Sennheiser HD 620S Headphone Review

[staticV3]

Hey, that might be a slightly off topic, but where do I find the list of recommendation made by amirm? I somehow cannot find it.

Review Index->Headphones->Click on Recommended to sort

 

[Bernard23]

I have owned these now for about 3 months, I needed a closed back at sensible prices for bedtime listening and when on public transport. I've set them up using Oratory1990s EQ settings and they're better than I expected. My reference is a pair of LCD-X using the Audeze Roon eq profile and I was surprised how good the 620s are. I mostly use them with a LG phone or a Fiio KA17 dongle on a Samsung phone, both via the UAPP app.
Biggest issue for me is the seal, I can see that for some folk they might not work consistently, but that's an issue for lots of closed back designs. Distortion is inaudible to me at the levels I use them so that's a non issue, if I want to damage my hearing, there's the LCD-X for that.

 

[Salt]

1kHz is as good as the easiest frequency for a headphone to reproduce. Often distortion is at the lowest in that region. Also true for electronics b.t.w. one can get the best 'numbers' there.
Also as SINAD is noise and distortion and there is always some sound 'leaking' in (unless measured in a very silent box) and the measurement system also has some self noise the SINAD number at an arbitrary level is a completely pointless number for headphones and, just like in electronics, that number says nothing about sound quality.

And now something completely different..
I was recently sent a HD620S to check as the owner found it a bit 'weird' sounding.
View attachment 403893
As can be seen the left channel had 2.5dB more bass than the left channel.
After some experiments and checking for leaks etc. it turned out to really be something in the drivers.
No leakage in either cup.

My copy did not have this and looked most like the right channel.
Scrutinizing Amirs measurements I saw something similar.
View attachment 403895
About 2dB difference below 150Hz where the left channel is a bit higher in level.
It seems there are some QC issues or matching issues possible with this model.
Rtings measurements showed also around 2.5dB difference but in the mids and here the R channel was a bit higher.

This, as well as possible seal issues is something to keep in mind when shopping for a HD620S.
I have 2 other HD620S and both had good channel matching (within 1dB) so good ones exist but one might encounter one with some channel imbalance.

Update:
I sent back the HP 'for repair', mentioning the imbalance. No requests since.
Received a new one today and the sound is as expected.

Remembering a report here on ASR about a DCA E3 that also sounded not as expected (though B-ware): maybe QC might be a concern regarding headphones.

 

[Booker]

My brain is just getting used to them after yesterday's impulse purchase, inspired by the Closed headphones below 500 thread and @solderdude's recommendations. Earlier today, when I first listened to them, I would have hit the return button if it had been active on the e-shop website. But I gave them another chance tonight, and I haven't been able to take them off my head for two hours now. Halfway through the listening session, I tried Oratory's EQ. They fit perfectly on my head.

 

[Limopard]

Tomorrow I'm in Cologne, where the local Saturn markes has the 620s on display. If time is permitting (and Deutsche Bahn isn't too late) I will try it just to satisfy my curiosity. @oratory1990 's EQ profile already is fed into the neutron player, the NX 4 will do the amp job.

 

[oratory1990]

if Deutsche Bahn isn't too late

One can dream!

 

[Limopard]

One can dream!

.and wake up. Train is cancelled. Next one is overcrowded, so I take the alternative route via Hannover/ Bielefeld, which is more time consuming. No time for the 620 anymore. In case the 620s would be good I effectively saved 300 €.

 

[Limopard]

A prolonged lunch break allowed me to have short listen to the 620s.

I instantly achieved a good fit and seal, but the clamp is very firm, it starts to get a bit annoying after 10 minutes. It gets sweaty too.

Bass is exceptional, one of the best I had until now. Deep, punchy, not bleeding into the midrange.

Midrange is a bit shouty/sharp for me. Less so with EQ, but still not completely satisfying. This is an issue with the HD 560s too, maybe I'm not compatible with angled drivers.

Treble is okay, could have a bit more air from time to time.

It's a decent headphone, but not fully compatible with me.

 

[lc6]

Based on this review and recommendation, I purchased these headphones to replace my trusted 30+ year old Sony MDR-V6. Unfortunately, the HD 620S had a perceptible channel imbalance: the left was playing a few dB louder than the right one, causing the soundstage to shift (this imbalance is also visible, albeit to a smaller extent, in @amirm 's first measurement graph). The MDR-V6 has no such issue in the same setup. While this could be corrected by changing the balance in the amp, there were also not negligible differences in the channels' FR. Another problem was that the 3.5 mm plug was difficult to insert into the socket; a fair amount of force was needed to push it in (not so with the MDR-V6). Sennheiser should do a much better QC on these $350 headphones. Sadly, they had to be returned.

 

[solderdude]

The headphone plug is a twist-locking plug. Must be inserted in the right position and then rotated a little.

Channel imbalance is inexcusable. You are not the first one to complain this.

 

[Bernard23]

if I haven't already commented earlier, my pair also have a slight imbalance. It's reassuring that it's not some phychosis (I've had phones in the past that drove me nuts, you can't unhear it once it's there). However, since I use them almost always with UAPP then I have a slight balance adjustment in the PEQ profile I set up for them.

 

[Bob from Florida]

The headphone plug is a twist-locking plug. Must be inserted in the right position and then rotated a little.

Channel imbalance is inexcusable. You are not the first one to complain this.

I wonder about the channel imbalance question. The pair reviewed is one of 2 pair I own and both sound identical to me - with different DAC/Amps. The iFi idsd Signature and the JDS Element 3 MK2. The 620S has some impedance swings that might create some issues with higher impedance headphone amps regarding frequency response versus near zero output impedance amps - perhaps?
Certainly, some of the more expensive headphones measure more “perfect”, but the cost is more. Two pairs of 620S’s ran me about $550 versus a cool $2K for well regarded DCA headphone.
Maybe I am not “picky” enough.

 

[solderdude]

Output impedance would have to be very high and not cause channel imbalance but a slight warming up of the sound.

The measured channel imbalance in the lows (in the sample Amir tested) is most likely a seal issue (the wrinkles in the pads) and above 5kHz could be position dependent.
Not something to worry about. Between 100Hz and 5kHz there is no channel imbalance visible and that's the most obvious (important) part of the frequency range.