PCM61 and PCM61P are two audio processor chips. The difference between them mainly lies in function and performance. PCM61 is an early audio processor chip, and PCM61P is its upgraded version.

Compared with PCM61, PCM61P has the following improvements and improvements:

1. Performance improvement: PCM61P has relatively better performance in audio processing. It may have a higher sampling rate, lower noise and distortion levels, and better dynamic range and signal-to-noise ratio, among other metrics. These improvements enable the PCM61P to provide higher quality audio processing effects.

2. Increased functions: PCM61P may have expanded and added functions. It may add more audio processing modes, filter types, reverb effects, etc. The addition of these functions makes PCM61P more flexible to cope with different audio processing needs.

There are several explanations for the reasons for this upgrade and improvement:

1. Technological progress: As time goes by, audio processing technology continues to develop and improve. The purpose of upgrading the chip is to use new technologies and algorithms to provide better audio processing effects. Technological advancement is one of the main reasons for upgrading.

2. Market demand: As users’ requirements for audio quality continue to increase, audio processor chips also need to be continuously upgraded to meet market demand. Higher performance and richer functions can provide a better audio experience, so upgrading the chip is also to cater to market demand.

3. Competition pressure: In the audio processor chip market, competition is inevitable. In order to maintain competitiveness and market share, chip manufacturers need to continuously introduce new products to meet user needs. Upgrading chips is a way to improve product competitiveness.

To sum up, compared with PCM61, PCM61P has been improved and upgraded in terms of performance and functions. These improvements may be made to take advantage of technological advances, meet market demands and respond to competitive pressures. Such upgrades can provide better audio processing effects and richer feature selections.