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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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Pioneer SE-300

The reason why the Pioneer SE-300 is measured is not because of it’s sound quality. This is quite an old headphone (1976) but that’s not what is so special about it.
This is one of the very few piezo-electric headphones out there. The driver differs completely from what’s normally used in headphones.
This was the entry level headphone in that range. The SE-500 and SE-700 were the bigger brothers … or eunuchs as they appear to be lacking balls.
Most headphones are dynamic types. They can be either ortho-dynamic (flat membrane with wires on it sandwiched in a magnetic field (or only having a magnetic field on one side) or have a cone with a voice-coil attached to it. The voice-coil can make a piston like motion in a magnetic field around it.
I’ll exclude the ribbon driver which is very rare.
Then there are the electrostatic (also planar, meaning a flat tensioned membrane) and electret drivers. The electrostatic one needs a high bias voltage (several hundred volts) and a high voltage audio signal applied to it where the electret has a ‘fixed’ charge so works without the DC bias voltage but does need a high voltage audio signal.
Usually though transformers or special high-voltage amplifiers.
A piezo-electric driver is closest to an electret driver but only in the sense that both are capacitive (unlike dynamic ones which are Ohmic) and don’t need an extra DC bias voltage.
The Piezo-electric driver produces sound by the material (in this case the membrane) which flexes/expands when a voltage is applied.
One can find piezo drivers in loudspeakers. They are used in a horn (because of their poor efficiency) but only in tweeters.
The big disadvantages such drivers have are…
A: The load is highly capacitive and can de-stabilize amplifiers
B: It needs quite some voltage to operate (low in efficiency)
C: It can’t make large excursions so … no bass.
So this (it being piezo-electric) is the only reason it is on this website.


Type: On ear, open
Usage: Home.
Driver type: piezo-electric
Pads: non replaceable,  pleather.
Collapsible: No.
Headphone connector: fixed
Cable entry: single sided (left)
Cable: 2.5m with a  6.3mm TRS jack
Driver size: 8,5 µm thick membrane 60mm x 70mm
Max input voltage: 30V
Max. S.P.L.  119dB (calculated)
Impedance: capacitance of around 80nF (0.08μF)
Efficiency: 90dB/1V (I suspect the real value is lower than this number)
Weight: 280 g.
Clamping force: medium

Sound description:

This headphone is all about the mids and treble. There is absolutely no bass/body to speak of. For that reason the sound is ‘thin’.
The sound quality of those mids (and treble) is very high and smooth. No sharpness or sibilance.
This needs to be connected to the output terminals of a speaker amplifier (max 200W/Ω or 100W/8Ω) to make sound. Can’t be driven by portable equipment at all.
Even with a power amplifier the sound remains ‘thin’. Using tone controls can slightly warm up the mids but no bass will ever come out of these headphones.
Judging from the specifications it says 20Hz to 20kHz so maybe the one I have is defective (membrane can’t move/swing any more) and may open up the driver so see what’s wrong with it. However, the plots I found from the top of the line SE-700 shows a very similar bass response. But these plots show a nice response down to 100Hz (K500 style) what means these drivers could be defective but in a similar way for left and right.
Could also be that the flaked off vinyl from the pads makes some difference as well.
The driver seems not to be serviceable and seems to be glued together.


Below the frequency response of the SE-300 (Left, Right)FR 300.pngThe channel matching above 400Hz is excellent. period.  The tonal balance is .. well bass less. The bass starts to fall off quickly below 500Hz. At 30Hz (where the lowest bass signals are) it is already -30dB.
From 500Hz to 10kHz it is extremely ‘flat’. From 10kHz to 20kHz it is only -5dB

The mids and  treble sound quality is excellent. One should build a 2-way system with these drivers.

Below the distortion measurements of the SE-300 (Left channel).DIST L SE300

Distortion levels are not very high >400Hz. Below 400Hz down the distortion increases so boosting the lows will increase distortion even more.

Dist L percent 300

Below the CSD (Waterfall plot) of the SE-300. (Left and Right channel are superimposed)
CSD SE-300

This plot looks pretty decent. a small, narrow and short resonance at 6kHz aside this looks very clean and fast.


This Pioneer SE-300 is a very old headphone with (possibly) defective drivers. There is foam against the membrane which may have decayed and cause this frequency response. I may attempt to repair it… or buy a second one.
To drive it with some authority you really need an amplifier that can supply enough voltage such as a speaker amp.

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