Let's talk about the rational choice of headphones such as DT660 and DT860.

There have been many researches on amps, and headphones have rarely been systematically studied. However, some people have asked about the combination of headphones and amps, and even the choice of headphones. In the past two years, there have been more thoughts on headphones.

I recently paid attention to and asked about DT860, DT880 is more, I also spent some time, compare it, here is a simple statement:
In fact, each person's listening tendencies are very different. The conclusion of A's hearing on DT880 and the conclusion of B's ​​hearing on DT990 must not be put together, even if A and B are identical twins.
Even if the AB comparison of A science, listening to DT880 and DT990, only said simple good and bad, there is no reference to B, unless there is a clear relative difference, specifically where.
Below, according to my personal feelings, the relative difference between DT660, DT860, DT880, DT990.
The units of DT660 and DT860 should be exactly the same. If the volume is the same, the sense of hearing is very close. (This is very important when comparing AB. For headphones with different sensitivity, it is best to have the sound pressure detection consistent, otherwise it will affect the hearing conclusion) Only DT660 is closed type, DT860 is open type, slightly different, the difference is very small, the difference in sense of hearing is far from the price difference, the closed DT660 is definitely not stuffy, but the sound insulation is relatively good. If the surrounding environment is noisy, or if you don't want to influence the person next to you at night, the DT660 is more suitable than the DT860.
DT660, DT860 is relatively balanced. If balance is the main body of "quality", I think they are "high quality" headphones, higher than some brands with higher price headphones, even higher than DT990. Please note the premise of the conclusion.
However, DT660 and DT860 may be flatter than DT880 and DT990. It can also be said that the taste is lighter and more fidelity. Dive to think a little weaker, tighter.
The following quotes the curve of headphone.com to cite this:
DT660 frequency response curve


DT860 frequency response curve


DT880 frequency response curve, high and low frequency boost


DT990 frequency response curve, high and low frequency boost


DT880 and DT990, compared with DT860 and DT660, have increased in high frequency and low frequency, DT880 adds less, DT990 adds more (not too much, and PP does not have the dive and momentum low frequency boost) It's completely different), so I feel that the DT990 is thicker, more atmospheric, slower, and more analytical than the DT880. The two ends are slightly tilted, and the relative mid-range is slightly weaker, which is only relative.
Today's civilian high-end headphones, most of them have 3-6dB improvement in low frequency, including DT990, HD650, K701, etc., so that the headphones have a sense of atmosphere close to the big speaker.
Especially the frequency below 100Hz, although it is not in the frequency range of vocals, but to do this very low frequency, in order to express the thickness of sounds such as percussion, double bass, wave sound, low frequency background sound, bring the momentum .
Whether the frequency below 100Hz can be done is also one of the main differences between high-end headphones and bottom headphones.

Comparison of multiple frequency response curves, PP belly is big but below...


Here is a point:
Headphone's amplitude-frequency curve has an inherent defect, that is, around 11KHz and 17KHz, there will be a -6dB, -10dB recession, which is not the problem of the headphones itself, but the high-frequency reflection of the test environment, which is in the headphone The test page is also available in English. When you look at the picture, you can raise it in the brain.

The pictures here are typical headphone test charts. Different versions and different batches may have some differences, which is normal.
It is very important to pick a good earphone: the left and right units should be as symmetrical as possible.
In the above 1-4 figures, the red and blue lines correspond to the left and right units of the earphone respectively, and it can be seen that they are not completely coincident. The left and right units are recessed by 10dB at the same time, and the relationship is not big. If the left side of a certain frequency band is 3dB higher and the right side is 2dB lower, it will bring serious sound image localization problems.
The left and right channels differ by 3dB and there is a significant positioning offset. Many earphones in the low-end and mid-range have more than 3dB difference between some frequency points. The high-end is selected by strict matching, and it will be much better, and some can reach 1dB.

The harmonic distortion of these 4 headphones is relatively small, the sound is good, this is similar to the high-end Senhai, so there will be no more overtones of ER4B and individual AKG headphones. Even if it is not well pushed, it is not easy. Make your ears uncomfortable.
Here are the test curves for headphone.com several types of headphones harmonic distortion:
Dt660 harmonic distortion


Dt860 harmonic distortion


Dt880 harmonic distortion


Dt990 harmonic distortion


Er4b harmonic distortion, overtones are easy to stimulate bad control, estimated to be related to 0.22uF capacitor


HD650 harmonic distortion, looking forward to HD800 performance


K271 harmonic distortion is not too small, "parsing" is a bit high


Added: How to see the harmonic distortion curve:
From the perspective of fidelity, adding a 500Hz monophonic sine wave to the earphone, the earphone only emits a single 500Hz tone, which is the most perfect, but it is practically impossible, because the earphone diaphragm is limited, reflective back and forth, elastic, Features such as damping characteristics, in addition to the sound of 500Hz, there are other sounds. The sum of the power of all other sounds, divided by the power of the test tone, is the total harmonic distortion rate THD, the average earphone is less than 0.2%, the high-end earphone is lower than 0.1%, the HD800 is 0.02%, and the big Austrian standard is lower than 0.01%.
The % and dB can be converted, the sound pressure is 20dB every 10 times, that is, 1% distortion is -40dB, 0.1% distortion is -60dB, and 0.01% distortion is -80dB. Note that this is not a certain harmonic, but the sum of all harmonics.
As can be seen from the figure, the second harmonic distortion of er4b is -30dB, the third harmonic distortion is -45dB, the fourth harmonic distortion is -76dB, and the fifth harmonic distortion is -50dB... ,
The HD650 harmonic distortion control is very good, and the highest one is not -80dB.

About the new and old versions:
I haven't compared it, but one thing, I don't know if you noticed it. The old version of the nominal distortion is 0.2%, and the new version is 0.1%. For a manufacturer in charge of the same person, the same model only changed this parameter. It must be done in the new diaphragm material and design, so that the distortion is smaller.
The application of new materials is often a multiplier effect.

Here is a personal experience data, not necessarily accurate:
The second harmonic is higher than -40dB, and the third harmonic is higher than -50dB, there will be a significant difference in hearing.
The second harmonic is higher than -60dB, and the third harmonic is higher than -70dB. The big dynamic concert has a sense of hearing, and the general music feels slight.
Harmonic distortion below -80dB can be ignored.
The above is only from the perspective of fidelity. If you think that the harmonics are good, then the sound is good, of course, ER4B is the best.

I have said very early that the difference in sound will inevitably be reflected in the test, and the difference in testing may not be heard.
However, because of the complexity of the sense of hearing, the current general laboratory does not have as many tests as the equipment.
However, headphone.com recently published several very important curves: 50H, 500Hz square wave response waveform curve; impulse response waveform curve; frequency phase curve, etc., very valuable reference, read, even if not heard, can Judging the basic characteristics of this earphone diaphragm, and having a framework understanding of certain sound characteristics.
However, this is a relatively deep level and requires a relatively large amount of knowledge and experience. The average person may not be applicable.
DT880 impedance curve

How to look at the impedance curve:
The impedance of DT880 varies from more than 250 ohms to 320 ohms. There is no difference between good and bad. It can be seen that the impedance of different frequencies corresponds to the magnitude of the impedance. If the undulation is too large, it will be greatly affected by the output impedance of the amplifier. The amplifiers with different output impedances are pushed, and the sounds coming out are different. The high frequency of the bulge is generally more difficult to control.

Supplementary views on the DT990 of 32 Euros, 250 Euros and 600 Euros:
The same model, different units, frame, diaphragm are the same, but the voice coil thickness, number of turns, impedance, will cause subtle sense of hearing.
32 ohms, 250 ohms, 600 ohms DT990, the power sensitivity is exactly the same, are 96mW / dB, that is, input the same power, the sound size is the same, but for the voltage sensitivity, the difference is huge, that is, for The constant voltage amp is easy to push and the impedance is proportional. For the constant current amp, the easy push and the impedance are inversely proportional.
After calculation, it can be known that the number of turns of the three types of elements is proportional to the square of the impedance, that is, the number of turns of 600 ohms is more than four times that of 32 ohms. If the materials are the same, the cross-sectional area of ​​the voice coil is less than 1/4. The overall weight of the voice coil is basically the same.
The high-impedance inductive reactance is stronger, and the impedance curve is more fluctuating. For amplifiers with high output impedance, the change will be larger and difficult to control.
For the portable audio source, it is obviously better to choose 32 ohms; for the general Taiwan machine, you can use 250 ohms; if you want to spend energy, you can use 600 ohms to do more good things.

DT880 shielding curve

How to look at the shielding curve:
DT880 is an open-type earphone, so the shielding effect is very poor, the sound below 1KHz, 100% pass unimpeded. The sound of a few KHz is only about 10dB, and only half of the sound is filtered out. It is estimated that the sponge absorbs a little bit.
You can look at the in-ear earplug shielding curve, such as er4b, 40dB, 50dB or more, and less than 1% of external sounds enter the ear.

DT880, 50H square wave response waveform

DT880, 50H square wave response waveform curve:
This curve can see the instantaneous sound characteristics of the unit diaphragm, the characteristics of elasticity, damping, etc., the unit with low frequency and deep dive, the square wave will be slower, the high frequency damping is good, and the ringing will be quickly obtained during the falling process. inhibition.

DT880,500H square wave response waveform

DT880, 500H square wave response waveform curve:
Similar to the above, you can see the details of the ringing more clearly.

DT880 impulse response waveform

How to look at the DT880 impulse response waveform:
Give the unit an electric pulse, and then there is no signal. It is said that the unit should stop vibrating immediately, but it will not actually, and some will vibrate for a long time, and the sense of hearing will drag the water.
The duration of vibration and the frequency can be roughly reflected from the graph. If the fluctuation is too large, the unit with too long time will inevitably compose music into a group.
These are also related to the control capabilities of the amplifier. It is complicated to say, so I won't say much.

DT880 frequency phase curve, etc.

How to see the DT880 frequency phase curve:
This is the difference between the different frequency and unit feedback signals.
20-20KHz, if all is 0 degrees, of course, it is best, but it can't be done.
50-15KHz, the undulation can be good at +-30 degrees. If there is a very large jump on a certain frequency, it means that the unit diaphragm has resonance or resonance point, which is not fidelity.

The above is only a small part of the many features of the headset, most of the curve test is cumbersome, and will not be announced.

Headphone sensitivity, which is also the driving characteristics, is also very important, which involves whether it is easy to drive and whether it is good to push, but these figures are not reflected.