Grado Reference Series RS-1 Headphones
Bringing about infectious enthusiasm.
Review By Dick Olsher
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  Grado Labs, an iconic name in the annals of American audio, celebrated its 50^th anniversary in 2003. John Grado, the nephew of founder Joseph Grado, has been at the helm since 1990 of what has steadfastly remained a family business. Its early years coincide with the Golden Age of audio. My copy of the 1959 Hi-Fi Buyer's Guide already lists five Grado products including a stereo phono cartridge with a frequency response of 10Hz to 35kHz per channel at a huge (for its day) price tag of $49.50. Since then the Grado name became synonymous with cost effectiveness and musicality in two specific niche markets: phono cartridges and headphones. Who hasn't owned a Grado phono cartridge sometimes in their audio life? And the affordable SR60 and SR80 phones have turned out to be a commercial hit. My current phono system incorporates the Grado Reference cartridge. And for the record, I've lived with a pair of the SR80 phones for many years.

So why focus now on the RS-1, a product that has already been the subject of numerous reviews and accolades? For me it represents a personal listening progression, following in the footsteps of the SR80 to see just how far its sound could be improved upon. The improvement in materials is most obvious: ear pads are thicker, and most notably, the transducer chambers are crafted from selected mahogany that undergoes a complex curing process. A low-mass polymer diaphragm is coupled to a high-purity, long-crystal copper voice coil. The diaphragm mass and compliance are tuned to minimize resonances within the audible bandwidth and provide for an extended bass response. A common thread is the application of powerful neodymium magnets for increased efficiency and low weight. Each pair of transducers is said to be matched to 0.05dB. Overall weight is a mere nine ounces. The RS1 rests comfortably against the ear, but in common with the SR80 I could not generate sufficient tension in the headband to couple the pads to my ears with the level of tightness I prefer.

Technical Stuff
Materials do make a difference. I am reminded of a paper authored some 25 years ago by Ingo Titze, then chairman of the Wendell Johnson Speech and Hearing Center at the University of Iowa that examined the human vocal tract from a materials science perspective. He argued (in slightly paraphrased form) that “the human larynx is made of materials that vary considerably with time, temperature, and biochemical composition, … and even fails to obey Hooke's law; the stress-strain curves of vocal fold tissue being quite nonlinear.” He felt that given these facts, “the larynx as a musical instrument would appear to be in the class of a plastic ukulele with rubber strings, and control of such an instrument to maintain accurate pitch and consistent quality would seem to be a formidable problem.” Acoustic transducers certainly do not suffer from such limitations. In particular, headphones have always enjoyed an advantage over loudspeakers in terms of linearity and greatly reduced distortion levels. The fact that they sit on or over the ear makes for greatly reduced drive requirements. A fraction of a watt is sufficient to drive many phones to excruciating sound pressure levels. In fact, John Grado warns against extended listening at very loud levels, which "could seriously impair your hearing."

By virtue of leaking sound into the ears, headphones bypass the route followed by an external sound source. Shadowing effects of the head and external ear produce Left-Right time delays and cross-talk differences that allow the auditory system to project an external soundfield by analyzing the incoming sound stream. This so called head-related transfer function is missing in action during headphone listening with the result that sound is typically localized inside the head. The auditory system literally has no clues as to where the sound is coming from and defaults localization to the space between your ears. Of course, I'm describing the sensation associated with listening to ordinary stereo program material on headphones. Binaural recordings produced with microphones embedded in one's own ears or in an artificial head can produce a spectacular your-are-there sensation when played back over most headphones. But since binaural recordings are rare, headphone aficionados have to cope with ordinary stereo.

Sonic Performance
The RS-1 was driven by the Antique Sound Lab MG-32DT amplifier for all critical listening tests. Not surprisingly, the ASL's low-impedance setting worked best, considering the RS1's nominal impedance of 32 Ohms. The ASL is currently my favorite cost-effective headphone amplifier and its tube qualities nicely complemented the RS1's strong sonic attributes.

Let us start with imaging and soundstage presentation. There's no way an ordinary (non binaural) stereo recording can sound totally natural through headphones. Fortunately, Grado Labs headphones cope better than most designs with the soundstaging issue. A feature common to all Grado headphones is the vented or open-air rear chamber. I have already mentioned its role in minimizing resonances and extending bass response, however, it also plays a crucial role in expanding the perceived soundstage somewhat outside the head. It seems to me that the sound leaking out of the open back provides a cross talk signal to the opposing ear, thereby broadening the apparent soundstage width and depth perspectives. Some headphone makers have offered electronic boxes with a blend control to allow cross feeding of the L-R channels toward mono in order to reduce in-head localization. It would appear that the Grado designs use acoustic means to accomplish such a result, thereby reducing the artificiality of the headphone experience. For me, the Grado headphone presentation is much more natural and conducive to extended listening relative to a conventional design such as the Sennheiser HD600. I find the latter's strong inside the head impression to be simply annoying. On the other hand, the HD600 managed to more tightly focus image outlines; the RS1 sounding a bit more diffuse. Overall, the RS1's ability to dish out an organic soundstage proved to be the deciding factor in my long-term musical enjoyment.

Overall distortion levels were quite low, and in this respect the RS1 easily exceeded the performance of the SR80. In other words, the RS1was considerably smoother sounding and on this basis alone justified the price differential. In terms of tonal balance, it would be fair to say that neutrality is nudged aside in favor of verve – or what John Grado refers to as the FUN factor in music. I am referring to the intrinsic energy and enthusiasm of the original performance. This the RS1 displayed in spades. Dynamic nuances were unfolded with speed and conviction. There was mucho charisma in the midrange, which was voiced on the lively side of reality, assisted by a slight upper midrange-presence region emphasis. The combined effect was to catapult musical lines forward. The warmth region, closely associated with the upper bass range (160 to 320 Hz), was full and slightly lush sounding, very much in line with vintage tube sound. With a robust warmth region and midrange for a foundation, harmonic colors were convincingly fleshed out. The midbass (80 to 160 Hz), however, only managed to sound middleweight instead of heavyweight. Note that squeezing the ear pads against my head greatly improved the bass balance. Of course, head size is a major variable; for me, however, a tighter headband would have been most helpful.

The treble range was well extended and transients were free of resonances. Despite the perceived presence region accent, there was no obtrusive brightness or glare to interfere with soprano voice or violin overtones. There was a high level of coherence about the sound. It's easy to forget that most headphones are full range transducers without intermediate crossover networks. I think that much of the appeal of phones over loudspeakers has to do with their full range presentation that contributes to a heightened sense of immediacy. Granted, taking the room out of the equation is also a major factor. It is by now well know that over half the sound energy at a listening seat in an average domestic environment is due to room reflections. That's one reason recording engineers rely on headphones as much as they do during a session, for the added clarity phones afford, though most actually prefer to balance and EQ a multi-track project using studio monitors.

Bottom Line
If you're looking for headphones to enjoy the music with, the Grado RS1 adds up to a resounding no-brainer recommendation. Some refer to it as foot tapping, or pace and rhythm, I prefer the term kinetic energy. Whichever term resonates with you, be aware that the RS1 brings all of the above to the musical table. Its brand of infectious enthusiasm, yet smooth and organic presentation, define the essence of the Grado sound. Let it be know far and wide – I'm proud to be a Grado customer!

Specifications
Type: Stereo headphones

Transducer Type: Dynamic

Frequency Response: 12Hz to 30kHz

Sound Pressure Level: 98 dB re. 1mV

Nominal Impedance: 32 Ohm

Price: $695

Company Information
Grado Laboratories
4614 Seventh Ave.
Brooklyn, NY 11220

Voice: (718) 435-5340
Website: www.gradolabs.com