Stored Category Comparison

FiiO JT7 vs Sennheiser HD 660S2

This page compares two published headphones profiles using stored summaries, source-attributed scoring, and a single lines-only radar for fast visual difference checks.

Back to FiiO JT7Open Sennheiser HD 660S2

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FiiO JT7
Sennheiser HD 660S2

Category Scores

Stored score comparison

Every score is pulled from the stored product intelligence snapshot for this category pair.

AxisJT7HD 660S2Delta
Bass
7.6
7.5
-0.1
Mids
7
7
Even
Treble
6.6
7
+0.4
Technicalities
7.1
7.4
+0.3
Soundstage
6.8
7
+0.2
Value
8.5
6.3
-2.2

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FiiO JT7 can only be compared against published headphones profiles.

Quick Read

FiiO JT7

The JT7 is an open-back planar magnetic headphone sold under FiiO's Jade Audio sub-brand, built on a proprietary 95x86mm driver rated 18 ohms and 92dB/mW, weighing about 318g and folding flat for transport. Reviewers agree on three things: the mechanical design and comfort are unusually good for roughly $110 to $129, the bass is a genuine strength for an entry-level planar, and pad swaps move the tonality a long way. Past that the readings split hard. One camp hears a warm, full, slightly bass-forward headphone. Another hears and measures forward upper mids around 3-5 kHz, calling the stock presentation shouty and the treble blunted and uneven. Treble divides on the same line: airy and extended in several reviews, rolled off or troughed near 4-5 kHz in others. Drivability is contested too, from lean and harsh on portable dongles in one account to no measurable source dependency in another. The most serious single finding is mechanical driver clipping reported near 88dB SPL, audibly worse on one channel.

Sennheiser HD 660S2

The HD 660S2 is a driver-level revision of the HD 660S rather than a new headphone. The voice coil was reworked and impedance moves to 300 ohms, matching the HD 600 and HD 650. The low end is the headline change: sub-bass extends further and the mid-bass carries more body than the predecessor, with the missing fundamental in lower-register instruments described as finally present. The tuning still stays measured rather than bass-forward, and it is explicitly not aimed at bass-heads. Tonally it sits between the HD 600 and HD 650 with a lean toward the HD 650, cleaner through the mids than the HD 650 and less forward than the HD 600. Treble is where reviewers split: one account hears considerably more bite, sizzle and crispness than the original without harshness, while another frames the profile as relaxed and deliberately not treble-emphasized. Staging is reported as taller and deeper with more precision than the predecessor, though the presentation is still called intimate rather than expansive. A dip through roughly 3-5 kHz is flagged for dimming detail on some tracks, with a few dB of parametric EQ offered as the remedy. The chassis, velour pads and headband carry over unchanged, and the packaging is judged a downgrade. Value is the real fault line: at a street price near $500 one verdict reads it as a clear technical step up on the HD 660S, while another concludes it does not differentiate itself from cheaper models in the same family and tells existing HD 660S and HD 600 owners to save their money.

FiiO • Headphones

FiiO JT7

Open page

The JT7 is an open-back planar magnetic headphone sold under FiiO's Jade Audio sub-brand, built on a proprietary 95x86mm driver rated 18 ohms and 92dB/mW, weighing about 318g and folding flat for transport. Reviewers agree on three things: the mechanical design and comfort are unusually good for roughly $110 to $129, the bass is a genuine strength for an entry-level planar, and pad swaps move the tonality a long way. Past that the readings split hard. One camp hears a warm, full, slightly bass-forward headphone. Another hears and measures forward upper mids around 3-5 kHz, calling the stock presentation shouty and the treble blunted and uneven. Treble divides on the same line: airy and extended in several reviews, rolled off or troughed near 4-5 kHz in others. Drivability is contested too, from lean and harsh on portable dongles in one account to no measurable source dependency in another. The most serious single finding is mechanical driver clipping reported near 88dB SPL, audibly worse on one channel.

Strengths

  • Mechanical design punches far above the price: 318g, spring steel headband, folding cups, replaceable pads and headband cushion
  • Bass is the most consistently praised region for an entry planar, described as deep, fast and physical, and it accepts EQ boosts well
  • Responds strongly to pad rolling, with aftermarket FT1 Pro, velour and ZMF pads repeatedly credited with smoothing the upper mids
  • Measured channel matching is called excellent for the price, with low distortion through most of the range at normal levels
  • Ships with both a 3.5mm single-ended and a 4.4mm balanced cable plus a 6.35mm adapter, so it drops into desktop or portable chains

Weaknesses

  • Upper mids near 3-5 kHz read as forward or shouty in several reviews, and the stock tuning is called uneven rather than refined
  • Treble is the weakest axis by consensus of the critics: variously blunted, rolled off, or dipped around 4-5 kHz
  • One detailed review reports the driver clipping near 88dB SPL, which puts a hard ceiling on macro dynamics at higher levels
  • Plastic yokes and general material quality draw durability doubts, and clamping force is heavy enough that one reviewer calls it fatiguing

Sennheiser • Headphones

Sennheiser HD 660S2

Open page

The HD 660S2 is a driver-level revision of the HD 660S rather than a new headphone. The voice coil was reworked and impedance moves to 300 ohms, matching the HD 600 and HD 650. The low end is the headline change: sub-bass extends further and the mid-bass carries more body than the predecessor, with the missing fundamental in lower-register instruments described as finally present. The tuning still stays measured rather than bass-forward, and it is explicitly not aimed at bass-heads. Tonally it sits between the HD 600 and HD 650 with a lean toward the HD 650, cleaner through the mids than the HD 650 and less forward than the HD 600. Treble is where reviewers split: one account hears considerably more bite, sizzle and crispness than the original without harshness, while another frames the profile as relaxed and deliberately not treble-emphasized. Staging is reported as taller and deeper with more precision than the predecessor, though the presentation is still called intimate rather than expansive. A dip through roughly 3-5 kHz is flagged for dimming detail on some tracks, with a few dB of parametric EQ offered as the remedy. The chassis, velour pads and headband carry over unchanged, and the packaging is judged a downgrade. Value is the real fault line: at a street price near $500 one verdict reads it as a clear technical step up on the HD 660S, while another concludes it does not differentiate itself from cheaper models in the same family and tells existing HD 660S and HD 600 owners to save their money.

Strengths

  • Sub-bass extension and mid-bass body are a clear step up on the HD 660S, with lower-register fundamentals finally landing with weight.
  • Tonality sits between the HD 600 and HD 650 with a lean toward the HD 650, reading smooth and even without a heavy treble roll-off.
  • Staging gains height and depth over the predecessor with more precise placement, and is called the standout improvement of the generation.
  • The 300 ohm load matches the HD 600 and HD 650 and rewards OTL or SETA tube amplification, where the most expansive pairings were found.
  • Detachable two-pin cables with 6.3mm and 4.4mm terminations make it easy to re-cable and repair over a long ownership period.
  • Weight is low at a rated 260 g with virtually no vertical pressure, so long sessions stay viable once the new-pad clamping settles.

Weaknesses

  • A dip through roughly 3-5 kHz dims detail on some tracks, and the fix offered is a few dB of parametric EQ rather than the stock tuning.
  • A subtle harmonic dissonance around 5-6 kHz sits over the upper mids and vocals, and EQ lifting the 2-4 kHz region can exaggerate it.
  • Lateral clamping pressure is high when brand new, and the velour pads need time in use before they soften.
  • The design was not changed for the S2, so the price increase over the HD 660S buys no hardware revision to the chassis, headband or pads.
  • Packaging was cut back from the previous generation to a smaller, simpler box that reads as more disposable.
  • Fully open, so isolation is effectively nil and outside noise comes straight through.