Grado SR125 Headphones Review

Grado Laboratories of Brooklyn, New York, is one of the handful of audio manufacturers that have retained their original family ownership and quality standards for over forty years. Founder Joseph Grado, the inventor of the moving-coil stereo phono cartridge, later turned his talents to designing other audio products, including tonearms, turntables, and stereo headphones. Many Grado products, most notably the headphones and phono cartridges, have achieved wide recognition among serious audiophiles.

The current president and owner of Grado Laboratories, Joe’s nephew John Grado, led the development of the company’s recently introduced Prestige Series of affordable, high-quality headphones, consisting of five models priced between $69 and $295. They share the same basic design and performance characteristics, differing slightly in their driver level matching and the specific materials that are used in their construction.

The Grado SR125’s price places it in the middle of the Prestige Series. Its earpieces contain dynamic transducers whose voice coils are wound with ultra-high-purity long-crystal (UHPLC) oxygen-free copper wire. Grado says the use of UHPLC copper minimizes coloration and produces the finest sound quality. The transducers are of the open-air type, with light foam earcushions that rest comfortably on the wearer’s ears but provide little isolation from ambient sound.

The low-mass polymer transducer diaphragm is formed to broaden its resonant modes and minimize their amplitude. The diaphragm is vented into a relatively large air chamber to reduce its resonance frequency and extend its bass response. The back of the chamber opens to the outside through a perforated plate. Grado rates the SR125’s response as 20 Hz to 20 kHz (no tolerance specified). The levels of the two drivers are said to be matched to within 0.1 dB. Powerful neodymium magnets are used for maximum efficiency.

The headphones’ foam-plastic earcushions are removable for cleaning. The comfortable spring-type headband is easy to adjust for size and is clearly marked to identify the left and right earpieces. The 6-foot connecting cable is fitted with a gold-plated standard quarter-inch stereo plug.

We measured the performance of the Grado SR125 phones mounted on a standard headphone coupler whose internal volume approximates that of the external human ear, with a Briiel & Kjaer 4133 microphone about 3/8 inch from the plane of the earcushion. The input signal was supplied by our Audio Precision System One, which also analyzed the microphone output.

The headphone’s acoustic output, measured with a sweeping one-third-octave band of random noise, was greatest at the lowest frequencies, very flat through the midrange, and fell off above 20 kHz. The overall variation was only +4, -5 dB from 20 Hz to 10 kHz, falling to -10 dB at 16 kHz. Referred to the 1-kHz level, the output was about +4 dB from 30 to 150 Hz, and between 350 Hz and 3 kHz the variation was less than 0.5 dB.

We measured the distortion in the SR125’s acoustic output across its frequency range with a constant input level of 1 volt. Between 100 Hz and 20 kHz the total harmonic distortion plus noise (THD+N) was typically 0.8 percent, reaching its maximum of 1.5 percent at 100 Hz. A spectrum analysis of the distortion from a 1-volt, 1-kHz input showed only a single component at 3 kHz, 60 dB down (0.1 percent). Grado’s impedance rating of 32 ohms was confirmed by our measurement, which showed only minor variation, between 31 and 36 ohms, from 20 Hz to 20 kHz.

The sound character of the Grado SR125 phones was closer to that of a good speaker system than to that of most headphones I have used in the past. The SR125 had a smoothness and balance across the audible range that I have rarely (if ever) experienced from headphones. Its reproduction of low-bass frequencies was strikingly good, far surpassing in clarity and dynamic range almost all speakers I have tested or heard (even test tones at 20 or 30 Hz sounded cleaner and better than I have heard from any but the best subwoofers).

Unfortunately, good as it is, neither the Grado SR125 nor any other headphone provides the infrasonic body massage that can come from a good bass loudspeaker in a good listening room. Headphone and loudspeaker listening are two very different experiences, each with its advantages and disadvantages. That is particularly true in the deep bass (below about 40 Hz), which we experience as much by the overall “feel” as by the sound.

Still, in its own realm the Grado SR125 is a real winner and an excellent value. I cannot imagine a better sounding headphone at anywhere near its price. I do not, however, accept the premise that the use of UHPLC copper for the voice coil has the slightest bearing on the SR125’s superb sound. My hunch is that Grado simply knows how to design and build a first-rate headphone — good enough that, in comparison with most other high-end phones, its performance might almost be interpreted as magical.

That conclusion was reinforced by my memory of my first meeting with Joe Grado some forty-odd years ago, when he demonstrated, to my amazement, his unique talent for creating some of the best-sounding phono cartridges of the time (or future times, for that matter). Apparently John Grado shares his uncle’s talent.

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