Denon PerL Pro

Let’s clear this up: My colleague Ulf Kaiser has been following the development of the Australian start-up Nura for the last few years and most recently tested the NuraTrue Pro , and it was a product development that left us fairly impressed.

Denon securing the rights could be a good move because behind the Nura technology is the solution to a problem that applies especially to in-ears: not only does each human ear vary anatomically, but everyone’s hearing ability is different, and hearing ability can also vary greatly in someone’s left or right ear. Also, hearing ability decreases with age, and this likewise varies from person to person. So now the Nura True Pro has been relaunched by Denon under its own brand as PerL Pro.

Measuring the ear

The Denon PerL Pro offers the very same calibration of your hearing. This is unique in the field of headphones and has previously only been used in the medical sector. The PerL Pro enables you to create three hearing profiles. The procedure is kept simple but offers amazing results.

As can be seen in screenshots 1 and 2 (see below), the shape of the profile shows how the different frequencies of sound are perceived. Low frequencies are shown at 12 o’clock and move clockwise to higher frequencies around the “dial”. The further the shape is stretched outwards from the centre, the more sensitive you are to these frequencies. When personalising, your age must also be taken into account. The bulge in my ears probably offers the classic impression of the hearing of someone in their early 60s. In the mid-range, I hear clearly very well; towards the top, the sound becomes thinner, while a second measurement (screenshot 3) showed a slightly different picture.

Something was surprising: when I switched between “Neutral” – i.e. without individual treatment – and “Personalised”, the result was extremely impressive. While in Neutral, a rather dull audio signal reached my ears; in Personalised mode, it was literally like the lights coming on.

AptX Lossless enables lossless CD audio via Bluetooth

Another highlight of the Denon PerL Pro was the Bluetooth codecs. When provided with the appropriate player hardware (these are unfortunately still quite rare), audio signals can be transmitted uncompressed via aptX Lossless over the Bluetooth wireless link. There is also support for aptX Adaptive, aptX Classic, AAC, SBC.

Immersion mode and spatial audio

The Denon PerL Pro are technically at the highest level, and with immersion mode and spatial audio function, they really drill down into the listening experience. With the immersion mode, extra depth is given to the audio experience, and it can also be taken away if needed. You can become immersed in the sound as the bass virtually envelops you. If you want, you can experience “bass” to the full. Spatial audio is no different from 3D audio. Both Dolby Atmos tracks and signals that have been processed as “normal” stereo are played via the PerL Pro’s Spatial function with a distinctly audible depth effect. However, head tracking features such as those used by Apple’s Air Pods Pro or Beats Studio Pro are not supported.

Noise cancelling (ANC) and social mode

The Denon Pearl Pro have effective Adaptive Noise Cancelling and a transparency mode that is significantly lower when compared to ANC, which on this device is called “Social Mode”. If you switch this on, the volume is reduced and an audio signal optimised for speech intelligibility is passed through. Compared to competitors, the PerL Pro show weaknesses here. It almost seemed to me that the processing power of the DSPs is not enough to handle both core tasks: the calculation of the personalisation as well as the processing of the ambient noise supplied via the microphones.

The Denon PerL Pro in practice

During the two weeks of our test, we subjected the Denon PerL Pro to various “everyday” challenges. First of all, the pairing was problem-free when using iOS, Mac OS and Android. The PerL Pro also handled Multipoint Connection and this worked flawlessly between Android, iOS and Mac OS systems.

The Denon app also proved to be extremely user-friendly. The instruction manual PDF provided sufficient information about the functions and operation of the Denon PerL Pro. At the time of our test, there was only an English-language manual available to us. However, the language guide can be changed to other languages after a software update.

Four pairs of silicone ear tips, one pair of foams and two wings are supplied, and these ensure an optimised hold in the ear as needed. The earpieces themselves are flattened into a disc shape and so barely protrude from the ears, but they are very effective. Movements below the level of a workout do not harm the tight fit, and thanks to IPX4 certification, the earpieces can also tolerate moisture well.

The personalisation process is very well described in the app and is easy to carry out. However, when you carry out the test, you should make sure that the earphones fit perfectly and seek out a quiet environment in order to exclude interference and measurement errors as much as you are able.

You can create up to three listening profiles, although I was initially unable to create a second one with the Android app. This is in case several people want to use a pair of Denon headphones with this function. In the real world, the three-person profile is more likely to make sense for using the upcoming on-ear or over-ear headphones from Denon, but not for in-ears. Using the iOS app, I was able to set up another personalisation while I was testing the headphones – this time with the tighter-fitting foam tips – these showed a different result again and corrected the calculation accordingly.

Operation via the touch-sensitive outer sides of the PerL Pro worked smoothly, and individualised adjustments could be made down to the smallest detail via the app. If desired, a 5-band EQ can be switched on, and via High Gain, it is even possible to bypass the EU-compliant volume control and operate the Denon PerL Pro with fuller “throttle”, but this can easily lead to distortions. However, hearing-impaired people might get some benefits from this function.

The battery life is stated as 8 hours, and we came close to this in our test with the personalisation mode switched on almost all the time. Battery life can be tripled to another 24 hours via the case, which can be charged via the included USB-A-to-C mini cable as well as wirelessly.

The Denon PerL Pro at work

The PerL Pro are well suited for daily office work due to the high level of functionality and the very successful integration of various audio and computer systems thanks to Multipoint. The speech intelligibility during telephone calls and video calls was very good. The Denon PerL Pro can be worn for several hours at a time due to their good wearing comfort.

How do the Denon PerL Pro sound?

I did most of my listening tests in Personalised mode and hardly touched Immersion mode, as “immersion” quickly produced too much bass and disturbed my perception of sound too much. I enjoyed switching on the Spatial Auto button in the app when listening to Dolby Atmos recordings.

The best results in terms of sound were achieved with the Google Pixel 3a, which, with its aptx-HD codec, was already capable of transmitting high-res audio files to the recently measured ear.

This meant that Diana Krall’s “Superstar” from a 48 kHz FLAC displayed the desired silkiness in the strings and the openness and depth of detail of this production, a track I often use for headphone testing purposes.

Our Spotify playlist also performed competently with the PerL Pro. The energy density of the bass was a particular joy to listen to without losing focus on tonality. The PerLs transmitted the mids as very defined, and transient-rich instruments like choirs and strings delivered the silkiness I would expect from high-quality headphones.

However, we must remember that sound quality depends on accurate calibration (see above). If you are unable to do this with the silicone tips supplied, we recommend buying more memory foam tips. In this case, the pair of foams supplied was very well suited to my ear anatomy.

While using ANC, the PerL Pro had a few problems with the lower interference frequencies during the noise of a summer thunderstorm. The PerL Pro also failed to block out rumbling trams as well as I would expect from the otherwise very good noise-cancellation.

Conclusion

With the PerL Pro, Denon offers a very good pair of in-ear headphones; they excel because of Masimo’s Adaptive Acoustic technology. You need to be meticulous to calibrate them, but then you’re treated to an excellent sound that’s tailored to your hearing. Very good ANC, reliable multipoint, lossless audio codecs and a good battery performance were impressive in our test. I see some room for improvement in the transparency mode, where the bar has been set quite high by Apple, Beats, Sony, etc.