graph does not use three-wave smoothing. Time zones with an interval of 1 ms are painted in a certain color. For convenience of perception, the graph does not have vertical displacement, limited only to horizontal displacement. From the position of 3D - this is a view with a small turn in the horizontal plane. You can accurately assess the level on a vertical scale. To obtain good resolution in the time domain, a small window of 2048 samples is used, which directly affects the low resolution of the low frequency region and the graph in the region below 200-300 Hz does not show useful information.

Original text in Russian report. You can help with translation via the feedback or select text and press Ctrl+Enter (anonymously).

Delta QSD / Delta Watterfall of Dexp BT212 Bluetooth headphone

Graphics setting view

Channel:

Left Right

Brief information

The change in the cumulative spectrum ^F.A.Q. of the signal attenuation is a cumulative spectrum of the signal attenuation, where the original frequency response is represented by a straight line.

Time zones are painted in a certain color.

Sharp peaks above 0 dB are formed in the presence of a narrow-band dip at the initial frequency response. This can be a resonance or an error in the interference of waves, it needs to die according to the graph of cumulative spectrum signal attenuation.

For the convenience of estimating the amplitudes, the graph has no vertical and horizontal displacement.

To obtain good resolution in the time domain, a small window of 2048 samples is used, which directly affects the low resolution of the low frequency region and the graph in the region below 200-300 Hz does not show useful information.

Original text in Russian report. You can help with translation via the feedback or select text and press Ctrl+Enter (anonymously).

What is the cumulative signal attenuation spectrum? How do headphone resonances affect sound?

On-line comparison and selection services for Dexp BT212 Bluetooth

Comparison the frequency response

Impedance

Electric phase

Compare the frequency response of the bundles

Comparison of basic characteristics: Sensitivity, Impedance

Determination of the required voltage level from a headphone amplifier for BT212 and comparison with other models A additional analytics of compatibility with specific amplifiers

Comparing changes in frequency and sound pressure as a function of the applied voltage and a impedance of an amplifier

Headphone square wave comparison at the required frequency

The automatic selection of the optimal AMP models from BT212

More detailed

Measurements of Dexp BT212 Bluetooth were carried out by Roman Kuznetsov on the hardware-software complex RAA.

The Dexp BT212 Bluetooth test was conducted as a black box test, without regard to cost and prestige. This is the basic principle for making measurements, measurement reports and developing tests in RAA.

Kuznetsov Roman
Founder of RAA

Known by the nickname romanrex
Аuthor of articles iXBT.com

Information for Authors. You can freely use the graphics in your articles with a link to us.

Dexp BT212 is available in reports and services. You are in a professional report.

Information for entry level users

reports for a newbie (Headphones)

Wire
Bluetooth

The automatic selection of the optimal AMP models

Information for all

Versus of characteristics

Compare the sensitivity and impedance

Information for professionals
reports for a pro (Headphones)

Wire

report for a pro
MultyTarget/Settings for the equalizer

Bluetooth

report for a pro
MultyTarget/Settings for the equalizer

Comparison of on-line graphs

Comparison the frequency response
Impedance
Electric phase
QSD / Watterfall
Comparison of the frequency response/SPL of the bundles of headphones and amplifiers
Voltage and Sensitivity
SPL from bundle
Impulse, Envelope, Step responses and Square wave
Selection of headphones for the target frequency response
Export Frequency response

Quick jump to the schedule in this report: Bluetooth

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The RAA project web site offers on-line services for the matching of audio devices, direct comparison and evaluation of devices compatibility. The RAA web site presents 2738 reports of measurements of headphones, musical players, amplifiers, DACs, smartphones, sound cards and other audio devices. The measurements were carried out in our research laboratory, on the hardware-software complex designed by RAA. We are improving the tests and test reports. RAA make tests and reports more understandable to customers and amateurs, not just professionals.

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