The main disadvantages of hardware synthesizers are the following:

1. Limited timbre diversity: Hardware synthesizers usually have limited built-in timbre libraries and cannot be compared to software synthesizers. Download and add new sounds anytime. This limits the variety of timbres and personalization options.

2. Lack of real-time editing capabilities: Compared with software synthesizers, hardware synthesizers have relatively weak capabilities in real-time editing. Adjusting parameters or effects requires doing so through a hardware interface, which may not be as intuitive and flexible as a software interface.

3. Difficulty in updating and upgrading: Updating and upgrading hardware synthesizers usually requires firmware upgrades or replacement of hardware components. In contrast, software synthesizers can get new features and bug fixes through simple software updates. This makes it relatively difficult for hardware synthesizers to keep up with the times in terms of functionality and performance.

In addition, due to the working principle and structural limitations of hardware synthesizers, they are larger, more expensive, not portable, and difficult to expand. However, hardware synthesizers also have their unique advantages, such as high stability and good real-time performance. Therefore, when choosing a synthesizer, you need to weigh its pros and cons and make a decision based on your personal needs and budget.