The 510s were great BUT only at higher volumes (too loud for daily listening) in my 396s. At reasonable to low levels, they needed significant HF boost otherwise they sounded like less and completely lacking detail to my ears. They jbls are completely opposite. Very detailed at any volume, crystal clear and just the right amount of top end sparkle for my liking. The soundstage and vocals are massive on these JBLs. They sound as they look, large and true to life. Had I not I upgraded on my purchase, these would be going anywhere. They make the Cornwalls I am selling sound like small bookshelf speakers in comparison if that tells you my thoughts? Not a fair comparison whatsoever.