Reviewed on: SoundStage! Solo, October 2020
I measured the Technics EAH-TZ700 earphones using laboratory-grade equipment: a G.R.A.S. Model 43AG ear/cheek simulator/RA0402 ear simulator with KB5000/KB5001 simulated pinnae, and a Clio 10 FW audio analyzer. For isolation measurements, I used a laptop computer running TrueRTA software with an M-Audio MobilePre USB audio interface. The headphones were amplified using a Musical Fidelity V-CAN and a Schiit Magnius. These are “flat” measurements; no diffuse-field or free-field compensation curve was employed. If you’d like to learn more about what our measurements mean, click here.
The frequency response of the EAH-TZ700s is pretty standard for dynamic earphones. At a glance, the only thing even slightly unusual is that the bass output is proportionately high relative to the upper-midrange and treble peaks; I’ve seen this in a lot of mass-market models, but it’s not as common in earphones targeted at audiophiles.
This chart shows how the EAH-TZ700s’ tonal balance changes when they’re used with a high-impedance (75 ohms) source, such as a cheap laptop or some cheap professional headphone amps, or some exotic tube amps. There’s no difference, so the tonal balance of the earphones won’t change when you change source devices, provided the response of the source device is flat.
This chart shows the EAH-TZ700s’ right-channel response compared with several other earphones -- including the AKG N5005s, which are the earphones said to measure closest to the Harman curve, when used with the reference filter attachment. As you can see, the norm seems to be a little more treble and a little more bass. You can also note in the AKG’s curve the reduced response between 100 and 300Hz, which is characteristic of the Harman curve.
The EAH-TZ700s’ spectral decay plot shows no significant resonances.
Harmonic distortion in the EAH-TZ700s is insignificant even at the crazily high listening level of 100dBA, measured with pink noise.
In this chart, the external noise level is 85dB SPL, and numbers below that indicate the degree of attenuation of outside sounds. The lower the lines, the better the isolation. The isolation of the EAH-TZ700s is quite good for passive earphones. I also threw in the measurements of Ultimate Ears UE5 earphones (which were custom-molded to my G.R.A.S. ear/cheek simulator) and the new Bose QC earbuds so you can see how a good universal-fit model like the EAH-TZ700 compares with them.
The EAH-TZ700s’ impedance magnitude is flat at 36 ohms (which is why its response doesn’t vary with the source impedance), and the impedance phase angle is also quite flat.
Sensitivity of the EAH-TZ700s, measured between 300Hz and 3kHz, using a 1mW signal calculated for 37 ohms rated impedance, is 106.7dB, so any source device can easily drive them.
. . . Brent Butterworth