Placement tips for Synergistic Research HTFs


I just bought 15 HTFs and will also be making about a dozen of Ozzie's homemade models.  While I will re-fresh myself with SR's placement tips, and I get that I will have to do some experimenting to tailor the HFT effect to MY listening room; are there any "Advanced HFT Placement Tips" some of you would like to share with us?  Something that might be overlooked by many of us?  Or maybe, just a good rule-of-thumb tip for someone just starting to use these?
The tips could be tips for bring out more highs, solidifying the bass response, placement hi vs low, in front of vs behind speakers, on side walls, at reflection points, behind the listener, on the ceiling above the equipment or above the listener, on the equipment.
Any ah-ha that you would like to share?  I would also be very interested in hearing from people using Magnapans.

toolbox149
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.
The second round of testing.

For the second round of testing I first started with six transducers or resonators for each test. Three on each side, all mounted face forward on the wall, one about a half-foot off the outside edge of my speakers, one just above my speakers (about 42" off the floor), and one about six feet above the floor. I constructed a few smaller jkbtn resonators, just to make sure I wasn't missing something. After a couple of listening sessions I narrowed my list to a final six resonator types - which are pictured in my “system pictures” section here on Audiogon. For the final I reduced the number of resonators for each test down to four with only a resonator just above my speakers and a resonator just to the outside edge of my speakers. I was only listening for resonator characteristics not placement optimization.
For the final notes portion I used only one song. I had just received a copy of Steely Dan's "The Royal Scam", and decided the first track, "Kid Charlemagne", features a number of good evaluation parts in it. In the first verses the bass and one of the keyboards are having a nice playful dual. This was an excellent part to evaluate bass response and clarity. Some resonators were rather muddy sounding; some were able to keep the two instruments separate.
The first verse also offered an opportunity to get a good reading on the amount of stage depth each resonator type produced.
During the second verse the cymbals and percussion come into play giving a good opportunity to gauge percussion, drums, and overall kick-in-the-gut impactfullness provided. As the second verse ends and the song transits into the chorus you get a good chance to gauge how each resonator handles vocals. Steely Dan vocals are fairly nasal sounding and keeping the vocals sounding musical was a challenge for some of the resonators. The chorus magnifies these difficulties as the main vocals become more forceful and background singers enter the song with gusto. This is where harshness can really rear its ugly head.
The guitar solo and remaining verses are great spot to reaffirm your thoughts on the overall performance.
I played this song over & over, going back & forth between resonators, I also occasionally went back to the no resonator sound – just to refresh my memory as to where the starting line was.
So here are my impressions of the six finalists. Once again – your mileage may vary.

The Small Ozinators (rear left in photo)
Depth of soundstage................................ 1
Clarity of bass and piano......................... 4
Percussion and drums impact.................. 4
High frequencies (cymbals)..................... 4
Vocals/guitar solo quality and purity....... 4
Harshness/raspiness avoided.................... 2
Overall..................................................... 19


The Large Ozinators (front left in photo)
Depth of soundstage................................. 1
Clarity of bass and piano.......................... 4
Percussion and drums impact................... 5
High frequencies (cymbals)...................... 4
Vocals/guitar solo quality and purity........ 4
Harshness/raspiness avoided..................... 4
Overall........................................................22

The Small jkbtn cone - press fit or glued   (rear center in photo)
Depth of soundstage.................................. 3
Clarity of bass and piano........................... 3
Percussion and drums impact.................... 3
High frequencies (cymbals)........................4
Vocals/guitar solo quality and purity….... 4
Harshness/raspiness avoided.......................3
Overall...................................................... 20

The large jkbtn cone in 3/8” copper bottom   (Center front in photo)
Depth of soundstage............................... 4
Clarity of bass and piano......................... 4
Percussion and drums impact.................. 4
High frequencies (cymbals)..................... 3
Vocals/guitar solo quality and purity....... 4
Harshness/raspiness avoided.................... 3
Overall.......................................................22

The large jkbtn cone in 1/8” brass bottom     (Right rear in photo)
Depth of soundstage................................. 4
Clarity of bass and piano.......................... 3
Percussion and drums impact................... 4
High frequencies (cymbals)...................... 4
Vocals/guitar solo quality and purity........ 3
Harshness/raspiness avoided..................... 3
Overall........................................................21

The large jkbtn cone in large ¼” brass bottom     (Right front in photo)
Depth of soundstage................................. 5
Clarity of bass and piano.......................... 4
Percussion and drums impact................... 4
High frequencies (cymbals)...................... 3
Vocals/guitar solo quality and purity.........4
Harshness/raspiness avoided.................... 5
Overall.......................................................25

So there you have it. My take on evaluating the resonators.

Ultimately, I sold my HFTs and reduced my usage of resonators in my main system way down. I tried using eight Big Bottom jkbtn resonators with two other smaller resonators thinking that I might be able to bring a little extra hi-frequency zing to the Big Bottom jkbtn sound. For me there seems to be a thin grey line when it came to the harshness factor and I just could not find another resonator that that didn’t push me over the harshness edge. In the end I cut my usage down to only eight Big Bottom jkbtn resonators. Two are mounted on the back of my front channel speakers – facing the front wall, two are mounted on the inside edges of the front speakers, two on the outside edges of my front speakers, and lastly two mounted on the sides of my rear speakers, which means they are facing the rear wall of my listening room. (I’ll post some pics soon)
This setup produces a somewhat deeper soundstage and helps keep the stage away from me. Vocalists and instruments are generally positioned more toward center stage. There is a little better bass clarity, smoother vocals, a little more kick to percussion, drums and transients, better all-round clarity, and a little more ambiance.

I hope your final choice affords you as much. The experimentation has been worth the trouble. I’m glad I have my favorites in place.


The following parts were used in the construction of the different resonators:

For the smaller Ozinators Here are Ozzy’s own words. - “I used 1/8" copper caps with a large copper cones from a company called Hareline. Hareline makes items for fishing lures and can be bought from Amazon. The caps however, will need to be purchased from a plumbing house. Then just simply glue the cone inside the cap. The cone is a direct drop in. I used Elmer’s school glue to seal the cone inside the cap.”

For my larger Ozzinators - I substituted the larger Hareline Alaska Brass Cones – I buy them at online fishing lure stores, wherever they are in stock. They come in packs of 15 for $4.50 plus shipping. These are 3/8" or 9.5mm cones. I glued these into 1/4” copper caps and later into 1/8” brass caps from Valley Hydraulic

For the rest of the resonators I used these bell-shaped brass cones. All you need to do is to place the bell into a 3/8" copper cap by hammering it gently. Tight and secure! And it makes a very nice resonator cup. Or you can glue it in and have half the cone sticking out from the base.

Here is the ad for the jkbtn brass caps – I mostly use the 14mm models. You get 30 for about $8.00 including shipping
http://www.ebay.com/itm/302130537660?_trksid=p2060353.m2749.l2649&var=600948813663&ssPageNam.

My 1/4" Big Bottom brass caps come from Valley Hydraulic.
http://www.valleyhydraulic.comhttp://www.valleyhydraulic.com/store/pc/Brass-1-4-quot-Female-Pipe-Cap...
SKU: 3129X4

A slightly smaller 1/8" Big Bottom brass cap also comes from Valley Hydraulic.
http://www.valleyhydraulic.com/store/pc/Brass-1-8-quot-Female-Pipe-Cap-21p1266.htm
SKU: 3129X2

Toolbox
Damn toolbox, you are one productive human! This thread has become quite the treasure trove of info. Since you seem to rate the version of the resonators I’m using the lowest, I’m going to pick up some heavy brass caps today and make some using those. I’ll still go the press fit route and may try the glue ins later.

@ozzy I haven’t tried them on top of the speakers yet. I’ll do that. As for the bb or crystal, I’m assuming you glue them in?

Crystals. Ha. We’re getting all new agey! What’s next? Dream catchers? Ooh, that’s not a bad idea for diffusion...
Dream catchers? I thought that’s what this is all about. The ability for us to go to our listening area and catch a dream of some musical performance. I was dreamin’ pretty good last night.

I’d be very interested in reading your opinion about the heavy brass caps coupled with the 14mm jkbtn brass cones. You WILL need some kind of glue to assemble them. The cones are too big to presss fit.

Throughout this whole episode, I’ve been trying to figure out if the bigger bases help produce better sound, or if it’s the big 14mm cones, sticking way out of the bases that add the most to the sound. While I’m kinda leaning toward the idea that the bigger bases have the bigger impact - I could make an argument for either point of view.

The one, big drawback to my favorite resonators is that they ARE heavy. It takes a pretty good wad of Blu Tack to hold them in place. Every time I head to the listening room for some music, I start out by making sure all eight resonators are still in place. Luckily I have carpeted floors. It’s not uncommon to find one on the floor.

Hope you’re having fun.

Toolbox