A lot of interesting comments, above, that illustrate how much a particular preference is a matter of taste more so than of particular technology and vintage of the gear. I found it interesting that Doug Schroeder much preferred the Volti Vittora over the 757s among speakers based on horn-compression drivers. I like the tonality of the Volti speaker, but, in the three instances that I heard the speakers, they sounded very polite and dynamically dead compared to the compression driver speakers that I personally prefer. I did not hear the 757s he heard at RMAF, and most of the 757s I've heard were restored/modified, so I don't know if it sounded anything like the 757s that I favor over the Volti.
I tend to agree with the comments above about the tunefulness of some vintage woofer/enclosures. Yes, they do not go very deep and deliver the same kind of punch, and I will agree that punch is a plus with some music, but, I will take the trade-off to have the tuneful and "less mechanical" sound of old school bass.
As for the sub-woofer for a Quad, a friend of mine likes the Gradient dipole sub-woofer he uses with a Quad 63. I haven't heard his setup with the Gradient (he changes out various speakers that as often as most people change underwear and I missed that setup), but I have heard them elsewhere, and they do sound quite natural. It may be the case that dipole bass would be a better match with dipole speakers like the Quads. I heard, at a show, BG Radia dipole speakers with the Sound Insight SI 300 sub-woofers, and the combination sounded pretty good.
