I measured the Wave 5s using a G.R.A.S. Model 43AG ear/cheek simulator, a Clio 10 FW audio analyzer, a laptop computer running TrueRTA software with an M-Audio MobilePre USB audio interface, a Musical Fidelity V-CAN amp for most measurements, and an Audio-gd NFB-1AMP amplifier for distortion measurements. On the G.R.A.S. Model 43AG, I used the original KB0066 simulated pinna for most measurements, as well as the new KB5000 pinna for certain measurements (as noted). These are “flat” measurements; no diffuse-field or free-field compensation curve was employed.
The Wave 5s’ frequency response is a little unusual, but not crazy unusual. Normally we see a pronounced peak around 2.5kHz, but here it’s a gradual peak rising from about 500Hz. Note also the strong peak at 6kHz. It’s common to see a second treble peak, but usually it’s about 6dB lower than the peak at around 2.5kHz. This is probably the cause of the occasional mid-treble brightness I heard. Note also the hashiness between 500Hz and 2kHz; I’ve seen this in some other planar magnetics, but I can’t recall seeing it so pronounced.
This chart shows the Wave 5s’ measured right-channel frequency response, measured with the old KB0066 pinna (which I’ve used for years) as well as with G.R.A.S.’s new KB5000 pinna, which I’ll be switching to because it more accurately reflects the structure and pliability of the human ear. I’m including this mostly for future reference rather than as something you should draw conclusions from; I intend to show both measurements in every review for at least the next year, before beginning to use only the new pinna.
This chart shows the results of adding 70 ohms output impedance to the V-CAN’s 1 ohm, to simulate the effects of using a typical low-quality headphone amp. There’s no audible difference in the response, which means the Wave 5s’ tonal balance won’t change with a change in amp.
This chart shows the Wave 5s’ measured right-channel frequency response compared with some other high-end open-back headphones. The Wave 5s’ response looks, at first glance, flatter than the others above 100Hz, but in general, a headphone that sounds subjectively flat will have more of a bass hump, plus a strong peak at about 2.5kHz and a less-strong peak around 6kHz. The Tidal Forces also seem to have the most restrained bass response of all the models represented here.
The spectral-decay (waterfall) chart shows a strong resonance at about 400Hz, and another at that frequency’s second harmonic, 800Hz. Above 1kHz are some more very narrow, “hashy” resonances, but this is fairly common for open-back planar-magnetic models.
The Wave 5s’ total harmonic distortion (THD) is slightly high, at 1% to 3% below 1kHz, but I doubt that such a level of THD in a transducer would be readily audible. Unusually, raising the level to 100dBA -- which is extremely loud -- had a minimal effect on the distortion measurement.
In this chart, the external noise level is 75dB SPL; the numbers below that indicate the degree of attenuation of outside sounds. (Note: I took this measurement before I switched to measuring at a level of 85dB instead of 75dB. That doesn’t change the way the isolation curves look, but an 85dB level lets me get better measurements of noise-canceling headphones, which demand a lower noise floor.) The Wave 5s offer a tiny bit more isolation than typical open-backs, but not much compared to the closed-back and noise-canceling models also included in this chart.
As with most planar-magnetic headphones, the Wave 5s’ impedance magnitude and phase are dead flat, in this case at 31 ohms.
The sensitivity of the Tidal Force Wave 5s, measured between 300Hz and 3kHz with a 1mW signal, is 103.2dB. That’s excellent for planar-magnetic headphones, and enough to ensure that the Wave 5s will play loudly from any source device.
. . . Brent Butterworth