Considering the apparent simplicity of playing a record and the sheer scope it offers when it comes to innovation and Heath-Robinson engineering, it’s remarkable how few new ideas have really stayed the course. Linear tracking tonearms remain, as do direct drive motors (recently enjoying a resurgence), but it’s remarkable just how many new record players represent a refinement or amalgamation of older thinking. Even the once omnipotent suspended sub-chassis seems to have had its day. Perhaps it reflects the fact that the engineering was indeed all too Heath- Robinson, a fact readily revealed by a problem that demands a pure engineering solution. Or perhaps it is the result of a lack of global thinking, in the sense that too many products offered solutions to a single problem rather than reflecting the all embracing and conflicting nature of the challenges. However, there are two obvious exceptions to this rule, and both attract small but vociferous and dedicated followings. One is Bill Firebaugh’s Well Tempered Arm and ‘Table, in all its various iterations. The other is the Rock…
Of course, the Rock isn’t a single turntable, just as there are various Well Tempered designs. Indeed, the various Rocks differ in almost as many ways as they possibly can, from solid plinth to suspended designs, universal motor units to integrated record players. But the one thing they all have in common, the thing that divides opinion into the pro and anti lobbies and in many respects, the thing that dominates the nature of their performance and musical presentation, is the front-end damping trough. That variation in design tells its own story: for every engineering challenge represented by a turntable or tonearm, there’s more than one solution – save one. Critical damping of the tonearm/cartridge resonance can only be achieved by applying that damping as close as possible to the source of energy, and that means the stylus record interface. That in turn dictates some form of front-end damping arrangement and nothing yet has superceded the fluid filled trough. “But why the fuss?” I hear you ask. After all, there’s plenty of wellregarded tonearms that use minimal damping applied at the pivot or no damping at all.
Interesting to note then, that that other great turntable innovator, Bill Firebaugh damped his entire tonearm tube with sand and effectively immersed the main bearings in a silicon-oil damping well. For controlling resonance in the pickup arm is one of the great, unsolved conundrums of record replay.
Look at it this way. Move the stylus and that movement is detected by the magnetic circuit contained in the cartridge body and thus produced as signal. But that signal depends on the movement of the coil relative to the stationary magnet (or vice versa in a moving magnet cartridge) so an accurate transcription depends on holding that magnet stable. But as the stylus is moved sideways by the record groove modulations, it will tend to drag the cartridge and tonearm in the same direction, creating inaccuracy in the signal: This is why designers refer to the closed loop between platter, arm and cartridge and place such emphasis on the rigidity of their arm bearings. And yet, herein lies the biggest conundrum of all.
The arm must dissipate mechanical energy that would otherwise move it in sympathy with the stylus and it must do so without creating dominant resonant peaks that would themselves be read as signal. Yet at the same time, it must allow the cartridge and stylus assembly the freedom to read microscopic variations in a groove and trace those grooves across the surface of the record, making lateral or vertical friction absolute killers when it comes to accurate reproduction.
You can tackle these issues in a number of ways involving the structure of the arm and its physical arrangements, moving potentially harmful resonance outside the audible band, damping the structure of the arm itself. But the fact that the Rock sounds so different to other turntables tells its own story.
The Rock solution is to place a fluid-damping trough right next to the cartridge, allowing slow, gradual movement, but resisting faster or more sudden deflections. At the same time it effectively offers a far shorter route to close the mechanical loop between platter and cartridge. You just need to remember that damping one end of the arm will encourage the other end to flap about, so you can’t afford to skimp on the bearings there, even if the frontend damping carries some of their load. Once you’ve engineered the practicalities of the design (allowing the trough to move for placing and replacing records, fixing the arm’s arc of travel and thus effective length) the rest of the deck can rely on established engineering principles. As I’ve already suggested, these have varied over the years, dictated by price and technology as much as anything else. However, to real understand the Rock V, we need to look at the stillborn Mark IV, or Rock Reference Master.