Room impulse response measurements including directivity are becoming a vital component of room acoustics. The results of these measurements allow for the room acoustical analysis regarding specific source receiver combinations and enable the realistic simulation of acoustical scenarios in virtual environments. Besides the widely applied microphone-arrays, electroacoustic sources with a steerable directivity are necessary to retain all degrees of freedom during the measurements. Due to the relatively large dimensions of the transducers, the number of possible physical transducers in a loudspeaker-array is very limited, resulting in a low spatial resolution. A solution to this problem are sequential measurement methods, which virtually enlarge the number of transducers by moving the source during the measurement and superposing the results. The attainable high spatial resolution is ideal for substituting the most complex source or receiver directivity in forward or reciprocal measurements. However, sequential measurement methods are very susceptible to time variances, which diminish the achievable accuracy. This study is an experimental approach with various source receiver combinations to evaluate the practically achievable accuracy in forward and reciprocal sequential loudspeaker-array measurements in different environments and the corresponding sources of error.