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
Placement findings for music transducers and resonators.

First off, thanks to Todd for also testing a lot of different resonator positions. I was glad to see Todd’s results were comparable to my results. I feel the commonality of our results is a good thing because we have much different speaker types. Todd has box style speakers in his system while I use Magnepans in my main system. I also tested a lesser developed system I have in the main living area. If Todd & I have similar results, I think many of your experiences could be the same as ours. I guess I should issue the disclaimer that while we have heard some common traits in these three systems YMMV. Also, thanks to Ozzy for all his starting tips and suggestions.

Just one quick heads up here. I’m 67 but I like to listen to music at, what I consider to be, a full bodied volume level. Not loud, but loud enough that the Magnepans sing. At my listening level the upper mid-range is still sweet, but it is close to becoming a little harsh. If you play music at a volume level less than full bodied, your results may vary.

Whether you use transducers or any of the resonators we have been talking about, my placement results were similar enough for me to generalize about placements.

I did start off with the published placement guides for HFTs, and then started modifying them with Ozzy’s suggested placement tips. I started off placing one on my front wall two feet up from the floor and a half foot inside the speakers. After listening a bit I added two more about 6 foot high, inside the speakers. I tried many of the other recommended positions as well. I also tried side walls, the back wall, the ceiling, down low in the corners – next to my bass traps, and finally placed directly on my speakers and components. I also tried only using HFTs and then only using resonators as well as a mix of both.

The first thing I noticed is any of these little helpers move the music (the soundstage) and also they tend to highlight certain frequency ranges. The two frequency ranges that were affected in both my systems were the mid-bass range (when I place some low and in the corners) and the upper mid-range area, especially impacting vocals.

For me any transducers or resonators placed near the lower corners of my room caused the bass to become boomy and muddy - not a good trait with Magnepans. I utilize corner bass traps and a pair of subwoofers in my system but make sure my bass remains very tight. If you can stand a little loss of detail in the bass department you might try placing one or two down low, in your corners. I started off with two in each of the four corners (which was very exciting for the first half hour) and gradually backed off until I just had one each, in the front two corners. Even that was too much for my tastes.

Now for the upper mid-range. All of these transducers and resonators embellished my upper mid-range, increasing mid-range definition but overdoing it to the point of slightly diminishing my listening pleasure. The more transducers or resonators I installed, the more I noticed vocals becoming more shrill whenever a vocalist would be singing powerfully, violins became more edgy than sweet, and listening fatigue started to set in. This wasn’t a knock-you-over-the-head change, but enough of a change to be a definite negative. My first step to lessen this was to move my transducers and resonators down lower on the walls & off the ceilings. Taking Ozzy’s advice I moved everything down until no transducers or resonators were higher than my standing chest height. This went a long way toward taming the beast, but in the long run, it still was not enough for me. More about this later…

As far as soundstage goes these transducers and resonators all have a positive effect on the depth of the soundstage. They also have a pronounced effect on the position of the soundstage. In a few days I hope to have a post describing the differences I hear between all the different resonators I have tested and also between different resonator sizes. There are some very noticeable differences in the depth and warmth of the soundstages and frequency responses.

What I want to address here is the position of the sound stage. What both Todd and I have found is the soundstage tends to move toward the direction the transducers/resonators are pointed in.

In my systems, when the resonators are pointed in toward the listener the soundstage moves closer – or the listener’s seat seems closer to the stage - not unlike turning up the volume will move you closer to the stage. If you place a resonator or two on the inner side of both your speakers the soundstage will move in, further constricting what engineers place in the center and bringing centralize sounds such as vocals into a more focused position between the speakers. Likewise, resonators placed on the outside of your speakers will widen the stage and some of the instruments that are panned wide, left or right will sound even further left or right. Pointing my transducers and resonators backward from the back of my speakers did not have as much of an effect but it did have some effect. However, placing a resonator on the back of a couple of objects about a foot or two from my back wall - so that the resonator is facing the back wall - pushed my back wall away from my listening position and helped surround me with more ambiance than I had before.

The more transducers and resonators you place in any one direction the more pronounced the stage movement becomes. (I had a large number or resonators on my front wall and then tried a bunch more, pointing in from my back wall and ended up moving and concentrating my listening area sweet spot so tight, in the middle of the room, that I was no longer sitting in the sweet spot. - Abort Abort!)

I also came to the realization that one can quickly experience “Too much of a good thing”, with these. After experimenting with just a few or having many, many of these I have scaled back my own usage to the point that I only use 8 -10 of these in my system (still haven’t made a final decision). In the end I now have: 2 facing backwards from my speakers - directly toward the front wall but angled slightly upward so they bounce sound off the front walls & up & over the speakers, 2 facing in towards the middle of the soundstage positioned just behind my front speakers, 2 facing in outwards from just behind my front speakers, and 2 on either side of me - facing the rear wall of my listening room from about 15 inches away. I’m experimenting with 2 additional resonators, also facing the front wall, but from outside of my front speakers.
With NO resonators facing in toward me or the room, and using a smaller number of resonators; IMHO my mid-range is more tame and listenable, my soundstage is moved back a bit – where I like it, and my ambiance is a little more enjoyable.

So while some people may have all their transducers or resonators pointed at them and like it (can’t argue with that), and some may have a huge number of resonators in their listening room and like it (can’t argue with that either), I thought I would add an alternative.

Happy listening,
Toolbox
Great write up!

I'm going to have to play with the effects of placement on frequency. I have noticed a subtle shift in which frequencies seem more prominent since I've installed these crazy little things. 

I think putting them lower is where I need to head.. thanks again for the detailed write up. You definitely went more in depth than I..

Excellent write up of results with the transducers and resonators. As I predicted trial and error is not really an effective way to obtain maximum results with resonators or transducers. And even following general diagrams can be risky. The only methodology that avoids all the pitfalls described in Toolbox’s post is the one is suggested early on - using a SPL meter and test tone to establish where exactly the sound pressure PEAKS are in the room. The best you can possibly do with a trial and error methodology is what is usually called a local maximum. It’s a lot like trying to find the absolute best speaker locations by trail and error. Only worse, since there are many more things to find locations for. Make sense?

The technique of Trail and Error is like trying to solve say 10 simultaneous equations in 15 unknowns. This problem with resonators is exactly the same problem at audio shows where there are a number of empty beer or coke bottles lying around on tables and on the floor. They act as resonators and affect the sound, mostly negatively, moving the soundstage around in weird ways and changing tonality and frequency response. Once you misplace one resonator or more, it will be more difficult to get good results even when proper locations are found as you proceed. Make sense?

With the SPL meter technique you can cut your time down tremendously and you will obtain much better results. Think of soundstage as a 3D sphere, what you really want to achieve is a centered deep and wide and high soundstage, one that is transparent and full of details and life. As the soundstage becomes more fleshed out and centered you should observe the 3D sphere expand like a balloon being filled up. CORRECT placement of transducers and resonators will results in smoother and more extended frequency response, without the peakiness some have noted. 


Thanks for the great write up, toolbox. Today I took all the DIY resonator cups off the walls and speakers. I'll probably throw them away. But I did have a ton of fun making them and playing with them for the past couple of weeks. I thought these things deepened the sound stage... but I was wrong. I was simply trying to defend my investment ($30 and labor and expectations). Just a placebo effect.




Well, I went from a gazillion resonators down to just ten.  With the smaller amount,  I do hear a nice addition to, and a repositioning of my soundstage.  Not the groundbreaking, earthshaking change some have stated, but a nice little tweak, nonetheless.  I'm happy!
My most pleasurable gain came by adding a resonator to each side of my front speakers. The outside resonators provided me with a slightly wider stage but also more ambiance. The inward facing resonators brought the singers and main instraments closer in toward center stage while providing much more definition for the individual parts.  This was done with just four resonators.  I got a little greedy and doubled the resonators (now with four facing inward and four facing out) with the new resonators placed about 15-18" below the first resonators.  The result was more muddy and harsh.
So now, I'm a confirmed minimalist when it comes to using these things.
Hopefully, you don't throw your resonators away.  Maybe after some time with no resonators, you might try adding one to the inside of both your speakers or maybe try the outside edge.  For me, I found that having my inward facing resonators at ear level (when seated) and my outward facing ones about 1 - 1.5 feet higher gave me the best reward.  That's as high off the floor as I would ever want to go.
But in the end, it's all about what makes the best music to you and your ears only.  So, if you end up liking music better without them - leave em' in a box.
BTW I have a couple of different versions of your resonators and they work very well for me.  I just built a few more smaller resonator types so I could test if different cone sizes affect different frequencies.  I also used heavier and lighter bases for the resonators to find out if the base material affects the sound.  Hopefully, I'll have the time to do the testing a couple of times, and write up a report soon.  I'm gonna try get it out this weekend or maybe early next week.  
Thanks for all your help.

Toolbox