The hyperscanning method simultaneously acquires and relates cerebral data from two participants while performing cooperative activities. The aim of this work is to evaluate the performance of our novel EEG recording concept, termed ear-EEG, against on-scalp EEG as an alternative, user-friendly data acquisition approach for hyperscanning, in the task of identifying the most robust, EEG subbands for inter-individual neuronal synchrony detection in cooperative multi-player gaming. This is achieved through the estimation of neuronal synchrony produced by a highly localised time-frequency data association measure, termed intrinsic synchrosqueezing coherence (ISC). It is shown that for both the recording modalities the lower theta band is the most robust neuronal marker for inter-brain synchronisation during our own cooperative game called Bar Balancing. This is because the lower theta band yields: (i) highest correlation in neuronal synchrony between the modalities; and (ii) enhanced discrimination ability of significant neuronal synchrony detected in the easy and hard tasks in both the modalities.