Sennheiser HD 650 review

Sennheiser’s line of open-backed headphones has grown a bit over the years, but the HD 650 remains a stalwart of the brand that’s been around for close to two decades. Along with the HD 600, it’s considered by many as a true reference headphone, not just in terms of the sound signature but for listener comfort, too. Plenty of products have come and gone during this headphone’s lifetime, so let’s see where it stands compared to the current competition and the HD 600 we tested recently.

Editor’s note: this is the first version of the article. Updates will follow as the market changes.

What’s it like to use the Sennheiser HD 650?

No storage case is included with the HD 650; you get the headphones, the Y cable, and a short adapter cable. You’ll need to look for a carrying case if you plan to take them anywhere regularly, especially considering the open-back design. Also, there are no folding hinges to compact the headphones further, underscoring that they are intended for home (or studio) use only.

The headphones are built on a frame Sennheiser has fully optimized over the years. The plastic parts are finished with a subtle grey metallic sparkle. The badges on each side over the open grilles are light grey and give the model number. All other parts are black. Identifying the left and right sides in low light conditions isn’t apparent until you remember that the Sennheiser logo on the headband goes to the left. I still would prefer a Y cable with color-coded ends, which used to be the standard for this line but sadly isn’t anymore.

The large ear cups easily accommodate larger than average ears, and the padding material works okay over glasses.  I find the clamping force appropriate, and the small amount of swivel in the ear cups means they follow the contours of my head perfectly. The low weight of the headphones and ample padding means that very long listening sessions are possible without discomfort—I sometimes forget I’m wearing them. Notches on the headband make it possible to recall your size setting, but only by counting the clicks made by each adjustment of the relatively stiff metal mechanism.

How does the Sennheiser HD 650 connect?

The Sennheiser HD 650 connects to your source via the included 3-meter (just under 10 feet) long cable, which can be cumbersome in some situations and terminates in the larger standard 1/4-inch TRS plug. The Y-shaped cable connects to each ear cup using Sennheiser’s standard two-pin push-fit connectors. I share my colleague Chris Thomas’ opinion that the supplied adapter arrangement is backwards (using a dongle to offer a 3.5mm plug instead of an adapter to get a 1/4 inch one), and prefer the threaded 1/4-inch adapter on top of a 3.5mm plug that doesn’t add even more cable length. Of course, it isn’t an issue if these headphones will live by a desk or recliner and never leave.

How well does the Sennheiser HD 650 block out noise?

These are open-backed headphones, so you get minimal noise isolation. You shouldn’t expect to use them outside quiet places like a private office or den. It’s also good to confirm that HD 650 doesn’t exhibit any notable passive amplification (<1dB) of ambient noise, which we have seen on some openbacks.

How does the Sennheiser HD 650 sound?

Multi-Dimensional Audio Quality Scores (MDAQS)

The chart below is a visual representation of how the sound of the Sennheiser HD 650 was assessed by the Multi-Dimensional Audio Quality Score (MDAQS) algorithm from HEAD acoustics. Be sure to check out our full explainer here.

Timbre (MOS-T) represents the headphones’ spectral properties (how faithfully they reproduce the frequency spectrum) and temporal resolution (timing information).

Distortion (MOS-D) represents non-linearities and added noise: higher scores mean cleaner reproduction.

Immersiveness (MOS-I) represents perceived source width and positioning: how well virtual sound sources are defined in three-dimensional space.

Should you buy the Sennheiser HD 650?

The HD 650 was never cheap, but with the recent general upward trend in pricing in the industry and the emergence of many premium-priced offerings from more audiophile-oriented brands, it’s now a better-looking price proposition than it’s ever been. That said, it’s worth doing some listening comparisons with the HD 600 to see if the price difference is worth it to you. You basically can’t go wrong with either one.

How does the Sennheiser HD 650 compare to the Sennheiser HD 600?

The Sennheiser HD 600 is held in similarly high regard to the HD 650. But what’s the difference?

In terms of frequency response, the two models are extremely similar. You’d be hard-pressed to find two headphones more similar in their measured response. If we’re going to split hairs, the HD 650 has a marginally higher output at 20Hz, giving it slightly better bass extension. The HD 600 is a tad brighter thanks to a little extra output at 7kHz. Also note that the HD 650 is 6dB more sensitive than the HD 600, which is meaningful and could make the difference between using the headphone output from your source device or needing an external amplifier for extra help.

What should you get instead of the Sennheiser HD 650?

If you’re into the Sennheiser HD sound, we recommend first checking out the Sennheiser x Drop HD 6XX. Its sound is close to the HD 650, and some may even argue it’s better. It’s certainly a better deal price-wise. Keep in mind the fit and finish of the Drop product aren’t up to the same standard as the HD 650, but it’s close enough for most.

The only other comparable brand that can provide such surefire classic designs is Beyerdynamic. Pick up the Beyerdynamic DT 900 PRO X for a great-sounding, comfy, open-back pair of headphones. The DT 900 PRO X provides a more accurate representation at the low end than the Sennheiser HD 650. Some may prefer the oval-shaped ear pads of the HD 650 compared to the circular pads on the DT 900 PRO X, but that’s dependent on your head and ear shape.

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