Omnidirectional directivity is a difficult-to-achieve characteristic of acoustic measurement sources. If the measurements are executed in a diffuse field, then the uncertainties caused by the source directivity can be minimized by averaging more measurements. However, nearly ideal omnidirectionality is significant when performing measurements in a free field, e.g., in an anechoic chamber [7]. The typical case in room acoustic is the mixed reverberant field, where the omnidirectionality is less crucial than in the free field but still can cause significant dispersion in the measurement results regarding the source used. The parameters such as C80 and EDT based on the early part of the decay curve can especially differ regarding the source directivity and their rotation. Omnidirectional sound sources are required in most standard room and building acoustic applications, as they are claimed to reduce the effect of the used source on the measurement results [8; 9; 10]. One of the best approximations of an acoustic point source is a dodecahedral loudspeaker array, which, in theory, is almost ideally omnidirectional in a frequency range depending on the source radius [11; 12; 13]. To be qualified for the field measurements, its directivity characteristic should meet the minimum requirements specified in ISO 3382 or ISO 140 standards [14; 15]. Discovering a perfectly omnidirectional source causes the development of diverse dodecahedron alternatives, as some of the disadvantages of these solutions are already known. In the past, few papers were published providing comprehensive information on the influence of the non-ideal omnidirectional sound source directivity on the measured room acoustic parameters [2; 4; 16]. The research on dodecahedral source replacement focused on using impulse sources [17; 18; 19], but they do not offer complete control over the measurement signal. It was proved in previous research that impulse sources can replace electroacoustic sound sources, especially in places where the use of electric devices is limited, such as caves or catacombs [20; 21; 22]. The other alternatives studied [23; 24] have significant limitations, such as the increased measurement length or the complication of measurement conduction. It eliminates the need for fast field measurement performance, which is crucial in experimental room acoustic. Some of the research provided the conclusion that the multiple-speaker arrays may cause significant changes in the measured acoustic parameters if one of the speakers is directly facing the microphone, so in that case, the limited number of loudspeakers in the omni-source simulation may provide better results and reproducibility. To obey the known limitations of multi-speaker arrays, some novel sources were developed, such as the inverse horn approach source [25], elastomer balloon source [26], or laser induction-based sound source [27]. Those original solutions were efficient; however, they required developing complicated R&D processes, which are expensive in reproduction and may be challenging to recreate in a typical sound lab. Other researchers provided better methods for the external calibration of omni-sources to control their radiated sound field [28; 29]. Those methods improved the radiated sound power level but did not offer significant gain in directivity, which is the main reason for troubles with the uncertainty of room acoustic measurements. At the same time, researchers also pursue alternatives that may be cheaper in construction as they may allow the undertaking of new types of measurements, such as those requiring multiple omnidirectional sources. Simple, cheap, and efficient omnidirectional sound source development is still needed. The proposed research describes the experimental validation of the new concept of omnidirectional sound sources, called coupled speakers, where only two loudspeakers are used.