Here are my measurements comparing the Arya Stealth's stock pads to
the four Dekoni pads available. Descriptions of the differences, particularly those for the distortion, CSD (cleanness of transients), and impulse and step response (transient sharpness) measurements which I won't be posting here should otherwise be similar to those for the HE1000se in
https://www.head-fi.org/threads/hifiman-he1000-se.886228/post-17865003 (post #4,788).
Ignore REW's displayed frequency band terminology; I subscribe to the one below:
The magnitude response is the upper trace while the phase response is the lower trace. The measurements were taken without changing the DAC/amp's volume setting, whereby I have within the Room EQ Wizard (REW) application vertically offset the charts to be volume-matched at around 300 Hz; differences were less than 0.5 dB. Unlike with the HE1000se measurements, I am excluding the ultrasonic measurements which I am considering not of interest for this comparison.
Figure 1: HiFiMan Arya Stealth fresh stock pads (taken from my HE1000se) frequency response.
In order of decreasing (infrasonic) sub-bass extension, else in order of decreasing seal and hence greater bass around 20 Hz to 150 Hz.
Figure 2: HiFiMan Arya Stealth Dekoni Elite Sheepskin frequency response. These pads nigh completely fill the "HiFiMan dip", having more forward of an upper midrange. These pads along with the Hybrid Elite Velour happen to provide the most attenuation of the 4.3 kHz peak, but only slightly. These Elite Sheepskin pads in addition to having the best infrasonic extension provides a marked improvement in the bass distortion performance.
Figure 3: HiFiMan Arya Stealth Dekoni Elite Hybrid frequency response. These pad slightly fill the HiFiMan dip.
Figure 4: HiFiMan Arya Stealth Dekoni Elite Velour frequency response. These pads shift the "HiFiMan dip" a bit to the right.
Figure 5: HiFiMan Arya Stealth Dekoni Elite Fenestrated Sheepskin frequency response. These pads fill the HiFiMan dip a bit more than the Elite Hybrid pads, their being an intermediate between those and the Elite Sheepskin pads.
Figure 6: HiFiMan HE1000se fresh stock pads frequency response. Note that my Arya Stealth's left driver and stock pad happen to have greater than normal sub-bass and infrasonic extension insofar as I have found much less of a difference for the right channel measurements which I am not showing due to my right in-ear microphone having greater bass and treble roll-off not present in the left in-ear microphone, so this curve should only be used for comparison above 150 Hz.
Figure 7: Comparison overlay.