Skip to main content

Ultrasone HFI-2400 Review

ultrasone hfi 2400 review hifi
Ultrasone HFI-2400
“Move over, Sennheiser. Ultrasone’s HFI-2400 combine the best of German design with a price tag we can live with.”
  • Tight, punchy bass
  • Very Dynamic
  • Solid, high-quality construction
  • Extremely comfortable
  • Open-backed design doesn’t provide sound isolation
  • No 1/8” adapter provided
  • Require precise positioning for the best sound
Image used with permission by copyright holder


Ultrasone is a relative newcomer to the U.S. headphone market. Founded in 1991 and based in Tutzing Germany, Ultrasone has provided the European market with products for the past 19 years. Fortunately for us, the brand is beginning to catch some mainstream attention here in the U.S. and, if they keep making products like the HFI-2400, we think that trend will continue upward. Ultrasone doesn’t tip-toe around the notion that there is more than one German high-end headphone maker (Sennheiser, are your ears burning?) and makes some pretty bold claims as to being “THE German Headphone Company”. In our review of the HFI-2400, we find out if Ultrasone’s bravado translates to hot sound or just a bunch of hot air.

Out of the Box

The HFI-2400 comes with a minimum of packaging fluff. Inside the unassuming box we found the HFI-2400, the headphone’s detachable cable, a demo CD, an instruction manual and a black velvet carrying and storage pouch.

The HFI-2400’s robust construction makes them appear as if they will be fairly heavy but at just 10 ounces (292 grams) the headphones turn out to be reasonably light. The black headband is wide and sturdy with strategically placed padding and oversized hinges that secure it to the individual earphones. The earphones are made of black and grey plastic with a shiny aluminum plate decoratively placed in the center of the earphone’s backing. The inside of the earphone includes foam earpads covered in black velvet cloth.

The HFI-2400’s detachable 3m cord connects at the base of the left earphone. The headphones swivel inward 90 degrees and can swivel up another 90 degrees for more compact storage. Ultrasone clearly indicates which side is which on both the earphone’s back-plates and hinges.

Features and Design

The HFI-2400 headphones are packing a few proprietary designs that are worth noting: Ultrasone’s patented S-Logic Natural Surround Sound doesn’t rely on complicated digital processing or any other electronic wizardry to achieve a surround sound effect. Instead, Ultrasone uses “decentralized driver positioning” to achieve a natural surround feel. The idea is that by directing sound at several parts of your ear (not just dead center) what you hear will seem to come from all around your head and not just in your head. We took off the easily removable ear pads to have a look at the drivers. Indeed, rather than place the drivers in the center of the earphone, Ultrasone has positioned them at the 5:00 position. This decentralized driver positioning means that the user must put the headphones on correctly. When reversed, there is a noticeable and unflattering change in the upper midrange and treble response.

Ultrasone also makes a big deal about their Ultra Low Emission (ULE) electro-magnetic shielding. Apparently, wearing headphones for long periods of time exposes us to electro-magnetic radiation that can be hazardous to our health. To keep us safe, Ultrasone has implemented magnetic shielding that reduces the electro-magnetic field emission by 98%. We’re not sure how helpful this shielding is in the long run, but the placement of a large metal plate over the bulk of the driver section did not seem to negatively affect the HFI-2400’s performance. Though we’re not sure how beneficial this shielding actually is, we’re pleased that it didn’t adversely affect the sound quality.

Ultrasone may lay it on a little thick with the marketing gems but the HFI-2400 really is a well conceived set of headphones. They are extremely comfortable and rest securely on the head without creating un-needed pressure on the areas around the ear. The velvet cushions do a great job of keeping things cool and dry over long listening sessions. The long, 10 foot cord screws into the base of the earphones for a very secure connection and is strong enough to withstand an above average amount of abuse. The stout hinges allow for the ‘phones to be collapsed down for more compact storage and transport. In fact, after handling the HFI-2400 for a couple of weeks we were left believing that this set of cans will hold up in the long term..

Positioned at the top of Ultrasone’s HFI line, the 2400 have the look and feel of a high-end headphone, but lack some of the accessories that we’ve come to expect from a top-of-the-line offering. Our guess is that Ultrasone has chosen to leave some of these perks out of their HFI line in order to make these ‘phones more affordable and, if that is the case, we applaud them. Those fancy extras are available in the more expensive PRO line for those that will make practical use out of such extras as a hard case, coiled and straight cords and alternate earpad materials. To have the same guts as the more expensive PRO line without the extra cost involved shows careful consideration of the customer’s need and that’s something that we can all appreciate.

Our only complaint about the HFI-2400 is that, at this price level, we still expect to see an audio adapter that allows the HFI-2400’s large ¼” plug to be downsized to suit an iPod, laptop or other portable audio/video device. While this sort of adapter comes cheap at most electronic stores, we hope for something that is on par with the quality of the headphones themselves.


Our experience with the HFI-2400 was particularly interesting because, more than any other headphone we’ve tested, the performance of the Ultrasones seemed to change for the better the more we used them. Those that believe strongly in providing a break-in period for all things speaker-related will find that the HFI-2400 benefit a great deal from some pre-evaluation use. Straight out of the box, the high frequency response was extremely hot. It was enough to make us want to remove the HFI-2400 and come back to them later. After about 45 hours of use, however, the HFI-2400’s sound signature changed significantly and for the better.

We love the deep, punchy, super accurate bass response of the HFI-2400’s straight out of the box. While we expected some hearty bass from a headphone of this size, we were pleasantly surprised at how immediate and articulate the 2400’s bass response was. When we listened to Jimmy Smith’s organ on “S Wonderful” from The Sermon we could feel the weight of each key being struck as if we were sitting right next to Jimmy’s leslie speaker. The bass was naturally resonant and never over-bloated as we’ve often heard in other high-end headphones. For something more modern, we pulled up Sheryl Crow’s “Steve McQueen” from her C’mon C’mon album. This track has the drums front and center in a sort of super-produced way. Over-produced as it may be, the ultra-big bass at the top of the tune makes for a good test of low end capability and the HFI-2400 did not disappoint. We got all of the big bass that the recording engineer intended but no more. In fact, it was a little like jumping behind the scenes in the recording studio and getting some insight into what the engineer’s intent must have been.

Fortunately, the Ultrasone’s are not a one trick pony. Many large, over the ear headphones deliver mind-pounding bass but fall short on midrange and treble accuracy. Such is not the case with the HFI-2400. Their midrange response was extremely appealing and open and had a warmth to it that we found to be on par with headphones that cost 5 times as much. Listening to Michael Buble’s “Feeling Good” from the It’s Time album through the 2400’s was an unexpected treat. Buble’s sculpted vocals came across with stunning clarity and accuracy. To get any closer to the real thing would have required having Buble’ himself sing directly into our ear.

High frequency response, initially, was a concern. For all that the HFI-2400 did well, we couldn’t get over how metallic the extreme high frequencies sounded. Fortunately, the aforementioned break-in period tamed this unwelcome attribute and really evened out the sound. Once broken in, the HFI-2400 reproduced incredible inner detail, texture and air around all of the high frequencies. Rather than sounding sterile, the highs now brought realism to the sound that we simply didn’t expect from a headphone at this price point. The only down side to this intense high frequency response is that it exposes compressed music files for all of their limitations. When listening to compressed versions of our test cuts the raspy, digital edges around the high frequencies were exacerbated to an embarrassing degree and the upper midrange was compromised as well. Once natural vocals now sounded squashed and honky by comparison.

We tested the HFI-2400 with an iPhone, iPod Touch, Dell Laptop Computer, Onkyo and Harman Kardon receivers and through a HeadRoom DAC and Amp combo. As one would expect: the better the source, the better the sound. But the delta between the good and the bad was more sharply pronounced with the HFI-2400 than almost any headphone we’ve reviewed to date. They hide nothing, so be prepared to hear just how bad (or good) your computer’s sound card or iPod really is.

We have only a few criticisms to offer in regard to the performance of the HFI-2400 by Ultrasone: As open backed headphones, these are not great at keeping outside noise from bleeding in nor are they adept at protecting your neighbors from enjoying your musical selections. However, we feel that this trade-off is worth their exceptional performance. Just know that you’re better off enjoying these cans in the privacy of your home or office than on the bus or in your local coffee shop.


The Ultrasone HFI-2400 sound incredible and, at $299.00, they outperform headphones that cost much more. Their balanced, engaging response and tremendous dynamic capability are the stuff that audiophiles drool over. We found them extremely entertaining and satisfying. We would encourage you to give the HFI-2400 a listen and consider putting the money saved into a headphone amp to raise them to their full potential. The return on investment here is very much in the listener’s favor. Highly recommended!


  • Tight, punchy bass
  • Very Dyanamic
  • Solid, high-quality construction
  • Extremely comfortable


  • Open-backed design doesn’t provide sound isolation
  • No 1/8” adapter provided
  • Require precise positioning for the best sound
Caleb Denison
Digital Trends Editor at Large Caleb Denison is a sought-after writer, speaker, and television correspondent with unmatched…
Can a lower price and the Grammys save one of 2023’s most controversial products?
Dyson Zone air-purifying headphones.

Maybe not the best way to sell headphones. Matt Alexander / PA wire

If I had to pick just one gadget as the weirdest and most controversial from the last 18 months, it would be -- without hesitation -- the Dyson Zone. By blending a set of noise-canceling wireless headphones with an air purification system, Dyson created a product that looks ridiculous even when worn by supermodels.

Read more
Beyerdynamic’s DT 770 Pro X offers premium features for less
Beyerdynamic DT 770 Pro X closed-back wired headphones.

If you need a robust, closed-back set of wired studio headphones, Beyerdynamic has a new option that could be very appealing. The DT 770 Pro X brings two of the best features of the more expensive $269 DT 700 Pro X down to a $199 price.

Based on the popular $169 DT 770 Pro, the new Pro X model gets a detachable cable system with a mini-XLR connection. The included 9.8-foot cable has 3.5mm jack at the other end, and comes with a 3.5mm-to-6.3mm adapter. You can swap it out for other lengths and other connector types, or simply replace it if it becomes damaged -- something you can't do on the DT 770 Pro.

Read more
Sennheiser Accentum Plus aims at the middle ground between budget and baller
Woman wearing Sennheiser Accentum Plus in black.

With a familiar shape and several new features, Sennheiser's newest wireless headphones -- the Accentum Plus -- are a much-needed ption between the excellent (but bare-bones) Accentum ($180) and the company's flagship Momentum 4 Wireless ($350). Announced at CES 2024 and priced at $230, the Accentum Plus will be available on February 20 in black and white color options.

The Accentum Plus are essentially identical to the regular Sennheiser Accentum, with the same fold-flat design and a lightweight, plastic chassis. But the Plus takes a page from the Momentum 4 Wireless in the controls department -- now, instead of buttons, you can use taps and swipes on the outside of the right earcup to control everything from playback to volume.

Read more