Very often we get asked – which are the most flat sounding closed back headphones out there? In regards to neutral frequency response, is there a Sennheiser HD 650 equivalent among closed back headphones? Shure SRH1540 will be mentioned in answers to both of these questions. However, there are a couple of things to know before you grab your credit card. Read on!

Pros
  • Exceptionally flat frequency response
  • Lightweight
  • Comes with two sets of ear pads and cables, and a sturdy hard case

Pros list with Sonarworks Reference calibration

  • Improved both low and high frequency extension
Cons
  • High 3rd harmonic distortion in the low-end
  • Price
Use cases Best use case:
Mixing
Production
Tracking
Recreational listening
Tech specs Type
Closed back, Over-ear
Impedance
46 Ohm
Frequency response
5 Hz to 25 kHz
Connector
3.5 mm straight jack
Adapter
Screw-on 6.3 mm adapter
Weight
286 g (without cable)
Require headphone amp
No
Cable
1.8 m, straight
Build quality

Shure SRH1540 are built using lightweight materials more common in race cars than studio headphones – aircraft grade aluminium alloy yokes, alcantara covered ear pads, carbon fiber enclosure end caps. All these fancy parts are put together really well and the build feels durable. Ear cups are still plastic but that doesn’t take away from the premium feel and look of the headphones. Every little detail is pleasant to touch, including the cable. The spare ear pads and cable are a great inclusion and the extra sturdy transport case has a dedicated pocket or compartment for each of the accessories so it’s easy to take them with you along with the headphones, so you won’t get stranded with a broken cable.

Sound

Shure states that SRH1540 “steel driver frame with vented center pole piece improves linearity and eliminates internal resonance”. Headphone manufacturer marketing claims rarely can be backed up by our measurements but with SRH1540 it’s exactly the case.

All studio oriented Shure closed back headphones that we’ve ever measured are remarkably flat when compared to competition and SRH1540 are the flattest of them all – like true flagship should be. SRH840 is a close second but SRH1540 has better low end extension and more smooth highs. Apart from the bump at 100 Hz, there’s relatively little correction needed. The response deviates only +/- 3dB in exceptionally wide range, from about 170 Hz all the way up to about 17 kHz. At the time of writing, out of the all closed backs we’ve measured, only the now discontinued Oppo PM-3 and the aforementioned Shure SRH840 come close in regards to neutral frequency response.

Channel balance

Out of the seven pairs measured, five had pretty much perfectly matched channels, but the other two had some flaws. One had a low-shelf like disbalance of 2.5 – 4 dB from 200 Hz down, which really isn’t appropriate for the price tag. The other one had similar issues but at more narrow bandwidth and lesser magnitude, making the disbalance nearly imperceivable.

Comfort

Our testers had mixed feelings in regards to long listening session comfort. Unlike most other over ear studio headphone designs, the ear cups can’t swivel, so there’s a set angle for ear pads and headband to rest against the listener’s head. If this angle matches the shape of your head, most likely you’ll find SRH1540 divinely comfortable, if not, it’s likely that after about an hour of use you’ll feel an uncomfortable pressure applied by the headband. According to some users online, the steel headband can be bent quite easily to tailor the ear cup angle to one’s head shape, which solves the headband pressure problem. Others mitigate this issue by applying additional DIY cushioning to the headband.

Nonetheless, the memory foam ear pads, wrapped in gentle alcantara, were loved by everyone – they’re very comfortable and pleasant to wear.

Value

SRH1540 cost about €500, which is a lot. All the fancy materials used in building SRH1540 don’t come cheap, I would imagine the research and development work involved to design so neutral sounding drivers requires some resources as well. When it comes to closed backs with flat frequency response, these Shures are second to none, yet as an overall package, sadly, they’re still not perfect. The value score is dragged down by the relatively poor THD performance and comfort that’s less universally loved than some of its rivals.

In the pre-digital correction era €500 for flat headphones would be fair enough, but now when you can get the same results with much more affordable hardware paired with headphone calibration software, SRH1540 seems more like a luxury one can easily do without. It’s a different story if you need headphones for computer-less setup though.

Observations on how headphones perform after applying Sonarworks Reference calibration Total Harmonic Distortion

This is the greatest SRH1540 weakness. If you work with sub bass heavy material, unfortunately you can’t expect completely transparent sound in the lows – the 3rd harmonic distortion rears its ugly head. There’s numerous genres of music where this will not be an issue but if you require pristine transparency in the sub bass region, SRH1540 is not for you.

How accurate and consistent is the correction effect among different listeners?

Adaptiveness is great, meaning the perceived acoustic power response will be very similar to most listeners and the calibration effect will be accurate.

How much do they differ pair to pair in terms of frequency response?

Among the pairs measured there’s a +/- 3 dB spread in the low end below 100 Hz, but other than that they don’t differ much. 

Rating

7.5 / 8.2 / 8.9

Sound rating is a weighted average of Frequency Response, Adaptiveness, Harmonic Distortion and Channel Balance scores, with Frequency Response and Adaptiveness having the greatest influence.

7 / 9 / 10

The flatter the frequency response – the higher the score. When evaluating the frequency response score with the Average calibration profile, the pair to pair consistency of the given model is taken into account – if we have measured a considerable frequency response inconsistency among multiple pairs of the given model, the score drops, as the profile loses accuracy. Individual calibration will grant perfectly flat frequency response.

8

Adaptiveness shows how capable these headphones are at delivering the same perceived frequency response to any listener. Headphones with high score will sound nearly identical to everyone.

6

Harmonic distortion – the lower the Total Harmonic Distortion (THD) figure, the higher the score. Headphones with prominent 3rd harmonic distortion above 100 Hz will score lower.

8 / 10

Channel balance – the closer to identical the frequency response of both channels, the higher the score. Individual calibration delivers perfect channel balance.

7

Comfort – shows if headphones can be used for long listening sessions comfortably. Every model is tested by at least a few individuals.

9.5

Build – evaluates how well the headphones are put together, the materials used and indicates the expected longevity. Easily replaceable (and easily available) parts will boost the score. We don’t do any stress tests and very few models are used for longer than a couple of days, so this is a fairly subjective score.

7

Value – indicates the price-performance ratio of the given headphones and how they stack up against the competition. High score means that you won’t find more neutral sounding alternatives for the price.

Conclusion

Work with a computer-less setup and want neutral sounding headphones, and you don’t require pristine bass, and you have some cash to blow? SRH1540’s are for you! If only there wasn’t the THD issue and the comfort was more universal, SRH1540 would be the best closed back studio headphones for anyone, period. They could’ve been perfect, hence every con feels especially harsh. However, If you work with acoustic music, classical, rock music, basically anything without prominent sub bass – Shure SRH1540 are the best closed back studio headphones you can buy. Just be sure to try them on for as long as possible to check the fit!

Final Rating

8.1
With Sonarworks Reference 4
Calibration Enabled
7.5
Without Sonarworks
Calibration

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headphones with Reference 4

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