inputs.text: satisfied - ive found using l9 really improved quality sound iphone using fiio e11 portable headphone amp could not happier simple effective way get best possible sound devices getting lod noticing marked degradation sound quality using headphone jack line amp adding l9 sound crystal clear completely unstrained price performance ratio nobrainier use mine iphone 4s inside otterbox defender case fits perfectly setup even pretty good job running set pretty inefficient sennheiser hd600s away desktop setup efficient set cams shocked quality ive happy fiio far acquiring e12 available