Well, now to my last piece of the puzzle - how do the individual transducers or resonators sound?
For my evaluations I used my serious stereo setup for the preliminary testing and then used my secondary set (Sony CD, McIntosh C-28 pre, Adcom 545, and Sony Speakers) for the final two testing sessions. Just to remind you, I play music at a fairly robust volume level - a little below symphony concert level - as if you're sitting in the 20th row, dead center, in a venue that normally seats about three thousand people. The later tests were performed at a slightly lower volume than my usual. Your results probably will vary - especially if you listen at louder or softer volumes.
The initial testing was between the HFTs, four different versions/interpretations of the Ozinators, four versions/interpretations of jkbtn's resonators, and a very complicated resonator I built. I have to say the ultimate differences between the tested prototypes were noticeable but not earth shaking. The final results were comparable to the experience provided by swapping fuses or tube rolling. That said, after all my listening and positioning testing I only found one that was ultimately, acceptable to me.
When I first got started in this effort I made a large amount of a large amount of resonators (almost 100) and succumbed to the idea that more was better. As I have previously posted, eventually I came to the conclusion that less is more. I now only use eight in my serious listening room.
I became interested in do-it-yourself resonators after reading Ozzy's posts about his design and I thought I would also give them a try when I got a good deal on 15 HFTs. Obviously, a great time to do a comparison. While I was waiting for all the Ozinator parts to arrive I also assembled a collection of larger and smaller cones as well as larger and smaller bases. A short time later, jkbtn suggested a different style, larger cone and by the time I was finished I had more than a dozen resonator types to go along with the transducers.
The initial testing was between the HFTs, five versions/interpretations of the Ozinators, four versions/interpretations of jkbtn's resonators, and a very complicated resonator I concocted. I never did get a press fit Ozinator built. Either my cones were too large to be pressed into the bases I had, or they easily slipped into my other sized bases but were loose enough to slip back out. Initially, I bought fly fishing lure cones in three sizes but only used the large cones and ultimately switched to the 3/8” or 9.5mm "Alaska" Brass Cones, since (to my ears) the smaller cone sizes never provided as much musical value.
Enter Gorilla Glue.
Gorilla Glue proved to be excellent for attaching the cones to the bases. A couple of drops on the edge of the open bases, then plop it down on top of an upside-down cone (like a hat on a bald head) and five minutes later you had resonator all welded together. The Gorilla Glue provided a nice lightweight but sturdy bond. Pushing some Blu Tack into the cap and then pushing a cone into the cap also worked, but I thought it dulled the music a little.
While I was working with the Ozinators I received the jkbtn cones. The jkbtn brass cones are more like tiny, little bowls than cones. I ordered three different jkbtn cone sizes, but ultimately only used the 14mm and the 12mm sizes. The bases I used for the jkbtn cones ran the gamit from 1/4" and 3/8" copper caps, to 1/4" compression fittings, to big, honkin' 1/8” & 1/4" brass female pipe caps.
I tried many different styles, sizes and placements of resonators, but quickly settled on four representatives for my first round of testing. The four were: the Synergistic Research HFTs, the Ozinator in a 1/8" brass base, the jkbtn 14mm cone pressed in a 3/8" copper cap, and a big jkbtn 14mm cone glued in the big 1/4" brass cap.
Using only my front channel speakers (Magnepans) with and without the subwoofers I tried six of each prototype. For this test I placed three prototypes on the wall, around each speaker. One just off the inside edge - about 30" up from the floor, one just off the outside edge - about 30" above the floor, and one just above the speaker.
I started listening for many details but during these tests but soon zero'd in on four very noticeable tendencies with large differences. First, how deep was the soundstage; second, the positioning of the vocalists and instruments; third, how much clarity of detail came through; and lastly, how much harshness did each resonator type produce.
My lowest ranking of the four went to the 14mm jkbtn cones in the 3/8" copper caps. On the downside, they did not contribute very much to soundstage depth nor did they add to mid-range and bass clarity. On the positive side they did not contribute much to the upper mid-range harshness and even added a little bit of hi-frequency zing. Overall, they just did not provide much of an impact.
The next two finishers were tied for second. Not because they were equal, they were very different, but because I couldn't figure out which one was necessarily better. The SR HFTs were the best of all in producing a warm and very deep soundstage. The actual stage itself just seemed alive and so much more physically deep than most of the others. The HFTs could easily have walked away as my champions except for one, major flaw. They produced more upper mid-range harshness/raspiness than any of the resonators. Now, every one of these produce some harshness, especially if you place large numbers of them into your system, but to my ears the HFTs were the most harsh of all. I tried multiple placements to no avail. I brought out my test disk and my SP meter just to make sure I wasn’t placing them in hot spots. I tried turning them away from the listening area but the harshness remained. In the end this turned out to be a deal-breaker for me
This is where I have to insert the YMMV language. At robust listening levels my upper mid-range is somewhat close to being raspy as it is. It doesn't take too much to push the music into the harsh range. If you listen at a moderate volume level or if your speakers have a softer mid-range than Magnepans, the HFTs could possibly be your winner.
(In referring to upper mid-range harshness, what I am hearing is most noticeably heard when vocalists reach the part of a song where they put a lot of oomph and volume into the part. To use two very popular songs to demonstrate: during the Police single, ”Every Breath You Take”, when Sting sings "Now my POOR HEART ACHES, with EVERY STEP you take" - and also on k. d. lang’s single, "Constant Craving", when she sings the chorus, "CON-STANT CRA-VING has AL-WAYS been". At these intense moments the harmonics produced above the notes sung, can bring a hard, harsh, or raspy sound to the vocalist's voice).
Tied for second place with the HFTs were the biggest Ozinator I built, the Alaska cone in a 1/4" brass cap. The biggest Ozinators produced the most pleasant sound of all the Ozinators I built with a good tight bass, a clear mid-range, and pleasant but subdued highs. These were the best Ozinators at not producing mid-range raspiness/harshness but unfortunately, the soundstage they produced almost sounded two dimensional. If the HFTs produced a soundstage that was forty feet deep then the Ozinators stage was only fifteen feet deep. (FYI - Smaller Ozinators produced better highs - very nice cymbals - but the harshness became more evident. Plus they had the same soundstage lack of depth).
This left the large, big bottom jkbtn resonators as the champ of the first testing. These excelled at almost everything except their high frequencies were not quite as prominent as with the smaller sized resonators. The sound stage was the equal of the HFTs while the lower level and mid-range became clearer and more focused than with any of the other resonators. The big bottom jkbtn resonators also moved the stereo image quite effectively. While the official tests all were done with forward facing resonators, I did try placing these on the inside edge of my speakers which caused the vocals and instruments to move closer to center and become better defined physical position-wise. Likewise, when I placed them on the outside edge of my speakers the listening area expanded outward adding to the ambiance that is built-in to modern recordings.
Flat out, the big bottom jkbtn resonators were the most holographic, clearest, impactful, and pleasant sounding of all the contestants - by a fairly noticeable margin. Truth be told, I oh, so, didn't want these to be the winners. With the biggest cones stuck in the biggest, honkin' bases they are not only large and heavy but also kinda ugly. Nevertheless, IMHO they outperformed all of the others.
Just to make sure I took the top contestants, plus a few others, upstairs to a different stereo and performed a second round of testing.
