INTRODUCING MY HEADPHOENES MEASUREMENT SYSTEM
I just finished the process of creating a compensation curve for my pinnae based headphone measurement system.
(My other measurement system is based on the Bruel&Kjaer Artificial Ear 4153 which works without compensation, but does not always show results that can transfer to the real world).
The goal was to get detailed results that represent how headphones do sound in reality, even in the critical high frequency range.
To reach this required lots of measurements, decisions and testing.
Mechanically the Dummy is based on a copy of my own pinnae made from silicon.
The measurement microphone is located at, and seals the ear-canal-entrance.
The compensation curve is based on three parts:
- Multi position measurement of the Dummy's HRTF in a real, extremely high quality listening environment, with focus on the direct sound that originates from the speakers.
Of course the speakers were measured with a traditional measurement microphone too, and this was used as compensation for this measurement.
- Measurement of 30 highend headphones.
- Slight correction based on experience and listening tests.
According bass frequency response target:
There is no Harman Type Target Curve bass boost included in the compensation, the range below 1.6 kHz is a flat line.
My measurement will show a Headphone's real objective frequency response in the bass.
My system does not have any irregularities below 1.6 kHz, so no compensation needed there.
In my opinion, this way it's much easier to interpret what's going on in the low frequency range.
If headphones have a bass boost I want to see it and not the boost being eliminated by a Harman bass target curve.
Neither I want to see a rolloff on a headphone like the AUDEZE LCD2 which objectively does reach down to 5 Hz without drop in level.
I think the amount and shape of a needed bass boost is very personal, and very much depends on the music style and loudness level people use the headphones with.
There is no place for personal taste in objective measurements, as far as this is possible with headphones.
Now comes the Mobius related part:
Here is what I get when I measure the Mobius, for comparison along with two very famous high end headphones - with completely different constructions!
The well known characteristics of each of those is clearly visible in detail, and the curves speak for themselves.
Watch out for the unusual fine scale of only 1 dB/line, making detailed observations much easier.
Green: STAX SR-009
Orange: AUDEZE Mobius Firmware V5, Flat preset with 3-D off.
Blue: Sennheiser HD-800S