Audio Engineering Guide: Playback of Analog (vinyl) Records

1 Introduction (below)

2 Disc/Record Dimensions

• 1 Record Diameter
• 2 Maximum Outer Diameter
• 3 Groove Dimensions
• 4 Stereophonic Groove
• 5 Channel Orientation
• 6 Channel Phasing
• 7 Channel Levels
• 8 Speed of Rotation
• 9 Lead-In Groove Pitch
• 10 Lead-Out Groove
• 11 Finishing Groove

3 Signal Equalization in Disc Recording

4 Turntables

• 1 Drive Systems
• 2 Turntable Design in the 21st Century

5 Tonearms

6 Phono Pickup/Transducers and Styli

• 1 Cartridge Styli
• 2 Cartridge Voltage Output
• 3 Electrical Loading

7 Phono Preamplifiers

8 Laser Turntable System

9 Record Care Suggestions

• 1 Brushes
• 2 Record-Cleaning Machines
• 3 Record Storage
• 4 Cleaning Records

1. Introduction

In the past 100+ years approximately 30 billion phonograph records have been produced and sold. Music of the most famous composers and performers, orchestras, and bands, and sounds of events have been immortalized in intricate excursions of the analog record groove.

Millions and perhaps billions of discs are still in the hand of the audiophiles, archives, musical libraries, DJs and radio stations. (Indeed, there are some reports that vinyl is more durable than CD, on the basis of longevity)

In any case, the contents of all of these records can never be completely rerecorded onto the compact discs or another medium, so it is important that we can preserve, restore, and reproduce analog recordings.

The information contained in this section is directed toward the new generation of engineers and technicians so they may understand the reproduction techniques that led to digital technology. As we witness the decline in popularity of analog LP discs, remember that many developing countries around the world are still very much dependent on analog technology and in some cases what we consider the old 78 rpm format is the only source of prerecorded music and entertainment available to them.

Early recorded sounds had a high-frequency cutoff of 2-3 kHz. It took over 100 years to reach the sophistication of today's recording technology only to take a couple of steps backward in sound realism by approximating the waveforms at the high frequencies and limiting them to 20 kHz with brick wall filters. Theoretically digital recording is fine, but the human ear deserves a higher sampling frequency. Perhaps only a select few can really hear the difference, but then how can we argue with them? In other fields, such as television, the trend is toward high-definition TV, and yet tube-type audio amplifiers are still sold at premium prices because of many so-called golden ear audiophiles don't want to give up the tube sound. The same is with LP records. For the average listener, CDs (and digital files) are great as long as they don't hear pops and clicks and cannot break the stylus or the tonearm.

This section will discuss playback equipment. To understand the production of records/discs, Google the topic.