DT770 Pro (250Ω)

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NO SMOOTHING is applied to the shown plots. Most measurement sites have some smoothing applied which ‘irons flat’ sharp peaks and ‘wiggles’. I do not use smoothing because some info about sound quality is lost when plots are smoothed.

Aside from a small correction of the microphone itself also some correction in the lowest frequencies is applied to the plots to compensate for the perceived loss of bass when using headphones. This is described HERE in more detail.
A ‘horizontal‘ frequency response curve on the shown frequency response plots on this website thus indicates a perceived ‘flat’ tonal signature.

ALL measurements are made with a good SEAL on a flatbed measurement rig.
shape of your head, bone structure, pad size, pad ‘softness,  (compliance), hair or no hair and or wearing glasses may (drastically) change the frequency response of some headphones, so… your personal experience may differ substantially from these plots.

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Beyerdynamic DT770 Pro-250Ω

DT770 Pro 250The DT770Pro250Ω is often seen in studios. It has a quite good attenuation of outside noises, is comfortable and durable. A very sturdy headphone.
Like the DT990Pro-250 below this headphone has a long and curled cable with a 3.5mm plug + 6.3mm adapter.
Not suited for on the go, but well suited for on-site recordings etc.  Far more comfortable than the often used Sennheiser HD25 in those situations for sure. The clamping force is moderately high, but not killing.

Below the (not smoothed) frequency response of the DT770Pro (Left, Right)

dt770 pro-250

There is something ‘odd’ about this measurement around 4kHz. When you take a look at the DT990 Pro below you will notice a small ‘dip’ at the same frequency. Here it is rather big and almost completely ‘nulling‘. At first I thought it was a typical measuring error as I did not hear the dip while running the sweep. Also when measuring this headphone using white-noise the dip is there but not nulling like in the plot above.
The CSD below provides a clue as to what’s happening.
The deep null is hidden ‘behind’ the wall and when using white noise (or music) the dip isn’t there.

dt770 pro-250 csd

So…. below the ‘corrected’ frequency response as it sounds like and the white noise measurements suggest. It is made from the non-smoothed original measurement where the sharp dip has been ‘replaced’ with a heavily smoothed (1/3 octave) part of the same plot.
This ‘corrected’ plot is shown below and am quite confident it is closer to the truth than the ‘real’ plot.

dt770pro fr

The DT770Pro goes etremely low and easily reaches an inaudible 10Hz. The mids are quite decent. The treble is ‘peaky’ and bright. Sibilant on some recordings. It appears highly detailed. The treble also is slightly less ‘smooth’ than the DT990, a bit coarser/rougher.
It is much less ‘forgiving’ than the DT990 and doesn’t appear to have ‘sucked-out’ mids. The mids aren’t very ‘silky’ but do sound pretty ‘forward’ and dynamic. The bass is another story. Much deeper and more impressive than the DT990 and not as ‘bleeding/warm’ into the mids either. BUT…. the bass isn’t very ‘accurate’ and a bit ‘loose’. This DT770Pro did sound better than the older DT770 I previously owned (as I remember it) as that one had a very ‘one-note’ and ‘resonating’ bass. The Pro version is better in this aspect but sounds somewhat ‘less’ in the upper mids. Still the bass quality isn’t excellent.

felt rings 770While ‘investigating’ the odd ‘4kHz dip’ I opened the cups and played with wool and damping materials inside, which lowered the amount of bass but the dip remained the same. Only when I removed the felt ‘ring’ around the back of the driver the dip became much smaller and narrower BUT the bass sounded one-note and even more accentuated again.
Much like how I remember the DT770 sounded that I owned a while ago.

Below the stock DT770Pro (left channel) and with the felt ring removed (see picture on the left). When filling the cup with wool the bass got lower and better but the dip became deeper and wider again.
no inner felt ring (grn) vs stock (blue)ue)
Adding wool when the felt ring was there resulted in slightly more balanced lows but not in a higher quality though.
To remove some of the piercing treble/sibilance I once again turned to my trusted 3 thick felt in front of the driver.
Below the results of the DT770Pro with 3mm thick wool-felt in front of the driver (replacing the foam disc).

stock + 3mm felt
The higher frequencies (treble) have improved and it sounds much less sibilant. The treble is still elevated and the DT770Pro thus retained its ‘character’ but in a more pleasant way. This simple, and easy to revert back, modification increases the SQ of this headphone and is worth trying. You do sacrifice a bit ‘ear-room’ inside the cup but when the foam disc is removed this is just 1 mm or so.

I think this headphone is great for monitoring purposes. Especially when having to wear it for longer periods. In that case it is better suited than the Sennheiser HD25. They are not suited for a final mix nor to apply EQ to individual tracks, monitoring only.
As a Hi-Fi headphone I find it lacks ‘finesse’ is a bit ‘strange’ in the mids, but not in a bad way. While seemingly having an impressive bass the quality of bass is lacking somewhat when compared to better headphones in this aspect.

The bass quality difference between the DT770Pro-250 and DT990Pro-250, aside from the obvious differences in frequency response is also visible in the CSD (Waterfall plots)

On the left the CSD of the DT770,   on the right the CSD of the DT990, notice the difference in resonances below 100Hz.

CSD DT770ProCSD DT990Pro

There is also a Kameleon filter designed for the DT770Pro-250. It should be noted that this filter will ONLY work correctly with the DT770Pro-250 and NOT with the countless other variations that exist. All of these variants have different frequency responses.

Below the plot of the stock DT770 Pro-250 and when used with the Kameleon amplifier with DT770 module:

dt770The bass is still deep but slightly less prominent. The treble peak has been removed. The overall sound signature is very realistic yet not super refined.  find it an improvement over the stock DT770 which IMO is a bit too bright and ‘boomy’. Bass extension is well below 10Hz !

Below L and R of the DT770Pro-250 via the Kameleon:

dt770pro 250 on kameleon final version

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