I have 604 based speakers which are in enclosures built by Serious Stereo. I disagree that they do not sound full or open at low volumes. I suppose it would depend on the implementation of the speaker though. Mine are in a 11.5 cubic foot bottom vent enclosure. I normally listen around 70-80db and they sound very good to me at this level. They still sound good at lower volumes but I think you will find that most all speakers will need at least this much volume to sound their best.
Altec 510 reviews?
I would like review information or opinion on the Altec 510 speakers that were re-issued I believe in about 1999. My brothers each had 511's from the 80's and one had studio 14's. They both kept the 511's as they loved the full sound. I purchased the 510 model as 511's are not in the re-issue group. I have thought about moving toward some 604 based speakers or some Klipsch but really just want to hear of any reviews. I may save myself the cost if the difference in listening experience is not that substantial. Problem is I cannot really 'try out' any other speakers as in this area only new systems are available. Help!