Vibrotactile actuators, such as voice coils, are effective, non-invasive solutions commonly used in haptics to render tactile information. Among voice coils, sound exciters offer several advantages to wearable haptics through superior economic affordability, compact size, and commercial availability. This study explores the feasibility of using disk-shaped sound exciters actuators for wearable haptic applications, bench-marking them against traditional voice coil cylindrical actuators. Seven participants took part in contact and roughness discrimination experiments. The qualitative and quantitative study investigates the Just Noticeable Difference (JND) and Absolute Threshold (AT), exploiting standard psychophysical methods. The proposed protocol effectively compared the performance of the two actuators. Our preliminary results show that sound exciters may be a viable alternative to more commonly used vibrotactile actuators for practical haptic applications.