I have owned examples of every generation of Sansui speaker from 1967 SP-300's to 1988 XL-500'S, and most of the ones in between. Even SPL-700's. Best I've had that are readily available and inexpensive are SP-1500's. If your on a budget, try 'em, they are pretty decent. Best ones that are hard to find, SP-300'S hands down. SP-300's are amazing. Bass you can feel to 30 hz and slightly below. Mids and highs that I felt the need to dial back slightly with the pots on the back. They sound nothing like a Heresy, even though they both use a 12 inch woofer, and have horns for the mids and highs. (I've had Heresy original and series 2.) Heresy's are nice, but were originally designed as a center channel for k-horns, and sound weaker by comparison, A-B'd on the same system. Heresy has no real bass output due to the cabinet size. Out of the many, many speakers I have had since I started collecting over 10 years ago, they have all been sold with the exception of 2 pairs of sp-300's, 1 pair of sp-1500's, one pair of JBL 2440's and one pair of JBL 2405's. 1968 SP-5000's (not 5000x)are pretty sweet as well. To me they sounded like a 1500 on steroids. As with any 40-50 year old speaker, they are going to need the pots cleaned and possibly capacitors replaced to sound their best.