I can remember being a young guitar player flipping through the pages of my favorite guitar magazines. Among the articles I liked best were interviews with players and recording engineers. Invariably, the articles featured pictures of these individuals in some kind of recording studio. One thing that I always seemed to notice in these photographs was the presence of a set of headphones close at hand. At the time, I didn’t realize the importance of headphones, but over the years, I have come to realize just how valuable great headphones are for studio work.

Professional headphones (or “cans” as most studio professionals refer to them) have been used in recording studios forever. They are utilized for tracking, mixing, mastering, as well as for personal monitoring. In some cases, these high end headphones carry a hefty price tag that can go into the thousand of dollars, and like a guitar player with a loyalty to their favorite axe, most audio engineers will take their headphones with them when working away from their home base.

In 1991, a new company entered the headphone market with some of the most significant advancements in headphone technology to date. Their ideas and design concepts would turn the industry on its ear (so to speak) and their products would quickly become an industry standard for professional recording engineers and musicians around the world. For this review we will be looking at two models in the “PRO” series by Ultrasone in their “PRO 550” and “PRO 750” models.

Both the PRO 550 and PRO 750 headphones arrived at my door complete with nylon covered hard-shell cases. Anyone with a studio can identify with the unintentional abuse your equipment will be forced to endure, even in a controlled environment. Storing your headphones in these zippered cases will provide a great deal of protection when the phones are not in use. Additionally, the cases afford easy storage since they allow you the ability to stack them or place them neatly on a shelf without worrying about damage or tangled cords. The form fitted case cradles the headphones nicely and includes an accessories section which holds the two included cables (1 straight and 1 coiled), a 1/8” adapter, and an extra set of ear pads. Overall, this looks to be an extremely professional and all inclusive headphone system.



I have used other professional level headphones in the past, and even among the best models, most feel as if they are compressed around my ears. This makes them feel somewhat uncomfortable and even constricting over long periods of usage. The Utrasone PRO series however feel very light and comfortable. They almost feel like they are just resting on my head and over my ears rather than pressing in on my head. The narrower headband incorporates a thick pad on top of the head which breaks from the traditional wide, flat bands of most other pro level headphones.

Another feature that I found advantageous is the fact that the ear cups have a substantial range of movement; much more than I am used to. Multiple pivot points allow you to achieve a nicely personalized fit. I found the interchangeable ear pads to also be a nice touch. This is perfect when you are sharing headphones between other players of engineers. As mentioned, each set of the 550s or 750s come with a spare pair of ear pads, but others are available for purchase separately if you have the need for more. The ability to replace the signal cable with an easy threaded connector on the phones themselves is also an invaluable feature.

My final observation has to do with the 1/8" adapter jack, and brings me to the only real gripe I have with these headphones. The adapter jack is one of the plug in styles that fits over the 1/4" jack. This adds about two inches to the length of the input plug. In my opinion, this makes it easier to bump or hit the jack which could theoretically result in a possible broken input jack. I would have preferred the jack adapter where the 1/4" jack screws down tight over the 1/8" jack thus reducing the length of the connector. This is the type of input jack styles used in Ultrasone's HI-FI series.

Overall, however, I would deem the construction durable enough to take on the rigorous demands of both the studio and the road. I have to admit that I was more than satisfied with the quality and feel of these cans even before I even plugged them in.



When it comes to the all important aspect of sound quality, Ultrasone has done some significant research and development and incorporated the results into the design of the PRO Series. To better understand these advancements, we need to take a step back in time and look at the engineering and design of headphones relative to how our ear works to perceive sound.

When perceiving sound, the outer ear or “pinna” collects vibrations in the air and funnels these waves into the ear. The sound waves hit the pinna at different angles depending on the location of the source. You can hear this when someone drops something in a quiet room, and all heads turn suddenly in the direction of the noisy event. Without the pinna, we would have very little perception of the direction or location of a sound source.



Most headphones however are designed so that the sound travels directly into the ear canal, the effect of which completely bypasses the pinna. By missing this very important first step in the natural hearing process you end up with the effect that I term "sound in a box". Even good, headphones do not sound quite as natural as when something is heard live or through speakers. Additionally, since the ear is not functioning as designed, headphones often cause fatigue to the ears over long listening periods - even at relatively low volumes.

In their research and development, Ultrasone realized that no other company had addressed this issue so they set out to create a better user experience with their patented S-Logic™. Instead of aiming the drivers directly into the middle and inner ear, they opted to point the drivers off center at a slight angle. This configuration allows the sound to efficiently utilize the pinna of the ear as the sound is directed at the outer ear instead of directly into middle and inner parts. This has two incredibly beneficial aspects for listeners. First, in contrast to older technologies, the sound is very natural. Second, the fact that the signal is not aimed directly into the ear helps to relieve stress on the eardrums by reducing the sound pressure by 3-4 decibels at the same volume level. This equates to safer listening at the same perceived loudness as well as less fatigue over longer listening periods. keep in mind, that once you have lost hearing you can never regain it, so this is of great benefit and should be a major consideration for people who spend a lot of time with a set of headphones on their head.

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Gear Guy Tip: It seems that everywhere you look these days, you see people with headphones or ear buds listening to their iPods. Many of these people listen to their music at high volume levels using listening devices that are directing the sound directly at their ear drums. Ultrasone offers small compact headphones called “iCans” that offer the same S-Logic technology as their PRO series, with the same 3-4 decibel reduction for safer hearing.

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Another very notable Ultrasone advancement is the incorporation of shielding in the ear pieces. Most people have by now heard about the possible health risks from low-frequency magnetic fields from cellular phones. Many do not realize however that long before the advent of the cell phone, they were bombarding their ears with the same types of low-frequency magnetic fields through the use of headphones. Ultrasone designed the PRO series to combat this effect with “ULE (Ultra Low Emissions) Technology” This shielding has been proven to dramatically reduce the these low-frequency magnetic fields and hopefully mitigate these health risks.

In my research for this review, I spoke with Neil Cherian (Staff Neurologist at The Cleveland Clinic and Owner, Synapse Records Inc.) about these low-frequency magnetic fields. What I found through this conversation was that most experts in the medical field believe there are indeed health risks associated with these types of magnetic fields, but the level of risk is still largely unknown and difficult to prove directly. Research on this issue continues on a daily basis, but in the meantime, Ultrasone is the only headphone company to my knowledge that is being proactive in working to reduce musicians risk level.



For many years I have used a set of headphones that many consider the industry standard in professional music production. I use them in the studio, as well as for practice time with my guitars, but I found that I could only play or record for a limited amount of time before my ears were uncomfortable, and I stated getting a somewhat irritable feeling. At first, I never attributed this fact to the headphones themselves, but I now I realize that I was actually experiencing the aforementioned hearing fatigue issue. With this in mind, I was ready to put the Ultrasone PRO 550 and PRO 750’s to the test. I decided to do a general head-to-head test against other comparable professional level headphones. I connected my headphone amplifier to my Mackie VLZ3 Pro mixing board. Using a single set of headphones, I set up two headphone mixer channels, making sure that they sounded as close to identical as possible at the same volume level. Once this was set, I put the Ultrasone PRO 550’s on channel one, and then the other brand phones on channel two. Switching between the two set, I listened to a variety of sound sources that included pre recorded CD’s, microphones, acoustic and electric guitars, as well as bass guitar.

It did not take me long to realize that the Ultrasone PRO 550 was a clear winner in every category. There were two obvious differences that I noticed which set the Ultrasone PRO headphones in a class of their own.

First was the sound quality as it came across as much more natural, lively and pristine. Interestingly, the effect was not unlike that of a Sonic Maximizer or Aural Exciter when added to your instrument or vocal signal chain.

Secondly was the way the sound is perceived by the ear. It is as if the sound is all around you. Ultrasone describes it as “sound moving around your head”. I am usually not a fan of manufacturers marketing descriptions because I find most of these statements to be sales and marketing propaganda, but in this case, I have to say that this is a more than fair assessment by Ultrasone. It really is as if the sound moves and comes at you from different directions. This goes back to the earlier mentioned offset transducer and how it interacts more naturally with the “pinna” of the ear. The difference is incredible. The Ultrasone Pro headphones *almost* give you the perception of a surround sound speaker configuration.

For fun, I also decided to compare the PRO 550 against the PRO 750 to see if I could distinguish the difference between the two models. Although both sets have a notable flat frequency response, I was surprisingly able to discern a tighter and more focused bass response with the PRO 550’s while the PRO 750’s had a more balanced full spectrum approach to the frequency range. This gave me the impression that the 550’s would be best when tracking or monitoring bass and drum tracks while the 750’s would be better suited for use in monitoring the overall mix.

For my final test, I decided to check the Ultrasone headphones against the competition in the longevity of the listening experience. I often use headphones for practicing, and I have found that I can only practice for a certain amount of time before I just feel fatigued and need to let me ears rest. I started this test using the competitors pro level cans. I was able to practice for about 45 minutes before I felt I needed to just stop. To make the test fair, I waited until the next day so my ears would be fully rested. I plugged in the Ultrasone PRO 750 set, and with the same guitar settings and volume, I started my practice routine. The difference was amazing. I was actually able to practice twice as long (about 90 minutes), and I would have been able to continue with no problem other than the fact that I needed to stop to attend to some other activities.

Pro's - Flat frequency response, comfortable fit, reduced ear fatigue.
Con's - 1/8" adapter makes input longer, and easier to break off inadvertently.
Street Price - PRO550-($235) PRO750-($389)
Grade - A



If you look in any professional studio in the world, you will find recording, mixing, and mastering engineers using pro level headphones to do their jobs. The listening environment created by these higher end headphones will often times allow them to pick up on anomalies in the sound mix they would have otherwise missed. Since they rely on their ears to get the program material into a finished product, the best tools are essential.

Today’s recording environment has certainly changed dramatically in the last decade. Technology and low prices have made recording at pro quality at home a reality. When it comes to the home studio, headphones are often overlooked as an important tool in the recording and mixing process. Many people believe that a good set of studio monitors are all they will need to get that perfect sound. While I will agree that the monitors are very important part of the process, I will also submit that the addition of a quality set of cans will help to take your mix to a new level.

When I heard the Ultrasone PRO 550 and PRO 750’s, it became very clear to me why this company has quickly stormed the market and built such a strong reputation. I highly recommend that you put Ultrasone on the short list when you are ready to compare and purchase a set of headphone. While they may be more expensive than some of the others on the market, I think you will find the prices to be reasonable for their quality and fidelity. As such, the Ultrasone PRO 550 and PRO 750 headphones receive the GuitarGearheads.com “Studio Ready Award” for 2009.