Ultrasone Pro 900I Studio Headphones Review

Ultrasone Pro 900I, Studio Headphones Review

The Bavarian manufacturer Ultrasone offers professional studio headphones with the Pro 900i. A total of five models with the suffix “i” can be found in the company’s repertoire, whereby the Pro 900i is supposedly the best and the most expensive model. We took a closer look at the Ultrasone Pro 900i and listened to it.


  • Capable to deliver awesome bass
  • Very comfortable
  • Detachable cable
  • Straigt and coiled cable
  • Two pairs of velour pads
  • Slick look


  • Way too strong on the lows out of the box
  • Perhaps not so good for music with vocals

First impression

Well made, if not roadworthy – that was the first impression of the Ultrasone Pro 900i. The headphones always make a stable impression and are therefore sufficiently well designed for studio use. As with the other headphones in the i-series, Ultrasone uses plastic. The 900i is correspondingly lightweight and weighs 295 grams. That is a more than bearable weight, which is also reflected in the wearing comfort. In combination with the fully padded headband, the weight of the headphones is evenly distributed, and longer sessions are easily possible. The headphones can be extended by almost 3 cm on both sides, which should also be sufficient for larger heads. The set size is retained even after pulling it on and off several times.

The contact pressure on the Ultrasone Pro 900i is moderate. It sits well but doesn’t press too hard on the head. He can do beat-like bobbing with his head, but headbanging should be avoided if possible. Everything fits for studio use. The Pro 900i cuts a very good figure here.

The interchangeable cable can be connected to the left side of the headphones. You can choose between a 3 m long straight cable with a 3.5 mm jack plug and a spiral cable that ends on a 6.3 mm jack plug. Both cables are included with the Pro 900i. The cables are attached to the headphones using a 3.5 mm jack plug. This can be screwed tightly, preventing it from being pulled out unintentionally.

You get everything together in a sturdy transport hard case made of fabric. The headphones can not only be stored here but also transported.

In terms of optics, the Pro 900i is subtle. The structure is straightforward. The color is dominated by classic black. Only the outside of the ear cups shines in light silver. The auricles are lined with velvet on the inside, which makes them very soft on the ears. In the past, I had one or two headphones with velvet ear cups with me, which quickly became warm and uncomfortable. Fortunately, this is not the case with the Pro 900i. Coupled with the moderate contact pressure and the low weight, the result is a relaxed and comfortable fit despite the closed design.

The ear cups of the Pro 900i are attached to the headphones with a clever mechanism. These can be easily detached from the headphones with a kind of bayonet lock.


According to Ultrasone, the closed, dynamic Pro 900i headphones offer a frequency response of 6 to 42,000 Hz. The impedance is 40 ohms in the lower range, the maximum SPL is specified as 96 dB. Unfortunately, as is so often the case, the technical values ​​say relatively little about the sound. We will devote ourselves to this in the next section.

As closed headphones, the Pro 900i is particularly suitable for recording and monitoring. In principle, it is not impossible to use closed headphones for mixing and mastering, especially because headphones with ADAM SP-5 and Neumann NDH20 do a very good balancing act here and are very broad in their field of application. As a rule, however, you get a very compact and tight sound through closed headphones, which can partly be reflected in the mix.

A special feature of some Ultrasone headphones is the “S-Logic Plus” technology. As usual, Ultrasone does not place the headphone transducers in the middle but shifts them to the front and bottom. In this way, the sound is first directed to the outer ear, and the anatomy of the auricle is included in the hearing. This is intended to improve spatial perception.

Even from the outside, you can see the different positions of the transducers compared to other headphones.

In addition to the improved spatial perception, the S-Logic technology should also be easy on the ears. With the same volume perception, the headphones require a sound pressure level around 3-4 dB lower. I have already seen with some Ultrasone models that this technology can sometimes tend towards “effect.” So I’m curious to see what the Pro 900i will sound like in the end.


As usual, the headphones have to prove themselves on various signal sources. In addition to the headphone output of an RME HDSP card, a Mackie 1604, an iPhone, and an SPL Phonitor Mini are used. In addition to current electronic productions, acoustic live and studio recordings, classical orchestral music, and current pop/rock productions are listened to via the Ultrasone. The open AKG K812 Pro serves as a comparison.

The sound of the Pro 900i immediately presents itself with a decent bass foundation. Suitable for electronic productions or hip-hop songs, that’s way too much for other songs. This may be okay for vocal or instrument recordings, but I would have problems with mix and mastering. The headphones also come across as a bit sluggish in this frequency range because, for example, they do not act as fast and jaggedly as the K812 with short kick drum hits.

The Pro 900i, on the other hand, brings voices to the ear in a clear, precise, and detailed manner. I particularly like the upper mid-range. Here, frequency-like instruments are also mapped well and differentiated. The Ultrasone does not give cause for criticism in the height range either. It never gets sharp but is not too gracious with poorly mixed highs either and brings the high-frequency range clearly and brilliantly to the ear.

The Pro 900i can also score points in terms of spatial representation. The Ultrasone headphones are particularly good at presenting live concerts; individual signals can be located easily and perceived separately.


With the Pro 900i, Ultrasone has professional studio headphones in its range that are well made and come with a large scope of delivery, including a transport box and two cables. In addition, the quality is very good.

The spatial representation of the headphones is very good. The in-house S-Logic technology from Ultrasone seems to work well here. The Pro 900i is suitable for recording and monitoring and cuts a fine figure in these disciplines as closed headphones. However, due to the very prominent bass range, you should use other headphones for mix and mastering.

Ultrasone Pro 900I Studio Headphones Review
Ultrasone Pro 900I Studio Headphones Review

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