Invisible speakers?

[fas42]

some sounds would just happen to be exactly where the speakers are and when it happens they pull your attention to their position

That's an interesting point. Again, because I was listening on a friend's system yesterday I understand where you're coming from. When what I have is working as I keep claiming here, any image that happens to be perfectly in line with the speaker floats totally free from that speaker. In other hands, if I move in front of the speaker and stand up the image moves up as well, and typically it registers in my brain as being behind the speaker. The speaker just happens to be like the hat of someone sitting on the seat a row or two away from me -- it doesn't get in the way of the sense of where the sound is coming from. To give an example of some 30's big band swing: on some recordings, obviously because of the nature of the recording studio and the technology of the time, you can hear the drummer is about 60ft back in the room from the vocal soloist, who is slightly overloading the mic. That drummer still sounds 60ft back whether I stand in the centre or directly in line with a speaker.

Frank

 

[Phelonious Ponk]

Measurement, Tim, measurement ...

Or do you mean at the precise moment your nose is in line with left edge of the speaker?

You know, I've got a feeling it's gonna be hard work dragging a number out of you ...

Frank

I don't have a number for you, Frank. I don't listen with a tape measure. I'm a big believer in listening blind, though. Next time I get a chance, I'll scoot back and forth in front of the system, pointing to the thing that started out in the center (usually the vocals) and opening my eyes to see when I'm pointing at a speaker. But I already know the answer. It'll happen when I've scooted right in front of the speaker!

Tim

 

[fas42]

Tim, I know you're not going to believe me ("so why the heck am I telling him ... I dont know (shrug shoulders)") but if the fates are favouring you, you will actually get past the speaker.

Believe It ooor Not ...

Frank

 

[fas42]

Tim,

Sorry about the tape measure quip, hope it didn't offend ...

Frank

 

[JackD201]

That's an interesting point. Again, because I was listening on a friend's system yesterday I understand where you're coming from. When what I have is working as I keep claiming here, any image that happens to be perfectly in line with the speaker floats totally free from that speaker. In other hands, if I move in front of the speaker and stand up the image moves up as well, and typically it registers in my brain as being behind the speaker. The speaker just happens to be like the hat of someone sitting on the seat a row or two away from me -- it doesn't get in the way of the sense of where the sound is coming from. To give an example of some 30's big band swing: on some recordings, obviously because of the nature of the recording studio and the technology of the time, you can hear the drummer is about 60ft back in the room from the vocal soloist, who is slightly overloading the mic. That drummer still sounds 60ft back whether I stand in the centre or directly in line with a speaker.

Frank

Hi Frank,

Maybe I'm not being as clear as I should be. An image can float in the direct line of one of the speakers (let's say it's the left one) in front or behind it. What causes the placement is still the summing from the output of the right speaker with the left one in that given space. In an instance where there is too low a signal from the right speaker or no signal at all, the location will be traced directly to the driver handling the dominant transient frequency. To be fair, it is a very rare occurrence in normal stereo program material but this does happen and when it does it doesn't matter if the system is extremely low in mechanical or electrical distortion.

I think I see where you are coming from too. In speaker systems that have gross distortions like ringing tweeters and mid drivers, or cabinets or frames that resonate (in a bad way) the distortions call attention to the offending loudspeakers. I think we should separate the two ideas because each are independent issues when it comes to attempting to create a sustainable level of suspension of disbelief granted that one needs a decent loudspeaker and chain of sources and electronics to extract the potentials of a recording.

Jack

 

[fas42]

If I click my fingers in front of me, the sound starts there, I guess I could imagine it coming from a point directly behind my clicked fingers

That's a useful point to start: at the moment we are talking about mono recordings, which simplifies things. If we had a instrument playing 15 ft in front of us our ear/brains reacting to the direct and reflected sound would be able to judge that distance quite accurately. Record that sound to a decent level of fidelity in mono with the microphone 10ft away from the musician, and then replay it on our system where the speaker is 5 ft in front of us.

If the system is working as well as I'm talking about then your ear/brain will tell you that the instrument is still of the order of about 15 ft away, irrespective of you standing in the centre, or moving in front of a speaker, stooping down and looking directly at the drivers, or getting up on your toes and looking over the top of the speaker, and "seeing" the instrument 10ft behind it. If the acoustics clues are reproduced well enough the ear/brain will decode what it means, and ignore the fact that it just happens to be coming from a speaker driver. The illusion is that the instrument is always 15 ft away, the speaker has "disappeared" as far as the ear/brain is concerned.

It might be relevant that I can still pick up 18kHz tones, not loudly but definitely there

Frank

 

[fas42]

A quick reply to both Jack and Tom: confusion is still the name of the game, and I certainly confused myself with the reply to Tom. At issue is still the driver disappearing, from, say 2" away: I'll try another thought experiment.

An instrument is recorded 10 ft away, ONLY on the left channel, within a reasonable, normal accoustic. Put your ear 2" from the driver: the music will sound as if it's 10ft directly behind the driver. Lift your head straight up, say 6", the ear is still 2" away horizontally from the driver, but 6" vertically from it. The music will sound still exactly as before, 10ft away and directly in front of you. It won't sound at all as if it's coming from that driver 6" below you -- the sound is coming completely from the phantom instrument 10ft behind the speaker!

THAT's the effect I am talking about, and any so-called "bad" recording fails terribly if the system is not right. If the system is right, that test will work.

Hopefully that makes more sense ...

Frank

 

[c1ferrari]

Monitors

ala Rogers LS3/5a!

 

[JackD201]

It works in a relative scale but not an absolute one. I have no doubt that in Tim's near field system he'll get good relative scale and distance in relation to his overall stage size. Think scale models at 1:30 with small systems and 1:2 in very large systems, 1:1 if you actually have an auditorium

 

[fas42]

Jack, it's not quite clear, ansd am curious: would your speakers to be invisible by your standards or anyone else's, under all circumstances?

Frank

 

[JackD201]

From the listening position totally invisible in mono. Definitely not invisible in or under all circumstances not that I didn't wish it were physically possible. I do wish it.

Even with mono, they are no longer invisible once I am within the radius of the loudspeaker where the drivers are too near to me to integrate properly and when their output is much higher than the other speaker. Within this radius the phantom mono image will collapse.

If I'm not clear about scale. Think of it as a 19" TV vs a 100" screen. Same thing with speakers and displays. The small screen still has images in proper relative positions as the bigger screen. The absolute positions however can differ in feet and not just inches.

Also like screens the closer you get the more you notice the "pixels" thereby making the illusion fall apart. Like screens there are optimal listening distances as there are viewing distances. Tim's monitors are meant to be listened to from 3 or 4 feet away, my large floorstanders from 10 to 15 feet away. Every system has an area where the illusion is most easily sustained. Venture outside it and it's sayonara. I'm pretty sure that every single person that says their speakers are invisible are saying so within the context of being within the sweet spot or sweet zone.

 

[fas42]

no longer invisible once I am within the radius of the loudspeaker where the drivers are too near to me to integrate properly and when their output is much higher than the other speaker

That's what I would have guessed from your comments, and my experience with other people's systems.

Using the terms that you have just used, invisibility occurs because there is no radius too small, you can never be too near the speaker, the drivers always integrate. Likewise, no matter how much higher the output from one speaker is compared to the other, because you are nearer to one versus the other, you still get the invisibility.

That's what the system will achieve if the remaining weaknesses are eliminated ...

I will do a tit for tat with an edit too: I brought in just a few comments ago the sweet spot analogy, so in that context, again, what you are always aiming to do is enlarge the sweet spot as much as possible. I claim that it can be made to be the whole room, if sufficient effort is expended in fine-tuning every aspect of the system, irrespective of the size of the speakers

Frank

 

[JackD201]

But Frank sound does not propagate in air in such a way no radius will ever be so small. You yourself noted that there is a 5 to 6 dB drop for every doubling of distance for non line sources anyway but even linesources drop intensity in distance just by less. Those are logarithmic drops. What you propose would require that the laws of physics be amended The illusion of invisibility again is not dependent solely on driver integration. Even if one were to invent the holy grail of all drivers, a truly full range, distortion free, massless thing of infinite output potential at an infinitely small point of origin, It's output will still have to deal with the air around it. The sound pressure closest to the source will always be greater than away from it. There will always be pressure zones that will dominate the ear/brain interface once you enter into one of them.

The phantom effect as said earlier by other members aside from, but including myself, is the effect of two or more signals summing and how the brain deals with this. A solid mono image is achieved with symmetry between the loudspeaker outputs first and foremost and aided by symmetry of their reflections. To a certain degree the mono image can stay put while you move around. In my case since my speakers are 10.56 feet apart and have broad directivity (off axis response) I can move a couple of feet to the left or the right. Once I get on axis to one of the speakers BAM! Hello speaker. That's where you've been hiding!

Now in an example I gave earlier where a signal is sent to only one point of origin there is just no illusion to be had. You might get projections from a single loudspeaker but it will be confined mainly to the frequencies where drivers overlap.

 

[fas42]

Jack, all those explanations are perfectly valid if you believe that the ear/brain works in a very rational, always mechanical way. I would have said, Hear, Hear, myself to what you just said many years ago if I hadn't experienced the effect myself. The effect, what effect? That the BAM! Hello speaker moment DIDN'T happen, no matter where I went in the room! I said in so many words to myself, "What the ...".

My journey since has been to replicate the effect at will, as well as understand it. I can certainly understand why essentially all listeners refuse to believe in it, simply because they haven't experienced it and it DOESN'T make sense. Hence the red wine analogy, I'm afraid (sorry about that, now if you had asked for just one case rather than two ...)

My conclusion so far is that our sensory systems are willing to be deluded, if we supply them with sufficient high quality information. Interestingly enough, sometime earlier I had read about an exactly equivalent phenomenon with the visual system, which may make it easier to get a handle on things ...

What they were doing was to develop a very high quality movie projection system, in the belief that it would attract more patrons -- similar concept to IMax but more advanced. They did research, and found that removing flicker between frames was crucial, the frame rate was upped dramatically and the resolution and screen size increased.

One big problem. They got the technology working, early 70's I think, made a exciting test film of a car racing down a mountain road and tried it on a test audience. And disaster! The people watching could not stop their system and bodies reacting to what was happening on the screen as if it were real, I can't recall the exact details, but something along the lines of heart attacks, vomiting, fainting, you name it. And that was the end of the technology, shelved indefinitely, I guess ...

The assessment by the doctors was that no matter how certain people were in their heads that what they were watching was not real, the quality of the presentation was enough for the eye/brain to cross a threshhold and say to the physical self, This Is The Real Thing!

So my evaluation of this speaker invisibility thing, to this point, is that the ear/brain connection can pull the same trick but in our case we have a bit more control of the material being sent to our sensory system! Cross a threshhold with the quality of presention, and the ear/brain can be totally fooled ...

Frank

 

[JackD201]

Ok then Frank could you please recount the details of this experience. When, where, what the system was that you could actually trip over the loudspeaker or bump into them. The curious want to know.

 

[fas42]

Jack, if you go over all my postings so far in this forum you will find that I have already described the circumstances in fair detail. But I will repeat for the sake of continuity here and add more bits ...

Like most of you here I have been fiddling with audio since high school days. When CD came along, it was all very exciting, I waited until you could get a well made Japanese unit which had a digital volume control, connected it directly to a pretty powerful NZ amp and some quite reasonable English speakers. The latter two were second hand in fact. Sounds pretty good, I thought, I'll try some of this new fangled tweaking people are talking about. Luckily, I had an Electrical Engineering degree so I knew at least one or two things about what to do ...

So the system got better and better. I'm a bit of a perfectionist and I kept hearing things not quite right, so basically fixed up what I perceived as weaknesses in the way the whole lot hung together, and kept on doing this. Then, one momentous day, this effect occurred and I thought, what the hell is going on! The trouble was, the flash of enhanced realism only lasted a very short time, literally minutes only and it then became a struggle to have it sustain. The whole thing became very frustrating, because I knew how good it could sound, but I could not have that quality last for more than a track or so.

In the end I gave it away for almost 15 years, thinking surely someone else will sort this out, I won't have to worry about trying to make it work. Every now and again I would try a high end store to see if progress had been made. No, same old crap, no matter how expensive.

Anyway, a few years ago I decided to give it another go, and now have a much, much better handle on it. As I have stated a number of times I believe Vince (muralman1) has also got it, but like me is having a hard time convincing anyone ...

So, to repeat myself for the thousandth time, it is not the system which is the answer, but how well and thoroughly all the weaknesses, every last one of them, that all systems have, are eliminated that allows it to happen. The better the system, the harder it can be because the components are more sensitive to every little thing you do, like a finely tuned high performance car. All you tweakers know this, oh, so well!

Okay, enough for now,
Frank

 

[JackD201]

I subscribe to the same philosophy of removing distractions Frank. It really is a fragile illusion and perhaps one's state of mind is the biggest hurdle. Some people have the knack of switching from receptive to critical at will, most of us can only envy those that can. I mean each and every one of us I think could have stopped at any point and left well enough alone. I guess what I'm saying is that not only are there physical limits as to what today's technology both recording and playback, can achieve in the physical realm but even our own preferences change over time. The paradox is that you have to be critical while tuning so it will be easier to accept the illusion later.

There's a fine line between eliminating distractions and seeking perfection. I try my best to steer clear of the latter as all this has ever gotten me is frustration and disappointment. Am I satisfied with my system now? Definitely. Can it be better? I'm even more definite. I even know what has to be done. Thing is even with this improved system I'll still be far from perfect. I'm electing to take a break though. I don't want to be signing checks my body can't cash If you look at my system page I think you'll find I've gone quite an extent to stabilize the "illusion" as so many others have on this forum albeit in their own sometimes unique ways. That's why I like this forum. It isn't a forum that's all about the gear.

Where I disagreed with you is in areas where limits must be recognized. Scale is a function of dynamics both in output and the available space for the output to properly propagate. You are right. The more you know and the better a system gets the more difficult it becomes not only because they must be treated with greater precision but strongly because our personal standards keep rising. At some point however I accepted the limits. It's a very personal thing. Vince might be on cloud 9 but it doesn't mean that if I walk into his room it will affect me as profoundly as it does him right? Yet I don't think even Vince, our most satisfied member, would go as far as saying that if he put his face to his speakers he'd hear whatever 15 feet behind it or that he can get any sort of phantom image from there. I will not dispute that what he hears from his favorite spot or anywhere else within a certain range from his loudspeakers sounds eerily real to him. These are the limits imposed on us by the current technology. I'm not abandoning the quest, I'm just being practical about what is possible in the here and now.

 

[Robert]

Frank, You state that any system is capable of making any recording sound outstanding from any place in the room if distortions are eliminated. You also note much experience tweaking systems to eliminate the noise.

Please provide your top 5-10 ways of reducing distortion, so we can benefit. I'm always wanting to improve what I got.

 

[Phelonious Ponk]

This is a pretty accurate assessment in my view. In the near field I listen in relative scale. In your living room, you listen in relative scale. These are the trade-offs. They are on the long list of reasons why, no matter how much our perceptions may aid us in the creation of the illusion, audio reproduction is an illusion.

Tim

 

[tony ky ma]

tony, that is an excellent tweak, so to speak. That Tim's systems works well for him is helped for the same reason

Unfortunately, that to me says that things are not quite right. For me, this is the key indicator, it most definitely should NOT sound like noise; I would in fact use the word distortion.

Frank, Tom is right that is the sound "sheet" like noise mainly from the JBL tweeter, very low level of music that I can hear is below 15K is not distorted, without those "sheet" sound the whole thing will getting live less, one more tweak, set up a system that the image can be heard in out side of the speakers left or right, and turn off one channel to see where the image move (probably stick with the channel which is on ), turn it on again to see the image back to out side again, that means with the help of other speaker, image can go out side of two speakers not in between ( my system does )
tony ma