I have the good fortune to live nearby Dennis Murphy (who designs the crossovers for Salk speakers) and the equal good fortune that he is such a terrific fellow to have me over to his house today to listen to some of the speakers that he's worked on with Jim Salk.
He had on hand the prototypes for the HT1-TL, the HT4, and the SongTowers (not RT). Being prototypes, the crossovers were outboard in a couple of cases , only the SongTowers were veneered, and the HT4's and HT1-TL were not exactly the same on the left and right (more on that below). He has a Van Alstine amp and pre-amp, and a hand-made A-B-C-D switch that can also adjust volume to account for the varying speaker sensitivies. He was using what looked like a 12 gauge (maybe 10?) stranded speaker wire with bare wire running into the speaker terminals.
We started out comparing the SongTowers to the HT1-TL. Initially we listened with the curtains open along his picture window behind the speakers, but he had the good notion to close the curtains after we played a couple of tracks and this cut down on the acoustic reflections from the glass and got rid of the slight brightness in the highs. I should note that both speakers are voiced as closely to each other as one could manage. The differences heard are most likely coming from the drivers and issues of geometry (MTM vs. two way); Dennis would probably have more to add on that point. And there were times when one or the other of us switched between speakers with his remote and it took a bit of listening to catch the switch. In most cases, however, the differences noted below were consistently and observably there--something that anyone would hear without straining to detect.
We listened to a number of CDs that I brought: Cowboy Junkies (The Trinity Session); an XLO Sampler from Reference Recordings (Dennis really liked the Janacek, and I did too!); Jimmy Smith (Back at the Chicken Shack); Johnny Adams (One Foot in the Blues); Bebe (Pafuera Telaranas); and Garcia/Grisman (Shady Grove). So we had a good mix of classical with strong dynamics, male and female vocals, acoustic stringed instruments, funky jazz, blues, and atmospheric country (or however you would describe that Cowboy Junkies album).
If I took delivery of a pair of SongTowers tomorrow and they were my speakers for the next ten years, I would be happy. With that said, I had the opportunity to A-B compare them to the HT1-TL's, and there are differences. Of course the highs are more articulate with the HT1-TL's since it has the ribbon tweeter and the SongTowers did not. This is audible in the natural shimmer of tinkling bells, stringed instruments, and cymbals (to pick a few examples). Having said that, without the A-B comparison the SongTowers are still satisfying and engaging in their high end presentation.
Another area that consistently differentiated the SongTower from the HT1-TL's was depth of soundstage. The obvious conundrum is that without the SongTower RT around, it wasn't possible to determine whether this was primarily due to the more accurate ribbon tweeter on the HT1-TL giving better spatial clues, or whether something else was going on as well. Regardless, the HT1-TL (in Dennis's room and in the recordings we listened to) opened things up in depth.
The other area where I heard consistent differences was in the ability of the HT1-TL to unravel complicated orchestral pieces. This was particularly evident in the Janacek on the XLO/Reference Recordings disc. This is a highly dynamic piece (performed beautifully by the Czech State Philharmonic), and the SongTower did a good job with it, but the HT1-TL did better in my opinion. I think Dennis agreed also. The delineation of the instruments and the handling of the dynamics was more precise (to choose a word; could have said "better" or "controlled").
However, there was one peculiarity that struck us after listening to a few tracks. In the Grisman/Garcia recording, Jerry Garcia's voice sounded a bit more nasal (Dennis thought of it as "recessed") in the HT1-TL, and we heard something similar (or I did at least) on the female vocals (especially Bebe). After hearing it on a couple of different CDs, Dennis remembered that the HT1-TL's were not a matching pair. The right-hand speaker was an early prototype, and sure enough when we isolated the left and right channels the "nasal" or "recessed" quality was coming from that early draft version.
So, we finished up the SongTower and HT1-TL comparison in single channel listening. On the Johnny Adams album (a terrific R+B singer from my home town, New Orleans), the HT1-TL left speaker sounded fuller and more even top to bottom than the SongTower left speaker. It's quite an interesting way to compare speakers since it pares down the number of things that you're listening for. I'm not sure if I would do it this way on all occasions, but at a minimum it made it clear that the recessed vocals were an artifact of the early prototype right channel HT1-TL.
Unfortunately I wasn't able to compare a SongTower RT with the HT1-TL, so I don't know how much (if any) more I would prefer the HT1-TL. However I've decided to take the safe bet and upgrade my order for the SongTower RT to an HT1-TL since a) I have a 500 watt per channel amplifier (ridiculous, I know) that won't care about the lower efficiency in the HT1-TL and b) I can sell my HSU subwoofer (locally, I hope!) and c) I've heard the HT1-TL and I know I like it (a lot). Not all of those things will apply to everybody.
Finally, we did switch in the HT4. The left was an HT4 12" and the right was an HT4 10". Together they rattled the windows with Dennis's 28 Hz test tone. I told him it reminded me of living through the Loma Prieta earthquake in California in '89. Aside from the obvious addition of bass extension (high-quality bass extension), the HT4's also had a different midrange presentation that was very nice, and they seemed to refine the depth of the soundstage that the HT1-TL had (maybe it was more refinement of space between the instruments?). To be honest we only listened to a couple of tracks, and knowing that I could never afford the HT4's I didn't focus too hard on the differences. I focused just enough to hear that I could live with what I was missing for the price.
A big thanks to Dennis for having me over and to Jim Salk and the other folks who make these speakers. I am going to be one happy member of the Salk owners' family.