The appearance size of speakers can be classified according to their dimensions. Here are common classifications of speaker sizes based on appearance:

Compact Speakers: These speakers typically have relatively small dimensions, making them easy to carry and install. They are commonly found in portable audio devices, computer speakers, and small audio systems. The size can be determined by diameter or length, width, and height, typically ranging from a few inches to a dozen inches.

Mid-sized Speakers: Mid-sized speakers fall between compact and large speakers in terms of size. They are commonly used in home entertainment systems, bookshelf speakers, and car audio systems. The dimensions usually range from tens of centimeters to a meter, determined by length, width, and height.

Floor-standing Speakers: Floor-standing speakers are typically tall, freestanding speakers used in hi-fi audio systems and home theater systems. They have larger dimensions, typically exceeding a meter in height, including the main speaker unit and subwoofer unit.

Wall-mounted Speakers: Wall-mounted speakers are designed to be mounted on walls, saving space and offering options for elevated installation. They are usually thin and lightweight, suitable for home theaters, conference rooms, and commercial spaces.

In-ceiling Speakers: In-ceiling speakers are installed inside the ceiling, providing advantages such as elevated installation, space-saving, and surround sound capabilities. They typically have smaller dimensions, ranging from a few inches to several tens of centimeters in diameter.

These are common classifications of speaker sizes based on appearance. In reality, there are other types and sizes of speakers, such as bookshelf speakers, mini speakers, outdoor speakers, etc. Speaker sizes based on appearance may vary depending on specific usage and design requirements.