Beyerdynamic DT 240 Pro Affordable Over-Ear Sealed Headphones Measurements

Click on graphs image to download .pdf for closer inspection.

Raw frequency response plots show that even though this is not a fully over-ear headphone, frequency response canges very little with changing position on the head. This is a remarkably stable response; this headphone's sound will be quite consistant when taking it on and off the head.

Bass response is a broad hump centered at around 70Hz and elevated about 7dB at that point. Elevated response continues up to 350Hz, which is a bit too high resulting in a slightly thickened sound in the low midrange.

Response above 350Hz is quite close to the neutral target, rising slowly at first then faster above 1.2kHz to the 10dB peak at 3kHz. This gives vocals a nice natural balance between fundamental and overtones.

The 3kHz peak is a couple of dB low, and subsequently falls off 15dB at 5.5kHz. This causes the headphones to sound a little laid back. Unfortunately, the missing consonant sounds in this area seem to cause the vocal fundamentals and overtones to sound a little shouty in comparison.

Treble above the notch at 5.5kHz returns to a peak at 9kHz. Overall energy above about 7kHz is about right, but response is a bit rough. I tend to hear this as cymbals not taking on their full heft of resonances and sounding a bit thin.

30Hz square wave has pretty good shape with a tilted but linear top. This measurement would indicate good phase response in the bass, which is a bit surprising given the moderately strong primary driver resonance centered at 80Hz as seen in the impedance response and the humped bass response. 30Hz square wave looks a bit better than the sound I heard in the bass; problems likely come from bass distortion as seen in the THD+noise plot.

300Hz square wave has an appropriately scaled initial transient, and is nicely noise-free thereafter. The upward tilt is too strong, however, evidencing this headphone's warm character.

Impulse response is a little weak on the initial transient and following waveform is a bit rough. This likely points to the uneven treble response of the DT 240. Fortunately, the impulse settles down quite quickly and noise is fairly low after 600uSec. This, coupled with the fairly low distortion plot above bass frequencies, indicates a clean sounding headphone. Maybe it was the unevenness of the treble, but I didn't hear these cans as particularly clean or coherent sounding. On the other hand, I was often surprised by the nice imaging of the headphone, which might be where this goodness showed up.

Impedance plots shows a nominally 42 Ohm headphone with a moderately large primary drive resonance of 55 Ohms at 80Hz. This curve is remarkably feature-free in the 1kHz-5kHz area indicating a well controlled driver that isn't breaking up. Frankly, I applaud Beyerdynamic for bucking the trend towards bigger drivers and sticking with a 33mm diameter driver. In my view, the smaller the driver, the less likely you are to have problems with modal break-up.

Isolation is fairly good, and remarkaly so considering it's not really a full-size ear pad.

Needing only 57mVrms to achieve 90dBspl at the ear, the DT240 will play plenty loud from phones and portable devices.

beyerdynamic Inc. USA
56 Central Ave.
Farmingdale, NY 11735
(631) 293-3200