Sennheiser HD 650 Review: Sometimes Classics are Classics for a Reason

We live in an era where most headphones see updates every few years, well beyond simple cosmetic changes. That isn’t the case with the Sennheiser HD 650 headphones, which have been more or less the same since 2003, aside from a minor design change in 2019. Nothing else was necessary, apparently.

The comfortable fit and open-back design make for headphones that are well suited to long hours mixing or even mastering music, but they’re also a popular choice for home listening. Without any sort of wireless connectivity or battery, there really isn’t much to change, so it makes sense that they’ve gone relatively untouched for so long.

While the HD 650s have remained still, competitors have had plenty of time to catch up. Sure, they’ve been impressive headphones for years, but are they still as great now as they were twenty years ago? Yes, they are.

Classic Design and a Sturdy Build

Compared to your average headphones, the Sennheiser HD 650 aren’t necessarily cheap. That said, to look at them, you may not think they cost what they do. There isn’t a lot of metal used in the construction outside the headband, and the bulk of the headphones is made from less-than-premium-looking plastic.

That said, these are very robust headphones. I’ve been using my pair of the HD 650s for nearly four years, and while there are some signs of use looking at the finish, the headphones haven’t seen significant damage, even after plenty of drops and other accidents.

There are also plenty of user-replaceable parts here, which means that even if you damage certain parts of the headphones, you don’t need to give up and buy a new set. We’ll look at this more in the following sections.

Fit and Comfort: Ready for Long Days

As I mentioned above, I’ve been using my pair of HD 650s for nearly four years, sometimes for very long days. The headphones have never been anything other than comfortable. The velour ear pads are large enough that I can’t imagine a proper fit being a challenge for most people.

Even better, those ear pads are replaceable. If you’ve ever had a pair of headphones long enough, you probably know that the ear pads are often the first part to go. Knowing that you can replace the ear pads and essentially have a set of headphones that feel brand new gives you a certain peace of mind.

That said, don’t expect to have to replace pads all that frequently. The pads on my personal pair still feel great, and I’ve been using them several times a week for years.

A Simple, Bulletproof Setup

• Connectors: 1/4-inch (6.35mm) cable with 1/8-inch (3.5mm) adapter
• Cable length: 9.8ft (3m)

Similar to the ear pads, the 9.8-foot cable is also detachable and replaceable, which is nice, since the cable is another of the easiest parts to wear out on a set of headphones. The cable connects via a quick-release mechanism on each ear, and has a 1/4-inch jack, with an included 3.5mm adapter to plug into smaller, more portable devices.

In my years using these headphones, I have stepped on the cable more times than I can count. Every time the cable yanks out of the ear cups, I’m positive I’ve finally killed the cable or even damaged the headphones. To date, both the headphones and cable are well intact, but it’s heartening to know that if I do finally render the cable useless, I can just buy another.

The removable nature of the cable is useful in another way as well. If you have a higher-end amplifier or digital audio player with a balanced output, you can buy a balanced cable for the HD 650s. Sennheiser doesn’t make one, but for audiophiles, this is a nice option to have available.

The Test Setup: Make Sure You’ve Got the Power

The Sennheiser HD 650s have an impedance of 300 Ohms and a sensitivity of 105.1 dB/V SPL. If you’re not familiar with what either of those figures mean, it essentially means that you may have a harder time getting the best sound out of these headphones with your phone or computer. You can plug them into anything and get sound out of them, as with any headphones, but you may need an amplifier for the best sound quality.

In my case, I typically listen through a Schiit Modi 3 digital-to-analog converter (DAC) and a Schiit Asgard headphone amp. These easily power the HD 650s, though you can also get away with many more affordable options. For example, the headphone output on the Universal Audio Volt 2 had more than enough power to get the best out of them.

For portable listening, I use a Sony Walkman NW-A35. This doesn’t offer the optimal power for the HD 650s, meaning they don’t sound quite as good as they do with the headphone amp. That said, it sounds good enough that I often use this setup for portable listening.

If Sennheiser does produce a new version of the HD 650, there would be a single item on my wishlist: multiple impedance options, as Beyerdynamic offers with the DT770 Pro and other headphones.

Superb Sound, But Not Overly Flattering

• Driver size: 42mm transducer, 38mm diaphragm
• Impedance: 300 Ohms
• Frequency response: 10 Hz – 41,000 Hz
• Total harmonic distortion (THD): < 0.05 % (1 kHz, 1 V)

The Sennheiser HD 650s feature a 42mm transducer and a 38mm diaphragm, which isn’t as large as the drivers in some other headphones, which can be 50mm or more. That said, they manage to deliver impressive sound despite the smaller driver size.

Part of this has to do with the open-back nature of the headphones, which lends itself toward a larger, more spacious sound. This can also reduce bass impact, as bass frequencies tend to “leak” out of the open side, unlike closed-back headphones. That said, reducing the sound that comes out of these headphones to some sort of equation based on the type of design and driver size is doing them a drastic disservice.

Marvin Gaye’s “What’s Going On” might be a perfect song to show how well the HD 650s treat a song that has been superbly recorded. Gaye’s voice has plenty of presence but never feels unnaturally focused. While the bass is laid back in the mix, the headphones make sure that you feel every note just like the band is in the room with you.

“Low Desert Punk (Remixed and Remastered)” from Brant Bjork shows the excellent interaction between the midrange and the bass. The bass isn’t thunderous, but it is tuned low with harmonics putting it in the same frequency range at times, but the two don’t talk over each other. Instead, the headphones help them work together, with the rhythm section and guitars leaving plenty of space for each other.

Stephen Stills’ “The Treasure (Take One)” shows the relatively relaxed nature of the treble in the HD 650s. The hi-hats and cymbals bells still retain plenty of crispness but don’t sound as strident as they can on other headphones. This soft treble response is what some refer to as the “Sennheiser veil,” and while it is noticeable compared to other headphones, I’ve never found myself wanting an equalizer to bump up the treble.

While the headphones sound huge, soundstage is one area that may not be as impressive. Open-back headphones typically offer better soundstage, but in this case, you don’t get the pinpoint precision you may be looking for. Granted, this can be overly distracting on some headphones, but this is one area where the HD 650s make a rare misstep.

This review has been particularly interesting because, in revisiting a set of headphones I’ve been using for years in a more critical context, I’m reminded more than ever of how much I still enjoy listening to them.

Once you’re used to it, the sound of these headphones is somewhat like a comfortable pair of shoes. If something in a song sounds harsh or out of place on other speakers or headphones, I can check it on the HD 650s and instantly know whether it is the song or something about the playback.

Should You Buy the Sennheiser HD 650?

Above anything else, the one thing the Sennheiser HD 650 headphones do better than many other headphones, both in their price range and above, is walk the fine line between accurate and enjoyable. If you’re looking for headphones that you can use for audio production during the day and then kick back and listen to your favorite music at night, these are a fantastic option.

If you’re only looking for an audio tool, the Sennheiser HD 600 may be a better option, as they’re generally less flattering to the source material. That said, plenty of people do audio work on the HD 650. They’re my main headphones for mixing, although I do turn to closed-back headphones for recording simply to prevent bleed into the microphones.

The HD 650s are simple, with just a cable and a 3.5mm adapter, and depending on your setup, you may need to buy a headphone amp to get the best out of them. Still, while they are pricier than many headphones, you’d have to spend considerably more to get a noticeably better listening experience. Now let’s see if they’re still in production in another 20 years.