Hello again Head-Fi!
Hot on the heels of the HD 505 comes the new HD 550. Although close in name, this new flavor of the 500 series comes with some delightful optimizations for those seeking a modern neutral tuning with polite-yet-pronounced bass response. We'll get back to the name/number, but want to first introduce you to this new entrant into our 500 audiophile headphone series.
While both the HD 505 and HD 550 pick up where the venerable HD 560S left off, the HD 550 folds in some additional community feedback into its performance. Since the 560S was announced, we learned that fans of the neutral/analytical profile were split into two main groups: ones that wanted a less fatiguing fit/sound (HD 505) for longer listening, and those that, in short, wanted all of that plus more bass presence (and the accompanying balancing act that comes with retaining a neutral profile...the HD 550).
Up Close & Personal
The HD 550 is indeed designed for listeners diving into the world of serious sound and are looking for detail, soundstage, and honesty. At the heart of it is a new 150-ohm transducer manufactured in our state-of-the-art audiophile facility in Tullamore, Ireland. It shares some DNA with the recent 500 series models, but sports different diaphragm composition than the HD 505, and also utilizes a different voice coil and baffle design. The open-back earcup design and angled transducers recreate the natural imaging of nearfield loudspeakers, offering that immersive soundstage modern media was mixed for. Upon first listen, the low-end comes across slightly warmer with a great deal of control and clean extension. This added punch, combined with the panoramic imaging, gives you an intimate look at your music. In particular, percussive tracks and well-mixed material is instant ear candy, intended to inject some fun into the nuanced honesty of the tuning.
[reserved for the upcoming Head Gear page]
As followers of the brand have noticed, the HD 550 is built upon the fan-favorite 500 series chassis. At just over 230 grams (less than many smartphones and gaming controllers) it feels balanced and confident without as much lateral squeeze as the HD 560S. The metal mesh grilles work in tandem with the baffle for the optimum acoustic impedance--the results are a lightweight, remarkably open listen that is effortless. The synthetic leather headband complements the overall design, which is purposefully suited for longer listening times.
Modularity (and ease of maintenance) remain—the single-sided detachable 1.8m cable (~6 ft) with a 3.5mm plug (and included 6.3mm adapter) can be swapped out in seconds without tools for cable swaps and earpad exchanges. It comes ready for balanced cables or those with in-line microphones for added versatility as your needs evolve.
The HD 550 will be available for pre-order starting today from select Sennheiser audiophile retailers, and also at sennheiser-hearing.com. For a limited time in the US, pre-orders will include a free balanced cable upgrade (4.4mm).
@ericpalonen will be here to help answer any questions, and has an HD 550 within arms reach if you want to geek out.
Which HD 500-series is for me?
The resulting discussion in this thread will be very helpful as the community chimes in, and we have an upcoming video about this. But until it is published, we can steer you with just a few keywords:
HD 505 - neutral with a cooler, analytical tuning, brilliant treble, and wide soundstage
HD 550 - neutral with deep & smooth bass extension, brilliant treble, politely balanced, and wide soundstage
...of course, your preferences will dictate which you prefer best, and as always, we hope you get to try both.
###
A note about naming: Like many audio brands, we use an alphanumeric system for many of our products. With an 80 year anniversary on our heels, we have no doubt amassed an enormous catalog of product names....some of the rules we have established have been bent as the markets and products evolve. As of this writing, we're simplifying the names so that it becomes a bit easier to classify our products. While not perfect (and not entirely retroactive) our next few releases are a great demonstration of the new naming methodology.
The first letters classify the headphone at the widest part of the funnel: "HD" stands for Headphone, Dynamic, as it always has. IE is an In-Ear (dynamic), HE is Headphone Electrostatic, etc. This remains unchanged.
The next number (in this instance, "5") places the headphone in a performance series: HD 500, 600, or 800..again, unchanged.
The numbers after that is where we are going to tighten things up.
x20 will be reserved for closed-back models (example: HD 820, HD 620S)
x50 and x00 will lean towards neutral tuning (example: HD 800S)
x60 will lean towards a warmer tuning (example: HD 660S2)
xx5 will, in most cases, indicate a retailer limited release in your market (example: HD 505)
Our back catalog is full of exceptions and nuances, so feel free to ask any questions if you have them, and thanks for coming along with us on the journey!
Hot on the heels of the HD 505 comes the new HD 550. Although close in name, this new flavor of the 500 series comes with some delightful optimizations for those seeking a modern neutral tuning with polite-yet-pronounced bass response. We'll get back to the name/number, but want to first introduce you to this new entrant into our 500 audiophile headphone series.
While both the HD 505 and HD 550 pick up where the venerable HD 560S left off, the HD 550 folds in some additional community feedback into its performance. Since the 560S was announced, we learned that fans of the neutral/analytical profile were split into two main groups: ones that wanted a less fatiguing fit/sound (HD 505) for longer listening, and those that, in short, wanted all of that plus more bass presence (and the accompanying balancing act that comes with retaining a neutral profile...the HD 550).

Up Close & Personal
The HD 550 is indeed designed for listeners diving into the world of serious sound and are looking for detail, soundstage, and honesty. At the heart of it is a new 150-ohm transducer manufactured in our state-of-the-art audiophile facility in Tullamore, Ireland. It shares some DNA with the recent 500 series models, but sports different diaphragm composition than the HD 505, and also utilizes a different voice coil and baffle design. The open-back earcup design and angled transducers recreate the natural imaging of nearfield loudspeakers, offering that immersive soundstage modern media was mixed for. Upon first listen, the low-end comes across slightly warmer with a great deal of control and clean extension. This added punch, combined with the panoramic imaging, gives you an intimate look at your music. In particular, percussive tracks and well-mixed material is instant ear candy, intended to inject some fun into the nuanced honesty of the tuning.

[reserved for the upcoming Head Gear page]
As followers of the brand have noticed, the HD 550 is built upon the fan-favorite 500 series chassis. At just over 230 grams (less than many smartphones and gaming controllers) it feels balanced and confident without as much lateral squeeze as the HD 560S. The metal mesh grilles work in tandem with the baffle for the optimum acoustic impedance--the results are a lightweight, remarkably open listen that is effortless. The synthetic leather headband complements the overall design, which is purposefully suited for longer listening times.
Modularity (and ease of maintenance) remain—the single-sided detachable 1.8m cable (~6 ft) with a 3.5mm plug (and included 6.3mm adapter) can be swapped out in seconds without tools for cable swaps and earpad exchanges. It comes ready for balanced cables or those with in-line microphones for added versatility as your needs evolve.

The HD 550 will be available for pre-order starting today from select Sennheiser audiophile retailers, and also at sennheiser-hearing.com. For a limited time in the US, pre-orders will include a free balanced cable upgrade (4.4mm).
@ericpalonen will be here to help answer any questions, and has an HD 550 within arms reach if you want to geek out.

- Coupling – Over-ear (circumaural), fabric earpads
- Acoustic principle – Open-back
- Transducer – Dynamic
- Frequency response – 6 - 39,500 Hz
- Impedance – 150 ohms
- SPL – 106 db @ 1kHz
- Total Harmonic Distortion – <0.2% @ 1 kHz, 90 dB
- Weight – 237g (without cable)
- Cable – 1.8m (~6ft) detachable with 3.5mm (⅛-inch) stereo plug; includes 6.3mm (¼-inch) adapter; single-sided entry
Which HD 500-series is for me?
The resulting discussion in this thread will be very helpful as the community chimes in, and we have an upcoming video about this. But until it is published, we can steer you with just a few keywords:
HD 505 - neutral with a cooler, analytical tuning, brilliant treble, and wide soundstage
HD 550 - neutral with deep & smooth bass extension, brilliant treble, politely balanced, and wide soundstage
...of course, your preferences will dictate which you prefer best, and as always, we hope you get to try both.
###
A note about naming: Like many audio brands, we use an alphanumeric system for many of our products. With an 80 year anniversary on our heels, we have no doubt amassed an enormous catalog of product names....some of the rules we have established have been bent as the markets and products evolve. As of this writing, we're simplifying the names so that it becomes a bit easier to classify our products. While not perfect (and not entirely retroactive) our next few releases are a great demonstration of the new naming methodology.
The first letters classify the headphone at the widest part of the funnel: "HD" stands for Headphone, Dynamic, as it always has. IE is an In-Ear (dynamic), HE is Headphone Electrostatic, etc. This remains unchanged.
The next number (in this instance, "5") places the headphone in a performance series: HD 500, 600, or 800..again, unchanged.
The numbers after that is where we are going to tighten things up.




Our back catalog is full of exceptions and nuances, so feel free to ask any questions if you have them, and thanks for coming along with us on the journey!
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