For more testing here's the tom sample panned from left to right. No interchannel delay, only interchannel level differences:
Tom, panned from left to right
Tom, panned from left to right
how about more of testing of the original Stereolith?
let me take this opportunity (for the sixth time) to draw Your kind attention to couple of questions posted above that You haven't asnwered yet:
are they working in one volume or is there any kind of partition inside? from:
http://www.diyaudio.com/forums/multi-way/10962-stereolith-loudspeakers-question-33.html#post2523007
how do they look alike in case of the original Stereolith?
from:
http://www.diyaudio.com/forums/multi-way/10962-stereolith-loudspeakers-question-45.html#post2528343
You experience with what? What's the setup?
from:
http://www.diyaudio.com/forums/multi-way/10962-stereolith-loudspeakers-question-44.html#post2527585
what is exactly pretty amazing about it?
and
Do You mean AVR + an upmixing algorithm?
from:
http://www.diyaudio.com/forums/multi-way/10962-stereolith-loudspeakers-question-40.html#post2525359
and
Could You be a little bit more specific? Which conlusions exactly?
and
What is more to it?
and
which book?
from:
http://www.diyaudio.com/forums/multi-way/10962-stereolith-loudspeakers-question-40.html#post2525362
regards!
graaf
Simple diagram for first lateral reflections in a room. Only one side reflections are shown. This model is valid in upper midrange and treble, it should cover the most important freq range.
Small blue dot is the speaker. Red dot is a virtual source formed by room reflection. Green arrow shows the main intended radiation direction of the speaker.
Stereolith:
All the sources are placed outside of the room boundaries, the walls really disappear. The sources are also quite wide angle. The front wall should be reflective. The reflections are almost at the same angle from the driver axis so it's easy to make them almost equivalent in spectrum. There is automatically added distance to the sources which makes them more realistic.
Beveridge:
Only one source outside room boundaries, also quite far away from the real source. Speaker should be very wide dispersion. However since one source is inside of the room head rotation or movement can localise the speaker inside, not realistic.
Stereo:
The source outside the room boundaries is formed by about 90 degrees off axis of the driver, which is very hard to make it spectrally equilavent with direct sound. Probably for this reason most of the stereo speakers fail. Also source is very close and direct sound dominates so head rotation and movement diminishes realism. No added depth.
Corner:
Interesting since no first reflections. Does the image allways remain inside the room? Walls never disappear? Or is it the best of everything and the walls do not exist? The speaker should be specially designed for this placement, not any box placed in corner will do.
- Elias
Small blue dot is the speaker. Red dot is a virtual source formed by room reflection. Green arrow shows the main intended radiation direction of the speaker.
An externally hosted image should be here but it was not working when we last tested it.
Stereolith:
All the sources are placed outside of the room boundaries, the walls really disappear. The sources are also quite wide angle. The front wall should be reflective. The reflections are almost at the same angle from the driver axis so it's easy to make them almost equivalent in spectrum. There is automatically added distance to the sources which makes them more realistic.
Beveridge:
Only one source outside room boundaries, also quite far away from the real source. Speaker should be very wide dispersion. However since one source is inside of the room head rotation or movement can localise the speaker inside, not realistic.
Stereo:
The source outside the room boundaries is formed by about 90 degrees off axis of the driver, which is very hard to make it spectrally equilavent with direct sound. Probably for this reason most of the stereo speakers fail. Also source is very close and direct sound dominates so head rotation and movement diminishes realism. No added depth.
Corner:
Interesting since no first reflections. Does the image allways remain inside the room? Walls never disappear? Or is it the best of everything and the walls do not exist? The speaker should be specially designed for this placement, not any box placed in corner will do.
- Elias
Sorry, but this is not what the Sterolith sounds like. It's more like a central source with varying image size. Never larger than +/- 30°. Mostly narrower.
Only the Stereosphere concept creates phantom sources to the left and right. They're not that far to the left and the right as your picture indicates because there's always the direct sound that pulls the phantom sources towards the center.
The back wall reflections are not needed. I even think they're detrimental. Second order reflections from the ceiling are more likely to contribute to the perceived spaciousness.
Then there's a effect that hasn't been discussed yet - interchannel time delays of recordings change the polar pattern of the speaker...
Only the Stereosphere concept creates phantom sources to the left and right. They're not that far to the left and the right as your picture indicates because there's always the direct sound that pulls the phantom sources towards the center.
The back wall reflections are not needed. I even think they're detrimental. Second order reflections from the ceiling are more likely to contribute to the perceived spaciousness.
Then there's a effect that hasn't been discussed yet - interchannel time delays of recordings change the polar pattern of the speaker...
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nice demonstration and convincing in it's simplicity
what is shown is that bipolar stereo - please scuse me for this another try at cool sounding name
- is clearly the bestthat's convincing on paper but with my flooders against the wall I also experienced disappearing of this wall and impressive depth, of course flooders are not Beveridge speakers but these were widely reported to have huge soundstage in Beveridge arrangement as well
corner horns have long tradition, in the end this seems to be Dr Geddes' way of doing things, althoughs to be perfected it really requires integration of the speaker into corner
precisely speaking there are first lateral reflections of course - they come from back wall and opposite side walls
regards,
graaf
cardboard boxes of Elias and Scott do this, and my old - almost professional-looking in comparison
- ply boxes did that as well, Radugazon impressive speakers do that tooand what is Stereosphere? especially without it's ™
what is this concept?
surely hasn't been discussed on the forum
so TIE fighter incorporates The Stereosphere™ principle?
but it's just a silly-looking implementation of my old hypothesis that:
from: http://www.diyaudio.com/forums/multi-way/121385-loudspeakers-room-system-25.html#post1621032
perhaps it works as I supposed but apparently Victor Brociner's idea of deflecting of the direct sound works at least equally well
and it's implementation doesn't look silly
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I haven't tested out this format for quite some time now..
(more than 8 years.) (..and in fact was started far earlier than that with a basic pair of book shelf speakers in the 90's.)So "how big was the soundstage?" I don't remember that aspect as it relates to the venue (..well, except for some of the effects of a low freq. response when moving the speaker further from the garage door.) It is of course rather program dependent, the greater the sp-level of the venue in the recording (vs. the average), typically the more apparent the venue.
I *suspect* the soundstage was very low in level without the room's reflections. But again, I honestly don't remember.
I do remember that imaging certainly extended beyond more than a foot.
(..and a fair bit more, but certainly not nearly as expansive as in a room.) Generally the sense of depth was proportional to it's width outside vs. the listener's distance from the loudspeaker. Move closer - depth increases while imaging becomes more diffuse. Now add the garage door reflection and depth increases substantially. (..of course lower freq. emphasis ALSO increases as well.)Sorry Graaf, I'm not in a position for current testing. For that - I'll leave to others to explore.
I don't think for LR separation however that it's so much a matter of "how much is really required", rather how much can you get? *More* seems to be clearly better as you go higher in freq. (up to 7 kHz).
As an additional note (after looking over Elias binaural measurements and thinking more about them):
With regard to venue presence and *enhanced* imaging because of a better venue presence.
A sense of venue provides context to an image(s).. sort of an aural "grid" to better delineate BOTH position and size. (..and in this respect I've always maintained that loudspeakers that "strip" out the sense of venue and leave a "they are here" perspective are fundamentally incorrect.)
Clearly room reflections can enhance this, and are not dissimilar to the recording itself (i.e. direct/reflection ration within the recording). However just as clearly, reflections can detract from this. (..sort of a push vs. pull effect, which is true even for the recording or live sound.)
After seeing (and thinking over the wavelet plots), I'm starting to believe that at least one significant factor to mitigating those reflection effects (with stereo reproduction) that DETRACT from the presentation are substantially LR separation effects. In other words keep the right side reflection on the right side, and the left side reflections on the left side.
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Except for a big barrier, how can that be done? Or do you mean the 1st reflection?
In addition, even if we can keep all reflections on the same sides, they still arrive both ears. Crosstalk is still there.
Except for a big barrier, how can that be done? Or do you mean the 1st reflection?
In addition, even if we can keep all reflections on the same sides, they still arrive both ears. Crosstalk is still there.
The "first reflection". Of course the "first reflection" usually entails a rather large number of reflections (..depending on the design of the loudspeaker and it's placement relative to most listening rooms and the reflective quality of the room itself).
I don't think crosstalk will ever be eliminated (unless the design is *very* unusual, or the room is), and I'm not even sure that it would be advantageous UNLESS the recording is convolved to binaural. So as previously mentioned, I think it's a matter of how much *effective* separation can you get (..both in pressure and time)? Clearly in the wavelet plot, Elias was getting rather excellent results with this design in this respect.
How might it be improved? Larger room, or perhaps an alternate position within the room (.. like utilizing one of the two "long walls" as the "front wall"). Of course a larger room or an alternate position may entail creating other problems as a result.
I could also envision a "layering" of floor to ceiling curtains between loudspeakers that would each absorb just a bit of the reflected energy, but in total *should* help (..depending on the material). (..of course in the case of the stereolith the curtain design wouldn't work, BUT it might work very well with a slightly more conventional 2 loudspeaker with a radial horizontal pattern. )
yes, and this is what I call fidelity
absolutely! though I would like to reword this to a more specific formula - keep most of the energy of the right channel signal on the right side, and of the left on the left, because:
from:
http://www.diyaudio.com/forums/multi-way/121385-loudspeakers-room-system-9.html#post1506366
and...
exactly! excellent results in keeping the energy of the right channel signal on the right side, and of the left on the left
Crosstalk is still there.
yes, but perhaps loudspeaker crosstalk is problematic only in the very first milliseconds?
or perhaps on the contrary - as it is about interaural level leakage it should be estimated with reference to the difference of total sound energy of a channel signal received by both ears during the first 30-50 ms when reflections add to the perceived loudness?
and as we can see in the WTF plots this difference is indeed very significant
crosstalking reflections - reflections off the opposite wall are much weaker and also more delayed (also a significant factor IIRC)
here are some my old speculations on why convetional stereo fails, perhaps somewhere there is also hidden a clue as to why bipolar stereo works better:
http://www.diyaudio.com/forums/multi-way/130352-loudspeaker-perception-27.html#post1625969
regards to all,
graaf
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Let's go 3D.
Here is a simple model of first early room reflections of the cardboard and conventional stereo. Only ipsilateral reflections are shown.
The cardboard:
The blue box is the speaker. Green arrows indicate the main directions of radiation.
There is no direct sound. The red and magenta dots indicate the points where the ray from the virtual source pokes through the room boundaries. They are located on the locus which is vertical on the wall and connects the points directly above and below the listener head.
Point 1: side wall reflection
Point 2: floor - side wall reflection
Point 3: side wall - ceiling reflection
Point 4 - 6: similar but also reflected from the front wall.
The time of arrival of the points:
2 and 3 arrives allways later than 1. 5 and 6 arrives always later than 4. But depending on the room geometry order of 2, 3 and 4 (and 5 and 6) may vary.
This is clearly a wall of sound. These reflections arrive from quite wide lateral angle and generate very spacious sound. Also, these reflections are having almost the same spectral balance and create very believable perception of space.
Also note: by damping the front wall reflections 4-6 can be eliminated at will.
Stereo:
The direct sound is indicated by green arrow.
There is only one lateral reflection 1. Reflections 2 and 3 are floor and ceiling. 2 arrives from very deep donwstairs and 3 very high upstairs and they lateral angle is small so they don't generate much spaciousness.
As indicated in previous post, reflection 1 comes from about 90 degree driver off axis so typically it has very distorted frequency balance. Also typically if high directive source is used e.g a horn or a waveguide reflection 1 is almost nonexistent. Also a dipole will cancel reflection 1.
These early reflections don't generate a spacious sound, a very dull sounding perhaps. Certainly not realistic.
- Elias
Here is a simple model of first early room reflections of the cardboard and conventional stereo. Only ipsilateral reflections are shown.
The cardboard:
The blue box is the speaker. Green arrows indicate the main directions of radiation.
There is no direct sound. The red and magenta dots indicate the points where the ray from the virtual source pokes through the room boundaries. They are located on the locus which is vertical on the wall and connects the points directly above and below the listener head.
Point 1: side wall reflection
Point 2: floor - side wall reflection
Point 3: side wall - ceiling reflection
Point 4 - 6: similar but also reflected from the front wall.
The time of arrival of the points:
2 and 3 arrives allways later than 1. 5 and 6 arrives always later than 4. But depending on the room geometry order of 2, 3 and 4 (and 5 and 6) may vary.
This is clearly a wall of sound. These reflections arrive from quite wide lateral angle and generate very spacious sound. Also, these reflections are having almost the same spectral balance and create very believable perception of space.
Also note: by damping the front wall reflections 4-6 can be eliminated at will.
An externally hosted image should be here but it was not working when we last tested it.
Stereo:
The direct sound is indicated by green arrow.
There is only one lateral reflection 1. Reflections 2 and 3 are floor and ceiling. 2 arrives from very deep donwstairs and 3 very high upstairs and they lateral angle is small so they don't generate much spaciousness.
As indicated in previous post, reflection 1 comes from about 90 degree driver off axis so typically it has very distorted frequency balance. Also typically if high directive source is used e.g a horn or a waveguide reflection 1 is almost nonexistent. Also a dipole will cancel reflection 1.
These early reflections don't generate a spacious sound, a very dull sounding perhaps. Certainly not realistic.
An externally hosted image should be here but it was not working when we last tested it.
- Elias
Elias,
In the absence of direct sound, the positioning of the phantom sources in the stereo scene would depend on ILD and ITD informations being preserved in the different reflections. So no patches of absorbing material (curtains, windows etc.) or protruding furniture anywhere in the 150° space in front of the listener, right?
What kind of imaging do you experience with that system in your room?
In the absence of direct sound, the positioning of the phantom sources in the stereo scene would depend on ILD and ITD informations being preserved in the different reflections. So no patches of absorbing material (curtains, windows etc.) or protruding furniture anywhere in the 150° space in front of the listener, right?
What kind of imaging do you experience with that system in your room?
what is the carrier of ILD and ITD informations and how could those be distorted in reflections?
but why anywhere? after all first reflections are not coming from anywhere in the 150° space in front of the listener, they are coming from more or less specific locations, aren't they?
regards,
graaf
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Hi Rudolf,
In the old times when pictures from photographic slide film were projected on the white screen on the wall at home one would not have hanged just any white bed sheet to view his precious pictures, but a carefully chosen screen with proper reflective properties was chosen. Do you remember? This is no different. Some think it is important to have wall absorption according to strict specifications, some think it is as important to have wall reflectivity in control.
As indicated numerous times already, and let me repeat myself again, the images are very stable and don't move when turning my head. Music sounds very much like it would sound in the real event. Easy to listen. Enjoyable. It sounds real, not artificial. Stereo never achieved this level of realism.
- Elias
In the old times when pictures from photographic slide film were projected on the white screen on the wall at home one would not have hanged just any white bed sheet to view his precious pictures, but a carefully chosen screen with proper reflective properties was chosen. Do you remember? This is no different. Some think it is important to have wall absorption according to strict specifications, some think it is as important to have wall reflectivity in control.
As indicated numerous times already, and let me repeat myself again, the images are very stable and don't move when turning my head. Music sounds very much like it would sound in the real event. Easy to listen. Enjoyable. It sounds real, not artificial. Stereo never achieved this level of realism.
- Elias
I'm pretty sure that IF Toole would have included The Cardboard type of speaker in his listening tests, it would have been preferred over the others by most of the listeners.
- Elias
* The reason to mention Toole in this context is that he is constantly being referenced here (in this forum) as a proof to make conclusions in various subjects, even though his listening tests were quite one dimensional in loudspeaker variety. But that is understandable. I don't mind.
- Elias
* The reason to mention Toole in this context is that he is constantly being referenced here (in this forum) as a proof to make conclusions in various subjects, even though his listening tests were quite one dimensional in loudspeaker variety. But that is understandable. I don't mind.
How to make a valid comparison, stereo never worked for me
Before it was image jumping from tweeter to tweeter with head turning or movement, terrible tonal errors when not exactly in the midline, not much sense of space but, as I say, dull sound. Now all of this has been corrected. Brand new world !
- Elias