Section 01
First Impressions
What I thought before listening.
Familiar shape, refined fit, and a tonality that immediately feels like ‘home’ for anyone who grew up on a 6-series Sennheiser.
Section 02
The Setup
What source, DAC, headphones or IEMs were used.
- Amp: FiiO K13
- Source: Qobuz CD-quality via Mac
- Reference: Focal Clear MG
Section 03
What I Loved
- ✓Effortless vocal presentation.
- ✓Genuinely all-day comfortable.
- ✓Improved sub-bass extension vs the original HD 660S.
Section 04
What Drove Me Slightly Mad
- ✕Treble can get slightly polite on already-warm sources.
- ✕Stock cable still feels stuck in 2009.
Section 05
The Reluctant Audiophile Verdict
I have owned, sold, and re-bought the 6-series Sennheisers more times than I am comfortable admitting. The HD 660S2 is the version that finally makes me think I might stop the cycle. We’ll see.
Section 06
The ARSE Breakdown
Audio
Tonality, resolution, technical performance.
8.7 / 10
Regret
Buyer’s remorse. Lower is better.
2.0 / 10
Spend
Value per pound. Higher = better value.
7.6 / 10
Enjoyment
The goosebumps metric.
9.3 / 10
Overall
ARSE Score
8.4
Section 07
Who Should Buy This?
Buy It
You want one open-back headphone you can live with for years.
Maybe
You crave a more sparkly, exciting top end.
Walk Away
You demand bone-rattling sub-bass slam from an open-back. Not the brief.
