Introduction

Ultrasone is known to produce some of the very best closed headphones on the market. Their latest headphone in this category is called the HFI-680 and features many of their patented technologies that are also employed in their more expensive headphones.

There are a few advantages to a closed design like for instance isolation. While they do not provide -26 dB like in-ears do they block out enough noise to enable you to get a good listening experience in a crowded place. The fact that they are closed also means that they do not leak sound so you can use them on the bus or train without annoying other passengers.

While a closed design may seem ideal, it does pose a few major problems especially when it comes to sound quality. Ultrasone employs a lot of tricks to increase the performance of their closed and semi open headphones to get them to sound natural. One of the key elements in this is their S-Logic technology which should improve the sound stage a lot giving you a sensation of sounds coming from all around you. Also worth noticing is that most of Ultrasone's designs are pretty efficient and can be used with good results on the move just powered by either a good DAP or DAP plus portable headphone amplifier.

Specifications

• S-Logic™ Natural Surround Sound Plus
• Dynamic principle
• Frequency range 15-25.000 Hz
• Impedance 75 Ohm
• Sound pressure level 99 dB
• MU Metal bufferboard, reduced field emissions in accordance with ULE (=Ultra Low Emission) standard
• Driver 40 mm gold-plated
• Weight 285 g (without cord)
• Straight cord (length ca. 3m)
• 3,5/6,3 mm (1/8" to 1/4") screwable gold-plated plug
• Transportation bag
• Demo CD
• Instruction manual

With an impedance of 75 Ohms and a reasonably high sensitivity these headphones can be driven by almost any type of source with good results. Of course hooking these headphones up to a dedicated headphone amplifier will lift the experience. Compared to other high end headphones these are "easy" to drive. Only my Grado headphones are more efficient than these.