If you have a record at home, take a moment to look closely at the tiny piece of wonder. How can such a small thing result in such amazing sound you hear through your speakers? How Do Records Work? What is the physics behind the working of a record and how does it do what it does? We are here to answer all these questions.
When you are looking at the manual of a record, or doing your homework before buying one, you may come across some terms or glossary words which can be handy to know from beforehand. Hence, before going into the functionality of the record, we would like to discuss few terms.
Terms You Need to Know:
- Turntable: A turntable of a record is that circular thing you see in the record player, which rotates and on which you are supposed to place the record. This is often also referred to as the Platter.
- Tone Arm: The tone arm is the system or often known as the lever, which helps to hold the cartridge and the stylus in the proper position, above the record.
- Cartridge: Do not confuse the term with that of a printer. For a record player, a cartridge is mainly a magnet which is wrapped in a wired coil. It is found attached to the stylus.
- Stylus: The stylus is the needle which sits in the channels of the record. It is usually made from sapphire or diamond.
How Do I Hear a Playback?
Now that you know the most essential terms from the record glossary, you must be wondering- okay, but how do I hear the sound that comes out when the record is placed and rotating on the player. That is exactly what we are getting to.
The record is first placed on the turntable. It starts to rotate at a constant speed when the player is switched on. The constant speed is usually 33 1/3 rpm for an LP, while it is around 45 rpm for singles.
At this time, the stylus and the cartridge are lowered onto the rotating record with the help of the tone arm. In order to ensure that the grooves are well maintained, the stylus has to be placed onto the lead in. What is that? It is a 6 mm blank space, found in the outer rim of the record.
While the record keeps spinning, the stylus will fall into the tiny cut grooves, causing vibrations. When this happens (the stylus vibrates), it is quite understandable that the cartridge, which is attached to the stylus, will also continue to vibrate. This cartridge is a transducer. This means, it converts energy from the signal in one form to a signal in another form. Hence, an electrical current is produced, which keeps changing depending on the vibrations of the stylus.
Next, this generated electrical wave is sent to an amplified to be amplified (made louder) and eventually fed into the output device (such as speakers). The speakers have something called a diaphragm which keeps moving back and forth (longitudinally), imitating the motion of the stylus. This means, it will recreate the sound which was originally cut into the record.
What is a groove?
Now you are aware of the basics of how a record works. However, we mentioned grooves a few times. What are these grooves? Usually, every record has a groove (usually just one), which spirals softly from outside towards the center of the disc.
The groove is small or even easily called tiny- only around 0.04-0.08 mm wide [highly reliant on the level of the signal]. If you want to visualize it a little more, think about unwinding the groove. The groove on a 12- inch LP would be as long as around 500 meters.
The two sides of the groove sit at 90 degrees to one another, with the position of the angle facing downwards. Both these sides of the groove contain something like twists that represent the right- and the left-channel audio signals respectively.
The side nearest to the outer edge of the record contains the right-channel information. This signal can be stored in an area as small as one thousandth of a meter, almost a micrometer). This means, the scale of retrieving such a task is huge. You can, thus, already understand why record players are so sensitive to external vibrations and many other different kinds of disturbances.
Why is the cartridge so essential?
You already are well-aware about the groove now. And you might be wondering, alright, but how do we track the groove. Well, that is exactly why you need the cartridge. The tip of the stylus is responsible to take care of such tracking of the groove.
The tip of the cartridge has to be constructed from something very hard. Hence it is usually diamond (not the extremely expensive one, but the industrial diamond, and hence not as pure as the ones you are used to seeing in jewelries).
The tip (made of diamond) is mostly shaped into a tiny point, even though there are several shapes that the tip can assume. It is meant to sit in the record groove, following the twists as the record keeps spinning.
The nature and the grade of the motion of the stylus is what lead to the changing frequencies and the varying volumes that your speakers gives off as output. The movement occurs through the cantilever, which is basically the shaft to which this stylus tip is annexed, and into the body of the cartridge.
Knowing how the wonderful and fabulously engineered device, or piece of art- the record, works is indeed worth to comprehend the ingenuity of the music that comes out of the record. Once you know the parts and importance of each well, you will be able to decide on the perfect record and maintain the records well to last a lifetime.
You may also like: How to Record Music: A Guide for Beginners.