In this study, an acoustic system is proposed for online estimation of precision planting indices. The technique was based on rising the acoustic amplitude with impacts of seeds on a plate. By exceeding a defined acoustic threshold, each impact was registered as a meaningful event imported into an acoustic system algorithm for estimating precision planting indices. To evaluate the proposed system, a feeding platform was designed being able to apply different patterns of seed spacing with predefined precision planting indices. During the tests, dropped seeds from the feeding platform impacted to the plate and their spacing is estimated according to the time interval between seeds and simulated speed of planter. According to the ISO standard, calculated seed spacing was automatically separated in three ranges of spacing. The precision planting indices including multiple index, miss index, precision in spacing and quality of feed index were estimated based on the theoretical seed spacing. Considering the estimated precision planting indices with 99% coefficient of determination with referenced data in feeding platform and the acoustic system spacing measurement, the proposed acoustic system was evaluated as a powerful technique for laboratory evaluation of precision planting.