3D imaging

millercarbon,do you use HFT's with traditional acoustic treatments,or are these applied alone?

Sorry for the late reply. So many threads ruined so often and so fast by the same few people I tend to say what I think needs to be said and then that's that. But anyway...

Here's a photo of my room. Its old, 2004, but its good because it shows some of what I went through. http://theanalogdept.com/c_miller.htm
The yellow panels are Owens Corning acoustic panels, the same as used inside 90% of expensive professional room treatment. There's people like Duke (Audiokinesis) you can trust to post gold. Then there's guys like me who have to work at it more. This photo is working at it. 

Just like Duke said above, its real easy to over-do it, acoustic panels predominately affect the top end, and so can really alter the rooms acoustic. So this was moving them around learning first hand just what that means. The room now has none on the walls. Only the corner tunes remain. Very effective, with hardly any downside in terms of being overly damped.

My tests were made moving whole panels around. First reflections requires only about a one foot square. It could be that if I went back and tried just a small one like that, might like it. Heck now to think of it got some in the shop might just do that. Just because it sounds great doesn't mean it can't sound even greater. 

HFT are a completely different technology, much more sophisticated, work regardless of the room, and so are used together with the same traditional acoustic panels. 

They don't have to be. Look around YouTube, there's a demo in a very ordinary room, pretty crappy room actually, way too lively, way to sparsely furnished, no acoustic treatment at all. Ted adds HFC and even on laptop YouTube you can hear the improvement. Pretty remarkable stuff. 

My biggest compromise is distance from side walls, not much I can do about that,however I do have treatments at the first reflection points,which helps. I guess my next question will be a little more involved. How do downstream electronics help or hinder 3D imaging?

Distance from side walls is but one room factor, only mentioned because you were asking about speakers. The answer to how electronics help or hinder imaging is short and sweet and controversial as hell: no one knows.

Oh, there are theories galore, just none that hold water. 

But to segue back to the room segue, damping first reflections with what is basically a few bucks worth of OC703 is an old school Stone Age imaging tweak. Next generation room and speaker treatments like Synergistic Research High Frequency Transducers are far more sophisticated and effective.

HFTs work on the principle of dither. Professionally used in video for years now, dither is a very particular sort of noise that when added to a signal actually improves the perception of clarity and resolution. Each HFT is only about 1/4" in diameter, and shaped like a tiny little speaker horn. Exactly how the darn things work is a Ted Denney trade secret, but they do indeed work. The improvement in sound stage width, depth, layering, focus, and palpable presence is remarkable. 

I've got a lot of experience with room treatments. You simply cannot do with conventional absorber/diffusor panels and tubes anything even remotely on the level of HFT. They help, but not like this. Do a set for each speaker, plus a couple more for the walls and ceiling, realize you only thought your speakers disappeared. With HFT they are GONE! Heck, your room is gone! 

Thanks for the input millercarbon. I rotate 3 sets of speakers in my system,(Hornshoppe Great Horned Heils,Nola Boxer 2's,and Graham Chartwell LS3/5's). They all throw a great 3D image,so I guess I'm doing something right. I was just curious if the speaker design was responsible.

 I've read posts on other forums where posters think that attaining 3D imaging is just chasing unicorns. Obviously they are doing something wrong.
   
  As a side note,I've been at this hobby for a bit,and I'm no spring chicken. I just don't have a ton of technical knowledge. This is one reason I frequent this site. There are a large number of members here that DO have a vast knowledge of things audio. I find that exposing myself more to the technical aspect of this hobby will help me understand what I am hearing to a greater degree.
    Again,thanks for your response,
           Ray

Okay. Thanks. Got it. First stab answered your literal question. Now with more info I can give a much better answer.

Almost all our sense of location comes from the midrange on up, and is based primarily on arrival times. That's why location is so important, and makes a difference to the point even as little as 1/8" can be noticeable.

 I was just curious if the speaker design was responsible.

It is. Sound waves coming off a driver radiate out in an arc. Because of the way waves travel they reflect (bounce) or diffract (scatter) or refract (bend) off anything they hit. 

Now this is a Big Deal for speaker designers, because it turns out sounds that arrive within a window of about 3 to 5 milliseconds of each other tend to be perceived as coming from the same source. 

So let's say you have a midrange driver mounted in a great big speaker with an edge around the speaker like for a dust cover. Sound coming off the driver radiates out and all along the way is reflecting off the baffle, and then reflects and refracts again at the edge. 

Physics: sound travels roughly 1 foot per millisecond. So all the reflections and refractions are well within this critical window.

Now you know why so many drivers are mounted flush, in super smooth baffles, with nothing sticking out, and often with felt or other material to absorb these reflections, and all in a cabinet no bigger than it absolutely has to be. 

There's also the speaker cabinet itself. Its hard to notice because so much of the sound comes from the drivers, but play something loud and feel the sides of the cabinet, especially the front. If that is moving at all then its radiating sound. So now you know why so many really good speakers are massive and have super strong cabinets. If the cab vibrates at all it is in effect another speaker blurring arrival times and ruining imaging. This is really, really hard to do, especially as you get bigger and bigger, and goes a long way to explaining why so many small speakers are sound staging champs.

Then there is the fact that just as much sound radiates off the back of the driver and into the cab as out into the room. Very big problem. Unless its highly damped this sound will reflect off the back of the speaker and come right back out through the driver. Only delayed. Another hit to imaging. So even internal construction and damping matters.

Now if you caught the 3-5 ms rule then you also learned why it helps imaging to have speakers placed 3-5 feet away from walls. 

You ask for vast knowledge of things audio, you get vast knowledge of things audio. What else you wanna know?

What makes speakers produce a 3D image is being symmetrically equidistant and pointed towards the listener. Period.

All the other stuff contributes, of course. But you asked specifically about speakers. 

But hey, don't take my word for it. Prove it to yourself. Point one speaker off to one side instead of at you. Move one a foot closer or further away. Notice nothing else changed- same recording, same room, same components.

Speakers are like real estate: location, location, location.