Digital E, that almost sounded just a touch like a snipe. Let's be fair to the "Harman Target" aficionados. To review (for a LOT of us), the Harman Target is a frequency response curve developed through scientific research at Harman International, led by Dr. Sean Olive and building on earlier speaker work by Dr. Floyd Toole. It represents what most listeners prefer in headphone sound reproduction based on extensive blind testing.
The resultant frequency response curve aims to make headphones sound like good speakers in a good listening room. It features several key characteristics:
- A relatively flat midrange response
- A bass boost that mimics how rooms naturally enhance low frequencies, mebe 80-90 Hz and below

- A gradual downward tilt (about 6 dB) across the audible spectrum.
- The "gradual downward tilt (about 6 dB) across the audible spectrum" means that the frequency response curve gradually decreases in amplitude as the frequencies increase.
- Lower frequencies (bass) are reproduced with more energy, whether current-operated or voltage-operated
- As you move toward higher frequencies (mids and treble), the volumes at these frequencies progressing higher, continue to decrease gradually in energy
- From the lowest audible frequencies to the highest, this reduction totals approximately 6 decibels.
- An upper midrange and treble boost that accounts for how our ears naturally process sound (Remember "loudness compensation" from the 70s?)
The Harman Target isn't rigid, and probably doesn't stand up to really stoic evaluation - research still shows it satisfies about 64% of listeners across different demographics. Dr. Olive has acknowledged that individual preferences vary, suggesting "preference bounds" might allow for ranges in bass, midrange, and treble to accommodate different tastes. ME? In my non-Tinnitus-afflicted days, I was an orchestral bass-head, low string bass, low brass, organ, and of course percussion, with a slight tweak around 8kHz or so.
This "preference" curve has been influential in headphone design because it provides manufacturers with semi-objective criteria to work with instead of purely subjective judgments as a practically impossible target. It established a scientific approach to what makes headphones sound natural and pleasing to most listeners. However, there is no concrete indication that Sennheiser used the Harman Target as a design goal in the IE900's sound design. The IE900 actually follows Sennheiser's own house sound philosophy, with reviewers noting its "suppressed upper-midrange" and U-shaped sound signature. One reviewer even mentioned using EQ to match the IE900's midrange to different target curves, indicating it doesn't natively follow popular targets like Harman. When comparing the IE900 to devices that do follow the Harman Target, it's clear that Sennheiser pursued, and continues to pursue its own tuning philosophy rather than trying to match the Harman curve. Sennheiser has historically maintained its own distinctive house sound for its premium audio products rather than conforming to industry-wide target curves. The IE900, as their flagship IEM, continues this tradition with a tuning that prioritizes technical performance, detail, and a specific sound signature that aligns with Sennheiser's design philosophy.