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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.


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Sennheiser HD700


The Sennheiser HD700 is an open over-ear dynamic headphone. Its designator (HD700) positions it between the HD660S and HD800. Understandable when looking at the price (HD660S) and the looks of the top model (HD800). The pads are different from those of the HD800 but the looks and tonal balance have some resemblance to the HD800. It is designed for home usage. It retails for around € 600.- which is quite expensive for what it offers.
The headphone sits VERY comfortable on the head. One of the most comfortable headphones around for sure. It is a quite light weight design.


Type: Over ear, open
Usage: Home
Driver type: dynamic
Pads: replaceable velours
Inner pad dimensions: depth: 24mm, height: 63mm, width 45mm D-shaped.
Foldable: No
Headphone cup connector: 2.5mm TS (mono)
Cable entry: dual sided
Cable: 3m 6.3mm TRS to 2x 2.5mm TS
Driver size: 40mm
Nom. power rating: 0.5W
Max. voltage: 9V
Max. current: 60mA
Max. S.P.L.  124dB
Impedance: 150 Ω
Efficiency: 98dB/1mW  (105dB/1V)
Weight: 270 g.
Clamping force: low
Accessories: manual

Sound description:

The first impression one gets is: Hmmmm a lot of mids and sharp treble.
It is a very dynamic sounding headphone though but not in a realistic way.
The HD700 lacks deep bass.  Bass is ‘tight’ and integrates well with the mids.
The mids do sound a bit ‘cuppy’ and lack in ‘clarity’. It is too ‘laid back’ to be realsitic sounding.
The ‘negative’ sides I feel the HD800 has are worse here. Lacking bass/body, lacking in clarity/presence and sharp overblown treble a fair bit more than the HD800.
Difference being the HD800 may ‘lack’ somewhat in those areas but does this with style and has other properties that make that one great. These properties that make up for its ‘shortcomings’ are lacking here.


Below the frequency response of the HD700 (Left, Right)

FR HD700

Channel matching is excellent. From 100Hz to 1kHz there is a slight (1dB) difference though. Below 100Hz this headphone drops off gradually. No deep rumbles on an impressive level. Bass sounds ‘tight’ because of it and is not bloated or emphasized. The dip from 1kHz to 4kHz may be a little less ‘deep’ in reality compared to the measurement. This is because the measurement rig does not have a Pinna which does alter the response exactly in that area. Still the dip is still there and lowers the clarity/presence somewhat. The peak at 6kHz is peaking above the mids and thus audible. This ‘over accentuates’ certain instruments but may have less over accentuation with other instruments/voices because the peak isn’t very wide.
The treble response looks fine from 7kHz and up and is well extended.
Below the frequency response of the HD700 and HD800 in one plot.
HD700 vs HD800
It certainly has resemblance in tonal balance with the HD800. Somewhat recessed ‘bottom end / grunt’ polite in the mids (dip at 3kHz). It is realistic but slightly lacking in clarity/presence. The treble is accentuated which gives an extra ‘detail’ idea/feeling.
To see tonal balance differences more clearly below the same plot but heavily smoothed.

Tonal bal dif HD700 vs HD800

The HD700 is a bit ‘warmer’ in the mids, has a little less ‘clarity/presence’ and less treble.
Bass levels are about the same.

output resistance / damping-factor

As this is a dynamic headphone the frequency response might be amplifier output resistance dependent when certain higher output resistance amplifiers are used.
To test this the headphone is measured via a low impedance amplifier (0.2Ω) and a high impedance amplifier (120Ω). On a higher output resistance amplifier the output level will be considerably lower. To compensate for this the amplifier is cranked up to the same level (at 1kHz) as the low impedance amplifier. This way the plots are overlay-ed and it is easy to see how the tonal balance changes.
FR HD700 R 120

As can be seen the tonal balance changes when connected to a higher output resistance amplifier. You get about 2dB more mid-bass. This can make the headphone sound a little more ‘muddy/fat’. Lower bass is not boosted. Best to drive this headphone from lower output resistance amplifiers.


Below the distortion plots of the HD700 : (only Right channel shown)
Note that this headphone was measured at ears-unlimited-logo where  background noises were present in the demo room. As this is an open headphone distortion levels and spectrum plot performance may thus be better in reality than as shown on the plots.

The distortion products are shown in dB.

Dist HD700 R

The distortion profile is typical for a dynamic driver. Higher 2nd harmonic distortion in the bass. 2% distortion around 50Hz is not bad but also not a poor value. At 2.5kHz the distortion rises again to about 0.5%. It doesn’t look like the 2.5kHz is a measurement error caused by ambient sounds as this headphone was measured 3x and gave about the same results at that frequency. These are not alarming levels by the way.
Dist HD700 R percent


Below the CSD of the HD700 (Left and Right channel are superimposed)

The CSD shows some little issues but none that would ring any alarm bells as it were…
The treble range above 3kHz does seem to consist of a bunch of (very shortly lived) resonances very close to each other.

Below the spectrum plot of the HD700 (Left channel)Spectr HD700 L

The ‘noise’ in the mids is picked up from the room (around 40-45dB SPL). Aside from some small issues around 2.5kHz and 3.8kHz as well as 5.2kHz the plot seems fine.

By lack of oscilloscope shots (not enough time to measure that) below a step response plot of the HD700 (Right channel)
step HD700 R

The step response clearly shows the lack of ‘body/grunt/bottom end’ as evidenced by the downwards sloping line. Headphones with a good bass extension have a (close to) horizontal line. There is some overshoot followed by some ringing.


This headphone is top notch when it concerns wearing comfort. It’s relatively high price-tag can be justified by this aspect… perhaps.
The lack of ‘body’ may not be an issue to every one. Some will prefer a warmer and more full bodied sound. This headphone is mostly about the mids. The treble has an edge to it. Different than that of the HD800. In that aspect the laid back treble of the HD660S is better.
This headphone may not be liked by everyone. When you are considering this headphone try to audition it with music you are well familiar with, not with demo music selected by the shop that tries to sell it.

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