Synaptic noise is fundamental to information processing and transmission in the central nervous system, as it amplifies and optimizes sub-threshold signals, thereby improving action potential initiation and reliable firing maintenance (Ermentrout et al., 2009; Faisal et al., 2008; Wiesenfeld & Moss, 1995). This is particularly important at auditory synapses where acoustic information is encoded by rapid and temporally precise firing rate. In the auditory system, an excess of synaptic noise has been shown to be detrimental to acoustic information, as it contributes to the generation and maintenance of tinnitus and hyperacusis (Kaltenbach, 2006; Wu et al., 2016). Although numerous studies have examined the role of synaptic noise on single cell excitability, little is known about the contribution of presynaptic boutons to synaptic noise within a local circuit, owing in part to the problems of combining noise modulation with monitoring synaptic release. Here we show that positive Kv3 K+ current modulation using 30 µM AUT1 (provided by Autifony Therapeutics) in the dorsal cochlear nucleus of mice reduces the level of synaptic bombardment onto its principal fusiform cells. Using a transgenic mouse line (SyG37) expressing SyGCaMP2-mCherry, a calcium sensor that targets presynaptic terminals, we show that positive Kv3 K+ current modulation decreases calcium fluorescence in a third of individual presynaptic boutons. Furthermore, while maintaining rapid and precise spike timing, positive Kv3 K+ current modulation increased local cross-unit synchrony, a result arising from a reduction in spontaneous activity. In conclusion, our study identifies a unique presynaptic mechanism which contributes to noise reduction, and consequently the coherent activation of neurons in a local circuit.