In this paper, we consider the problem of adaptive multichannel signal detection in the presence of signal mismatch, and introduce a novel tunable detector,which is parameterized by two tunable parameters. It has the Constant false alarm rate(CFAR) property and covers Kelly’s generalized likelihood ratio test(KGLRT), Adaptive matched filter(AMF), and Adaptive coherence estimator(ACE) as its three special cases. The novel detector controls the mismatched signal by adjusting two tunable parameters. Remarkably, it can achieve improved detection performance for matched signals, enhanced rejection of seriously mismatched signals, and better robustness to slightly mismatched signals than its natural competitors. It has the Constant false alarm rate (CFAR) property and covers Kelly’s generalized likelihood ratio test (KGLRT), Adaptive matched filter (AMF), and Adaptive coherence estimator (ACE) as its three special cases. The novel detector controls the mismatched signal by adjusting two tunable parameters. Remarkably, it can achieve improved detection performance for matched signals, enhanced rejection of seriously mismatched signals, and better robustness to slightly mismatched signals than its natural competitors.