Invisible speakers?

fas42 said:

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

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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 said:

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

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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

Monitors

ala Rogers LS3/5a!

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

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.

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.

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.

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.

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.

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

fas42 said:

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

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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