Carvin Stage Mate – 4 channels include one specifically for acoustic instruments with bass treble and midrange controls – I use that input for a pickup that is up in the first octave and a second input with a dual pickup for bass and midrange, then blend the two depending on the job – this also lets me add some reverb on the top end – I have two of these units plus extension speakers and have been using them for over 10 years – Carvin only sells from their factory – Carvin.com –
( batteries are good for 3 hours on a charge)
Fourth and fifth octaves do tend to predominate