something to add in.....  i used sonic enhancers with all the systems i put together...  the last unit i had was the marathon ex-200, it is a good enhancer as well, however, after a year or so the left channel button lost its signal, i had to push button in and out the for it to work correctly...  more or less just a low quality button on the ex-200....  i decided to go with the bbe, it does not have all the buttons and switches as the ex-200, but does the job just fine... this unit looks well built, good solid knobs and power switch compared to the ex-200....  balanced xlr inputs and outputs as well....  for the sonic enhancement option, it does boost the system, noticed a vast improvement in base, tighter bass, however for high end not so much... note that i am running a equalizer prior to this unit.....  i think this unit should last a long time, not like the marathon ex-200......  overall it is a good part of any system, recommend using equalizer prior to this unit to get the best possible sound for your system....