Dali IO-4

Hi-Res enabled over-ear headphones with Bluetooth 5 and outstanding runtime

In a nutshell

The Dali IO-4 offers the same convincing sound quality as the larger model the IO-6. And they are equally comfortable to wear and straightforward to use. The only real difference is the lack of active noise cancelling, which saves the buyer one hundred euros; for this sacrifice, you get a battery life which is twice as long. At a price of 299 euros, we really recommend the IO-4 for sound-conscious music lovers.


The hi-fi manufacturer Dali from Nørager, Denmark, has completely specialized in making speakers since the company was founded in 1983. Their two new headphones models, the IO-6 and the subject of this review, the cheaper IO-4, are aimed at those who want an over-ear Bluetooth system for mobile use.
These products uphold Dali’s claims to the audiophile market. In a nutshell, the IO-4 could be described as a cheaper version of the IO-6, which offers the same sound characteristics, but comes without noise cancelling, but we can tell you a little more than that…

These closed over-ear headphones are available in black or caramel/white. Their design is similar to the more expensive model and their lightweight design is both attractive and sturdy, but instead of a carrying case there is unfortunately only a simple cloth bag available.

The headband is adjustable in length and the ear cups can be rotated 90 degrees in any direction, but cannot be folded. Both elements have memory foam padding with an artificial leather cover, which, in the case of the ear pads, can be replaced. The result is pleasantly comfortable to wear, even for several hours. It’s also worth noting that, at least in my case, the artificial leather cover didn’t lead to overheating.

In practice

The functionality of the headphones we tested, was straightforward and deliberately concentrates on sound. All the controls are located on the right ear cup. The switch for on and off is also used for pairing. In addition, there is the USB-C charging port, which can be used for audio transmission from your computer if required.


Music playback is controlled from the outside of the ear cup. The raised manufacturer’s logo acts as a multi-function button for start and stop commands, allows title jumps via double and triple clicks, and is also responsible for phone call management. Your smartphone voice assistant can also be called using this button.

Volume is controlled by pressing buttons concealed in the top or bottom of the ear cup. This works well in practice and, in my opinion, is more reliable and accurate than the solutions offered by many competing products. Dali completely does away with a control app for these headphones and the same applies to the noise cancelling on the IO-6.


In other respects, these headphones really shine with its’ wireless connection that is quick to set up and which has an extremely reasonable range reaching over several rooms. Their passive noise reduction is also exemplary, and most of the time you do not miss having noise cancelling. Even at high levels, your enjoyment of music won’t disturb the person sitting next to you.

The IO-4 score a lot of points for their maximum battery life of 60 hours (according to the manufacturer’s information), which makes it twice as long as for the larger model, meaning you can use the headphones for days without charging. Admittedly, we didn’t let them run for the whole 2.5 days, but after a full day’s use we still had a considerable residual charge which was indicated by a voice announcement at the end of the day.


Like the IO-6, these headphones use Bluetooth 5 and support 24-bit capable aptX HD as well as the audio codecs SBC, AAC and aptX. In practice, the latter feature obviously requires a correspondingly compatible smartphone (in our case, we used a Sony Xperia 10).

Using the USB port, you can stream high-resolution files to the headphones via Audirvana Pro without any complaints. The IO-4 also offers an input for cable operation, which works with the electronics switched on or just passively with any available resolution. The latter mode is not only useful for operation with an empty battery, but the qualities of the built-in patented 50 mm drivers are also still evident.

In practice over the aptX HD wireless link, the IO-4 delivers a coherent, stable sound image with a focus on neutrality. In addition, one enjoys excellent detail resolution and an airiness that is by no means typical for closed headphones systems.

If you’re into boosted bass and club sounds you are not going to find your perfect headphones with this model. Dali is aiming for immaculate sound reproduction, and in view of the price range, they succeed surprisingly well across several genres. In the bass, the dynamic drivers act with precision, with a confident delineation of pitch and dynamics. You don’t have to do without low bass, there is plenty of room to boom.

The subtleties of acoustic instruments, vocals, and the central elements of a mix are delivered effortlessly by the midrange without loudness in the frequency response. Whether you’re playing chart pop, powerful rock, jazz, classical or club sounds, the results are always satisfying.

The pleasantly tuned, airy and highly responsive treble range also contributes to this; the richness of detail also enhances the reproduction of the stereo panorama and the room. There are no complaints about harshness. Whether you’re listening to an intimate piano ballad, a broadly shimmering electronic composition, aggressive metal or a multi-layered, dynamic symphony orchestra – the tuning is always right. Nice one, Dali!

The voice quality during phone calls was also worthy of our compliments.

4 years ago by Ulf Kaiser
  • Rating: 4.25
  • Sound
  • Handling
  • Price/Quality
  • Function

Technical specifications

  • Ear couplingOver-ear
  • Typeclosed
  • Transducer principledynamic
  • Frequency response (headphones)10 - 20.000 Hz
  • Impedance25 ohms
  • Sound pressure level (SPL)100 dB
  • Weight without cable320 g

What's in the box

  • 3.5 mm stereo jack cable
  • USB C cable
  • Carrying pouch

Special features

  • BT codecs: SBC, AAC, aptX, aptX HD
  • BT version: 5.0
  • BT profiles: A2DP, AVRCP, HSP, HFP
  • Loading time: approx. 2.5 hrs.

Leave a Reply

Your email address will not be published. Required fields are marked *