Turning Tables Trivia Quiz

Answer: Heavier platters tend to produce better sound

When it comes to the platter of a turntable, mass and balance are the two most important factors. No motor construction can yield a perfectly even driving force and even if it could, small variations in resistance could affect rotation speed as well. The cure for such variations is inertia - having a large mass rotate and thus provide resistance against any change in speed.

The problem with heavier platters is of course that manufacturing tolerances decrease with mass - the heavier a platter is, the more pronounced the effect of a small weight imbalance on the playback will be.

The Technics SL-1200, an upper middle class turntable popular with disc jockeys, had a platter weight of 1.7 kg (3.7 lbs) while ultra-high end audiophile turntables went all the way to 30 kg (66 lbs) platters.

Answer: Variable gear drive

Turntables almost universally used one of three drive mechanisms: Idler wheel drive, usually found in cheaper players, used a movable rubber wheel between the motor's capstan and the platter. The capstan had several segments of different diameters, each corresponding to a speed setting. Today, this drive mechanism is almost extinct. Belt drives use a rubber or textile belt to transfer the rotation, again with the option of switching speeds mechanically, by using a multi-diameter capstan. Finally, direct drive puts the platter directly on the capstan and thus requires a motor capable of delivering the low RPM of the platter with great accuracy and stability, requiring more powerful and complex motor designs. Both belt drive and direct drive designs are found all the way up to the ultra-high end segments.

Answer: Sapphire

In order to give a clear sound and not damage the record, the stylus tip needs to retain its sharpness and exact conic shape. For this purpose, diamond, as the hardest known mineral, is the best choice but sapphire is still acceptable. Unlike diamond styluses, however, which usually last longer than the turntable itself, a sapphire stylus is subject to significant wear and needs to be replaced every few months, depending of course on the intensity of use.

Answer: 1 to 2 grams

On a higher end turntable, the tone arm to which the stylus is ultimately attached is carefully counterbalanced so that you can then set the actual weight (downward force) of the stylus on the platter with a simple rotating dial. Cheap models, on the other hand, may require more complex adjustments or even have no counterweight at all (and a much higher downforce than the ideal 1-2 grams recommended for a decent diamond stylus). 1 milligram is a typical weight for the actual stylus itself (which needs to be as light as possible in order to move freely) while 30 to 50 grams was the typical pickup weight on mechanical, steel-needle gramophones playing 78 RPM records.

Answer: Piezo crystal cartridge

All of these cartridge types are still being manufactured although piezo crystal cartridges are very rare, usually replaced with ceramic ones. However both the crystal and ceramic construction have one pretty significant limitation: They rely on the movements of the stylus to deform a thin crystal or ceramic element to generate the electric signal.

This however restricts stylus movement and especially high-frequency response is worse than for other cartridges. Moving coil and moving magnet cartridges work essentially opposite to a loudspeaker - a permanent magnet induces a current in a coil whenever these two move, relatively to each other. Strain-gauge cartridges do not induce an electrical current, they instead work by triggering a variable resistor.

Answer: It provided best compatibility with monophonic equipment

When the first stereo records were released, the industry needed them to be playable on the then widespread mono equipment so they would be able to sell the stereo discs without immediately forcing consumers to upgrade. Mono turntables read only the horizontal movement of the stylus.

The diagonal channel cutting is executed such that the horizontal movement is exactly the sum (or average) of the two individual channels, and the vertical movement their difference. Thus a mono cartridge can read a stereo record correctly and, in the inverse case, a monophonic record on a stereo player produces the same output on both channels.

The arrangement had the additional advantage of keeping the vertical stylus movement, which tends to follow the groove less accurately than the horizontal one due to mechanical limitations, relatively small.

Answer: Long play time and good bass reproduction

The two most difficult goals to reconcile in the creation of a vinyl record are a long playing time and a strong, loud bass reproduction. Strong bass sounds have a high amplitude, thus the groove will take more room, but this directly and sharply reduces playing time.

As a solution to this dilemma, bass signals are recorded much softer than they actually should be and, conversely, high frequencies which could otherwise lose quality due to their low amplitudes are overemphasized. The RIAA equalizer undoes this sound distortion, recreating a powerful bass signal as well as a clear treble sound from a narrow groove, allowing for playing times of 23 minutes per side on a high fidelity music recording (and sometimes more).

Answer: Sound quality near the outer edge of a record is better, important for loud finales

Near the outer edge of a record, a longer piece of groove passes under the stylus within one second than it does near the center (actually more than twice as much). Thus, towards the center, mechanical limitations will reduce the quality of the sound - there is simply less room for complex groove shapes.

As such, it would be desirable to reserve the outer edge for loud and complex passages like the finale of a symphony. Mechanically, however, it is much easier to build a turntable that automatically deposits the tone arm at a variable position depending on disc size and uses a constant stop position than vice versa.

The improved sound quality near the outer edge is also one of the original reasons it became common to put the signature tracks of an album in the first position of each side.

Answer: Apply gentle, careful pressure to the pickup cartridge as it plays

If you use a lightweight pickup and the damage to the record is not too bad, you can often already succeed by simply playing the disc with a heavier effective stylus weight. Your first try could be to use about triple the normal weight - 3 grams if you normally play at 1 gram, 6 if you normally play with 2. With some luck, this presses the stylus down far enough that it will follow the lower, undamaged groove. If you can't adjust the weight or don't want to fiddle with the controls, a coin on the cartridge serves the same purpose. If the higher weight alone is not enough, you still have a chance if you apply gentle pressure with your finger, pressing down and toward the center for a record that repeats, down and to the edge for one that skips a groove. Be careful however and do this only for the damaged track or passage - the excess pressure inflicts some heavy wear on both the stylus and the record. Also, practice this on a record you don't mind damaging (or a track on the damaged record that you have already digitized) first - if you overdo it, you might cause further damage!

Answer: Yes

Since all the information about the sound is contained in the shape of the groove, it can be reconstructed with very high fidelity from a high resolution photograph of the record's surface. This is one way the US Library of Congress digitizes sound recordings made with unusual groove sizes and depths for which no compatible player and stylus exist - the system in use there is called IRENE.

It also had some, albeit not perfect, success at reconstructing the sound from fully cracked records unplayable on any mechanical device.