The CORE unit works very well when directly with stethascope. Easy to assemble and straight forward directions. It also records well for play back later. I was hoping to connect real time with my blue tooth hearing aids but the sound is too quiet within the core program and if I turn my hearing aids up enough to hear it it beco.es distorted and too loud and I pick up interference. This was discussed with me before purchase but is still the best and most economical choice I had. I use it as a digital stethascope and it increases the volume perfectly. I am a paramedic and with the sounds from our truck and other outside influences this is a great fit. Thanks EKO. JOB WELL DONE!