Sennheiser HD 6XX vs. Hifiman Sundara
Gear used for testing: Fosi Q5 192 ESS9018 DAC/AMP with a Sony DVD SRH-200p as the transport. Generic RCA coax connector.
Sources are exclusively CD, SACD, HDCD, and SHM-CD. No streaming, Bluetooth, or digital file sources were used.
Both headphones were burned in on various Symphonic music for 70 hours apiece. After 70 hours minimal or no improvement in sound was noticed on either.
Quick Take TLDR:
Buy Both
Executive Summary:
These two are at a similar price point, though the 6xx is often discounted to $179 to $219 at Drop. Sundara is $299 from Headphones.com. Solidly 'Mid-fi' in pricing if not performance.
The 6xx is a Drop modification of the venerable Sennheiser HD 650, a headphone that has been around since 2005. They are a tweak on the HD 600, which first appeared in 1998. The HD 600 were, in turn, an improvement upon the HD 580 which was first manufactured in 1995.
Listening was done over a period of 3 months since mid-February on a variety of music styles from Avant Garde, 19th C Classical, Jazz, to Rock, Alternative, Folk, and Ambient.
Music Style:
6XX sounds as though it were 'voiced' on the classic Von Karajan 1962 symphony cycle. Which it very likely was.
These headphones sound fantastic on 'Classical' and Acoustic guitar with solo female or male voice.
They lack pinpoint staging and the extremes are rolled off, but on symphonic music you can easily visualize standing above the orchestra and see each instrument with ease. The violins sound like violins, female voice sounds like female voice, and so on.
Sundara is more of an even presenter, and for Rock, EBM, Jazz, and anything with electric bass or drums, these excel in giving proper slam and punch to the music. Classical sounds good, but lacks the realism of the 6XX.
Soundstage:
The 6XX has a closer soundstage with instruments that are not as pinpoint focused to a small area of the sound field.
The Sundara takes a step back and adds a "you can point to each player" effect with a slightly wider soundstage.
I can point to each instrument in the mix and hear the intent of the producer/engineer. With the 6XX this effect is dulled and instruments are larger and 'blobbier' than with the Sundara.
Midrange:
6XX is legendary in this regard and after 3 months of listening it is obvious why. The vocal timbre, guitars both acoustic and electric, and the verisimilitude of the instruments, is outstanding.
Cymbals have a realistic and brassy sound of actual brass being struck. Vocals both female and male are outstanding and life-like. Each performer sounds more like themselves via the 6XX. Tubey if the adjective applies.
Sundara has a clear midrange but the lack of the 6XX factor is obvious. Cymbals have more of a sheen minus the brassy accuracy. Vocals sound accurate but not life-like. Solid State if the adjective applies.
Treble:
6XX rolls off in both treble and bass and is bit muted. This is conveyed by the infamous "Sennheiser Veil".
Sundara has more extension in the treble. More crisp but lacks the brassy accuracy to cymbals the 6XX has in a strong fashion.
Bass:
6XX rolls off, bass is accurate and tuneful with 'toe tapability factor'. In that I find my foot tapping in time to the music. Lacks the deep bass impact, and sub-sonic detail of room ambience is lacking.
Sundara has deep, sub sonic bass, with appropriate extension and slam. Room volume is clearly conveyed with HVAC rumble, street noise, and drum riser thumps clearly audible in contrast to the 6XX.
Gaming:
I no longer do any gaming and thus cannot give a comparison. When I did game I was always single player and thus listening for footfall queues to sus out the detail of each headphone was not a function of my gaming experience.
Comfort:
The 6XX have a very strong clamp force out of the box that barely fades after 2 or 3 months. Placing these over a bookshelf speaker to spread out the headband will speed up this process. After a week or two the clamp, while still noticeable, becomes less noticeable and not as intrusive. First out of the box, however, these will be very strong on the sides of your head.
This clamp is to give them more bass than the HD 600. It will also age and wear out the pads quickly.
Pads are a comfy velour with firm but comfy foam that presses firmly upon the sides of your head. No issues with heat or sweat.
The Sundara are much less forceful and more comfortable. Pads are larger, circular, and of a fake leather/vinyl that rests easily around the ear and causes no discomfort with heat or sweat.
Isolation:
6XX has effectively none. If you are listening to something, it is audible 20 feet away in another room.
Sundara is barely audible from 6 feet away when worn. Well isolated for use around others.
Detail Retrieval:
One category I use to discern between headphones is how well they resolve non-musical detail. Room feel, kick drum pedals being struck before the track starts, conversations, clicking of horn keys, the thump of a player's palm against a guitar body - these are all things I look for in a headphone.
The Sundara excels in this area. Whilst it always lacks that magic midrange, the detail of what is presented balances out this loss. The 6XX presents superb midrange but lacks the level of detail the Sundara presents with ease.
Vintage Comparison:
AKG 240 and the CAL! Aurvana OG
AKG 240 (1978) have a polite, detailed, presentation that lacks the midrange smoothness of the 6XX and the detail and retrieval of the Sundara. 240 lacks bass when compared to both with more of the audible detail and attack at the upper bass in place of any slam or harmonic fullness. Zero deep bass slam from these vintage classics from 1978.
Excellent instrument harmonic clarity that compares well to the Sundara and is more neutral than the 6XX.
It is easy to see why these 45 (!) year old headphones have the reputation that they do. On classical, jazz, and small ensemble vocals, they sound excellent and are perfectly acceptable. With rock they lack slam and impact but present much of the detail present on the recordings.
Nowhere near outdated. Modern cans improve in many aspects, but a pair of AKG 240s would make a solid addition to any stable of headphones. An enjoyable listen.
CAL! (2012) compare most favorably out of all of my bargain cans to both. They have a fair representation of the SQ of these mid fi, without any of the precise soundstage or detail retrieval. Treble is accentuated, a common trick to get cheap cans to have an audiophile sound, but not overly bright as the Presonus HD7 or Takstar Pro 80/HyperX. In a pinch while travelling, the CAL! will suffice and at $15 I won't mind forgetting them on a long plane flight.
Both the 6XX and Sundara are superior and preferable in all aspects except the CAL! has very good bass for a small over-the-ear portable that competes well with the 6XX.
Portable Use:
I do not travel with either, but used the mini-jack output of my Android phone to briefly compare with online video. The 6XX are easier to drive and have good volume from my phone. The Sundara are just too power hungry for such usage. They are better with an amp.
Conclusion:
These are two modestly priced "mid-fi" headphones that are an enjoyable listen, provide many aspects of the "audiophile" experience, and reveal substantial detail and enjoyment over many hours and days. Each has its strengths and neither is an all around contender that does it all.
In terms of entry level to getting a variety of headphones that have strengths for particular music sources, these two are the best entry to getting a variety of headphones to enjoy different aspects of music.
As such, I recommend that BOTH be purchased in tandem as a way to hear different presentations of your music collection at a reasonable price.
