Reviewed on: SoundStage! Solo, August 2020
I measured the DT 770 Studio headphones 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 an Audio-gd NFB1-AMP. 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 above chart shows the frequency response. This curve is pretty standard; fill in that upper bass dip around 200Hz and reduce the energy between 4kHz and 9kHz by a couple dB, and you’d have a “by-the-book” curve.
This chart shows how the DT 770 Studios’ 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. The only difference with the high-impedance source is a boost of about 1dB in the bass, so it’s unlikely your choice of headphone amp will affect the headphones’ tonal balance.
This chart shows the DT 770 Studios’ right-channel response compared with several open-back planar-magnetic headphones -- including the AKG K371s, which are said to be within ±1dB of the Harman curve. This is a very straightforward voicing, so it’s highly unlikely anyone will find these headphones to sound weird or unnatural.
The DT 770 Studios’ spectral-decay plot looks pretty clean, except for a resonance centered at about 200Hz, but after just one cycle (5ms) at that frequency, the resonance is already down to -30dB, so it shouldn’t be troublesome.
Distortion in the DT 770 Studios is fairly high in the bass, even when measured with the powerful Audio-gd NFB1-AMP. At 90dBA (measured with pink noise), it breaks 5% at 30Hz, and at 100dBA, it hits 14% at the same frequency. Note, though, that bass distortion isn’t as audible because the harmonics it produces are at low frequencies and your ears are not so sensitive there; the generally accepted audibility threshold for subwoofer distortion is 10%.
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 DT 770 Studios is comparable to that of similarly sized closed-back headphones. I added the Sony WH-1000MX4s so you could see how headphones with noise canceling perform in this test.
The DT 770 Studios’ impedance magnitude and phase curves are fairly flat, with the magnitude averaging about 100Hz.
Sensitivity of the DT 770 Studios, measured between 300Hz and 3kHz, using a 1mW signal calculated for 80 ohms rated impedance, is 95.8dB, which means you’re best off driving these with an external amp or DAC-amp, or a high-quality portable music player.
. . . Brent Butterworth
brentb@soundstagenetwork.com