Hifiman Deva Pro (with Bluemini R2R)

A great two for the price of one audio experience

The Hifiman Deva Pro with Bluemini R2R delivers on a rare proposition, both a wireless headphone with audiophile sensibilities and a wired headphone with an excellent neutral tuning.

I had a little guilty pleasure earlier in the summer, when I was reviewing the Sineaptic SE-1 Wireless headphone, I just loved the freedom this offered both around my house and out in the garden and while that headphone has some excellent aspects provided by its ‘Ribbon’ driver, it also suffered badly when pushed and would distort when played loud. So I have been on the lookout for a similar wireless open back spacious experience, and I was delighted when Hifiman provided the Deva Pro with Bluemini R2R for this review.

Wireless Open Back - a forgotten category of headphone?

Before I get into the details I thought I should highlight that this category of headphone is sorely neglected and even in the recent “Ultimate guide to headphones” from Crinacle below, he also seemed to forgot that there are wireless open back headphones:

Read on to discover why I think having both a great wireless open back experience and a good wired planar headphone makes me a fan of the Deva Pro with Bluemini R2R.

Packaging and Build Quality

So lets start with what you get out of the box:

Packaging

The Deva Pro comes in sleek packaging:

Some specifications on the back:

But once you open the box, the experience is a little more premium than the typical Hifiman headphone at this price point:

Inside the box, you’ll find:

• The Deva Pro headphones.
• Bluemini R2R Bluetooth adapter.
• A 3.5mm detachable cable for wired use.
• A USB-C charging cable for the Bluemini module.

And you get some basic documentation:

The inclusion of the Bluemini R2R is a standout feature, providing SBC, AAC, aptX HD and LDAC codecs for some decent high-fidelity wireless bluetooth playback, though it lacks some of the latest Codecs like LE Audio:

Build Quality

The Deva Pro features Hifiman’s lightweight yet sturdy construction, though more reminiscent of the HD400SE than the more expensive Hifiman headphones like Sundara:

Ear Cups: Large, oval-shaped cups with a hybrid of synthetic leather and fabric for comfort and breathability.

Headband: Adjustable and padded, offering a secure but comfortable fit but this headband is poor compared to the one Hifiman use on the Sundara and some of their higher end headphones.

Bluemini Adapter: A detachable Bluetooth module that locks into the 3.5mm port on the left earcup.

Features

Wireless Mode

With the Bluemini R2R attached, the Deva Pro becomes a fully wireless planar magnetic headphone:

• Bluetooth 5.0 with AAC, LDAC and aptX HD ensures high-quality wireless audio.
• The R2R DAC in the Bluemini module provides rich, analog-like sound especially with the HIMALAYA DAC.

The open-back design allows for spatial, airy sound and making it unlike any other “wireless” headphone with it convenience. I also thought the R2R nature of Bluemini softens the “digital / analytical” sound you can get typical bluetooth codecs making it an excellent choice in delivery exceptional sound quality to the Deva Pro.

As you will see in the measurements section below the Frequency response and distortion were effectively identical via the R2R as well as via the cable.

For about 30 seconds when I first swapped over to use the R2R adapter I did feel it was slightly unbalanced on my head, due to the adapter only connecting on one side of the headphone, but I soon forgot I was wearing it and I haven’t really noticed this weight imbalance since even using it for 5-6 hours straight on some days.

Battery Life and Voice prompts

So, while I find the battery life with the Bluemini R2R pretty good, with easily 6-7 hours of wireless streaming audio, there are 2 things annoying aspects of this adapter that I think I should highlight:

Inconsistent reporting of battery life

When fully charged the battery level on my unit would quickly jump to 80% and stay at 80% for maybe 5 hours then suddenly would fall to 40% for maybe another hour.

This meant I mostly had to just ignore what the battery life indicated and charge up the Bluemini overnight.

Loud voice prompts

This is probably the most annoying aspect of the Bluemini R2R once you get to 20% you get a very loud voice prompt, telling you to recharge, it is actually much louder than the music so very jarring when it happens.

If this happened just one per 5 or 10 minutes this might be fine but it seem to happen about once a minute effectively making it impossible to use the Bluemini when it gets to 20% battery life.

Pairing

While not as annoying as the above issue, initial pairing of the Bluemini is also a bit odd and its worth reading the manual to understand how to get it into pairing mode. Specifically you switch it on and then double-click the button and the light changes and you can pair. You can pair multiple devices, which is handy when working on a laptop but listening to your smartphone via bluetooth.

Microphone quality

When in wireless mode, you can use the Bluemini R2R for mobile calls and I thought the microphone was reasonable good for indoor calls. I asked my colleagues to see if they could tell a difference between this microphone and my normal Macbook Pro microphone, and they thought it was slightly worse, but I was still clearly heard during the meetings I used the Deva Pro. I would guess the microphone will not cancel outside noises as the whole concept of an open back wireless headphone is to use it indoors or at least not in a noisy environment.

Wired Mode

Detaching the Bluemini and connecting via the included dual 3.5mm cable transforms the Deva Pro into a more traditional planar headphone. The sound quality in wired mode competes with Hifiman’s mid-range models like the HE400SE or even the Sundara in some respects, really showing that you essentially get 2 very good headphones for the price of 1.

Sound Impressions

For this sound impressions section, I initially listened to my typical long audio test playlist, but I could tell pretty quality the sub-bass was not there so after a few hours I gave it a little sub-bass boost (see my EQ recommendations below) and then listened again. I would highly recommend this little bass boost and my impressions below are based on using a subbass boost:

Bass

The bass on the Deva Pro is tight, controlled, and deep. It doesn’t have the exaggerated thump of bass-heavy headphones but instead delivers clean, textured lows that are true to the recording.

• Song Reference: Billie Eilish – Bad Guy. The sub-bass is precise, delivering a satisfying rumble without overpowering the mids.

Midrange

The midrange is where the Deva Pro truly excels. Vocals and instruments are rendered with clarity and warmth, creating an engaging listening experience.

• Song Reference: Adele – Someone Like You. Adele’s voice is rich and emotive, showcasing the Deva Pro’s ability to handle midrange detail with finesse.

Treble

The treble is smooth and detailed, with just enough sparkle to add airiness without becoming harsh or sibilant.

• Song Reference: Fleetwood Mac – Dreams. The cymbals and high-hats are crisp and well-separated, highlighting the Deva Pro’s excellent imaging.

Soundstage and Imaging

The open-back design provides a wide soundstage with excellent imaging, creating a spacious and immersive experience.

• Song Reference: Pink Floyd – Money. The positioning of instruments is precise, making it easy to visualize the band’s layout during playback.

Specifications and Measurements

So, the impedance is good but sensitivity is a little lower than I would like, so Deva Pro would benefit from some power, but I had no problem powering it via my Macbook Pro to louder than I could listen levels. Obviously this isn’t a problem via the Bluemini R2R bluetooth adapter.

Measurements

Note: All these measurements where taken with my KB501X soft ear pinnae and a 711 clone coupler and are avaialble on my measurements DB here

Frequency Response:

Here is the Deva Pro frequency response which other than the roll off in the bass frequency is mostly excellent and led me to do a comparison with my Sennheiser HD600 later in this section:

Comparing the R2R and the Wired versions:

These are effectively identical, so you’re getting the same tonal experience via both wireless and via a wired cable.

Distortion:

So since the FR is the same via wired and wireless I thought it would be useful to compare the distortion via both mechanisms, and they are also identical:

R2R Distortion:

Cable Distortion:

And as a percentage you can see it is well any level that might be concerning:

I thought it would be useful to push the driver so here is the distortion near 100 dbSPL and it is still below 60 dbSPL - so overall it handles distortion extremely well:

EQ Recommendation:

Because the distortion is so minimal it is very easy (and safe) to EQ this headphone, so I thought a simple EQ recommendation might be as follows:

A simple bass shelf is mostly the only thing needed for a very enjoyable experience with the Deva Pro.

This EQ was the following:

• Preamp: -6.5 dB
• Filter 1: ON PK Fc 45 Hz Gain 6.5 dB Q 1.000

Note: there are areas midrange and especially within the treble region which could be manually EQed for an even smoother response. In the graph this is the 6K-8K region but that will be different for most people and therefore if you want to add some treble in that region you should use a manual sweep to do this.

FR Comparisons and Alternatives

Here are 3 other headphones to compare with the Deva Pro:

• Hifiman HE400SE: A more affordable planar option but lacks wireless functionality and overall sound signature is not as good.
• Hifiman Sundara: Better detailed and refinement but more expensive even after the recent price cuts and wired-only. The headband is also more comfortable.
• Sineaptic SE-1: Fully wireless ribbon driver headphone with more distortion and worse frequency response.

But let’s compare the frequency responses of these headphones:

Note: mostly lets ignore the SE-1 in these graphs, as it uses DSP to boost the bass and push the Ribbon driver in the treble, so the Frequency Response is much less balanced than the various Hifiman’s.

I have highlighted 3 areas on this graph comparison:

1. The bass betwen the 3 Hifiman headphones is interesting, the Sundara has the best by default but the Deva Pro has arguable better bass than the HD400SE until it rolls off.
2. Both the Sundara and the Deva Pro have a more balanced midrange (and therefore a more tonally accurate sound) than the HD400SE
3. The Treble is really down to preference and will be very subjective different depending on your HRTF, with the Sundara have a slightly boosted 4K region while the Deva Pro is recessed a little in this area.

And as a bonus comparison I thought the general trend of the Frequency response (and therefore the tonality) of the Deva Pro was similar to my HD600 - though as you can see in this comparison graph the HD600 does have a smoother FR:

As for a visual comparison - here is the Sineaptic SE-1 compared to the Deva Pro:

Rating

I feel the Deva Pro deserves allot more attention and I decided to give it a 5-star pragmatic rating. At its current price of around $200 and offering both an incredible wireless audio experience and a solid wired
listening experience for those who like that neutral midrange focused HD600 sound signature.

I personally would have liked more sub-bass, but this is the easiest thing to ‘fix’ with some EQ, so with a simple bass shelf, it then offers a great value experience. But even without EQ, it offers a better sound signature than the already excellent HD400SE and then with some EQ it starts to rival those 2 great Hifiman mid-fi headphones the Sundara and the Edition XS. When you then add the flexilibuty provided by the Bluemini R2R module, you have a very pragmatic headphone at this price.

Summary

The Hifiman Deva Pro with Bluemini R2R offers remarkable versatility and value. It delivers a stellar wireless experience for casual listening while also functioning as a high-quality wired planar headphone for serious sessions.

Whether you’re relaxing in the garden, working around the house, or diving into a serious wired listening session, the Deva Pro offers versatility rarely found in its price range. Combining a high-quality planar magnetic driver with a detachable R2R Bluetooth module, it seamlessly bridges casual and critical listening and is without doubt the best sounding wireless open back experience you can get.