Jose Hidalgo
Addicted to Fun and Learning
My Sundaras are just like yours. There are only two versions of the Sundara: the original one, and the 2020 silent earpad revision that was introduced about 18 months ago. That revision didn't change anything driver-related: it was just new earpads with variable thickness which solved the small treble problem that previous version had. Which made the 2020 revision almost neutral, as shown by measurements. Only a soft 2 dB peak around 1000 Hz and a 3 dB peak around 6500 Hz, nothing more.What version are your Sundara's? I have bought my Sundara's very recently and have the HD6XX since last year.
The frequency plots of both the Sundara and the HD 600 by Oratory, made with professional equipment (GRAS 45), are self-explanatory.I've tested with slow sweeps and I get good extension down to 20Hz on my head with the Sundara's (no EQ) but not with the HD6XX.
- The un-EQed HD 600 reproduces 20 Hz @ -9.5 dB relatively to the usual Harman AE-OE 2018 target curve, as shown here.
- The un-EQed Sundara reproduces 20 Hz @ -10 dB relatively to the usual Harman AE-OE 2018 target curve, as shown here.
- The HD 6XX has little to do with the HD 600 since it's a cheaper clone of the HD 650. Still, it also reproduces 20 Hz @ -9.5 dB as shown here.
The 6XX has a slightly warmer sound out of the box (as shown once again by measurements) which makes it harder to compare with a neutral headphone like the Sundara. The HD 600 and the Sundara are easier to compare. Even more when EQed, which is my point here.Soundstage on the Sundara is indeed bigger than on the HD6XX (seems to be the same on all HD6xx series headphones).
I would rate the sound on both exactly the opposite as you rate them. Sundara sound more open and lively. That doesn't mean I don't love my HD6XX. It just more closed in, cozy and warm sounding.
My choice: On a budget = HD6XX, can spend more = Sundara
You are free to have your own subjective impressions and prefer the Sundara. That's great. The only thing you can't do is go against measurements and say that the un-EQed Sundara have "good extension down to 20 Hz". That is just not true, sorry. You can also find them comfortable for your head, good for you, but you can't dismiss the fact that they're 372g while the Senns are 260g. Those are just facts.
Last but not least, don't forget that you've just had your Sundaras, so you can easily suffer from recent buyer bias. The newest headphone is always the best, right ? I've had mine for almost a year, and during that time I've gone through several stages ("love them"... "love them less"... "love them more"...) in order to assess all that was right with them (which is a lot) and all that was wrong with them (which is little).
Both the Sundara and the HD 600 are excellent choices, and in the end it's a matter of personal preference. Only the measurements are unquestionable, and the fact that EQing them brings out the best in them and makes them much better.