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Sennheiser HD 650
315 x 254 x 110 mm
70mm x 40mm (inside ear cup)
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, as well as the HD 600 we tested recently.
Editor’s note: this is the first version of the article. Updates will follow as the market changes.
The Sennheiser HD650 is an excellent choice for anyone who wants a classic, great sounding, comfortable open backed headphone to keep at their listening station for extended sessions.
What’s it like to use the Sennheiser HD 650?
No storage case is included, you just get the headphones, the Y cable, and a short adapter cable. You’ll need to look for a carrying case if you’re planning on taking them anywhere on a regular basis, especially considering the open-back design. Also, there are no folding hinges to further compact the headset, underscoring that this is basically intended for home (or studio) use only.
The headphone is built using a frame design that’s been totally optimized by Sennheiser 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 totally obvious 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 any more.
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 mean 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 into each ear cup using Sennheiser’s standard 2 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, if these headphones are going to live by a desk or recliner and never leave, it isn’t really an issue.
You probably won’t need a dedicated amp but it’s possible that your source device won’t have enough power to make the most of the Sennheiser HD 650. It’s actually 6dB more sensitive than the HD600. If you find that you can’t get your headphones loud enough, or you’re running very close to the limit, you’ll want to explore getting an amplifier.
How well does the Sennheiser HD 650 block out noise?
These are open backed headphones, so you get minimal noise isolation. This means you shouldn’t expect to use them outside of quiet places like a private office or den. It’s also good to confirm that HD 650 also doesn’t exhibit any notable passive amplification (<1dB) of ambient noise, which we have seen on some open backs.
How does the Sennheiser HD 650 sound?
Editor’s note: this review makes use of a hover-enabled glossary to describe sound quality, based on a consensus vocabulary. You can read about it here.
The HD650 uses an exclusive 42mm transducer model (with 38mm diaphragms), and was tuned by Axel Grell, who defined the signature sound of the HD6XX series during his time at Sennheiser. It has the rare distinction of having a sound that receives practically universal approval, and is considered a benchmark by many.
Measured on our B&K 5128, the HD 650’s frequency response falls right in line with our expectations for this kind of legacy reference headphone, as exemplified by what we call our “Studio” target response curve, shown on the chart in pink. The only areas it really strays from our ideal is in a gentle roll-off in the low frequencies below 100Hz (to around -10dB at 20Hz) and in a slight undershoot of the high frequencies at 10kHz. So there should be very little to complain about here.
Murder By Death’s 2010 track Foxglove is a fairly dark sounding mix overall, and serves as a useful reference. Adam Turla’s slow, measured lead vocal rides low in the somewhat dense mix — it’s telling whether or not it can be heard without sounding too “rolled off” and indistinct — and the HD 650 does a good job in that area. The whole mix gets delivered with the clarity it needs, from the “localisability” of the dual cello parts pulling the stereo field in both directions in time with the rhythmic bowing pattern, to the multiple acoustic guitars being strummed more for percussion than for melody.
The Pretenders’ Brass in Pocket (2006 remaster) which I prefer over the 2018 remaster, is always a fun listen. Right from the fretboard slide to the fade out, the bass line bounces around, staying in the pocket and driving the song along, but I can’t help feeling it could use some help in the lowermost octaves, where the HD 650 doesn’t have the bass depth I sometimes wish it did. Everything above that is right where it needs to be, there’s plenty going on in this track and I enjoy listening out for the tastefully mixed cowbell when it comes in here and there.
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 definitely worth doing some listening comparisons with the HD 600 to see if the difference in price 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. In fact, you’d be hard pressed to find two headphones that are more similar in terms of 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 some extra help.
What should you get instead of the Sennheiser HD 650?
If you’re into the Sennheiser HD sound, we always recommend checking out the Sennheiser x Drop HD 6XX first. Its sound is extremely close to the HD 650, and some might 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.
Really 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 and 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.
Frequently asked questions
No, unless you need a different termination to use the Sennheiser HD 600 with your source device, or need a different length, there’s no need to change the cable.