How many audio products can you think of that were introduced more than 30 years ago but remain competitive with the best of today? Microphones and cables aside, I can think of only one: Sony’s MDR-7506 headphones, which were introduced in 1991 and quickly became a common fixture in thousands of recording and broadcast studios worldwide.
In fact, I can’t remember going into a studio in the last couple of decades that didn’t have a few 7506s laying around. That’s for very good reason, because the MDR-7506 hews closely to the Harman curve — the headphone frequency response target developed through extensive research that began two decades after the MDR-7506 was introduced.
Having used 7506s since the late 1990s, I was shocked — and, honestly, delighted — to learn that Sony had introduced a similar-looking but more costly model, the $249.99 MDR-M1.
Why was I so happy to find an alternative costing two and a half times the MDR-7506’s $99.99 price? Well, it’s not like the 7506s are my favorite headphones; to my ears, many audiophile-oriented models have a more detailed and spacious sound. But also, the 7506s are notorious for showing premature wear and tear. Many 7506s I’ve encountered in studios were in some state of decay, usually with pieces of the thin protein-leather covering flaking off the earpads, and some with their non-detachable cables damaged by the rollers of a desk chair.
“They’re cheap, you can just buy new ones,” was the common refrain I heard from recording pros. But I’d rather invest in something that will last me several years than risk failure on a day when I have an audio or video project due. Maybe a more costly model would make for a more reliable studio companion, perhaps with a boost in sound quality to boot.
Sony’s marketing materials promise a couple of benefits that aren’t clear to me. First is “Beat response control for tight, powerful bass,” which appears to be a fancy name for the small port at the top of each earcup; there’s no control you can adjust. I don’t see this as particularly special, as most sealed-back headphones have a small port somewhere to equalize the pressure on the driver when you put the headphones on. They also promise “Accurate sound localization for precise mic distance detection,” but it seems to me that any decent set of headphones would offer that, and Sony doesn’t elaborate on how the MDR-M1 achieves this feat.
Sony also notes the MDR-M1 was tuned “through extensive industry collaboration with high-end studios including Power Station at Berklee NYC and mix and mastering engineer, Mike Piacentini, from Sony’s Flagship Mastering facility, Battery Studios NYC.” That’s fine, but as a professional reviewer, I encounter such “tuned by recording pros” statements dozens of times per year. I haven’t found these products necessarily better or worse than others, and in my opinion, it’s better to tune based on scientific research with large numbers of listeners with verified hearing health, than on the opinions of a couple of professionals.
The Headphones
I couldn’t tell from looking at the MDR-M1 if the new model was any better-sounding than the MDR-7506, but it sure looked more rugged. The cables — each tipped with a four-conductor, 3.5mm plug on the headphone end and a three-conductor 3.5mm plug on the source end — are not only detachable for easy replacement, but they also have a threaded collar on the headphone end (Photo 1) to ensure the cable doesn’t accidentally unplug from the headphone.
Two straight (i.e., not coiled) cables are provided: one measuring 4’ (1.2 meters), and another measuring 8.5’ (2.6 meters). Each cable includes a threaded 6.3mm adapter. The short cable makes the MDR-M1 more practical for on-the-go listening and recording than the MDR-7506 because the MDR-7506’s long, coiled cable stretches to about 14’, and tends to get tangled in tripods, microphone stands, and other gear.
Like the MDR-7506, the MDR-M1 is a closed-back model, so you can use it for monitoring, mixing, and recording without much concern that the sound from the headphones will leak into microphones.
Sony fit the MDR-M1 with a new 40mm dynamic driver rated for a response from 5Hz to 80kHz; the MDR-7506 also sports a 40mm dynamic driver, but its response is rated only from 10Hz to 20kHz. While the MDR-M1’s specs may titillate the average listener, the reliability and relevance of headphone measurements below 20Hz or above 20kHz is questionable to say the least.
A look at the two headphones with their earpads removed (Photo 2) reveals their differences. The MDR-7506 protects its driver with a relatively thick, perforated piece of metal, while the MDR-M1 covers its driver with a much less massive plastic grille. This reduced acoustical impedance alone would likely result in a sonic improvement — in my experience, usually a more detailed, less colored sound.
The MDR-M1 has a softly padded headband, versus the MDR-7506’s thinly padded band, and the pleather covering seems much sturdier than the pleather on the 7506’s notoriously fragile earpads. (Of course, you can easily and cheaply replace the 7506’s pads with any number of sturdier aftermarket models, although this will change the sound somewhat.)
In Use
I used the MDR-M1s for three projects: putting the final touches on Plaid Pants, my new jazz album with saxophonist Ron Cyger; checking the final edits on the Audiophile Society’s Headphone Evaluation and Spatial Audio Test Album, a project I’ve been working on with composer and audiophile recording engineer David Chesky; and recording a couple of episodes of my podcast, Audio Unleashed.
It usually takes about three hours to record each episode of my podcast, including two hours of actual recording and an hour of preparation. Headphones can start to bother my ears after that long — usually because the baffle that holds the driver rubs against my earlobe — but the MDR-M1’s relatively firm ear pads held the baffles off my ears better than the soft stock pads on the MDR-7506 do. The MDR-M1 is also light: 235g with the cable attached, versus 249g for the MDR-7506, which itself is one of the lightest headphones I own.
A plus of the MDR-M1 is that its earcups fold flat (Photo 3), so slipping the headphones into a laptop bag is usually pretty easy. (No carrying case is included.) The MDR-7506 can’t, although its earcups fold up into the band to make the headphones more compact for storage or carrying.
I tried driving the MDR-M1 from Focusrite Scarlett 2i2 3rd generation and Focusrite Vocaster Two USB interfaces; from the headphone jacks of Asus and Lenovo Windows laptops and an Apple MacBook Pro; and from the headphone jack of my Samsung Galaxy S10 Android phone. All these devices easily drove the MDR-M1 to loud levels without strain or distortion.
The Sound
The MDR-M1 worked fine as monitor headphones when I was working on podcasts and rough mixes of my next album. But I wanted to see how the new model stacks up against potential competitors (Photo 4), so I compared it to my MDR-7506 (which has replacement pads that change the sound a bit, but only subtly) and the AKG K371 headphones, which are noted for their close adherence to the Harman curve. I use the K371 for much of my recording work because by design, it sounds very much like my JBL 305P MkII monitor speakers, which are also made by Harman.
I started by playing several mixes I’ve been working on lately. First up was from the Audiophile Society’s headphone test album: a test track that has voice and percussion sounds starting at 0 degrees directly ahead and passing overhead and behind the listener in 30-degree increments. It’s mixed in Atmos, using the Apple Logic digital audio workstation (DAW) and the Apple binaural stereo encoder. I was surprised to hear that the two headphones sounding most similar in this test were the MDR-7506 and the K371, both of which revealed lifelike treble detail in the voice and percussion sounds. In comparison, the MDR-M1 sounded mellow, with softer treble and a more prominent lower midrange. Probably because the MDR-7506 and K371 sound brighter, both did a bit better of a job of creating the overhead sonic images in this track. I also noticed that the MDR-M1 is a few decibels more sensitive than the MDR-7506, a difference that helped when I listened through the somewhat underpowered headphone amp built into my Asus laptop.
A similar verdict resulted when I played “Forças de Natureza” by Café, one of the demo tracks we included on the Audiophile Society test album. “Forças” is my favorite example of David Chesky’s Mega Dimensional Sound, a collection of mixing techniques he uses to create what in my opinion are mixes more immersive than Atmos seems capable of. On “Forças,” the MDR-7506 gave me the most “wraparound” effect, and the most precise sonic images of the voices and Brazilian percussion instruments on this track, probably because its treble was a little more elevated and revealed more detail in the percussion sounds — although the K371 came close. The MDR-M1, again, sounded softer in the treble, and much stronger in the bass; the deep surdo drum used in this tune is loud in the mix already, and through the MDR-M1, it felt almost as intense as standing right next to the drummer.
Next up was “Larry’s Lament,” a jazz tune from my new album that was mixed by Larry Crane, editor and founder of Tape Op magazine and owner of Jackpot! Recording Studio in Portland, OR; I also had my own mix on hand for comparison. I don’t know what Crane’s studio monitors sound like, so I can’t say for sure which headphone had the most accurate portrayal of his mix. However, these three headphones sounded different enough that they would have had me making substantially different mixing and EQ decisions.
To my ears, the AKG K371 sounded the closest to what I heard when recording the individual tracks; all the instruments sounded clear and easy to pick out from the mix, and I got a great sense of the reverb Crane used. With the MDR-M1, I heard a lot more bass, which made the whole mix sound subjectively softer. I’m sure I’d have dialed the bass down about 5dB had I mixed on this headphone. The MDR-7506 sounded the opposite: brash and trebly, with a thin saxophone sound and an overbearing ride cymbal.
I also tried listening to some of my favorite test tracks streamed from Qobuz through my Samsung Galaxy S10 phone, using a Fosi Audio DS1 DAC/headphone amp. Here, my opinion changed. On Tracy Chapman’s “Fast Car” (long a favorite test track of audiophiles), I thought the MDR-M1 sounded closest to what I’m used to hearing on this tune through the hundreds of headphones, speakers and soundbars I’ve tested with it. The bass was strong but not so strong that it drowned out the treble or colored Chapman’s voice; to me, it sounded closest to what I expect this tune to sound like. I especially liked the extra little bit of warmth in Chapman’s voice. The K371 sounded good, too, but with slightly subdued bass and a little extra treble that made the vocal sound subtly sizzly at times. With the MDR-7506, the sound was too sizzly, overpowering the midrange and thinning out the voice in an unnatural way.
Just to confirm what I heard on “Fast Car,” I played “Noir,” from my previous jazz album recorded a couple of years ago. I worked for weeks on the recording and the mix of this tune, and have heard it on countless headphones and speakers, so I know it well. Again, the MDR-7506 sounded too trebly, thinning out the saxophone sound. The K371 sounded like I remember this mix sounding; no surprise, as I mixed it on the JBL 305p MkII monitors.
But listening through the MDR-M1, I thought, “This is the way I wish this mix sounded.” The bass was strong but not overpowering, and I got a terrific sense of space; the reverb sounded realistic (even though it was just a $29 Waves plug-in) and the alto sax sounded as full as I’d always wanted it to. I tried listening to several other tunes I’ve mixed and kept coming to the same conclusion. I think if people listened to my music on these headphones, they’d be impressed with my mixing skills.
Measurements
I performed measurements (Photo 5) using a GRAS Model 43AG ear-cheek simulator, a RA0402 high-resolution ear simulator/coupler, an Audiomatica Clio 13 audio analyzer, and a M-Audio Mobile Pre USB interface with TrueAudio TrueRTA real-time analyzer software.
Figure 2 compares the frequency response with the MDR-7506 and the AKG K371, a roughly $150 studio headphone that conforms closely to the Harman Curve. The MDR-M1 has less energy above 2kHz than either of the other models, which would give it a subjectively smoother, less bright sound, and probably make the sound less spacious.
Figure 3 shows the frequency response with the Musical Fidelity V-CAN amplifier I use (which has a 5Ω output impedance), and with 70Ω of extra impedance added to bring it up to 75Ω, which is an output impedance encountered in some laptop computers and some older professional headphone amps. The difference is small—a boost below 150Hz that maxes out at about +1.5dB. So, the sonic difference you get when switching headphone amps should be subtle.
Figure 4 shows the difference in response when the headphones are moved about 6mm up, down, forward and backward on the ear-cheek simulator, then removed and reseated several times. For the most part, the difference is tiny, although one of the reseatings did show a dip of maximum -2dB centered at 1.2kHz. As long as you get the MDR-M1’s earpads comfortably seated around your ears, the sound is unlikely to vary much from wearing to wearing.
Figure 5 shows the spectral decay plot—or “waterfall”—of the MDR-M1, which reveals resonances. The response here looks clean, with essentially zero resonance in the mids and treble, and some well-damped resonance in the bass.
Figure 6 shows the THD of the MDR-M1 at 90dBA and 100dBA. Figure 7 shows how the result at 100dBA compares with the distortion of the MDR-7506 and the AKG K371. I was surprised to find this is the first time I’ve measured the MDR-7506’s distortion, which is quite high, although I must note that in a couple of decades of using MDR-7506s, I have never noticed the distortion. Clearly, though, the MDR-M1’s distortion is much lower; whether this difference is audible, I can’t say for sure. The K371 beats them both, though.
Figure 8 shows the impedance magnitude and phase of the MDR-M1. It’s mostly flat, running between about 49Ω and 62Ω, with negligible phase shift. (Sony rates it at 50Ω at 1kHz.) This is why the output impedance of the source device has so little effect on the MDR-M1’s sound.
Figure 9 shows the ability of the MDR-M1 to isolate the listener’s ears from outside sounds. The measurement was taken by playing uncorrelated pink noise at 85dB SPL from a six-speaker system with a subwoofer.
Conclusion
After testing the new model against the potential competitors, I found that in terms of design and build quality, the MDR-M1 is the hands-down winner among these headphones; after frequent use, the MDR-7506 and AKG K371 tend to look like they’ve been dragged down a gravel road, but the MDR-M1 seems much more likely to retain its looks and function after a year in a studio.
In terms of sound, it’s a tougher call. For casual listening to commercial recordings, I prefer the MDR-M1 over the other models; its richer sound won me over, and its added comfort is a huge plus.
For mixing, I’ll probably stick with the AKG K371, though. It doesn’t sound as pretty, but I expect the mixing decisions I make with it may translate better to the huge variety of audio systems through which people will hear my work. Although if I were spending hours a day wearing headphones in a studio, I’d be tempted to just put in a little time getting used to the MDR-M1’s sound and enjoying its superior comfort and build quality. aX
This article was originally published in audioXpress, February 2025
