Sennheiser HD 650
The reference open-back a generation measures everything else against: smooth, unhyped, honest. Here is exactly how it measures, and how to make it sound like your reference.
Our take
If you want to hear what a recording actually holds, the HD 650 gets out of the way. Bass is even and unboosted, the mids are its whole reason for being, and the treble is polite, some call it dark. EQ can lift that top end without breaking the tuning, which is exactly what Attune is for.
Measured by Warren Labs on a miniDSP EARS Pro. The headphone is seated deliberately for the best fit, the way someone who cares about sound adjusts a headphone before they settle in to listen, rather than placed at random, and the published curve is a single real seating chosen by an objective rule, never a blend. Both channels are measured and stored separately; the line drawn here is their average. Raw response, normalized to 0 dB at 1 kHz. An EARS Pro is not an industry reference coupler such as a GRAS 45CA, so read this as a house reference: repeatable against our other EARS Pro measurements, not directly comparable to another lab. Seating repeatability was characterized in August 2026 and turned out to be a property of the headphone rather than of the rig: reseating moves the midrange by about 0.06 dB on some models and 0.32 dB on others, so no single variance band is drawn here. The instrument itself contributes 0.002 dB. Do not read fine treble detail as settled.How we measure →
Common questions
Straight answers, the same ones our measurements support.
Does the Sennheiser HD 650 need an amp?
It benefits from one but does not require a big one. At 300 Ω it wants voltage more than current, so a decent USB-C dongle or any competent headphone output drives it to honest levels. A dedicated amp mainly buys headroom, not a different tuning.
HD 650 vs HD 600: what is the difference?
Small and real. The 650 is a touch warmer with slightly more upper-bass and a gentler top end; the 600 is a hair brighter and more forward. On the graph they are close cousins: pick by preference, not price.
Is the HD 650 good for mixing?
For tonal balance and midrange decisions, yes. It is a longtime studio reference. Its relaxed treble means you should check your highs on a second source, which is true of most headphones.
Why does the treble look like it rolls off?
Part is the headphone’s relaxed voicing, part is the measurement rig: above ~10 kHz, fixture and seating variance dominate, so treat the top octave as directional, not exact.
If you like the HD 650
Close on the graph, or a deliberate step in one direction.