Sennheiser HD 620S Review featured image

Sennheiser HD 620S Review

In this article, Marcus reviews the Sennheiser HD 620S, which are the company’s latest 600 series closed-back 42mm angled dynamic driver headphones. They are priced at $349.95.

Disclaimer: This sample was sent to me in exchange for my honest opinion. Headfonics is an independent website with no affiliate links or services. I thank Sennheiser for this opportunity.

Click here to learn more about the Sennheiser products we have previously reviewed on Headfonics.

Note, that this article follows our latest scoring guidelines which you can read in more detail here.

Sennheiser HD 620S Review featured image
Sennheiser HD 620S Review
Summary

The Sennheiser HD 620S is a surprisingly good 'mid-fi' set of closed-back dynamic driver headphones and thoroughly belongs in the same class as the HD 600. 

You get closed-cup performance that sounds anything but, and a well-weighted neutral to natural tonal signature amenable to a wide range of amplifier pairings and not just something that will keep you strapped to the desk.

Sound Quality
8.9
Design
8.5
Comfort & Isolation
8.9
Synergy
8.8
Slide here to add your score on the gear!42 Votes
8.3
Pros
Much improved sub-bass presence
Most comfortable pads on a HD6 Series headphones to date
Easy enough to pair with a wide range of amplifiers
Cons
No balanced cable included
Some flex noise in the housing
8.8
Award Score

We have a new edition to Sennheiser’s 600 series of dynamic driver headphones but unlike the HD 660S2 from last year, the HD 620S is a more affordable closed-back offering.

Priced at $349.95, the HD 620S is positioned closer to the classic HD 600 and HD 650 (6XX) but draws heavily on the aesthetics of the 500s series chassis with an angled 42mm dynamic driver more in keeping with the newer 600 models.

With a single-entry detachable cable and a drop in impedance from 300Ω to 150Ω, it looks like Sennheiser wants this new closed-back headphone to appeal to desktop and portable audio enthusiasts. 

From our testing and sound impressions, it delivers on that classic Sennheiser ‘love’ for a natural-sounding midrange presentation but now, we have a lot more presence and power from the lows. 

One of Sennheiser’s most Harman-friendly headphones to date at this price point? Read my detailed impressions and comparisons below to see exactly where the HD 620S fits into the company’s current 6-series headphone line-up.

Sennheiser HD 620S on wood headphone stand

Features

While the dynamic driver has the familiar 42mm total size and 38mm diaphragm size combined with the company’s ultra-light aluminum voice coil, it is the impedance rating of the HD 620S that stands out at 150Ω more given the rest of the 600 headphone series is rated at 300Ω.

The previous 150Ω outlier was the HD 660S first generation, however, this was a less sensitive driver at 104 dB/Vrms compared to this new custom-designed version at 110 dB/Vrms so it is not the older driver shoe-horned into a new closed-back chassis. 

The second key feature is the damped driver’s angled baffle mount and an acoustical surround build drawn from the HD 660S2 to create a stronger perception of depth and space.

The concept here is to combine the angle with a more open baffle design and steel plate to aim for something closer to the wider and more immersive triangular imaging of a loudspeaker setup while retaining the benefits of the closed-back’s improved isolation.

Considering the likes of the HD 600 are not known to be a highly spacious headphone, to begin with, a closed version and keeping the same driver positioning would create something far too closed-in sounding to impress.

And why go with the 500 Series chassis? For one, because the 600 series housing is hand-assembled, it is harder to prevent leakage on the production line than the 500 housing. For another, the housing has a proven long-term wearing comfort after angling the drivers

Sennheiser HD 620S headband

Design

It’s been almost 15 years since I last had a Sennheiser 500 series chassis in my collection. That was the open-back HD598 back then and it’s gone now but even if the housing has a similar design language, the HD 620S is a much beefier and heavier iteration.

Compared to the current 600 series lineup of open-backs the HD 620S 326g weight without the cable is over 60g more than the TOTL HD 660S and the classic HD 600/650 models. It feels more substantial in the hand compared to the alternative models.

Much of the additional weight seems to have gone into durability concerns with steel-reinforced earcup housings and headband sliders that look sturdier than the lightweight HD 660S2 headband design. The headband itself is wider and beefier than its open-back siblings. 

The rest of the housing is made of stiffened black smooth stiffened plastics with that classic 500 series ‘elegant flow’ to the design language of the yoke structure and compact circumaural ovoid earcups with a splatter paint finish.

You do get a bit of housing flex when articulating it, more so than the open-back models but not something that would overly concern me. This headphone feels fairly robust which is what I presume to be Sennheiser’s intention given it has some transportability aims.

Sennheiser HD 620S on its side

Comfort & Isolation

The HD 620S is a for my head in keeping with the 600 series headphones, ie., a smaller circumaural design with a stronger emphasis on lateral clamping than vertical downward pressure. 

However, I find the HD 620S more comfortable than the open-back 600 series alternatives due to the new detachable synthetic leather pads’ wider and deeper 5mm internal opening, (from the outer plane of the earcup to the wedge inside the earcup).

The likes of the HD 600 and HD 650 stock velour pads are narrower on the inside and tend to sit partially on top of my ear creating more perceived pressure. That is not the case with these new pads which clear my ear and nestle on the surrounding sides.

That creates two positive gains for the HD 620S wearability with enhanced comfort relative to the strong clamping and improved isolation from being able to rest on a more even contact surface, aka, the side of your head. 

The new synthetic leather pads do an excellent job of providing a good level of passive isolation. There will, however, be a bit of additional sweat building up over longer listening sessions compared to the more breathable velour pads. However, a small amount of inner perforation should assist with heat dissipation. 

Extra brownie points to Sennheiser for also introducing what seems to be the thick memory foam padding from the HD 560S on the underside of the headband.

It is a lot more substantial than the HD 660S/650/600 padding and helps mitigate what little vertical pressure there is when wearing the HD 620S.

Sennheiser HD 620S stock cable

Stock Cable

The HD 620S comes with just one single-ended 1.8m cable terminated for a single-entry connection into the left cup. As far as I know, all the internal wiring is 27-28AWG OFC copper Litz with enamel-coated stranding and additional Kevlar for increased tensile strength.

It’s a slightly lighter cable than the HD 660S2 version which runs the equivalent of 2 HD 620S cables side by side though I dare say that might be more welcome by users who want to use the HD 620S on a more portable basis. 

The cable is terminated with a proprietary twist-to-lock mechanism machined into the rubbery barrel housing a 2.5mm TRRS jack on one end and a 3.5mm TRS jack on the other with a treaded finish to accommodate a 6.35mm adaptor. 

The cable’s locking mechanism makes it more difficult to ‘cable roll’ if you want to use a balanced cable alternative. I am told that Sennheiser will produce a 3.5mm inline mic and an additional 4.4mm terminated alternative as an optional purchase sometime this summer for those who want to go balanced. 

Given its legacy socket, the HD 620S is also compatible with any other cable variant from the single-sided 500-series after 2007.

However, if you cannot wait until then, you can find plenty of adaptors on Amazon or AliExpress for around $5 that will allow you to connect your own suitable terminated aftermarket cables.

Sennheiser HD 620S black carry pouch

Packaging & Accessories

The Sennheiser HD 620S packaging is compact and functional but not aesthetically inspiring. It is similar to the new ‘simpler’ packaging rolled out for the latest editions of the 600 Series.

I wish they could give it a bit more ‘oomph’ in the boxing department to elevate the sense of worth on the retail shelf and capture the eye of the shopper a bit more. It is a competitive world out there guys.

On the plus side, you get a soft drawstring satin pouch to put your HD 620S headphones into which will do a good job of protecting from dust but not much in terms of mitigating bumps and impact.

I still stand by my previous review findings from the HD 660S2 for buying a 3rd Party carrying case. I have been using Geekria cases for the HD series with one ordered for the HD 620S costing around $30. They are of excellent quality with plenty of foam padding inside to protect the headphones.

Click on page 2 below for my sound impressions and recommended pairings.

Click on page 3 below for my selected comparisons.

Sharing is caring!