Over recent years, our online guides have created an extensive encyclopedia of audio terminology. We decided to bring these disparate dictionaries of audio terms together for the first time. This exhaustive guide is the result.

While the days of trying to baffle people with terms only the cognoscenti know are (hopefully) behind us – many readers might recall the patronizing salesman in the ‘Grammo-phone’ sketch from Not The Nine O’clock News in the early 1980s – this is still a terminology-led industry, and knowing the terms is a good idea if we are to be able to recognize how components might conceivably be different, and why.

While it’s important not to get too hung up on the terminology – we are in an industry where observed performance should always remain more important than specifications – knowing the difference between a ported loudspeaker and a sealed-box loudspeaker is important and knowing that a sealed-box loudspeaker and an infinite baffle design are basically one and the same is important, too.

ANALOG AUDIO TERMS

This brief section is intended for those who have little or no experience with analog audio and are eager to learn the basics. Treat this information as a set of foundational building blocks you can build upon later on.

JUST THE (ANALOG) BASICS

LPs, Records, ‘Vinyl’, or ‘Vinyls’

The whole idea behind analog audio is to achieve musically satisfying playback of vinyl phonograph records. Records are sometimes also called LPs (for ‘long play records’) or called ‘vinyl’ by the older generation or ‘vinyls’ by the younger buyers (as in, “I picked up some great new vinyls at the record shop today”). Vinyl LP records are relatively thin, flat vinyl discs, almost exactly 12-inches in diameter, with music—captured in the form of undulating grooves—pressed into their front and back sides. Traditionally, LPs rotate at 33 ⅓ RPM, although an increasing number of audiophile pressings now include multiple 45 RPM records, treating the LP as if it were a collection of 12” singles. In contrast, the single has commonly spun at 45 RPM and was often sold as either a 7” or 12” record. A small number of 10” extended play (‘EP’) records have also been produced, but – like the single – are rarely pressed today. By convention, the spiraling grooves in the record surface start at the outer rim of the record and move inward toward the record’s center. When the last piece of music on the record side is complete, the groove—no longer containing music—spirals inwards a bit further to a so-called ‘run-out groove’ where the stylus of the phonograph cartridge quietly rests, waiting to be lifted from the groove when the listener is ready either to turn the record over or to shut off the playback system.

Critically Important LP/Record Factoids

Staying within the (Straight) Lines: Masters lacquers for vinyl records are made on record cutting lathes where the lathe’s cutting head travels in a straight line from the outer rim toward the center of the master disc. In an ideal world, we would want the styli of our phono cartridges to follow this exact same straight line during playback, so that the phono cartridge/ stylus would remain perfectly tangent to the record grooves at all times. In practice, though, it is rarely possible to achieve true straight-line motion or perfect stylus-to-record-groove tangency at all times, so that engineers must create compromise solutions that position the phono cartridge stylus so that it remains nearly tangent to the record groove, most of the time.

Spacing Out: The spacing between record grooves is not constant, as some suppose. If you think about it, quieter musical passages require only very low amplitude modulations in the record grove, whereas loud and dynamic passages require groove modulations so high in amplitude that they are sometimes visible to the naked eye! Given this, record-cutting lathes can vary groove-to-groove spacing to allow for the dynamic swings that inevitably occur in music. This means that as the tonearm, phono cartridge, and stylus play the record from the outer edge to the innermost groove, their lateral motion is not absolutely constant, but rather varies in response to groove spacing variations.

Record Players

Some listeners (especially newcomers) sometimes use the informal term ‘Record Player’ to describe a complete record playback system, including a turntable, tonearm, and phono cartridge. However, audiophiles almost always discuss these playback components individually, as each has a separate role to play.

Turntables

Turntables are the devices we use to play or ‘spin’ vinyl records. The turntable’s job is to both support and rotate the record at a precise speed (typically either 33 ⅓ RPM or 45 RPM) during playback, while contributing as little noise and as few speed fluctuations as possible. (The human ear is extremely sensitive to speed fluctuations, because they translate directly into musical pitch fluctuations.) Some people use the word “turntable” to mean the whole record player assembly, but most serious audiophiles use the term to refer only to that part of the record player that is responsible for spinning the record.

Phono Cartridges

Phono cartridges are the devices tasked with ‘reading’ or tracking the grooves in the spinning record and then converting the physical movements involved in tracking the grooves into electrical signals that can be amplified for playback in our hi-fi systems. Phono cartridges have three basic elements: a stylus, a cantilever, and a motor (or signal generator mechanism) of some type. The stylus is the part of the cartridge that makes physical contact with the record groove and tracks the undulations in the grooves. Styli (the plural of stylus) are almost invariably made of extremely small, precisely shaped, and finely polished diamonds. The cantilever is a miniature rod or tube that forms a connection between the stylus and whatever type of electrical signal generator or motor the cartridge happens to use. The cantilever is typically supported by a flexible suspension system that serves double duty as both a ‘spring’ that supports the cartridge and as a damper to help control the motion of the stylus/cantilever mechanism. The motor of the phone cartridge translates the movements of the stylus in the record groove into an electrical signal that is analogous and proportional to the music encoded in the record grooves.

Tonearms

The tonearm’s job is to position the cartridge over the surface of the record and to hold the cartridge in place while the stylus is tracking the record grooves. This description sounds straightforward enough until you consider that the tonearm’s design brief can at times seem like a contradiction in terms.

For example, we want the tonearm to hold the cartridge’s body (or outer shell) almost perfectly still as the stylus, cantilever, and signal generating mechanism rapidly move in response to the groove modulations in the record. But at the same time, the tonearm cannot and must not hold the cartridge body in a rigidly fixed position; on the contrary, the tonearm must allow the cartridge freedom of movement in both the vertical (up and down) and horizontal (left and right) axes. These degrees of freedom of movement are necessary for three reasons.

First, tonearms must allow the phono cartridge to move so as to stay centered directly above the inwardly spiraling record grooves. Second, tonearms must allow cartridges to deal with the fact that many records are at least slightly eccentric, meaning the inward spiral of the groove is not necessarily smooth and continuous. Sometimes, listeners encounter records that require the tonearm to swivel back and forth (from left to right) as the record rotates, even if only very slightly. Third, many records are at least slightly warped, meaning the tonearm must allow the cartridge to move up and down to maintain a stable position relative to the surface of the record—a surface that, when viewed from the side, may at times appear to be ‘bobbing’ up and down as the record rotates.

Stated simply, the mission of the tonearm is to hold the cartridge in a stable position relative to record groove, while at the same time allowing the cartridge freedom of movement where necessary.

MORE ADVANCED ANALOG TERMINOLOGY

Anti-Skating Systems/ Skating Forces

The majority of tonearms on the market today are pivoted, non-tangential designs and the geometry of such arms makes for a condition where the cartridge stylus tends to be pulled inward toward the center of the record. This inward pull is called skating, and its result is that there is more stylus pressure on one side of the record groove than the other.

Ideally, we would want equal pressure on both sides of the record groove and to achieve this result many tonearms feature so-called anti-skating mechanisms that apply a compensatory force that is intended to offset skating forces.

Note that skating forces can and do vary with the amount of tracking force applied to the stylus, and also vary from one stylus shape to another (because styli of different shapes may have more or less ‘drag’ within the record groove). For these and other reasons, setting anti-skating forces is not an exact science and in fact some manufacturers advise against applying any anti-skating forces at all. In any event, adjustments to anti-skating force should—as with everything else in high-end audio—be verified by ear.

Arm Lengths/Stylus-to-Pivot Lengths

Phono cartridges mounted in pivoted tonearms move in an arc over the record and by following an arc the cartridge/stylus can achieve true tangency to the record groove at two points per record side. But at all other points the cartridge/ stylus assembly will experience some degree of tracing error, meaning the stylus will be just slightly askew to the ideal tangent-to-the-groove position.

This is where tradeoffs come into play and tonearm length looms large as a design variable. Generally speaking, the greater the length of a pivoted tonearm the lower its geometric tracing error will be—provided other length-induced design tradeoffs can be properly managed. However, increasing tone arm length is not a panacea, because longer tonearms may have potential problems with structural rigidity, unwanted resonance, cumbersome size, and excess mass.

These days the most common tonearm length is in the range of 9-inches from the pivot point to the stylus—a length that offers a good set of compromises in terms of structural rigidity, relative freedom from resonance, manageable mass, ease of handling, and reasonable physical size. At the same time, designers and listeners recognize that longer tonearms can and do reduce tracing error (because their arc shaped travel paths more closely approximate the theoretically ideal straight lines). For this reason, the analog world has in the past several years seen a resurgence of interest in 10-inch and 12-inch tonearms, with at least one manufacturer offering a turntable fitted with a 14-inch tone arm!

Azimuth

Azimuth refers to the degree of left/right tilt of the phono cartridge stylus as it rests in the record groove, where the ideal is for the stylus to be positioned exactly vertically in the record groove as viewed from the front.

One tricky factor, however, is that there is no guarantee that the stylus is perfectly aligned relative to the phono cartridge body, meaning that technically correct azimuth alignment might in fact require the cartridge body to be tilted just slightly to the left or right.

Not all tonearms (and especially not many inexpensive tonearms) offer provisions for making azimuth adjustments, but many mid and upper-tier tonearms do. Many enthusiasts have discovered that a very useful and simple tool for setting azimuth is a device called the Fozgometer (named for the veteran audio designer Jim Fosgate), which can used in conjunction with a set of recommended test records to check, revise, and adjust azimuth settings. It is also possible to use a test record and an oscilloscope for precision adjustment of azimuth, although this requires a considerably higher degree of user expertise… and the purchase of a test record and an oscilloscope!

Are the benefits of proper azimuth alignment audible? In high-resolution systems they most certainly are, making for a heightened sense of focus, clarity, and freedom from mis tracking on complicated musical passages.

Cartridge Overhang & Alignment/ Cartridge Adjustment Protractors

As stated above, the theoretical ideal would be for the phono cartridge stylus to move across the record surface following the same straight-line path followed by the record cutting head when the original master lacquer for the record was made.

The majority of turntables are fitted with pivoted tonearms that cause the phono cartridge/ stylus to swing in an arc across the record, rather than following a true straight-line path. Since an arc can only intersect a straight line at two points, the stylus can only achieve perfect stylus-to-groove tangency at two points on the record, meaning it will be slightly out of tangency at all other points on the record. To achieve best results with pivoted arms, two adjustments are critical: cartridge overhang (the exact distance from the arm pivot to the stylus) and cartridge alignment (the left-to-right angle of the cartridge relative to the tonearm and the record).

To help users adjust these two variables, many manufacturers offer cartridge alignment protractors, which are designed to slip over the turntable spindle and to rest temporarily on the turntable platter. Protractors provide markings that show where the stylus should be positioned in terms of overhang (X marks the spot) and that show how the cartridge/stylus should be aligned.

To use such protractors, listeners first loosen the fixing screws for their cartridges, then gently and carefully move the cartridges fore and aft and from left to right, following a gradual trial-and-error process until the desired overhang and alignment positions are achieved. Once the cartridge is correctly positioned, the fixing screws can be tightened to lock the cartridge in its properly aligned position.

Note that so-called straight-line or tangential-tracking tonearms also require overhang and alignment adjustments, but with the important difference that, once properly adjusted, they maintain perfect stylus-to-groove tangency across the entire record surface.

Cartridge Suspension & Dampening Systems

As noted above, the stylus/cantilever/motor assemblies used in all phono cartridges require some sort of suspension system, which in most cases will also double as a dampening system or ‘shock absorber’ of sorts. Many designs use either an elastomer ring or suspension block for this purpose, and as you may surmise the exact dimensions and compositions of these suspension/dampening elements are critical to performance.

If the suspension of the cartridge is too stiff or over damped, compliance will be reduced, and resonance problems may be introduced. On the other hand, if the suspension is too soft or under damped, compliance will be too high, and other types of resonance problems may arise (not to mention the potential problems of increased fragility and possible cartridge collapse). For obvious reasons, then, the idea is to achieve a carefully judged blend of appropriate compliance levels and damping characteristics that best suit the intended playback application.

It is worth noting that, in some moving coil cartridges, designers sometimes add a supplementary suspension/damping ‘tie-wire’ at the rear of the cantilever assembly to provide additional support and resonance control.

Cartridge Types

Phono cartridges tend to be classified by the types of signal-generation systems or ‘motor’ mechanisms they employ.

Moving iron & moving magnet: Moving iron and moving magnet cartridges are conceptually similar. In both cases, either a small magnet (moving magnet) or small ferrous metal tip with adjacent stationary magnets (moving iron) is fitted to the cartridge cantilever and positioned near a set of stationary coils of wire. As the stylus tracks the groove, the magnet or ferrous metal tip (acting as an induced magnet) is set in motion and generates a voltage in the cartridge’s signal coils. In most but not all cases, moving magnet and moving iron cartridges are considered high output designs and therefore should be used with phono stages that have a standard gain, moving magnet (“MM”) phono input.

As a general rule, moving iron cartridges are thought to offer better transient response than moving magnet designs, because their ferrous metal tips are lower in mass than equivalently sized magnets.

Moving coil: As their name suggests, moving coil cartridges feature cantilevers typically fitted with tiny cruciform frames around which are wound coils of wire positioned near sets of stationary magnets. As the stylus tracks the groove, the cruciform frame and coils are set in motion (within a fixed magnetic field), thus generating an audio signal. In the majority of cases, moving coil cartridges are considered low or mid-level output designs and therefore should be used with phono stages that have a high(er) gain moving coil “MC” input.

As a general rule, moving coil cartridges are thought to offer superior transient speeds and higher levels of detail than moving iron/ magnet cartridges, because their moving coils of signal wire are considerably lower in mass than moving magnet or moving iron signal generators. However, this theoretically superior performance comes at a price.

Generally speaking, moving coil models are more complicated to build and more costly to make and to buy than moving magnet/iron equivalents. Some moving coil models are prone to high-frequency resonances, which means designers must pay extra attention to damping schemes to mitigate potential problems. Finally, moving coil models typically require more costly high-gain/low-noise phono stages. With all this said, however, the majority of today’s top-tier phono cartridges are moving coil designs.

Optical: Optical phono cartridges use an optoelectronic mechanism to modulate a voltage supplied from an external power supply/ equalization box. In typical optical designs, which at this point are comparatively rare, the cartridge cantilever is fitted with a tiny light-permeable screen. When the stylus moves in the record grooves, the screen moves in response. An LED illuminates the screen, while an opto-electronic photodiode sensor located behind the screen ‘reads’ the light (as modulated by the moving screen) to produce an output signal.

Two theoretical advantages of optical cartridges are that their moving mechanisms are very low in mass, making for excellent clarity and transient speed, and they can in principle be very low in noise. One potentially significant drawback, however, is that they must be used with their own companion power supply/equalization boxes, which also serve in lieu of traditional phono stages.

Strain Gauge: Strain gauge-type cartridges are based—you guessed it—on strain gauges, which are flexible materials whose resistance to current flow changes as the materials expand and contract. In a stereo strain gauge cartridge, the cantilever is connected to two such strain gauges, with the strain gauges typically serving as both the suspension for the cantilever/stylus assembly and as the signal modulation mechanism.

Like optical cartridges, strain gauges require an external power supply box, but interestingly they do not require traditional RIAA equalization; this is because—unlike moving magnet, iron, or coil designs—strain gauges are not velocity sensitive transducers (where the signal depends upon how fast the stylus is moving), but rather are displacement-sensitive transducers (where the signal depends upon how far the stylus moves).

Advantages of strain gauges include the fact that their moving mechanisms are very low in mass and that their stylus/cantilever assemblies are directly and mechanically connected to the strain gauges that modulate their output signals. Three possible drawbacks are that strain gauge cartridges are costly to manufacture and to buy, are thought to be comparatively fragile, and they require use of a dedicated external power supply box.

Counterweights

Moveable counterweights are used at the back ends of tonearms, primarily to balance the arms once phono cartridges are installed, but also—in some but not all designs—to apply tracking force on the stylus. Also, for some unipivot tonearms, counterweights are deliberately eccentric in shape, so that the weights not only can move fore and aft, but also can rotate side to side for purposes of making azimuth adjustments. Typically, counterweights are made of relatively dense materials such as brass or, in some instances, even tungsten.

Headshells

The headshell is that element of the tonearm to which the phono cartridge is affixed, and which traditionally would provide a finger lift, if one happens to be used on the tonearm in question. Headshells may range from ultra-minimalist on through to quite elaborate designs that, in some instances, provide within-the-headshell adjustments for azimuth and for stylus rake angle.

Headshell designs can either be fixed (that is, permanently attached to the tonearm wand or perhaps even fashioned as an integral part of the wand) or detachable—usually via a locking collar of some kind. Proponents of fixed headshells cite their potentially superior strength, rigidity, structural integrity, and freedom from resonance, where proponents of detachable headshells emphasize the fact that detachable headshells facilitate cartridge swapping (because users are free to mount spare cartridges in separate headshells, thus making it possible to switch cartridges with a minimum of set-up hassles).

Motors

A wide variety of motors can be found in turntables, but some of the more common types are AC synchronous motors (motors that are in essence locked to the frequency of the mains), low-noise DC motors, and so-called ‘Hall Effect’ direct-drive motors (where in essence, the platter serves double-duty as the ‘armature’ of the motor).

Each type of motor has its ardent proponents, and each can, if well executed, give sonically superb results. The main points to grasp are that motors need to drive their associated platters at precise, unvarying speeds with as little noise as possible and with virtually no tendency to show speed fluctuations (not even extremely minor ones) in the presence of large or small-scale dynamic variations in the music.

Platters, Sub-Platters, Main Bearings, & Spindles

Platters: Platters are the relatively heavy, disc-like elements upon which records rest and rotate while in play. Ideally, we would want platters to be perfectly flat, perfectly round, and to be fitted with spindles that are perfectly centered in the platter’s top surface (the spindle is a round vertical post used to center the record upon the platter). Further, we would want platters to offer sufficient mass that, once in rotation, they would have enough inertia to be able to resist speed fluctuations—even when playing records where timing accuracy is hyper-critical (e.g., certain piano passages) or where there are wild dynamic variances over time (think of Tchaikovsky’s classic 1812 Overture). Finally, we would want platters made of materials that offer good internal damping and provide a solid, neutral sounding support surface for the record. It is common to see platters made of machined aluminum, glass, brass, copper, composite materials or combinations of the above.

Sub-Platters: Depending on the design brief being followed, some turntable designs feature platters that rest upon smaller sub-platters to which the turntable drive mechanism is connected and to which the main bearing of the turntable is attached.

Main Bearings: Main bearings must support the weight of the platter while allowing it to rotate as smoothly and quietly as possible. It is important to bear in mind that any noise— even seemingly very low-level noise—from the main bearing can be passed upward through the platter and the record, to be picked up by the phono cartridge. For this reason, precision-made main bearings are an absolute must for optimal sonic results to be achieved. It takes a great deal of expertise to design and to manufacture top-class main bearings, but the effort pays huge dividends in terms of sound quality. Indeed, one of the biggest differences between good vs. great turntables lies in the quality of the main bearings used.

Some common main bearing types include shaft and bushing designs (with or without continuous recirculating oil baths and with or without inverted bearing shafts), shaft and ball designs, air bearings (where the weight of the platter is borne upon a cushion of pressurized air), and opposed magnet supported bearings, where sets of opposing magnets are used to partially ‘levitate’ the platter thus relieving physical pressure on the bearing assembly. Bearings can be made of hardened tool steel with or without jeweled contact surfaces or balls, sintered bronze, other exotic metal alloys, ceramics, composites, specialized plastics/ polymers, and other man-made materials.

Spindles: Spindles are precision-made circular posts, typically made of metal, which protrude from the top center surface of the platter. Spindles are made to an industry standard diameter and their primary purpose is to act as a centering-pin for records, when records are placed on the platter for playback (and yes, there is a corresponding, industry standard, spindle-sized hole in the center of all LP records). But one other purpose for the spindle is to provide a gripping surface to which optional record clamps, if any, may attach.

Plinths

Plinths are the externally visible housings or structural frames for turntables. In some designs, the plinth is essentially an outer shell to which various sub-frames or assembles (for example, motor mounts) are attached—or from which they are suspended.

In other designs, however, the plinth basically is the frame of the turntable, to which the turntable’s tonearm, main bearing/platter assembly, and in some cases even the drive mechanism or motor is attached.

Can plinths affect sound? Recent Hi-Fi+ reviews of aftermarket plinths for popular turntables such as the Linn LP12 suggest that plinths can have a surprising high level of impact on the turntable’s overall sonic presentation.

For this reason, it is important to respect plinths as significant elements of turntable design and not as an afterthought.

Record Clamps and Vacuum Hold-Down Systems

Many analog audio experts think that it is desirable to clamp records firmly to the platters upon which they rest during playback and for this reason a number of turntable makers and aftermarket accessory manufacturers offer specialized record clamps, which typically are attached via the platter’s spindle.

Others go even further, suggesting that, since many records are very slightly warped, it is desirable not only to clamp records at their centers, but also around their outer perimeters (so that the records will lie perfectly flat upon the platter’s top surface). Accordingly, a handful of manufacturers offer ring-shaped clamps, typically made of metal, which slip over the outer edges of the record and turntable platter, thus coupling the record firmly to the platter, flattening out any warps in the record surface as a result.

Finally, it is worth noting that not all analog experts are devotees of record clamps, mostly out of concern that clamps might put undue pressure on the platter main bearing while potentially creating unwanted stresses in the record surface.

One way of achieving the benefits of clamping systems, but without actually using clamps, is to build turntables that incorporate vacuum-powered record hold-down systems. Turntable manufacturers such as SOTA and TechDAS have done just this, with very good results. The only drawbacks to the vacuum hold-down approach involve complexity, costs, and the need to manage the noise produced by the requisite vacuum pumps.

RIAA (and other) phono EQ curves

A fact little known among laymen is that records as pressed do not have flat frequency response. On the contrary, during the record mastering process specific equalization curves are applied curves that reduce the amplitude of bass frequencies and boost high frequencies. The typical EQ curve used is called the RIAA curve, where the acronym stands for Recording Industry Association of America. There are also other phono EQ curves that provide similar functions, although they are far less common than the RIAA curve. Alternate phono EQ curves include those from CCIR/Teldec, Columbia, DMM, and Decca/EMI. Arguments continue to rage today as to whether record companies switched wholesale to the RIAA curve when stereo arrived in 1958, or whether recordings cut in the 1960s or later used the alternate EQs derived in the monophonic era.

Why is phono equalization necessary? The answer is that bass content, if cut into the record with flat frequency response, would require record groove modulations so extreme that it is doubtful that even the finest phono cartridges could properly track them. What is more, the modulations would be so large in amplitude that they would force unfeasibly wide spacing between record grooves, which would severely limit the amount of content that could be included on each record side. At the other end of the audio spectrum, high frequency material, if cut into the record with flat frequency response, would potentially be so low in amplitude that it might get masked by naturally occurring groove noise.

Thus, phono equalization, complete with boosted highs and trimmed-back low frequencies, is always applied during the record mastering process. However, in order to restore flat frequency response when playing vinyl records, inverse phono equalization is applied during the playback process via a specific type of preamplifier called a phono stage. All phono stages provide inverse RIAA equalization, but some of today’s more elaborate, upper tier phono stages may also provide six or more specialized phono EQ curves, as mentioned above.

Rumble

Rumble is a measure of the detectable noise generated by turntables as they rotate, so that you could think of rumble as being the turntable world’s equivalent of the signal-to-noise-ratio in conventional audio electronics. Rumble is typically quoted as a negative dB figure (for example, -64dB) where—as with signal-to-noise ratios—the higher the negative number of dB, the quieter the turntable will be.

As with audio electronics, lower rumble in turntables may not necessarily be perceived as ‘lower noise’ (although it is just that), but rather as ‘enhanced low-level detail’ in the music.

Speed Controls

It is impossible to overstate the importance of proper speed control in turntables since even very minor speed fluctuations can, under the right circumstance, be painfully audible (long, sustained piano chords are extremely revealing in this respect). For this reason, many designers have developed precision outboard power supply/speed control regulation boxes that serve to tighten up the speed accuracy of their associated turntables.

Is this just an example of ‘gilding the lily’? No. Proper speed control can make all the difference between a good turntable and a great one.

Stylus Profiles

The exact shape and dimensions of the phono cartridge stylus have much to do with how well the phono cartridge will track the record grooves. Some common stylus shapes you will encounter are the following:

Conical/Spherical: As the name suggests, conical styli are cone-shaped, but with rounded, hemispherical tips. Conical/spherical styli are the easiest to make and are the least finicky about set-up, but they have performance limitations in that they are comparatively high in mass, have relatively large tips with respect to the dimensions of the record grooves, and also provide relatively small ‘contact surfaces’ (analogous to the ‘contact patches’ of automotive tires) between the stylus and the groove.

Elliptical: An elliptical stylus represents an improvement over the conical/spherical because, rather than having a large round tip, the elliptical stylus offers a tip with an elliptical profile whose narrower edges face to the sides and directly contact the record groove. Two benefits accrue. First, the elliptical stylus is lower in mass than an equivalent conical stylus would be, and second, the elliptical stylus’ narrower but more elongated contact surface offers a better fit for purposes of tracking the undulating contours of the record groove (those narrow radius contact points can much more readily track high-frequency details, for example). Elliptical styli require somewhat more attention to set-up, but are still relatively forgiving.

Shibata: The Shibata stylus, named after its inventor, represents an even more radical step forward from the elliptical stylus in that it has an even narrower tip shape that, under a microscope, looks somewhat like the blade of a garden trowel turned so that the flatter side of the blade is facing the viewer. The side-radius of the Shibata tip is even smaller than that of an elliptical stylus so that the contact surface is not merely a somewhat elongated ellipse (as with typical elliptical styli), but rather is a much taller and narrower ellipse that almost resembles a vertical line. Relative to elliptical styli, Shibata styli offer three compelling advantages: significantly lower tip-mass, even narrower side-radius dimensions for superior tracking of high frequencies, and—somewhat unexpectedly—an increase in contact area with the record groove (meaning that even if higher tracking forces are used there is still less stylus pressure per square centimeter than with an elliptical design). Because the side-profile of the Shibata stylus is narrower and more blade-like than with elliptical designs, greater care must be taken to make sure that the stylus rake angle is properly adjusted.

Line Contact/Fine Line: Line contact/fine line styli, often attributed to the designers A.J. van den Hul and Fritz Geiger, represent an even further advancement along the same lines that inspired the Shibata stylus. The general idea is to pare away yet more stylus tip mass while narrowing the side-radius of the stylus tip, so that the stylus contact area becomes an extremely narrow and elongated ‘fine line’. But don’t let the shape and dimensions of that fine line mislead you; the fine line/line contact shape still offers plenty of stylus-to-groove contact area, so that stylus pressure per square centimeter still remains reasonable. Once again, improvements are noted in high-frequency tracking and in overall ability to trace fine, small details in the record grooves. More so than other stylus types, line contact/fine line styli are sensitive to set-up and to stylus rake angle adjustments.

Stylus Rake Angle

Stylus rake angle (SRA) refers to the front-to-back tilt angle of the phono cartridge stylus vis- à-vis the record grooves (whereas azimuth is the side-to-side tilt angle of the stylus in the groove). Unlike azimuth, however, the optimal stylus rake angle is not dead vertical (90 degrees), but rather is thought to be in the range of 91.5–92 degrees (depending upon which experts you consult), with the stylus tipped back just a bit, as if ‘scooping’ into the oncoming groove by 1.5–2 degrees.

Why is this very slight tilt back desirable? The answer is that the cutting head used to produce the lacquer master for the record also had a similar degree of tilt back. As always, for best sonic results the ideal is for the phono cartridge stylus to come as close as possible to following both the horizontal path and the vertical ‘angle of attack’ of the original cutting head.

It is possible to adjust SRA by ear, but an even more foolproof method is to use a USB microscope to observe and adjust the stylus rake angle as the stylus is resting upon the record.

Note that not all tonearms make provisions for SRA adjustments and note too that many audiophiles and even some experts tend to use the terms ‘stylus rake angle’ and ‘vertical tracking angle’ (VTA) interchangeably—even though they aren’t precisely the same thing. Sonically speaking, though, SRA is the adjustment you want to get right.

Turntables with Suspensions vs. Mass-loaded Turntables

Almost all turntable manufacturers seek to isolate key elements of their playback systems from both mechanical and airborne vibration, but there is much divergence of opinion as to how best to achieve that result.

Some designers believe in using mass loading to prevent (or at least suppress) transmission of unwanted vibrations and their designs typically use fixed, solid plinths to which the turntable platter and tonearm assemblies are firmly affixed (though turntable motors/ drive units may, in such designs, be mounted in separate housings or ‘pods’ that stand apart from the main plinth). In such mass-loaded designs, there usually is no suspension at all, apart from feet that may, in some instances, provide built-in elastomeric or spring-loaded suspension elements.

Other designers, however, strongly believe that it is best to have the turntable platter and tonearm mounted on sturdy sub-chassis that is suspended and—to a degree—isolated from its surrounding plinth. For even greater noise isolation, such designs very often attach the motor to the turntable plinth and then use an elastic belt-drive system to transfer power from the motor to the platter.

As a general rule, mass-loaded turntables are sometimes more prone to mechanically induced noise and vibration transferred via audio furniture or the floor, while suspended turntables tend to offer somewhat better vibration isolation, but at the expense of considerably more elaborate initial set-up procedures and a certain tendency to drift out of adjustment over time.

Tonearm Types

In broad strokes, there are three main types of tonearms you might encounter, although pivoted tonearms are by far the most common types. The other two types of arms are radial-tracking/ straight-line tonearms and tangential-tracking tonearms.

Pivoted Tonearms: Pivoted tonearms may feature straight or curved tonearm wands with either fixed or detachable cartridge headshells at the front end, a bearing assembly toward the rear, and a counterweight at the back end. In a pivoted arm, the cartridge/stylus always moves in an arc across the record surface, though tracing errors can be mitigated by careful adjustment of cartridge overhang and alignment angles.

Radial-tracking or ‘Straight-line’ Tonearms: Radial-tracking or straight-line tone arms almost invariably feature comparatively short, straight tonearm wands with either fixed or detachable cartridge headshells at the front end, a bearing/arm carrier assembly toward the rear, and a counterweight at the back end. What sets straight-line tonearms apart, though, are their distinctive bearing/arm-carrier assemblies, which significantly allow the tonearms to move straight sideways—not swinging in an arc as pivoted arms do. In this way, the arms realize the ideal goal of having the stylus move in a perfectly straight line across the record, always maintaining perfect tangency to the record grooves. The downside of straight-line tonearms, however, is that they are complicated to design and build, costly, and can in some instances prove difficult to set-up and to keep in proper adjustment.

Tangential-tracking Tonearms: Tangential tracking tonearms are conceptually a cross between pivoted tonearms and radial-tracking tonearms. On one hand, tangential-tracking tonearms are pivoting designs, but with one crucial difference: their cartridge headshells are not locked in a fixed position on the tonearm wand, but rather are position on an articulated mount that—get this—allows the cartridge alignment angle to be continuously adjusted during playback to maintain stylus-to-groove tangency all the way across the record. To achieve this desirable result, most tangential-tracking tonearms are built with a main tone arm wand and a secondary control arm that rides beside the main wand and that is responsible for making continuous alignment adjustments as needed. When viewed from above, tangential-tracking tonearms and their associated, articulated headshells look something like slender, elongated trapeziums. For obvious reasons, tangential-tracking tonearms must be crafted with extremely tight-tolerance bearings for the arms’ several articulated joints.

Tonearm Bearing Systems

As mentioned above, it is very important for tonearms to offer nearly friction-free movement, while preserving tonearm/cartridge/stylus geometry with great precision. To this end, designers have devoted a lot of attention to the types of bearings used. Some types commonly encountered are as shown below:

Air bearings: Air bearings are typically shaft-and-sleeve bearings where the sleeve is fed pressurized air from an external source so that the shaft never makes metal-to-metal contact with the sleeve, but rather rides on a virtually friction-free cushion of air. This type of bearing is used in a number of straight-line tone arm designs. Examples would include the Bergmann Magne, Kuzma Air Line, or Walker Proscenium Back Diamond V tonearms.

Ball/Gimbal bearings: Precision-made ball bearings are popular for use in tonearms, often via gimbal-type mounts where one pair of bearings handles horizontal axis motion, and the other pair handles vertical axis motion. Ball bearings are often graded using ABEC (Annular Bearing Engineering Committee) ratings where the higher the ABEC number the tighter the bearing tolerances are.

Knife-edge bearings: Some tonearm designs have used so-called knife-edge bearings for vertical axis applications. A knife-edge bearing consists of a knife-like blade that rides within a corresponding, precision machined V-shaped trough.

Multi-point/Kinematic bearings: Multipoint or kinematic-type bearings, as used by a handful of manufacturers, combine the precision of ball/gimbal-type bearings but offer the promise of even lower friction and essentially zero ‘free-play’ in the bearings. The general idea is to precisely locate the center of motion typically using just three or four contact points. Examples would include the Kuzma 4 Point and Wilson-Benesh ACT-series tonearms.

Thread-type bearings: Some tone arms forego traditional, metal rotational bearings and use threads not only to suspend the tonearm but also to afford it both horizontal and vertical motion. Examples would include the Well Tempered tonearms or the Funk Firm F6 tonearm.

Unipivot bearings: As their name suggests, unipivot bearing feature just a single point of contact—an idea appealing in its simplicity. Such bearings typically feature a spike (with or without a jeweled tip) that rests in a cup (again, with or without a jeweled contact surface). One point to note, though, is that arms fitted with unipivot bearings must be balanced from side-to-side in order to achieve proper azimuth alignment.

Tonearm wands/tubes, etc.

As mentioned above, tonearms must position phono cartridges precisely without introducing resonance problems. For this reason, arm wands/tubes must be strong, rigid, well damped, and as resonance-free as possible.

Most tonearm wands are constructed as tubes that can be made of metal, plastics, composites, or hybrid combinations of materials. Many manufacturers enhance tubular tonearm designs either by adding internal stiffeners or by adding dampening materials, or both.

Lately, several manufacturers have begun to experiment with 3D-printing techniques for arm wands, some using plastic-type materials and others using metal materials. 3D printing allows complex shapes/designs that could not be made via traditional machining techniques.

Tracking Force

Tracking force is the amount of downward pressure applied to the phono cartridge stylus and that is necessary in order for the stylus cleanly to track demanding material encoded in the record grooves. Above all, the intent behind using the proper amount of tracking force is to make sure the stylus remains in contact with the walls of the record grooves at all times, yet without applying so much pressure that the groove walls are damaged or subject to undue wear.

When a stylus does break contact with the record groove, even if only to a slight degree, that condition is called mis tracking, which is audible, unpleasant-sounding, and hard on the record grooves. Typical tracking forces for most modern phono cartridges will range from the mid-one-gram range to the mid-two-gram range, in accordance with published specifications for the cartridge. The general idea is to use sufficient force to eliminate mis tracking, but not more force than is necessary.

Contrary to popular assumptions it is preferable to use slightly too much tracking force than not enough. While heightened tracking force does increase record wear to a degree it also tends to help prevent mis tracking, which can be even more damaging to one’s record grooves.

Turntable Drive Systems

Turntables are often classified by the drive mechanisms they use. Some common drive mechanism types are described below.

Belt drive: In belt drive turntables the motor stands separate from the platter assembly, while a precision-made belt (typically, but not always made of elastomeric materials) transfers power from the motor drive pulley to the turntable platter (or to a sub-platter beneath the main platter). Some designs use thread or magnetic tape in lieu of an elastomeric belt. The belt is thought to decouple the platter from the motor, keeping motor noise from being transferred into the platter where it could be detected by the phono cartridge.

Direct drive: In a true direct drive turntable the ‘armature’ of a Hall-effect motor is embedded within the platter, while other parts of the motor are contained in the turntable plinth. In other words, the platter is essentially its own motor. If properly designed, direct drive turntables can be extremely quiet as their motors, by definition, rotate at platter speed and thus do not introduce higher-frequency vibrations. Also, direct drive tables—again, if properly designed—also allow extremely tight speed control.

Early generation direct drive turntables sometimes got unfavorable reviews because their designs allowed some degree of audible motor ‘cogging’ and because their speed control mechanisms sometimes introduced noise and micro-variations in speed. More contemporary designs typically address and solve both problems.

Idler-wheel drive: Idler wheel drive, sometimes confusingly called ‘direct drive’, involves a motor with a drive wheel and an idler wheel that transfers motor power to the platter. Almost the opposite of belt drive designs, idler wheel designs forge a direct coupling between the motor and the platter, so that it is imperative to base such designs on extremely low-noise motors (typically very high-quality DC motors). Proponents of idler-wheel drive praise their dynamic immediacy and solidity as well as their freedom from such micro-variations in speed as can be introduced by elastic drive belts.

Magnetic drive: Magnetic drive offers another method for transmitting power to the platter while at the same time physically decoupling the motor, per se, from the platter. In this system, the motor typically drives a substantial sub-platter, which is magnetically coupled to a physically isolated platter positioned directly above the magnetic coupler. When the subplatter rotates, its magnets attract those in the platter above, causing the platter to rotate.

Vertical Tracking Angle (VTA)

Many audiophiles and experts use the term vertical tracking angle to describe what should properly be called stylus rake angle (SRA). See above.

Wow and Flutter

The terms ‘Wow’ and ‘Flutter’ refer to two undesirable types of speed variation in turntables. Wow is a slow, gradual fluctuation that might yield a slow “Wow” sound as speed gradually increases and then decreases. Flutter is a more rapid speed fluctuation with would produce vibrato or tremolo-like sounds as speed rapidly increases or decreases. For obvious reasons, it is desirable to have turntables that produce as little wow or flutter as possible, though of the two types of speed variation flutter is arguably the more noticeable.