Best Mixing Headphones? Grell OAE2 vs Sennheiser HD Series

If you're looking for a mixing headphone, chances are you've seen Sennheiser pop up in your search. The Sennheiser HD 600 is a classic amongst introductory audiophiles, and the step up of the Sennheiser HD 650 has long been praised as an excellent reference headphone. What happens when someone new enters the ring? The Grell OAE2 is a new open-back headphone that is said to really shake up the competition. After reviewing Audio46, we had to put it to the test against the classics. How does the Grell OAE2 compare to the Sennheiser HD series? Is one better for mixing than the other? In this review, we explore all the details and closely compare the three aforementioned headphones side by side. 

As always, we start with the physical build of each of the headphones. The Sennheiser series is pretty consistent in build quality, and the physical shape does not change much from one model to the next. The Sennheiser HD 600 and the HD 650 have the same oval-shaped earcup, with velour earpads and detachable cable. The clamping force is quite tight on both of these headphones; the HD 600 is a little smaller and feels a bit tighter compared to the HD 650, but both have the same overall feel. It is stable to wear on your head for long listening sessions, and the earpads are easily interchangeable to optimize comfort. You can check out some options from Strauss & Wagner here. 

The Grell OAE2 is definitely a different look. For starters, the headphone takes on a round earcup shape as opposed to the oval of Sennheiser. The earpads are made of a similar soft velour material, though it picks up dust and hair quite easily. A bit of regular maintenance will keep them looking like new. The OAE2 doesn't have a super strong clamping force, but it does feel stable on the head, so you can wear it for hours without issue. The headband presses lightly to the top of your head, and the sliding adjustable sides make it easy to optimize your comfort. It is a smoother construction than the Sennheiser, where the adjustable sides click rigidly in place. The metallic finish on the OAE2 is a step up from the plasticky feel of the HD series. 

The cable is detachable from each headphone. From Sennheiser to Grell, you can replace the cable should you find you need to replace it. However, Sennheiser and Grell face the same issue of needing a type-specific cable for best compatibility. The proprietary 2-pin connection and recessed 2.5mm single-ended connection are not the simplest to find, though you may see that there are more options for Sennheiser replacements than the Grell. Strauss & Wagner has upgraded cables called the Lucerne or the Olten, which offer nice upgrades to balanced terminations for the Sennheiser headphones.  

SOUNDSTAGE & IMAGING

Let's take a listen to all three of these headphones. What are their sound profiles like? The Sennheiser soundstage is known to be wide and pretty flat, and that's exactly what you get out of the HD 600 and the HD 650. The soundstage stays very linear with limited height, instead focusing on horizontal space and a bit of depth. The HD 600 certainly lays the flattest of the three, with very limited expansion in any other direction. In comparison to the HD 650, the HD 600 sounds more sterile; you have a bit more depth and color in the HD 650 that is hard to replicate in the HD 600. The HD 650 leans into neutrality by accentuating the balance of the signature. Instead of just lying flat and neutral, you have a better balance between horizontal space and depth, so the bass feels more lush and full. 

The Grell OAE2 is a bit different. While it does have a very balanced sound, its spatial reproduction really comes out the most. The Sennheiser HD series takes the sound and brings it right in front of your face, but the Grell doesn't feel the need to do that. Instead, it lets everything take a half-step backwards and gives frequencies room to breathe. The imaging is fairly accurate and stays mostly towards the center, but the separation of instruments makes everything easily recognizable. 

All in all, you'll get an excellently balanced and natural reproduction from each of these headphones. The treble is definitely brighter on the HD 600 and the Grell OAE2, with the Sennheiser HD 650 coming in with the strongest bass sound. In terms of space, the Grell OAE2 impresses with its laid-back but still detailed sound signature, highlighting three-dimensional space as opposed to just linear. 

BASS FREQUENCIES

The bass frequencies in all of these headphones aren't terribly strong, but they do have their highlights. Sennheiser has always had a very tight bass with precision as a focus, and that's what you get out of the HD 600 and HD 650. The bass on the HD 600 definitely takes a backseat and focuses on the detail of the lower range instruments rather than their depth. You sort of lose the punch and thickness of the bass in the HD 600, but if you wanted to hear that back, you may find it better with the HD 650. The HD 650 still has a very tight and controlled bass response, one that is detailed and precise in placement. The bass has more depth and warmth than the HD 600, which makes it a nicer balance to the already bright signature that Sennheiser has. 

On the other hand, the Grell OAE2 comes in with a very different bass response. It is likely most similar to the HD 600 in the way it takes a backseat in the signature, but it has the same warmth that the HD 650 does to make it a little warmer and punchier. You can hear how the detail of the bass comes out, and you can easily distinguish the various instruments. Drum kits are given space to build from the bottom up, and bass guitars are still recognized by their tone and thickness. If you want a more forward bass response, you may prefer the sound of the Sennheiser HD 650, but the Grell offers a nice foundation without being completely drowned out by the low end. 

MIDRANGE FREQUENCIES

The midrange is where all three of these headphones really excel. The midrange holds the most detail and texture in the signature. The Sennheiser HD series has a very recognizable midrange, with prominent detail to make instruments easily identifiable. The HD 600 pushes the midrange the most forward of the three. It makes sure you hear all the melodic elements front and center, especially vocals. Instruments sound natural and honest, highlighting neutral sound above all. The balance of all the instruments in the HD 600's midrange is treble-leaning, which can make some instruments sound sharper than they are. If that kind of sound is fatiguing, you may prefer the balance of the HD 650 a little more. The more dynamic overall signature makes the midrange less harsh, with a focus on tonal balance above all. You still get the same neutrality and natural textures of elements in the track, this time with more distinct separation of those elements.

Looking at the non-Sennheiser model in this comparison, you can see how the Grell shifts your expectations. If you are accustomed to the sound of the Sennheiser forward midrange, you'll probably find the Grell to be much less aggressive and almost recessed. In a way, you'd be correct; the OAE2 is much less forward as a whole and lets the sound take up more depth and height than the Sennheiser headphones. The midrange is still incredibly detailed, and you get a lot of textural detail in a lot of genres. The vocals come to the front naturally and make them the center of attention, so you can pay attention to those main vocal melodies with ease. I really liked how the midrange took up more space, layering backwards instead of side to side like the Sennheiser does. The sound does become more cohesive with less separation than the Sennheiser, but it will come down to personal preference for which presentation you prefer.  

TREBLE FREQUENCIES

Rounding out with the treble frequencies, the Sennheiser HD 600 and 650 both have a very bright response that stands out. The HD 600's treble is the most prominent part of the signature, making it a standout amongst other mixing headphones. Having that brightness allows for more minute details to be revealed in the rest of the signature, which is exactly what you hear in the HD 600. Comparing that to the HD 650, you have a little more balance between the bass and treble since the midrange creates a V-shaped signature. The treble is more forward on the HD 600 than the HD 650, but both are strong in detail and carry that throughout the signature. The spatial detail is also noticeable in the treble response. You can get a better feel for the spaces where tracks were recorded rather than just the sharpness or airy qualities. 

This spatial treble detail is heard more clearly on the Grell OAE2. Since the entire signature takes a step backwards in comparison to that of the Sennheisers, you can hear how the top end opens up just that little bit more to make the sound airier and brighter. The treble itself is very bright and colorful, allowing for top-end instruments to get full detail and textural precision to make them easily distinguishable. From my listening, the Grell OAE2 was able to take the top end and extend it out further than the Sennheiser series, where the treble was very up front but had a clearer cut-off point. Both of these responses were incredible in detail and precision, and it was sharp enough without sounding harsh or abrasive. The Grell OAE2 had the most relaxed treble response, and the HD 600 had the most forward of the three. If you value treble detail or anything, the Sennheiser series may be up your alley more than the Grell. If you are more sensitive to treble, the Grell OAE2 offers a good compromise of detail without being too in-your-face. 

As mentioned in the title, these two headphone companies compete for top-spot on the list of “Best Mixing Headphones”. Sennheiser remains an excellent option, showing off naturalness and neutrality in not one but two headphones. The treble shine in the HD 600 is great for people who need a bit more brightness, but the HD 650 is very well-rounded to make it a more balanced listening experience. If you're someone who mixes on the bassier side, it may be worth it to get the Sennheiser HD 650 so you have a little bass already added in, and it won't tempt you to use it further. The HD 600 offers bright neutrality and engaging spatial accuracy to any budding engineer. 

Where does the Grell OAE2 fit into all of this? The Grell offers the same brightness and natural tone, but has similar lushness in the bass like the HD 650. You have a bit more balance that is hard to replicate without the help of an outside DAC or amplifier with some applied filters. I found the Grell OAE2 to be great for imaging and getting a great sense of space, as opposed to the Sennheiser's flatter soundstage that kept things rather frontal. The Grell had better three-dimensional sound that could be dual-purpose in the studio or just for analytical enjoyment. If you were looking for imaging and placement, you may pick up the Grell OAE2 to get a better sense of the space you want your track to be in. For more analytical and exact instrumental editing, perhaps either of the Sennheiser series may be a better match for your setup. 

So, which headphone is for you? Looking at the Sennheiser HD 600, Sennheiser HD 650, and the Grell OAE2 all together, they offer a lot of the same features that make them stiff competitors. No matter which of these headphones you choose, you are sure to be pleased with the sound and be able to use them for studio or just casual listening. Depending on your preference for sound, you will definitely find that you lean towards one over the others. I highly recommend getting the opportunity to try the Sennheiser and Grell headphones out and see which one your ear leans towards. 

If you value spatial presentation above all else, choose the Grell OAE2. You'll find the relaxed signature and immersive quality to be great for placing all your instruments in the wide soundstage, all while making sure all your track elements work together in harmony. 

If balance is your number one priority, choose the Sennheiser HD 650. The forward detail across the frequency range will not go unnoticed, and the balance of treble and bass will be perfect for finding the right sound for each instrument. 

If cost-effectiveness and treble detail are what you need, choose the Sennheiser HD 600. You'll find the forward treble and midrange accentuates the naturalness of the sound, and you'll be able to tune your track elements with ease. 

You can find all three of these headphones at Audio46.