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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.
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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Sony MDR-1A


The Sony MDR-1A is a nicely made headphone with a luxurious feel about it. It also exists in black (with red accents) and in various iterations with bluetooth, noise cancelling etc.

The headphone can easily be driven directly from portable devices. The efficiency of the 40mm diameter driver is quite high (105dB/mW). The impedance is around 50Ω.
The combination of high efficiency and a, slightly higher than usual for portable headphones, impedance makes the headphone sensitive enough to be driven with a low output voltage (portable equipment has low output voltage levels) yet not draw currents as high as lower impedance (think 16 to 32Ω) do which is also beneficial for portable equipment.
The headphone folds flat so is easily transportable in a suitcase.
It comes with 2 cables and a carrying bag in a somewhat luxurious looking box.
Both 1.2m cables are detachable and have 3.5mm TRRS plugs on both sides. These are round thin and reasonably supple cables. One of them has a microphone + button in the cord the other one does not.
The headphone side has a straight connector, the source side an angled connector.

The headphone is not extremely lightweight but certainly not heavy either. The pads are very soft and compliant. They provide a good seal, even when wearing (reading)glasses.
They do tend to get a bit sticky when they become sweaty.
The fit and  comfort is very high. The clamping force is just right.

The sound signature is overly warm and bassy. Well suited for pop music and bright recordings.
For well made recordings the headphone is far from accurate/realistic. The bass is overblown and ‘bleeds’ in the mids which gives a somewhat muddled sound.

The mids are warm and lack ‘brilliance’and ‘clarity’.

The treble is slightly elevated in a particular area but O.K. at other frequencies. The treble has a small ‘edge’ to it.
Not particularly highly detailed but rather smooth. Detail whores might be disappointed.
The upper frequency extension (as well as the lowest octaves) are well extended.
The treble is just not vibrant and splashy but slightly subdued and ‘soft’.

Below the frequency response of the MDR-1A. left, right matching is excellent !


The overly bassy character is obvious. The elevation from 100Hz to 300Hz makes the bass ‘bleed’ into the mids. The 5dB decline to 4kHz gives the headphone a ‘warm’ character in voices and instruments. Lacking some clarity in better recordings. However, that gradual slope works quite well when listening to compressed (loudness wise, not file size) music.
The peak around 8kHz gives the impression of detailed sound but may also give a slight sharpish ‘etch’ to it.

The MDR-100AAP is a newer model, slightly cheaper but clearly related. Those looking for better clarity, more towards ‘neutral’ may prefer the MDR-100AAP.
Below the differences between the MDR-1A and MDR-100AAP. The differences in amount of bass, especially in the 60-300Hz region is obvious and in favor for the MDR-100AAP.


Below the distortion plot of the MDR-1A.


What’s obviuous is that the 2nd and 3rd harmonics are rather high at the lower frequencies. This together with the 100-300Hz elevated area makes the bass a bit wooly. overblown and not tight/well defined. Also the distortion peak around 5kHz doesn’t deserve much praise and is audible as a somewhat less defined treble.

The speed of the driver is good. The CSD below shows a few very short lived resonances.
500Hz lingers on a bit more than disirable. Overall quite good performance here.


Below the spectrum decay down to 100Hz. This plot shows that the lower frequencies linger on a bit longer than desirable. It also suggests there are certain frequencies the membrane prefers to resonate at spaced apart at (almost) multiples.


Not all people may prefer the overblown bass/warmth.
Those that would like the bass to be somewhat less but still like to have it sound warm/smooth might be delighted to hear that a more neutral tonal balance is easy to create without having to take the headphone apart. The headphone does not become ‘neutral’ though but stays warm but the bass doesn’t bleed in the mids nor over-power the rest.
On top of the earcup there is a small port that ‘improves’ the bass according to Sony.
There is a small port + a slit with cloth covering on it.


With these ports open the bass is boosted, covering this  tube/port only, slit only or both changes the tonal balance below 300Hz .
Below 4 plots of the same headphone but with slightly different tonal balance due to the port on the top of the ear cup being (partly) closed.


In the purple trace the effect of 1mm thick felt in front of the driver is visible.
The 1mm thick felt (1 layer of 3-ply toilet paper has about the same effect) lowers the 9kHz peak by a good -4dB which takes the ‘edge’ out of some recordings while not affecting the overall amount of treble.

When you are looking for a warm sound but without overblown lows and soft highs then covering the whole port + adding some 1mm thick (crafts) felt or 1 layer of toilet paper will help. Closing the ports is very easy by simply putting in a small amount of maleable eraser or newplast clay. Can easily be removed as well so easily reversible.
Removing the pads is an easy but scaring task. You have to pull the pads off. They are clamped on plastic posts so takes some force and may make sounds as if something breaks/snaps.


Once the pads are off cut some felt (or toilet paper) in the same shape as the black paper on the driver and put it on there. Press the pads back on (make sure the pads are properly seated again all the way around)


The benefits of this procedure (only for those who find the MDR-1A way too bassy and have an ‘edge’ in the treble sometimes) are shown below. Stock, port closed + felt


Below the squarewave plots of the stock MDR-1A (on the left) and modified on the right.


Personally I like a more ‘present’ sound with a better clarity and tight subbass rumble bass instead of bloated/fat bass. For this reason I also made a Kameleon filter module for it.

It ‘removes’ the warmth/fatty sloppy bass and replaces it with a tight and clear sound with excellent highs. Stock and via Kameleon. Still has big/deep bass (that’s what owners bought it for) but clarity is added because the muddy lower mids are gone and treble quality is improved.


Overall this is a nice looking and comfortable headphone. Quite suited to be connected to mobile phones (microphone/remote in the cable) and the efficiency which is high enough.
Also works well of desktop equipment
The sound signature is overly warm and bassy.
Those that really dig ‘warm’ sound and don’t like too much clarity but are looking for a subdued sound or listen at low loudness levels may like this headphone.
Mids are warm but lacking somewhat in clarity and brilliance.  It is not particularly highly detailed but rather smooth in the treble. Detail whores might be disappointed and might want to look elsewhere.
The upper frequency extension (as well as the lowest octaves) is excellent.
The treble is just not vibrant and splashy but slightly subdued and ‘soft’ and not its strongest point.

The good:

  • design
  • weight
  • suited for portable usage
  • folds flat for easy transort
  • clamping force
  • comfort
  • removable pads
  • interchangeable cable
  • warm sound

The less good:

  • resolution (finesse)
  • lacks brilliance and clarity compared to more neutral headphones
  • A bit ‘boring’ in the treble, lacks sparkle / lively-ness / dynamics / realism.

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