solderdude
Grand Contributor
There has been some discussions about pad thickness.
Mostly about the DT990.
I took some headphones I have lying around (all with lots of hours on it already) and put these on my flatplate. Measured the pad thickness on the outside and then pressed them onto the rig using velcroband around the rig/headphone and compress the pads.
This is not a scientific study nor is this done on a HATS and the measurements are done without a pinna.
This makes a different situation from reality where your pinna is inside changing the air volume and masking of rear sound.
It should be noted that when the pads are completely compressed (in most cases) the pinnae are bent so this too will have a different effect than what is shown here.
Especially in the region above 5kHz.
Anyway enjoy these utterly crappy and flawed measurements.
Lets start with the DT880 Black Edition but this one has the grey pads on them as these are less 'mid-bassy'.
These are the exact same pads as would be used on DT990 and already are softer than new pads.
It is interesting to note that the grey pads actually take a lot less pressure to compress than the black DT880 pads.
What can be seen above is that when the pads are compressed (green is normal pressure) that the amplitude of frequencies below 4kHz increase while above it they don't. Effectively, seen from the area between 100Hz and 1kHz, where we base our perceived loudness on, not only the amplitude changes but compared to the not changing treble that treble is seemingly lower. The efficiency increases effectively for the lows and the mids.
It should be noted that any normal user would not use this fully compressed as your pinnae would be crushed and is uncomfortable as hell. One would probably start to replace already at the 'blue' stage. Your pinnae would already be touching the foam on the drivers.
A similar effect will be seen on the DT990.
Interestingly enough, because the pads are compressed the foam becomes 'stiffer', which would not necessarily be the case when foam decays, you also see the 'pad bounce' frequency go up. Above nearly 200Hz (red), near 100Hz (Blue) and near 60Hz (green).
Yes... ignore the 50Hz wiggles.. it's mains leaking in the mic capsule.
Below the DT1990 with original A pads (the Analytical/flat sounding ones)
Here the same effect is seen. Hardly any changes in the area above 4Hz but much more below 600Hz. These pads are firmer (less soft) than the grey ones and takes more pressure to compress. I reckon they will stay in shape much longer than the grey ones. Relatively the treble becomes lower while in reality the efficiency for lower frequencies becomes 10dB higher and between 1kHz and 4kHz 5dB higher.
Here too we see pad bounce shifting in frequency.
Below the HD560S.
Upto 4khz the tonality not change much but for higher frequencies there are some changes especially in the 6khz range. When the pads (who are quite firm and take a lot of force to compress) are compressed and the drivers are angled the effects above 5kHz will differ depending on your pinnae.
Overall the tonality changes are smaller than those of the Beyers. Pad bounce also shifts frequency here.
Below the HD650 (black screen with old pads). As these are older pads (more comfy than newer pads) the green line is not present. That is reserved for newer pads.
The used pads here are already 20 years old and are very easy to compress.
A tonal balance change is observed when the pads are compressed even more. The change with the HD650 however is more of a tonality 'tilt' change.
Yes, it gets 'darker' sounding over time but not as extreme as the Beyers.
Below the X2HR. It should be noted that this headphone is modified. It has the bass boost lowered and the treble peak lowered using a filter.
These pads are quite thick and take a lot of force to compress them about 7mm.
The tonal balance also changes but more similar in effect than the Beyers (below 1kHz). Overtime the headphone thus becomes a but less 'clear' sounding. Pad bounce hardly changes (190Hz) with these stiff pads.
below the K702. I tried to maintain the angling of the pads (relatively) but of course the angle gets smaller when the depth changes. These pads are thick and firm so take a lot of force to compress. Didn't test the memory foam pads (should have in hindsight) which compress much easier.
There is something interesting going on. The efficiency above does not change much. Not more lows when compressing but instead lows get relatively softer.
The resonances I see clearly shift due to the changes in driver distance. These peaks will thus be lower when measured with a HATS as the reflection surface isn't flat in reality.
Below the most interesting one. The Hifiman Edition XX. I have nor reason to believe other similar looking models will behave much differently.
No tonality increase in efficiency nor tonality changes. Well.. in the clarity range (1-3kHz) the tonality changes very little. It becomes a bit clearer sounding as pads compress. 12mm compression is a LOT though. The same thing as with the K702 happens in the upper treble range. The resonance shifts a bit upwards because of the driver distance and air volume changing. This peak will also be pinna dependent.
Contemplating adding these tests to my regular measurements.
Mostly about the DT990.
I took some headphones I have lying around (all with lots of hours on it already) and put these on my flatplate. Measured the pad thickness on the outside and then pressed them onto the rig using velcroband around the rig/headphone and compress the pads.
This is not a scientific study nor is this done on a HATS and the measurements are done without a pinna.
This makes a different situation from reality where your pinna is inside changing the air volume and masking of rear sound.
It should be noted that when the pads are completely compressed (in most cases) the pinnae are bent so this too will have a different effect than what is shown here.
Especially in the region above 5kHz.
Anyway enjoy these utterly crappy and flawed measurements.
Lets start with the DT880 Black Edition but this one has the grey pads on them as these are less 'mid-bassy'.
These are the exact same pads as would be used on DT990 and already are softer than new pads.
It is interesting to note that the grey pads actually take a lot less pressure to compress than the black DT880 pads.
What can be seen above is that when the pads are compressed (green is normal pressure) that the amplitude of frequencies below 4kHz increase while above it they don't. Effectively, seen from the area between 100Hz and 1kHz, where we base our perceived loudness on, not only the amplitude changes but compared to the not changing treble that treble is seemingly lower. The efficiency increases effectively for the lows and the mids.
It should be noted that any normal user would not use this fully compressed as your pinnae would be crushed and is uncomfortable as hell. One would probably start to replace already at the 'blue' stage. Your pinnae would already be touching the foam on the drivers.
A similar effect will be seen on the DT990.
Interestingly enough, because the pads are compressed the foam becomes 'stiffer', which would not necessarily be the case when foam decays, you also see the 'pad bounce' frequency go up. Above nearly 200Hz (red), near 100Hz (Blue) and near 60Hz (green).
Yes... ignore the 50Hz wiggles.. it's mains leaking in the mic capsule.
Below the DT1990 with original A pads (the Analytical/flat sounding ones)
Here the same effect is seen. Hardly any changes in the area above 4Hz but much more below 600Hz. These pads are firmer (less soft) than the grey ones and takes more pressure to compress. I reckon they will stay in shape much longer than the grey ones. Relatively the treble becomes lower while in reality the efficiency for lower frequencies becomes 10dB higher and between 1kHz and 4kHz 5dB higher.
Here too we see pad bounce shifting in frequency.
Below the HD560S.
Upto 4khz the tonality not change much but for higher frequencies there are some changes especially in the 6khz range. When the pads (who are quite firm and take a lot of force to compress) are compressed and the drivers are angled the effects above 5kHz will differ depending on your pinnae.
Overall the tonality changes are smaller than those of the Beyers. Pad bounce also shifts frequency here.
Below the HD650 (black screen with old pads). As these are older pads (more comfy than newer pads) the green line is not present. That is reserved for newer pads.
The used pads here are already 20 years old and are very easy to compress.
A tonal balance change is observed when the pads are compressed even more. The change with the HD650 however is more of a tonality 'tilt' change.
Yes, it gets 'darker' sounding over time but not as extreme as the Beyers.
Below the X2HR. It should be noted that this headphone is modified. It has the bass boost lowered and the treble peak lowered using a filter.
These pads are quite thick and take a lot of force to compress them about 7mm.
The tonal balance also changes but more similar in effect than the Beyers (below 1kHz). Overtime the headphone thus becomes a but less 'clear' sounding. Pad bounce hardly changes (190Hz) with these stiff pads.
below the K702. I tried to maintain the angling of the pads (relatively) but of course the angle gets smaller when the depth changes. These pads are thick and firm so take a lot of force to compress. Didn't test the memory foam pads (should have in hindsight) which compress much easier.
There is something interesting going on. The efficiency above does not change much. Not more lows when compressing but instead lows get relatively softer.
The resonances I see clearly shift due to the changes in driver distance. These peaks will thus be lower when measured with a HATS as the reflection surface isn't flat in reality.
Below the most interesting one. The Hifiman Edition XX. I have nor reason to believe other similar looking models will behave much differently.
No tonality increase in efficiency nor tonality changes. Well.. in the clarity range (1-3kHz) the tonality changes very little. It becomes a bit clearer sounding as pads compress. 12mm compression is a LOT though. The same thing as with the K702 happens in the upper treble range. The resonance shifts a bit upwards because of the driver distance and air volume changing. This peak will also be pinna dependent.
Contemplating adding these tests to my regular measurements.
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