WH-CH700N

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NO SMOOTHING is applied to the shown plots. Most measurement sites have some smoothing applied which ‘irons flat’ sharp peaks and ‘wiggles’. I do not use smoothing because some info about sound quality is lost when plots are smoothed.

Aside from a small correction of the microphone itself also some correction in the lowest frequencies is applied to the plots to compensate for the perceived loss of bass when using headphones. This is described HERE in more detail.
A ‘horizontal‘ frequency response curve on the shown frequency response plots on this website thus indicates a perceived ‘flat’ tonal signature.

ALL measurements are made with a good SEAL on a flatbed measurement rig.
The shape of your head, bone structure, pad size, pad ‘softness,  (compliance), hair or no hair and or wearing glasses may (drastically) change the frequency response of some headphones, so… your personal experience may differ substantially from these plots.

Frequency response (tonal balance) is the most sound-determining aspect of headphones. A horizontal line shows audible neutral response in the plots on this website. Deviations in different severities at different frequency bands have an effect on the sound character.
The bigger the deviation the stronger the effect.

Below an aid to help determining the sound character of headphones with relation to the frequency response.

descriptors2

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Sony WH-CH700N

WH-CH700NThe Sony WH-CH700N is a closed over-ear wireless (Bluetooth) headset with Noise Cancelling. It retails between €100.- and €150.- and is avaliable in black and blue.
The bluetooth functionality includes operation of the phone/device it can communicate with like play/pause/skip and volume controls. One can also take phone calls with it as it has a mic. built in. N.F.C. is present so pairing can be quick.buttons

It has Bluetooth® version 4.1 and an effective  range (free field so smaller inside the house) of around 10m. Profiles: A2DP, AVRCP, HFP, HSP and it supports SBC, AAC, aptX and aptX HD audio formats.

The firmware inside can be upgraded using the app on your phone.
With that app you also have a 5-band equalizer (+/- 10dB) and some other functions.

Charging is done via a micro-USB port. It takes max. 7 hours to charge the battery and is specified to have 200hrs standby time (BT on) and max. 35 hours of playing time (BT and NC active).

The headphone can also be connected using a 3.5mm TRS jack. This is how this headphone is measured/tested/evaluated.

The headband feels comfortable and has quite an adjustable range. As the cups can swivel and tilt far enough this headphone will probably fit most head sizes.
The pads are not very comfortable and due to the shallow depth may be touching your ears. There is no memory foam and the pleather is not super thin. I have no clue of the longevity of these pads (when they will start to flake) but the pads are replaceable.
The pads get a bit warm and ‘sweaty & sticky’ after some time.

The noise cancelling works and does not hiss audible as some of the cheaper ones do.
Noise cancelling isn’t as effective as that of higher end models or a lot of other NC headphones but it provides some attenuation between 100Hz and 1kHz. Not enough to drown out all noises in busses and airplanes.

specifications:

Type: Over ear, closed
Usage: Home, portable
Driver type: dynamic
Pads: pleather, regular foam.
Internal pad dimensions: Height 65mm , width 42mm (oval shaped) depth: 15mm front, 20mm rear side.
Collapsable: no, but folds flat.
Headphone connector: 3.5mm TRS
Cable entry: single sided (left)
Cable: replaceable, 1.2m
Driver size: 36mm (slightly angled)
Nom. power rating: (assumed 50mW)
Max. voltage: (assumed 2V)
Max. current: (assumed 0.1A = 100mA)
Max. S.P.L.: (assumed 124dB)
Impedance: 22Ω (when active) and 48Ω (in passive mode, so switched off)
Efficiency: active mode = 97dB/1mW (113dB/1V) , passive mode = 91dB/1mW (108dB/1V)
Weight: 230 g.
Colour: black or blue
Clamping force: low/medium
Accessories: USB cable, headphone cable

Sound description:

Passive mode: In passive mode (thus switched off) the sound quality is decent. Bass sounds decent in quality. It extends well enough. Bass and lower mids are somewhat accentuated. The mids thus are not very ‘articulated’ and lack ‘presence/clarity’.
Also the highs are subdued and not very refined but at least are not shouty/bright/splashy nor is there any sibilance to be found.

Active mode: In active mode (when the power is switched on) the sound signature changes. The measurements below and the sound impression is done with EQ set to neutral.
NOTE: One can use the EQ on the app to change the tonal balance/sound closer to your taste.
In active mode the headphone plays a lot (5dB) louder and the upper mids and treble now is on the proper level. Bass and lower mids are still somewhat elevated/accentuated but in a tasteful way that will suit most pop music. Mids sound more ‘lively’ and clearer.
The upper mids don’t show an obvious dip any more but still lack when compared to ‘better’ headphones.
The treble is not subdued any more and on the proper level. The treble quality is not improved though and still not very refined. There is no sibilance and no harshness to the sound (when it is not in the recording) but at higher listening levels some shoutiness lurks around the corner.
Overall the sound quality when active is decent and not obviously flawed.
There is no difference in sound quality when noise cancelling is on and off. In most cases with noise cancelling on the bass quality improves/changes. Not so in this headphone.
Maybe this is caused by the not so affective noise cancelling.

measurements:

Below the frequency response of the WH-CH700N (Left channel only)
There are 3 ‘modes’ of which 2 modes measure and sound the same. Below the differences in level between the active modes (N.C. on, N.C. off) and the passive mode (power off) are shown. ch700n active vs passive level difference teal = nc off

Below the same plot but the level differences in the mids are now over-layed. This shows the change in tonal balance between the active and passive mode a bit more clearly.
In active mode there is 5dB more bass and treble and upper mids (around 3kHz) have increased by 10dB, the treble range is about 7dB louder.FR left 3 modes
Some DSP equalization is used to correct for the driver deficiencies.

LR matching is not very good but quite acceptable in this price range given its functionality. Below the Left, Right plots of al 3 modes.FR modes

What is obvious here is that when used in active mode the frequency response is limited to 20kHz. In passive mode the treble extension is better but as the treble is reduced in level quite a bit at that moment that isn’t audible.
The reason for this is that the incoming analog signal (via 3.5mm TRS) is converted into digital at 44.1kHz (I assume 16 bits) and processed before it is converted back to an analog signal for the driver.
In active mode there is thus no reason to play hires recordings. In fact it is even recommended to NOT play any hires files as the ultrasonics in the recording will ‘fold back’ in the audible range as the analog input is not brickwall filtered before A-D conversion.
This is clearly shown in the plot below which shows the frequency response in active mode between 18.5kHz and 24kHz.high frequency response

seal

As the seal of this headphone is of importance some experiments were done showing the effect.
(lots of) hair between the headphone and ear, or an ear/head shape that does not allow a proper seal will affect the tonal balance.
Below: Perfect seal, a small seal breach by thin armed (reading) glasses just above the skin and a big seal breach.  Plots are shown for each of the 3 modes (N.C. on, NC off, passive mode)sealA small seal breach isn’t really problematic and may even be preferable as the tonal balance is more neutral this way in all 3 modes.As 30Hz is reached in these cases bass won’t suffer much. When a bigger seal breach is present some bass roll-off is heard.

output resistance / damping-factor

As this is a dynamic headphone its impedance can change the tonal balance of the headphone. This would only be the case when it is connected via the 3.5mm TRS plug to a high output R desktop amplifier. The usecase of this headphone almost rules this out. Driven from 0.5Ω and 120Ω amplifier. The traces are over-layed to show tonal balance differences but in reality via 120Ω it will play 11dB softer in passive mode and 16dB softer in active mode (due to its low input resistance).

Below the active mode. What’s interesting here is that the rise in lower frequencies is not caused by the driver, as it is not directly connected, but due to a coupling capacitor which is increasing the input impedance for the lowest frequencies and because of voltage division increases the amplitude of lower frequencies.
120 Ohm -15.8dB nc on

Below the passive mode the same thing is happening here. A coupling capacitor rolls off the lows but because the impedance increases as well this is ‘undone’.120 Ohm -10.8dB passive

Below the distortion measurements of the WH-CH700N (left channel) in all 3 modes.
Alternating: Passive mode, N.C. off and N.C. on.  (distortion in percentage)distortion
The distortion in passive mode is slightly lower in the bass area compared to the active mode. This is caused by the bass boost in the active mode. The bass distortion in N.C. mode improves just barely indicating that the attenuation of outside noise due to the Noise Cancelling feedback isn’t that great. Distortion levels below 1% are not very sound degrading below 100Hz. The higher 3rd harmonics give the impression of ‘tighter’ bass that at higher listening levels turn into ‘clipping alike’ bass reproduction which is less desirable.
The biggest issue, however is in the 5.5kHz area where a driver resonance causes high levels of (2nd harmonic) distortion. In passive mode 2% is reached but the treble is subdued in that case so less audible. In active mode 5% distortion is reached which are audible levels. This is audible as the ‘shoutiness’/’coarseness’ in the sound when playing a bit louder. At lower listening levels it isn’t as bad.
The fact that the treble is ‘lifted’ +7dB in that part of the frequency range, in active mode, doesn’t help either.

Below the CSD of the WH-CH700N in passive mode. (Left and Right are superimposed)CSD passiveIt shows the dip at 3.5kHz is really there and that it is followed by a short resonance at around 5.5kHz. At 8kHz and 12kHz a very short lived resonance is seen but isn’t really problematic.

Below the CSD of the WH-CH700N in active mode. (Left and Right are superimposed)CSD NC on
Here we see the 5.5kHz resonance becoming more pronounced and the 12kHz resonance peaking out above the rest. This points towards the somewhat less refined treble.

Below the spectrum plot of the WH-CH700N. spectrumTagging the 2 images that alternate isn’t really needed here. It is quite obvious which one is the active plot and which one the passive. The large back folding ‘ridge’ is caused by the active mode’s 44.1kHz sampling frequency. For this reason it is recommended to not use any high-res material with this headphone when connected via the 3.5mm TRS plug.
The ultrasonics that would otherwise stay unnoticed will be audible as ‘hardening’ of the sound.

The step response (passive, active mode) below shows the sub-bass is just slightly rolled-off in passive mode and better extended in active mode. step response passive vs onIn passive mode the rising edge is merely reaching -10dB opposite the lower mids/bass (>250μs) and shows the warm/bassy character that lacks in ‘presence’ and ‘clarity’ and is on the dull side.
In the active mode the initial rise is only a few dB below the mids (<500μs) and it shows the bassy character as well (>1ms) as well as the enormous bass extension. Provided a good seal is present.

summary

The WH-CH700N is a decent sounding wireless headphone with a relatively poorly implemented noise cancelling feature. The fact that one can tune the sound using the equalizer in the app on your phone/tablet makes it more versatile.
For the price it has a decent build and average comfort. Battery life is long enough.
The sound quality is good to decent on lower listening levels but at higher levels some tears start showing in the sound quality.
When transporting it I recommend getting a decent hardcase for it.
An alternative could be the Sennheiser HD 4.50BT. That one also has deeper and softer ear pads as well.

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