vintage versus modern speakers

On the question of best speakers for $1500, unfortunately that is not a lot to get into really good towers, and American made doesn't make it any easier.

With a big amp like the SAE, if the OP could stretch his budget to $2000, Ascend Acoustics is an American company that has been making excellent speakers for over a decade, based in California. Their Sierra Tower is right up there with Salk speakers(also American), but more affordable. I just bought their Sierra 2 bookshelf speaker and I am seriously impressed.

Raymonda nailed it when he said

generally one can spend less today and get much better sound per dollar than yesterday.

IMO, partly as a result of what Timlub said:

Material technology... we now have Kevlar, carbon fiber, magnesium, aluminum, ceramic, pulp wood fiber cones & yada yada yada... This has changed along with a much improved manufacturing process. We used to have measure 50 drivers to match up a half dozen to tight tolerances. Today, they come off the line within 5% or better tolerances... Combine that with better caps & resisters along with compensation circuitry not typically used back then

to which I would also add:
computer modeling which cuts R&D costs substantially, and
lower cost manufacturing sourced from third world countries.

At the other end of the cost spectrum are the high 5 to mid 6 figure speaker systems which would have been beyond anyone's wildest imaginations "back in the day".

I really like the sound of many of my 60's and early 70's LPs like Jeff Beck's "Truth" and Tull's "Stand up"...some of this stuff sounds really cool on modern gear...Donovan's stuff with John Bonham et al...kick ass.

One issue with speakers made in the 3rd world country manufacturing: made by people for whom it is just a job, not by crafstmen. Therefore, I will only buy American made speakers.
Two, in regards to the quality of records in the seventies, here is the perfect quote: "Actually many of these so called poorly recorded rock albums you mention of yesteryear sound much better than the poorly engineered and compressed rock and pop albums put out today" by Raymonda!
Because , personally, I think that today pop/mainstream music is well represented by the Ipod: immensely repetitive monotony, absence of musicians, cheaply technically done....
So I will follow Almarg suggestions, to look for a set of speakers, but I will also look at some great classics: Infinity, JBL,EPI . To be followed......

At your price point most of the newer and better audiophile oriented loudspeakers won't play that loudly, nor will they have that much bass. They also won't match very well with your amp. A double Advent system with refurbished drivers and crossovers can be had for $500-600 and can do things that the audiophile loudspeakers can't.