Professional, Statement, Reference and Prestige series
All Grado headphones (except the models of the In ear series) have a vented diaphragm design that incorporates a large air chamber. This design concept lowers the frequency resonance (distortion) of the diaphragm and extends bass response. The diaphragm is made of a low mass polymer, carefully formed to broaden resonant modes to reduce their amplitude. The diaphragm mass is determined with the compliance of the suspension in mind so that the desired low frequency resonance is achieved. The diaphragm's total mass is calculated to provide a full 20 KHZ bandwidth, while avoiding break-up at lower frequencies.
The Professional, Statement, Reference Series and along with the Prestige Series SR325is, SR225i and SR125i feature voice-coils that are wound from ultra-high purity, long crystal (UHPLC) oxygen free copper. The copper is slowly drawn through the die in extremely small increments and is annealed following each drawing operation. Ultra-high conductivity copper yields the clearest transmission and lowest coloration possible. The sound of UHPLC copper is smoother, cleaner and more dynamic. All use very high power neodymium magnets to provide maximum efficiency and better sound. Each headphone driver is made to Grado's high standards, then pair-matched for exact imaging. These headphones also utilize UHPLC copper in the connecting cable.
All metal work for the PS1000 and SR325is is machined from a special non-resonant, very hard alloy. Grado utilizes a special processing method to increase the material's porosity. This complex treatment insures that the earphone chamber has no "ringing" which might obscure detail or add coloration.
Grado's wooden Statement and Reference Series are hand-crafted at our labs from a new specially selected species of jarah. An intricate procedure of curing is done between production steps to achieve optimal sonic quality. The overall sound remains pure Grado, warm harmonic color, full bodied vocals, excellent dynamics and an ultra smooth top end.
Technical refinements for Grado drivers include improved diaphragm and voice coil design for increased bass response and a larger perceived sound stage. A unique process to "de-stress" the diaphragm results in enhanced inner detail. An increased ability to control driver resonance virtually eliminates distortion. For all models, an improved headband spring will afford greater comfort for the majority of listeners.

Earphones: In ear series
Contrary to the above series the In ear models do not have their own chambers, they will use your ears to function properly. The transducers are extremely small: so small that they can easily fit inside the ear, they also have a tremendous side benefit: they will (if properly fitted) drastically cut down ambient noise. If the earphone is not properly fitted and the ear canal 2 problems will arise:

The transducers are very efficient, they were, for many years used in hearing aids but a recent improvement of their quality makes them perfectly adequate for serious listening of music.
The operating principle is called "balanced armature".
Here is a description borrowed from Wikipedia.
"A balanced armature is a sound transducer design primarily intended to increase the electrical efficiency of the element by eliminating the stress on the diaphragm characteristic of many other magnetic transducer systems. It consists of a moving magnetic armature that is pivoted so it can move in the field of the permanent magnet. When precisely centered in the magnetic field there is no net force on the armature, hence the term 'balanced.' As illustrated in the second diagram, when there is electric current through the coil, it magnetizes the armature one way or the other, causing it to rotate slightly one way or the other about the pivot thus moving the diaphragm to make sound.

BalancedArmatureTechnology cccBalancedArmatureTechnologyA

GRADO headphones can reproduce as natural a soundstage from stereo recordings and provide as much listening pleasure as a good pair of speakers do. GRADO headphones are free of room effects and placement problems, and they minimize any interference from external noise. They also offer portability and the ability to listen without worrying about the neighbors. With GRADO headphones, you will hear recordings with greater clarity and with deeper bass than others! GRADO headphones are the antithesis of mass production, as each GRADO headphone is hand-assembled and closely scrutinized to meet full performance specifications.



All GRADO cartridges now use a derivation of the moving iron principle which features patented OPTIMIZED TRANSMISSION LINE cantilever technology, PIVOTED FIXED AXIAL STYLUS-GENERATOR MODULE, and GRADO's FLUX-BRIDGER GENERATOR SYSTEM.

GRADO's OTL provides an ideal transfer of the signal from point to point, e.g., stylus to cantilever to magnet to coils, etc. This has been achieved by eliminating resonance at each of these key junctions. The transmission line cantilever consists of separate sections that are telescoped into each other. All sections are made of different alloys, some sections hollow, other sections solid. These sections are bonded together with materials that act as dampers, and are coated with a black proprietary material which controls and absorbs resonances that travel on the surface of the cantilever (known as skin effects). The OTL stylus/cantilever design will make your records sound quieter, improve the height, width, and depth of the soundstage, and offer more detail than previously obtainable. Cartridge Holography does exist...and that is what GRADO’s OTL technology is all about, more performance.

This design feature is basically quite simple. The "OTL" cantilever shaft is brought to a fixed axial pivot that supports the entire cantilever assembly. A miniature element attached to the end of the cantilever is allowed to move freely within the lines of flux of a stationary magnet and coil structure.


A. Styli
B. Cantilever
C. Miniature Generating Element
D. Armco Iron Disc
E. Rubber Grommet
F. Stylus Assembly Housing
G. Generator Pole Pieces
H. Fixed Axial Pivot

This system of support is mechanically more accurate (more linear) than conventional "teeter-totter" designs that utilize an iron armature to balance the mass of the cantilever. The teeter-totter design is supported in the center with a rubber donut mounting.

The fixed axial design has a very low tip mass, which results in lower distortion, improved transient response, and longer record life.

This proprietary design allows the implementation of the Flux-Bridger Generator System!

The Flux-Bridger design uses four separate magnetic gaps that the miniature element of the cantilever bridges. The miniature element moves between opposing flux gaps creating an increase in flux in one gap while reducing it in the other. The four separate magnetic gaps create a highly efficient and perfectly balanced system. This design requires fewer coil turns than conventional designs.

Fewer coil turns allow GRADO cartridges to have lower mass and lower electrical inductance, making them insensitive to tone arm cable capacitance. The four gap design is perfectly balanced and eliminates magnetic residue which contributes to increasing distortion over longer time periods. GRADO cartridges reduce distortions that cause listeners fatigue.

Each individual cartridge manufactured by GRADO is hand assembled and tested for frequency response, channel output, channel balance, phase linearity, inductance and resistance. This meticulous care in design and construction lavished on each GRADO cartridge contributes to an unchallenged consistency of performance and guarantee of reliability.

The Prestige series of cartridges are designed for high output and excellent stability under severe use. A considerable tip mass reduction results in a frequency response to 50 kHz and beyond and tracking forces from 1-2 grams. Acclaimed by experts as virtually the finest pickups in the world at their price.

Prestige models available in both 1/2" mount and P-mount. All styli in the Prestige series are user replaceable.

These series of wooden cartridges are a fixed coil design, hand-crafted at our labs from a specially selected species of Australian jarrah. An intricate procedure of curing is done between production steps to achieve optimal sonic quality. Unlike the Prestige series, these series generator/stylus module is not replaceable allowing a redesigned one piece magnetic circuit and a reduction of chassis resonances. The Statement and Reference series utilizes manufacturing and assembly techniques of fantastic accuracy and precision, the result is virtual perfection in a phono cartridge resulting in the finest cartridges in the world without exception. Should be used only with the finest equipment. Recommended tracking force 3/4 to 2 grams.

All wooden series cartridges are 1/2" mount. 78 RPM styli are not available with these series. All re-tipping on the Statement and Reference series will be done by GRADO.

Updated: August 2014