DT990 (600Ω)

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published: Jul-17-2013, updated: May-9-2021

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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.

Frequency response (tonal balance) is the most sound-determining aspect of headphones. A horizontal line shows audible neutral response in the plots on this website. Deviations in different severities at different frequency bands have an effect on the sound character.
The bigger the deviation the stronger the effect.

Below an aid to help determining the sound character of headphones with relation to the frequency response.

sound descriptions mine

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Beyerdynamic DT990-600Ω


This is an oldie (around 33 years old) and one driver has failed 2 times already. Fortunately I was able to repair it again. The drivers are not the same as the current DT990 (of which some variations exist) and this one is 600Ω. It thus requires a higher VOLTAGE to drive it loud. This was my first ‘serious’ headphone and still sounds quite nice and ‘forgiving’ a bit on the romantic side of things. Somewhat full (bassy) with clear highs but lacking a bit clarity in the upper midrange thus sounding quite ‘warm’. The frequency plot shown below shows the reason for this. Elevated bass and a peak in the 8kHz region. The upper mids are thus a bit lower and is why some call the DT990 sucked out in the mids. It misses the clarity but at the same time means it sounds ‘warm‘. Bass goes deep enough (50Hz is low enough for bass, everything below that is sub-bass) and the treble extension is excellent. The DT990 sounds very airy and smooth. left, right

dt990-600 nieuwe meting

This headphone measures (and sounds) quite similar to the current DT990 Edition (600Ω) version b.t.w.

A look at the CSD below shows why it sounds so smooth, detailed and airy… no ringing. The DT990 has lots of damping materials all around the driver and in the cups. This might very well have something to do with the nice behaviour and very detailed sound. It doesn’t come close to a good ortho or electrostatic headphones BUT it is a good dynamic headphone with a great sound quality.

dt990 wf l new pads

The original pads that came with this headphone have been replaced 2 times already (the foam rubber inside disintegrates) so the plots above have been made with new pads that are thicker and less compliant (soft).

This is one of the great oldies. I prefer it over the DT770 and DT880 as this is the more ‘fun’ and ‘nice’ sounding headphone of that bunch. A recommended headphone. If I were to buy one again these days, which I won’t as I have better ones, I would buy the latest DT990 Pro-250 version.

Of course this headphone can be used on the Kameleon amplifier with a DT990 module in it.
DT990-600Ω stock, DT990-600Ω on Kameleon, the treble has lost its edge but is still nicely present (Beyer like).
The Warmth and lack of subbass has been replaced with very realistic bass and mids. Not a subtle difference at all.

DT990 600 filterplotsThose that like the Beyer sound as it is but aren’t really fond of the ‘hot’ treble can improve that part by using 3 plies of soft toilet paper and position that in front of the driver. Below the ‘stock’ DT990-600Ω and the same headphone but with 3 plies of toilet paper.

DT990 600 vs DT990 -600 3 ply

As can be seen the treble peaks are lowered but the treble extension is still the same, no roll-off, just the peaky level reduced.

Below the FR of the DT990-600Ω with 3 plies of toilet paper: Note the freq range in the plot below is from 10Hz to 30kHz.

DT990-600 TP 30kHz

The ‘U shape’ is still there, the subbass is still missing but the treble is less ‘hot’.

Below the distortion plot of the DT990 with 3 plies of toilet paper:

DIST DT990-600 TP
And the CSD of the same configuration (left, right superimposed)

CSD DT990-600 TP

Of course this headphone is a good candidate for the Kameleon.

Below the FR response of the DT990 with 3 plies of toilet paper and the same headphone (with toilet paper) driven from the Kameleon.

DT990 TP vs Kameleon 30kHz

A better (more neutral) but still slightly warm sound signature with excellent subbass and silky soft non-piercing treble…. with Beyer comfort.

Below the distortion plot of the DT990 on the Kameleon.

DIST DT990-600 TP Kameleon
Bass distortion seems increased due to the 9dB increase in subbass levels. Above 100Hz the distortion is quite low.
Below the CSD of this combination:

CSD DT990-600 TP Kameleon

Then there is the square-wave and impulse response plots of this headphone.
On the left the DT990 with toilet paper and on the right the same headphone driven from the Kameleon.

Improvements in Low frequency response, in the mids and especially impulse response are greatly improved.

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