Update – A/B KLH 20 vs KLH 6

KLH 6 (brown weave grille) and KLH 20s in A/B test on my Sony STR-7045. NAD 7240PE and 5170 next to them on the bench.
I pulled out the KLH 20s (newly restored) against my old dependable KLH 6s.
Both have replaced Dayton capacitors, drivers sealed to the cabinets, and nicely sanded and restored finishes. A very attractive set!
I plugged them in to my NAD 7240PE running as a power amp off of my NAD 5170 CD player for a A/B demo to see what, if any differences I could glean. I was expecting little to no differentiation. I was right in this short test – I couldn’t hear a lot of difference. But I also cut the test short because the NAD wasn’t working the way I wanted it to – the preamp in the receiver is not functioning now and I wanted to use the variable output from the CD player as a preamp. That was not working and I didn’t want to damage the speakers so I plugged in my Sony STR-7045 which was also laying around.
Here there were some interesting differences. I had the 20s and 6s lined up and started to flip back and forth using the speaker selector switch on the receiver.
I was surprised to hear more of a marked difference than I expected, and a much more pronounced difference with the Sony than I encountered with the short demo on the NAD.
On the NAD they sounded almost the same, but on the Sony the 20s were much ‘hotter’ than the 6s. It seemed to my ears that the 20s were a bit louder and punchier at the same wattage. I don’t know if this is because of the smaller cabinet of the 20s, perhaps a tighter speaker seal, the 4-ohm woofer and slightly-different tweeter. It seemed that the highs were more out there and perhaps slightly higher. Bass was good, but when compared with the 6, there was a little bit of a drop in some passages (Pink Floyd ‘Breathe’ for one) where extra low bass oomph persisted longer in the 6.
I went back and forth a lot trying to determine which one I like better. Really they are both great, and very enjoyable to listen to. If I only had one pair and not the other I would be extremely happy with either. But I finally made my choice for the KLH 6s. The 20s are a bit brighter but I wonder if they’re a little ‘hotter’ too, not more defined or well-rounded. The bigger 6s are more laid back and may require a couple more watts to sing but I feel there was some more detail there that the 20s were missing. That could be due to the extremely new caps inthe 20s ( the 6s have many more hours of burn-in than the 20s) or due to the replacement Dayton tweeters in the 6s. While I observed no difference in performance between the original KLH 6 tweeter and the new phenolic ring tweeters when replacing, perhaps this test shows there is more of a difference than I first expected.
In any case, the 20s at some point will now find a new adoptive parent. Whoever gets them will be lucky- they are gorgeous!