The M1 system’s midrange is as close to harmonically neutral as any headphone I’ve heard recently. Not too dry or too lush, the M1’s midband characteristics are ideal for its primary intended use—as a reference monitor. Listening to my recording of the acoustic band, Mr. Sun, from a live concert at the Salina Schoolhouse through the Sonoma Acoustics system was both a delight and a very accurate rendition of the event, instantly bringing me back to the moment I made the recording.
And how does the Sonoma Acoustics handle bass? Very well, indeed. Even Mike Posner’s synth assault on “Silence (Sluggo x Loote Remix)” doesn’t ruffle the M1’s feathers one bit. Although not as bassalicious as the Sony MDR-Z1R, the M1 system pays bass its due with spot-on pitch control and fine definition. For deep bass and pulse control listen to Everything is Recorded’s “The Rhythm of Life and Death” from Close But Not Quite. Through the M1 system, even these low bass transients have definition and solid, visceral impact. This bass weight is one particular sonic attribute that separates the Sonoma Acoustics M1 from the Stax Lambda Professional series earspeakers. The Stax bass response is fast, but somewhat ethereal when it comes to in-your-face lower-octave weight. Through the Stax you are slapped instead of punched.
Analog adherents may not be completely comfortable with the fact that the M1 system converts all incoming analog signals to digital, but try as I might, I could not hear any sonic hints that the additional A/D and D/A conversion reduced the fidelity from analog sources. I will readily admit that I did not use the analog inputs, as much or as often as I used the digital inputs, primarily due to the input-level limits of the Sonoma Acoustics M1 and the plain fact that the bulk of my listening time is to digital sources, including Tidal and my own DSD recordings.
I recently reviewed the Stax SR-L700 ($1400) coupled with SRM-007tII amplifier ($2150) with a combined system price of $3650. The most notable differences between it and the Sonoma are how they handle bass, their fit, and their ability to withstand moderate abuse. The Stax bass is airier with less “meat and potatoes” impact than that of the Sonoma Acoustics M1. Both were fast and detailed, but the Sonoma Acoustics’ low end was more organic and impactful.
The two headphones fit quite differently, with the Sonoma Acoustics having a lot more side pressure, and the Stax being lighter, larger, and containing a far more delicate yoke/headband system. Having owned the Stax Lambda Pro for many years and having replaced the headband twice during that time, I can vouch for its delicacy. In comparison, I suspect the M1 headphones could survive several long tosses across the room with no lasting ill effects. To the Stax’s credit, I have been able to wear the SR-L700s virtually all day without a break while with the Sonoma Acoustics headphones I felt the need to take a “comfort break” after about 1½ hours of continuous use. Another difference that may be important to some listeners—the Stax amplifiers have provisions for L/R balance adjustments while the Sonoma Acoustics M1 does not. Finally, analog-or-death adherents may wish to remain in Stax’s all-analog domain versus Sonoma Acoustics’ digital one.
If you pair the HiFiMan HE1000 V2 ($2999) with the Inspire Dragon Inspire IHA-1 SE headphone amplifier ($1599) you have a headphone system that costs almost as much as the Sonoma Acoustics M1 system. But, even though both systems employ devices that wrap around your ears and are open-enclosure designs, almost everything else about these two systems, except for the high quality of their sound, is different. Like the Stax system, the Dragon headphone amp lacks any digital inputs and is analog-only. But unlike the Stax (and the Sonoma) the Inspire supports a wide range of headphones via either balanced or unbalanced connections. On the headphone side of things, the HE1000 V2 is easily in the M1’s league in fit, finish, comfort, and build-quality. For listeners who prefer less side-pressure the HE1000’s less intense fit could be far more to their liking. Sonically, connected to the Inspire, the HE1000 V2 bests the Sonoma Acoustics M1 when it comes to bass impact and extension, but the Sonoma Acoustics’ bass response seems more linear. The HE1000 V2/Inspire combo has a “juicier” midrange. In comparison to the HE1000 V2 the Sonoma Acoustics seems to add less embellishment, which could be a good thing or a bad thing, depending on the source material and your mood.
No audio component is perfect, and the Sonoma Acoustics M1 was certainly no exception. Its variations from perfection were small, involving long-term listening comfort, cable hardware, and distortion from excessively high analog input levels. None of these flaws are fatal, so if you are in the market for a superbly neutral, revealing headphone system for critical listening or monitoring purposes the Sonoma Acoustics M1 should be near the top of a very short list.
Specs & Pricing
Type: Open-back, circumaural electrostatic
Impedance: N/A (Closed Electrostatic System)
Sensitivity: 94dB SPL at -10dB full-scale digital input and 75mV analog input (the EN50322 specification)
Weight: 10.7 oz.
Price: $4995 (sold as system with M1 energizing amplifier/DAC)
M1 Headphone Amplifier
Type: Discrete FET, single-ended Class A solid-state
Outputs: 1x headphone connector for M1 headphones
Dimensions: 7.48" x 2.24" x 11.42"
Weight: 5.40 lbs.
Price: $4995 (sold as system with M1 electrostatic headphones)