Here are two experienced reviewers on the same IEM, the Sennheiser IE 6001:
Overall, the IE 600 has an excellent balance and a level of coloration that is smooth to neutral with the foam tips and neutral to slightly sparkling with the silicone alternatives.
Marcus, Headfonics
it edges more toward the spicy side of things to my ears, lacking the refinement that its older sibling, the IE900, approached this derivative of sound with.
Precogvision, Headphones.com
Both are careful listeners, both heard the same product, and on the treble they could hardly disagree more. Anyone who reads headphone reviews has seen this happen. What’s less obvious is how often it happens.
Every Overreview on Audiowords boils a product’s reviews down topic by topic (bass, comfort, value and so on) and records whether the reviewers agree or split. Line up the verdicts for all 350 headphones and IEMs in the catalogue and one topic stands apart. Value, bass and tonality split reviewers regularly. Treble splits them on nine in ten of the products.
Figure 1Live data
What reviewers disagree about
- Treble
- Value
- Bass
- Tonality
- Mids
- Build
- Comfort
- Soundstage
- Dynamics
- Detail
- Isolation
- Imaging
Almost nobody agrees
Full agreement is rarer still. An Overreview marks “strong agreement” when every source says roughly the same thing. That’s common for isolation and imaging. For treble it has happened three times in 350 products: for the Moondrop Skyland, Noble Audio FoKus Apollo Pro and the Symphonium Helios.
Nor are the treble splits lopsided. When reviewers divide, the two sides tend to be close to even: a genuine argument, not one grumpy holdout against a crowd.
Money doesn’t settle it
If treble were only a question of quality (cheap sets harsh, expensive sets refined), spending more would end the argument. It doesn’t. A set that costs under $100 and a flagship over $1,000 split their reviewers almost exactly as often.
Figure 2Live data
Treble disagreement by price
An argument about ears
So what are they arguing about? Each Overreview also records why its reviewers disagree, and for treble the same few reasons keep coming up. The disagreements are specific: almost all of them point to a particular range of frequencies, usually between five and ten kilohertz, rather than a vague sense that the top end is off. Many mention sibilance, the hiss on “s” and “t” sounds. And three in four bring up fit: which ear tips someone used, how well they sealed, how deep an IEM sat. For IEMs alone, it’s more than nine in ten.
Reviewers often say so themselves, like this one:
However, there is some emphasis between 7 – 9kHz (depending on insertion depth and tips used) that can be problematic.
audioreviews.org (Kazi Mahbub Mutakabbir)
That makes treble different from every other topic. With treble, the listener’s own ears, tips and seal become part of what’s being judged. Two reviewers can be equally careful and equally honest and still hear slightly different things. None of this proves fit is the cause, since the Overreviews only record what reviewers talked about, but the pattern is hard to miss.
Plot every treble verdict and the pattern is easy to see: about half sit above the line where reviewers split. Tap imaging above the chart and the cloud sinks and drifts right; only one in eight imaging verdicts get that high.
Figure 3Live data
Where reviewers stand on treble
Each dot is one headphone or IEM. The higher it sits, the more reviewers disagree about its treble; the further right, the more they like it.
What reviewers do agree on
Reviewers don’t disagree about everything, though. Imaging, how precisely sounds are placed around you, is the least contested topic of all, and reviewers generally like what they hear. Isolation and detail aren’t far behind. Isolation comes with a footnote: fewer reviewers mention it at all, which leaves less room to disagree.
Reading reviews, then
This doesn’t make reviews less useful; it changes how to read them. A reviewer’s take on build quality or imaging will usually hold true for you too. A take on treble is partly a report on their ears, their tips and their seal. So if a review calls a set harsh, check two things: whether other reviewers split on it (every Overreview shows this), and whether the split has a cause you can fix, like a different ear tip or a deeper fit.
The charts in this piece redraw whenever a new Overreview is published. This version covers 350 headphones and IEMs as of 10 November 2026.