I measured the Brainwavz S5s using a G.R.A.S. Model RA0045 ear simulator, a Clio 10 FW audio analyzer, a laptop computer running TrueRTA software with an M-Audio MobilePre USB audio interface, and a Musical Fidelity V-Can headphone amplifier. Measurements were calibrated for drum reference point (DRP), which is roughly the point at the center of the eardrum (in this case, the center of the measurement microphone). I used the largest silicone eartips because those best fit the RA0045. This is a “flat” measurement; no diffuse-field or free-field compensation curve was applied.
The S5s’ frequency response shows that they’re something a little different. See that big peak in the response centered at 6.8kHz? Move it down to about 3kHz, drop it by about 5dB, and you’d have a totally normal, “by the book” earphone response. But as you can see, the response is very smooth through most of the audioband, and the average amount of treble energy pretty well balances the average amount of bass energy.
Adding 70 ohms to the V-Can’s 5-ohm output impedance, to simulate the effects of using a typical low-quality headphone amp, has the completely insignificant effect of elevating the S5s’ bass response by 0.5dB at 10Hz.
It’s interesting to see how similar the response of the Brainwavz S5s is to that of the NAD Viso HP20s, the earphones that so closely resemble it. But there are differences: the NADs have a little more bass, a little less treble. The Sony XBA-H1s have a flatter overall response than either competitor, but considerably less treble energy above 5kHz.
The S5s produce an extremely clean spectral-decay plot, with no significant resonances except a couple of very well-damped ones at 9.5 and 13kHz, which correspond with the response peaks that show up in the frequency response.
The S5s’ total harmonic distortion (THD) is very, very low. At 90dBA, the distortion basically disappears into the noise floor at frequencies above 100Hz. At 100dBA, it rises to about 2.2% at 20Hz -- still exceptionally low, especially considering that 100dBA (measured with pink noise) is an extremely loud level.
In this chart, the external noise level is 75dB SPL; the numbers below that indicate the degree of attenuation of outside sounds. The S5s’ isolation is outstanding for universal-fit earphones, reducing noise at 1kHz by about 30dB, and reducing noise at about 3kHz by as much as 47dB. Note that your results may not be as good, depending on the size and shape of your ear canals and on the eartips you use.
The S5s’ impedance is fairly low, running almost dead flat at 17 ohms. The impedance phase response is essentially flat up to 10kHz.
The sensitivity, measured between 300Hz and 3kHz with a 1mW signal and calculated for the rated impedance of 16 ohms, is 105.1dB. That’s about average, and should be plenty enough to get you ample volume with any portable device.
. . . Brent Butterworth