HiFiMAN HE5XX vs HiFiMAN Deva - Do they sound the same?

Written by Andrew Park (@Resolve)

HiFiMAN HE5XX review unit was sent in by Josh Valour - big thanks to Josh for sending it over. You can see his review of it here.

HiFiMAN Deva review unit was sent by HiFiMAN.

Background

Drop (formerly Massdrop) has collaborated with a number of headphone manufacturers over the years to produce well-performing headphones at more modest or entry-level price tags. In some cases these collaborations have been quite successful - most notably the highly regarded Sennheiser HD6XX, Focal Elex, and the HiFiMAN HE4XX.

The way production has often worked for these collaborations is that the manufacturers will have an end-of-life product that then gets redesigned in some way by Drop, and then sold as a Drop product. So in the case of the Sennheiser HD6XX, while it carries the Sennheiser name, it should be thought of as a Drop product. In many of these instances, the original manufacturer can be thought of as the factory that makes the product for Drop.

While many of these products have been well-received, the recently released HiFiMAN HE5XX ($220) has turned out to be a highly controversial product. The reason for this is that it was marketed by Drop as a spiritual successor to the legendary HiFiMAN HE500, and for those who have heard that headphone, the potential for a new less expensive version is understandably exciting.

The product description says the HE5XX was "inspired by HIFIMAN’s iconic HE500 Series headphones", and "a brighter, more neutral take on the trademark HE500 Series sound, with upgraded efficiency and a better fit than ever before". Oddly, I never found the HE500 to be lacking in the treble department, but let's leave that aside for now. Unfortunately, after it became more clear what the HE5XX was, those same people who were initially excited about the HE5XX have been left with a bit of a sour taste.

What was it that turned excitement into disappointment? It has come to the attention of the community that the HE5XX bears a strong resemblance (in fact a visually identical resemblance in many ways) to the HiFiMAN Deva, which was released earlier this year. If anyone is wondering, the Deva is a 'wireless capable' headphone, with the wireless module being attached on the outside, and the wired Deva is the same headphone just without the Bluemini wireless module.

Now, I reviewed the wireless version of the Deva, and found that while it's an interesting product, its performance was more on par with the HE400i and HE4XX than the legendary HE500. So you can see why those of us who have loved that original product from HiFiMAN are a bit disappointed with the suggestion that this new collaboration between Drop and HiFiMAN might be sonically similar or even an upgrade to the original.

For anyone curious about how the wireless Deva performed in my testing, here is the review video:

In the following article, I've done a deep dive into the HE5XX controversy. I've taken both the HE5XX and the Deva apart to look at their driver structure, as well as done a significant amount of measurement evaluation to see how they perform acoustically relative to one another.

As a matter of diligence, I'd like to also respectfully acknowledge one of the earlier reports about this subject. We have had different findings in our evaluations, but there's also a likely explanation for this difference, which should become clear in the sound portion of this analysis.

It's at this point where I have to stress that there are still some things that cannot be verified about these two products. So consider the following article to be merely a presentation of my findings, you'll have to make up your own mind as to whether or not you find it to be sufficient. However, I do feel that there is compelling evidence here that may lead to a satisfying conclusion for many of my readers. 

Sources Used for Evaluation

• iFi iDSD Micro Black Label
• iBasso DX160
• iBasso DX220
• Matrix X Sabre Pro -> Cayin IHA-6
• Matrix X Sabre Pro -> SPL Phonitor X
• Matrix X Sabre Pro - > Cayin HA-1A MK2
• Matrix X Sabre Pro - > Topping L30

Specs: HE5XX - $220

• Operating principle: Open back
• Drivers: Nano Diaphragm planar magnetic drivers
• Magnets: Double sided
• Frequency response: 20 Hz – 20 kHz
• Sensitivity: 93.5 dB
• Impedance: 18 ohms
• Weight: 355 g

Specs: Wired Deva - $220

• Operating principle: Open back
• Drivers: Nano Diaphragm planar magnetic drivers
• Magnets: Double sided
• Frequency range: 20 Hz – 20 kHz
• Sensitivity: 93.5 dB
• Impedance: 18 ohms
• Weight: 360 g

Sound Analysis

To begin with, let's get the obvious out of the way - the HE5XX and the Deva use a different color scheme and have a different headband. For me, I find the Deva's headband more comfortable, but I like the look of the HE5XX more. The real question we're here to answer is whether or not we should expect these headphones to be acoustically identical to one another, and for all of the rest of the housing structure, cup and yoke design, visually they're identical.

For the sonically relevant question - whether or not we should expect them to sound the same - let's take a look at how the HE5XX and the Deva measure for their frequency response. While frequency response isn't everything, this will give us a good indication as to whether they have a similar or indeed identical tonal balance. The following is how both the HiFiMAN HE5XX and the wired HiFiMAN Deva measure on the GRAS 43AG standardized measurement rig relative to the combined Harman target curve (Harman 2013 bass but Harman 2018 mids and treble).

For reference, the Harman 2018 bass is noticeably elevated - too much for what I think most audiophiles would consider appropriate, even if some bass heads may like it. I prefer to use the more modest 2013 bass shelf. In any case, these are raw measurements, meaning it should not look like a flat line across. This instead shows the raw measurement relative to the target that would otherwise be normalized in compensated measurements.

HiFiMAN HE5XX Frequency Response:

 How do you read this? The dotted black line is the target (how we might want it to measure), and the colored line is how the headphone in question measures. Effectively, this shows how significantly the headphone’s frequency response deviates from the target.

Here is how the HE5XX compares to the Deva:

Note that for this comparison I used colors typically reserved for left/right channel matching to show just how closely they measure - close enough to where, if this were a channel matching graph, it would look pretty good. In this case I used both left side channels for the measurement, but as we'll see later on, this particular HE5XX doesn't actually have very good channel matching. I would expect better on other units, and HiFiMAN is generally quite good at this kind of thing.

For the left side driver measurement, this is an important point of evidence that suggests these two headphones are acoustically the same, and at the very least they have an identical tonal balance to one another.

The following graph shows how the HE5XX measures when swapping the pads from the Deva onto the HE5XX. This test shows whether or not there is any difference to the pads:

As we can see, there aren't any significant differences between the pads. The slight variation we see in the bass could be due to the fact that pads in general aren't perfect, and this could have some impact on the coupling of the headphone.

Perhaps a stronger point of evidence to corroborate the notion that these two headphones use the same driver is in the driver’s behavior when adding an air gap. For those unaware, when you break the seal on a HiFiMAN headphone, the bass will elevate substantially. In other words, the bass tuning for these headphones is in part determined by the coupling to the side of the head, but instead of losing bass when the seal is broken like on typical dynamic driver headphones, for HiFiMAN planars there's an elevation in the mid-bass when this occurs (you can test this as well just by holding the cups slightly away from your ears). Here we can see that both the HE5XX and the Deva elevate and roll-off at precisely the same spot:

So we have identical behavior for the air gap bass response. If the drivers were different, or even if there was a difference in diaphragm tensioning, you'd likely see some difference in this behavior in measurements.

Lastly, we can see some of the distortion behavior as well. What we're looking at here is 2nd harmonic distortion for the red line.

HE5XX distortion:

Deva distortion One:

Deva distortion Two:

While there’s usually some moderate variation when it comes to distortion measurements (even with the same headphone), we can see that 2nd harmonic distortion has similar features in all the same spots. Note that this does also vary in the same places where there are slight differences that show up in the frequency response. All of this is within unit variation tolerances and measurement variances due to coupling changes. This measurement is also amplified so this is not a depiction of either headphone's distortion characteristics in realistic listening situations, but merely to show how it behaves. They both have low enough distortion to where it's not really audible.

Notably absent in these measurements is the HE5XX right channel, and there’s a reason for this. For this particular unit, there’s some channel imbalance going on. While it’s likely not significant enough to be all that noticeable while music is playing, it is noticeable in a sine sweep - and of course it looks confusing in measurements.

The following shows the HE5XX channel matching:

At the moment, I’m running with the assumption that the L channel behavior in both frequency response and distortion metrics is the norm (and representative of what customers would be buying) - and indeed this is nearly identical to the measurements that are listed on the Drop store page as well.

The fact that this headphone has this kind of frequency response difference going on in the same headphone explains why there may have been some reports out there that suggest the HE5XX and the Deva don't measure the same. If you were to only look at the right channel, you could be forgiven for thinking these are different in a meaningful way. This also means that there is potential for some unit variation going on.

Driver Analysis

The official word from Drop has been that the HE5XX driver makeup and magnetic field is unique. Having reached out to Drop for further commentary on this, it's as of yet unclear to me in what ways the driver design of the HE5XX is different from that of the Deva. But, the official statement from Drop on this subject is the following:

"The 5XX's magnetic field makeup is unique, the magnet array design is unique, the diaphragm tension and coatings are unique."

You can read more on Drop's statement here.

Now, it seems like the folks over at Drop simply weren't aware of the Deva's driver design, since they've claimed the main thing that makes the HE5XX unique is the fact that it uses a dual-sided magnet array. And as it happens, the claim that this driver has been inspired by the legendary HE500 (and HE6) is accurate. The problem is that the HiFiMAN Deva also uses the same dual-sided magnet array. There have been some reports out there - including ones from Drop - that the Deva uses a single-sided magnet array (this was their initial point of difference between the Deva and the HE5XX), but as we'll see with the following driver teardown, the Deva does in fact have magnets on both sides.

I have to be clear that by all accounts this could very easily just have been a misunderstanding or miscommunication between Drop and HiFiMAN. This is an easy mistake to make because when the Deva was released, HiFiMAN published a schematic diagram of the driver and it looked like it was only using a single-sided magnet structure. So while there may be some concerns about the marketing a positioning of the HE5XX as an HE500 successor, it's perfectly understandable that there would be some confusion about whether or not the HE5XX magnet structure differs from that of the Deva.

Moreover, if you compare this driver structure to that of other modern lightweight planar magnetic headphones - the ones that have come out in the years after the HE500 - the HE5XX is more similar to the older designs in that the newer ones use a single-sided magnetic array (magnets on just one side). Traditionally, the single-sided array designs from HiFiMAN haven't performed as well as their dual-sided counterparts (HE500 vs HE560).

The problem with this, however, is that just because a planar magnetic transducer has magnets on both sides, that doesn't necessarily indicate that it will have better performance. We've seen single-sided array designs that have shockingly good technical performance from companies like Abyss with the AB1266 Phi TC.

So, while we in the digital media space may focus on single-sided vs dual-sided magnet structures, the truth of the planar driver performance question is far more complicated than just the makeup of the magnet structure. There are numerous additional parameters that we don't see that influence the overall sound quality.

Taking a look at the driver for both of these, we can see how the magnet structure is designed (the black bars), along with the conductive trace behind it.

Side One:

Side Two:

We can see that they look nearly identical. I think there’s a bit more glue on the Deva magnets, maybe part of the manufacturing process, but this difference is unlikely to produce any meaningful difference in terms of acoustic performance. Remember - they measure the same. Any additional point of difference would have to come from things we can't visually see just from looking at the driver, but this would likely also show up in frequency response or other measurements.

In any case, after taking both headphones apart, I can conclusively state that both the Deva and the HE5XX use a double-sided magnet array and that in both cases this is more similar to the design ideas that were found in the HE500 and HE-6 than some of HiFiMAN’s newer single-sided magnet array headphones. Let there be no more debate on that subject.

On both headphones, I also tested the magnet strength (just with an additional magnet), however I do not currently have instruments to accurately measure their exact strength and give a numerical value, but I can say that it did not feel like there was any difference in the magnet strength between the two. This isn't something that counts as evidence in my opinion because it's really just the feel test and nothing conclusive, but I thought it was worth noting.

Now, while they are visibly identical, at the moment we have to leave aside any of what we can’t see - like what’s going on with the diaphragm and tensioning - because it's absolutely still plausible that there's something unique about the HE5XX that we can't see. If this is the case, the fact that these two measure nearly identically to one another would have to be an unlikely coincidence. If there were a difference in both magnet strength and/or diaphragm tensioning, this is something that we could expect to show a different result in the measurements.

Lastly, it's worth mentioning that with every headphone there’s bound to be some unit variation, and in my mind this perfectly explains why the initial reports were that it’s not exactly the same as the Deva. The way I see it, there’s now enough evidence pointing to them being acoustically identical headphones (within unit variation tolerances) that the burden of proof is on the other foot.

At the moment I have to report that nearly all of my testing points in the direction of these two headphones being acoustically identical.

Key Findings

There are some additional context pieces to this that are unrelated to the headphones themselves, but I'll add them to the summary. The following is what I've found to be true in my comparison between the HE5XX and the Deva.

What we know:

• Same driver specs
• Same magnet array design
• Same trace
• Same housing
• Same pads (just different color. I know there were reports indicating otherwise… they’re the same pads in this unit)
• Same frequency response
• Same distortion measurements
• Same air gap behavior (this ‘sealed’ the deal for me)
• They sound the same (or close enough within unit variation tolerances) - with the same strengths/weaknesses
• Both the Deva and the HE5XX are more similar in terms of their design to the HE500 than planars with single-sided arrays
• HiFiMAN stopped selling the wired Deva ($220) at the same time the HE5XX came out
• Drop incorrectly alleged that the Deva was single-sided, and that this was where the HE5XX was different, when in fact the drivers are visually identical between the two
• Drop has stated that the review units sent out were representative of what people would be buying

What we don’t know:

• Diaphragm tension
• Diaphragm material/thickness (both would be ‘nano’ diaphragms, but we don’t know much beyond that)
• Exact magnet strength (although they feel the same to me)
• Whether or not Drop knew about the Deva - or any other internal conversations between Drop and HiFiMAN

Conclusion

With all of the findings identified in this article, I'm going to have to leave it up to the readers to decide whether or not the findings pointing to these two headphones being acoustically identical is compelling. As mentioned, there are still things we don't know, and this means there is still some room for uncertainty.

However, at this point any weaknesses in the claim that the Deva and the HE5XX are acoustically identical (within unit variation tolerances) should probably be anchored to the limitation of a one unit sample size. Even then, if there is any difference, it would have to be in something we can’t physically see or measure. I leave the door open to that idea, but with all of these findings now on the table, in my opinion it's up to Drop to prove it.

My personal take is that the HE5XX sounds the same as a wired Deva. Is that a bad thing? No, but anyone expecting this to sound like an HE500 will likely be disappointed. While the Deva/HE5XX is generally well-tuned, it simply doesn’t come remotely close to the technical performance of the HE500. At $220, in my mind the HE5XX is appropriately priced. Would I take it over an HD6XX? Probably not, but it does do certain things better, like its overall tuning (maybe with a bit of EQ to get rid of that 5.3khz peak), and it has a much more even and filled-in soundstage.

-Andrew Park (@Resolve)

Watch the video on this subject here:

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Discuss the HiFiMAN HE5XX on the HEADPHONE Community Forum.

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