Sennheiser • Headphones
Sennheiser HD 620S
Universal Summary
The HD 620S is a closed-back headphone built on a 42mm dynamic driver, listed at $349.95, rated 150 ohms and 110 dB/Vrms, and easy enough to drive that reviewers report full volume from a phone, an Apple dongle or a game controller. Three points are settled across the coverage: passive isolation is unusually strong for a sealed passive design, out-of-box clamping force is high and eases with wear, and the bass you actually hear depends heavily on seal. Everything else splits. One camp hears a near-neutral, HD 600 adjacent tuning with clean mids and a wide, natural stage for a closed back. The other measures and hears an asymmetric W-shaped response: strong sub-bass, a trough near 200 Hz, a 400-800 Hz hump that reads as boxy, a lower-treble recess and a mid-treble lift that leaves the highs sounding disconnected. A measurement-led review scored it 6.5 out of 10 with a 2.9 predicted-quality mean and called the price hard to justify, while a measurement forum still placed it on its recommended list. Detail and dynamics divide the same way.
Sources
8
Research Version
manual-dossier-v1
Comparison Ready
Snapshot available
Strengths
- Passive isolation and leakage control are class-leading for a sealed passive headphone, good enough to work in a cafe or a shared office
- Easy to drive at 150 ohms and 110 dB/Vrms, so a phone, a cheap dongle DAC or a console controller reaches listening volume
- Soundstage and imaging read wide and natural for a closed back, and several reviewers rate the staging above the open HD 600 series
- Deep synthetic leather pads, memory foam headband padding and steel-reinforced cups earn comfort ratings as high as 9 out of 10
- No hard treble spike in the 4-6 kHz region, so it avoids the glare that the same reviewers pin on the Beyerdynamic DT 770 family
Weaknesses
- The response is asymmetric and W-shaped: a trough near 200 Hz plus a 400-800 Hz hump that reads as boxy on some material
- Bass level shifts with seal, pad creasing and headband position, so two fittings of the same unit can sound different
- Clamping force is high out of the box and caused mild discomfort even for a reviewer who still recommended the headphone
- Dynamic punch, transient attack and detail retrieval are called unremarkable or weak for the price by more than one reviewer
Best For
- Shared offices, cafes and late-night listening, where leakage control matters more than last-word tonality
- Immersive single-player gaming and FPS titles, where the stage width and warmth help positional cues
- Listeners who want an HD 600 style midrange in a sealed package and can accept seal-dependent bass
- EQ users, since the mid-bass hump and the upper-bass dip respond to modest correction
Overview
What the research says
The HD 620S is a closed-back headphone built on a 42mm dynamic driver, listed at $349.95, rated 150 ohms and 110 dB/Vrms, and easy enough to drive that reviewers report full volume from a phone, an Apple dongle or a game controller. Three points are settled across the coverage: passive isolation is unusually strong for a sealed passive design, out-of-box clamping force is high and eases with wear, and the bass you actually hear depends heavily on seal. Everything else splits. One camp hears a near-neutral, HD 600 adjacent tuning with clean mids and a wide, natural stage for a closed back. The other measures and hears an asymmetric W-shaped response: strong sub-bass, a trough near 200 Hz, a 400-800 Hz hump that reads as boxy, a lower-treble recess and a mid-treble lift that leaves the highs sounding disconnected. A measurement-led review scored it 6.5 out of 10 with a 2.9 predicted-quality mean and called the price hard to justify, while a measurement forum still placed it on its recommended list. Detail and dynamics divide the same way.
Long-term ownership
Reliability
Known issues
No known issues recorded, which means no data collected yet, not a verified clean record.
Warranty by region
No warranty terms recorded for any region.
Retailer return notes
No retailer return policies recorded.
Community QC reports
Quality-control and unit-variation mentions extracted from Reddit and forum sources during research. Reported, never invented.
- Isolated reportMinor housing flex
One reviewer reports minor flex noise from the cup housings during handling, set against a build otherwise described as robust. No other source in this set raises it.
Reported by: https://headfonics.com/sennheiser-hd-620s-review/
Visible Sources
Approved source material
Sennheiser HD 620S - Reviews | Headphone Reviews and Discussion - Head-Fi.org
Owner reviews range from five stars for lows, mids and highs to two and a half stars for wonky, boxy sound.
Sennheiser HD 620S review: the oddball of the HD 600 series
Scores 6.5 out of 10: the response swings about 6 dB around the preferred curve, and the price is called hard to justify.
Sennheiser HD 620S Headphone Review
Measures good compliance with a neutral target apart from a 4 kHz dip, and lands on the recommended list despite heavy clamp.
Sennheiser HD 620S Review (2): Minority Report
The dissenting measurement take: great staging and isolation, but an asymmetric W-shaped response, fit-sensitive bass and light note weight.
Sennheiser HD 620S: Does It Deserve A Spot In The 6 Series?
Hears warmth without impact, boxiness from a 400 to 800 Hz lift, and ranks dynamic punch among the poorer options at the price.
Sennheiser HD 620S headphone Review - Surprise Hit?
Measures a 110 Hz bass hump plus a 300 to 800 Hz lift, yet rates the tuning good for a passive closed back.
Sennheiser HD 620S Review
Calls it a surprisingly good mid-fi closed back in the HD 600 class, with improved sub-bass and the line's best pads.
Sennheiser HD 620S Review
Praises build and comfort but flags clamping force as quite strong even for smaller heads, and confirms isolation both ways.
Each source is labeled with its incentive profile: how it obtained the unit and how it earns money. How we label and weight sources
Consensus & Conflicts
Where reviewers disagree
Real reviewer conflicts are shown side by side instead of being averaged into a fake middle ground.
Tonal accuracy
Tonality is neutral, smooth and close enough to the HD 600 that the headphone earns its place in the 600 series, with clean mids and natural timbre.
Held by: https://headfonics.com/sennheiser-hd-620s-review/, https://www.head-fi.org/showcase/sennheiser-hd-620s.27256/reviews
The tuning is asymmetric and W-shaped, sounds boxy and inaccurate on some genres, and is odd enough that the response swings roughly 6 dB around a preferred curve.
Held by: https://www.audioreviews.org/sennheiser-hd-620s-review-bio/, https://www.soundguys.com/sennheiser-hd-620s-review-the-oddball-of-the-hd-600-series-132402/
Soundstage
Staging and imaging are a highlight: perceived width and instrument placement improve on the narrow, three-blob character of the open HD 600 series counterparts.
Held by: https://www.audioreviews.org/sennheiser-hd-620s-review-bio/, https://www.head-fi.org/showcase/sennheiser-hd-620s.27256/reviews
The spatial impression is muted, blamed on a deep cancellation near 4 kHz, and the stage is only adequate to good by closed-back standards rather than a strength.
Held by: https://www.audiosciencereview.com/forum/index.php?threads/sennheiser-hd-620s-headphone-review.57952/, https://headphones.com/blogs/reviews/sennheiser-hd-620s-review
Sub-bass quantity
Sub-bass is strong to overdone once a solid seal is obtained, to the point of being unpleasant on bass-heavy material without tweaking the fit.
Held by: https://www.audioreviews.org/sennheiser-hd-620s-review-bio/
Sub-bass comes across softer than expected: a prominent mid-bass peak masks depth, the low end lacks the oomph a sealed design should give, and it resists being boosted.
Held by: https://www.youtube.com/watch?v=feMe6yjoxNg, https://headphones.com/blogs/reviews/sennheiser-hd-620s-review
Value at $349.95
Reasonably priced with no direct competitor at the price, recommended, and called one of the best closed backs under $500 by owner reviewers.
Held by: https://www.audiosciencereview.com/forum/index.php?threads/sennheiser-hd-620s-headphone-review.57952/, https://www.head-fi.org/showcase/sennheiser-hd-620s.27256/reviews
The price is hard to justify given the tuning, scoring 6.5 out of 10, and one reviewer would choose the cheaper open HD 600 or HD 650 without hesitation.
Held by: https://www.soundguys.com/sennheiser-hd-620s-review-the-oddball-of-the-hd-600-series-132402/, https://www.audioreviews.org/sennheiser-hd-620s-review-bio/
Reviewers agree on
- Passive isolation and low leakage are the standout practical strengths, rated better than most closed backs the reviewers own
- Clamping force is high on a new unit and loosens after days or weeks of wear
- 150 ohms with 110 dB/Vrms makes it far easier to drive than the 300 ohm HD 600 and HD 650
- It is not a basshead headphone, and the low end does not take a large sub-bass boost gracefully
- Bass response changes with fit and seal, so positioning matters more than it does on the open 600 series
- The midrange keeps recognisable Sennheiser character and stays free of the treble glare associated with the DT 770
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