HD 2.20

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published: Jul-1–2017, updated: Jul-10-2019

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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 HD2.20


The HD2.20 is an entry level closed on-ear headphone with a remote/mic in the headphone cable. It is designed for usage on the go (portable) connected to a phone or MP3 player. It retails for around € 60.- It is very light weight. Despite this being an on-ear the clamping force is not high. Yet, it stays on nicely when moving around due to its light weight.


Type: Over ear, closed, wireless
Usage: Portable, commuting, office
Driver type: dynamic
Pads: pleather (fake leather) and cloth in the middle part
Foldable: yes, but can not fold the earcups flat.
Headphone connector: 3.5mm TRS
Cable entry: single sided entry (left side)
Cable: 1.4m angled 3.5mm TRRS  with inline mic/remote
Driver size: 25mm
Max power rating: unknown
Max. S.P.L.: unknown
Impedance: 26 Ω
Efficiency: 96dB/1mW  (112dB/1V)
Weight: 246 g.
Clamping force: medium
Accessories: none

Sound description:

Bass is decent and certainly not bloated. Even though it measures as if it is having big bass  (because of perfect seal) in practice the seal may be partly broken. This depends on the shape and size of the Pinnae as this is an on-ear headphone.
So good bass for some, for others this may be less.
What this headphone does best is mids. It is forward and clear but lacks in brilliance and details in music. Hi-Fi fans should look elsewhere. The treble is the weak point.
It is sharp and grainy and lacks brilliance and details. Efficiency is quite decent and plays loud enough (with that treble) directly from portable devices. No need to amp it… pointless.
When compared to HD238 for instance the HD238 is more ‘fun’ and more ‘musical/enjoyable’. The HD2.20 however, is much clearer sounding. The HD238 sounds recessed in the mids where the HD2.20 is the opposite.


Below the frequency response of the HD2.20 (Left, Right)

FR HD2.20

The frequency plots appear to show this is a balanced headphone with a slight emphasis in the bass. Whether or not this applies to the one wearing it depends on the shape of the ear. Can be a hit and miss… audition if you want to know. From 300Hz to 3kHz it is slightly rising so the mids are just a tad more ‘clearer’ than realistic. The dip between 4kHz and 6kHz is responsible for the lack of clarity/brilliance. The treble peak and fast roll-off are responsible for the poor treble response. Lack of details and ‘air’ and a sharp/grainy treble because of the elevated sharp treble peak.

The frequency response, nor other characteristics, change when the headphone is fed from a higher source resistance. So no need to worry whether or not the few Ohm output resistance of your phone will alter the sound…. it won’t. from 0.2Ω and 120Ω source (level matched at 1kHz to show tonal balance issues. From a higher output resistance amplifier it will play 15dB softer.

FR HD2.20 R 120

Below the distortion plots of the HD2.20 : (only Right channel shown)
The distortion products are shown in dB.

Dist HD2.20 R

The distortion profile is typical for a smaller sized dynamic driver. Higher 2nd harmonic and 3rd harmonic distortion in the bass. 1% isn’t really bad though and the bass does sound pretty good. The 2% distortion spike around 5kHz and 1% at 8kHz certainly doesn’t help with the treble reproduction which is … well … poor.

Dist HD2.20 R percent

Below the CSD of the HD2.20 (Left and Right channel are superimposed)
CSD HD2.20

The CSD shows some issues around 1.5kHz, 3kHz and a narrow one at 8kHz.

Below the spectrum plot of the HD2.20 (Left channel)Spectr HD2.20 L

Just like the CSD above (this plot basically is a CSD seen from the top and with different scales) the 1.5kHz and 3kHz issues are visible. Otherwise pretty clean.

below a step response plot of the HD2.20 (Left channel)
Step HD2.20 L

The step response shows a good impulse response albeit with some poorly damped ringing.
Below the Right channel.
Step HD2.20 R

Driver matching is different when it concerns impulse response. The right channel is much better damped and looks quite good and ‘balanced’.

Below 40Hz and 440Hz square-wave responses and 100μs needle pulse.


The 40Hz square-wave response shows a slightly elevated and well extended bass response (remember, seal dependent) The 440Hz square-wave shows some overshoot indicating the mids are ‘brighter/clearer’ than neutral. The needle pulse looks really good (Right driver). The widening at the bottom reveals ‘stopping’ the movement is a bit over-damped.


This headphone can fold up is sort-of stylish, has a microphone/remote and thus is suitable for connection to phones etc. It plays loud enough and has good bass quality. Mids are also clear and forward. The downside is the treble.
When your only music source is 128kbs MP3 the poor treble quality won’t be problematic.
Not for Hi-Fi afficionado’s but they will be looking in another price range anyway.
Good enough to replace standard earbuds.


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