Audio-Technica ATH-ADX7000 vs Sennheiser HD 505

Audio-Technica ATH-ADX7000

The ADX7000's headline is its remarkable ~270-275g weight, achieved with a magnesium-alloy frame and a fully open honeycomb chassis. Reviewers split on comfort: the light weight and plush velvet pads are praised, but the thinly-padded dual-rod headband draws consistent criticism for top-of-head hotspots.

• At 275g with velvet pads (270g with Alcantara), reviewers call it exceptionally lightweight for a flagship — it 'practically disappears' on the head.
• headphones.com praises Audio-Technica for resisting the industry habit of adding weight to feel 'premium' — the light chassis makes the ADX7000 less obtrusive and more immersive.
• The frame is magnesium alloy with an aluminum housing, hand-assembled in Japan, with a stripped-back utilitarian aesthetic reviewers find handsome rather than gaudy.
• The fully open honeycomb-punched grille exposes the 58mm driver, placing little between the diaphragm and the outside world for a true open-air presentation.
• Two sets of earpads ship in the box — high-density velvet for a warmer, balanced sound and Alcantara for a brighter, more analytical tuning — effectively two headphones in one.
• The thinly-padded dual-rod headband is the most consistent comfort complaint — ecoustics found a hotspot 'blooms' on the top of the head after about an hour.
• headphones.com calls the headband's two narrow contact points a 'when, not if' for hotspots, but notes it can be physically bent by the user to redistribute weight and adjust clamp.
• Moon Audio's reviewer disagreed on the headband, finding it 'surprisingly comfortable' despite the lack of cushion thanks to the minimal clamping force.
• audio46's reviewer, a glasses-wearer, found the ADX7000 comfortable for hours without fatigue — notably better than the ADX5000 or ADX3000 with glasses.
• den-fi calls the ADX7000 one of the most comfortable headphones he has worn since the 195g Sony MA900, noting the out-of-box clamp runs a bit tight on large heads but the headband bends easily.

Sennheiser HD 505

The HD 505 reuses the proven HD 500-series chassis: a featherlight 237g frame, cushy earpads and gentle clamp that make it one of the most comfortable open-backs in its class. The trade-off is a functional plastic build that doesn't feel premium.

• Refreshingly light at 237g without the cable, with solid (if not premium) build and cushy earpads.
• It largely sticks to the HD 500 series' tried-and-tested design, keeping it compatible with first- and third-party accessories.
• Lighter and gentler than the HD 600 — it has the least clamp pressure on the table and is more comfortable than the rest.
• In a minor upset, the HD 505 is more comfortable than the HD 600 thanks to slightly gentler headband compression plus its lighter 237g weight versus 260g.
• The softer earpads give a better seal for larger ears and glasses wearers, though that matters less on an open-back.

Audio-Technica ATH-ADX7000

The ADX7000 is a purely passive, wired open-back: no Bluetooth, ANC, battery or mic. Its 490-ohm impedance and 100dB/mW sensitivity make amplifier pairing the single biggest variable, and the proprietary A2DC cabling is its most criticised practical limitation.

• A new HXDT-molded 58mm dynamic diaphragm with Core Mount Technology is the core engineering story — Audio-Technica aligns the driver components with micrometre accuracy for cleaner detail retrieval.
• Impedance is a high 490 ohms — den-fi measured a peak of 1,348 ohms at the 81Hz free-air resonance — making amplifier choice the biggest variable in how the headphone performs.
• Major HiFi found the iFi Valkyrie could not drive the ADX7000 well and had to switch to a Chord Hugo 2 for proper headroom and a fuller performance.
• audio46 warns that portable amplifiers leave the midrange sounding 'hollow and paper-thin' — a powerful desktop amp is needed to round out the sound.
• Despite the high impedance, the 100dB/mW sensitivity keeps it from being a true power hog — den-fi reached normal 80-85dB listening levels from an Apple 3.5mm dongle with clicks to spare.
• ecoustics found it scales beautifully — moving from a dongle DAC to a desktop chain brought clear gains in dynamics, impact and bass texture.
• It ships with two 3m cables — a balanced 4-pin XLR and an unbalanced 6.3mm gold-plated plug — both terminating in Audio-Technica's A2DC connectors.
• The stock cables draw heavy criticism — headphones.com calls the microphonics 'genuinely the worst' it has experienced in an open-back over-ear, and recommends an aftermarket fix.
• The proprietary A2DC connectors limit affordable aftermarket cables — ecoustics advises budgeting for an upgrade, though headphones.com notes A2DC has a very low failure rate in practice.
• Reddit owners flagged the proprietary cabling and lack of a stock 4.4mm balanced option as a recurring frustration on an otherwise endgame headphone.

Sennheiser HD 505

As a passive open-back the HD 505 has no Bluetooth, battery or codecs — it is purely a wired audiophile can. It is easy to drive from modest sources but its modular, replaceable cabling and broad amp/adapter compatibility reward those who scale up.

• Maintains a modular design with user-replaceable cables and earpads, like other 500-series models.
• The drivers are angled to mimic nearfield speaker placement, aiming for better soundstage imaging.
• It ships with a standard 3.5mm cable and a threaded 1/4-inch (6.35mm) screw-on adapter — the pack-ins make clear the headphones are the main event.
• The detachable cable uses a twist-lock 2.5mm connector, so you can swap in a standard cable as a replacement or balanced upgrade — a plus for longevity.
• It works with inline microphones and there's no shortage of first- and third-party accessories thanks to the HD 500-series compatibility.

Audio-Technica ATH-ADX7000

At $3,499 the ADX7000 sits squarely in flagship territory against the Sennheiser HD 800S, Focal Utopia, and HIFIMAN/Meze planars. Reviewers are unusually positive on its value-for-money — several call it one of the few flagships whose sound genuinely justifies its price.

• The ADX7000 launched at $3,499, replacing the $2,000 ADX5000 as Audio-Technica's open-back flagship — a complete rethink rather than a modest upgrade.
• headphones.com calls it one of the very few headphones it has heard at this price 'that has a sound that actually makes sense for that price.'
• Versus the Sennheiser HD 800S, den-fi found the HD 800S sounds too distant with a more dipped upper-midrange — and that the ADX7000 exposed the Sennheiser's treble as 'unimpressive.'
• audio46 frames it as the HD 800S detail experience with the bass the Sennheiser lacks — and more frontal midrange clarity than the bassy Meze Elite or Audeze LCD-4z.
• Versus the Focal Utopia, den-fi found the ADX7000 noticeably more dynamic and resolving than the 2022 Utopia, and 'a triumph' next to the Utopia's one-note bass and wall-of-sound presentation.
• headphones.com calls the $3,499 ADX7000 the better all-around headphone than the ~$2,000 HEDDphone TWO GT — lighter, more spacious and more listenable despite costing ~$1,500 more.
• Within Audio-Technica's own range, Major HiFi positions the ADX7000 as the choice for pure detail, neutrality and top-tier technical ability, with the easier-driven ADX5000 the more accessible pick.
• The Headphone Show is the value sceptic — it would take many cheaper headphones before the ADX7000, calling it hard to recommend at its flagship price.
• den-fi's verdict was his 'most effusive review ever' — he liked the ADX7000 enough to buy a pair, calling it worthy of the title 'flagship.'

Sennheiser HD 505

At $250 the HD 505 is the cheapest genuine entry into Sennheiser's open-back lineage, but it lands in a brutal price band: the older HD 6XX/HD 600 and the new HD 550 both make a strong case against it, and Beyerdynamic and HiFiMan add more pressure.

• The HD 505 competes in a crowded segment against Audio-Technica, Beyerdynamic and others in the sub-$300 price range.
• It slots in beneath the benchmark HD 600 series while ticking plenty of boxes for music fans chasing sonic quality on a budget.
• For around the same money you can get a used HD 650 or a new HD 6XX/HD 600 — any of which gives a truer representation of the source.
• The HD 6XX is meaningfully less expensive and remains the indisputable value king — not just in Sennheiser's lineup but in headphones at this price range.
• For $20 more the new HD 550 might steal some of the 505's thunder with even stronger bass and arguably less annoying treble peaks.