It is a good idea for anyone buying a record player to understand the basic principles of vinyl playback: it will give them a better chance of making a successful purchase.
If you are a turntable designer, you need to know these things. If you are a music listener and are considering buying a turntable, you will benefit from understanding the basics.
Ultimately, when it comes to playing a vinyl record, the issue is that the stylus should follow the microscopic groove engraved on the record as closely as possible. The more precisely it can do this, the better the sound. To be able to do its job, the stylus must be supported in place with absolute stability, the record must be held firmly in place. Ideally, the only moving part would be the diamond tip of the stylus. Then it would produce a perfect electronic copy of what is engraved on the record.
That's the theory. In practice, the record has to rotate for the needle to move in the groove, so it can't be fixed in place. The cartridge has to be mounted on a freely moving tonearm so it can follow the groove. So it can't be completely fixed either.
It takes skill from the designer to get close to the above-mentioned ideal. At a quick glance, turntables look very similar. However, this is not the case: a lot of design skill and, above all, production expertise are needed to achieve a good end result. The turntable should rotate the record at the right, steady speed without lateral (sideways) movement. The tone arm should be completely rigid, but at the same time light so that the stylus can follow the track of the record accurately from start to finish. The final performance of the turntable determines how close the design and implementation have come to the theoretical ideal.
Good design alone is not enough to get a quality instrument onto a music lover's shelf. The designer's ideas have to be implemented, and that requires a factory that can manufacture the parts to very tight tolerances and then assemble and adjust the turntable to exacting standards. Ideally, on a scale that makes the instruments reasonably priced.
