But when I listened it placed on the floor it sounded like a radio, if such a comparison can be made
I don't believe in this concept. It can do some things better than conventional stereo triangle, BUT:
1) The speakers may be unlocalisable at high freqs, while conventional direct firing tweeters can lead to speaker localisation.
On the other hand, the same improvement can be made to normal stereo speakers by simply tilting the tweeters upwards to reduce the direct to reflection ratio !
2) The spaciousness can be higher than with conventional direct firing stereo triangle.
On the other hand, spaciousness can be increased in the listening room by introducing a lots of lateral wall reflections. It can be done using a special sideways firing speakeror by appropriately toeing the speakers (according to some) or by adding extra speakers emitting 'surround' signal of sort.
Are you sure that tilting the tweeters back can bring the same improvement?
Well, I don't question this in principle - perhaps to You ears indeed it can. I am just asking if You are sure it's the same.
Then, we both know that sideways firing speakers has its own disadvantages, and as far as toeing is concerned according to some is again just according to some, and that it is not that easy and available solution of extra speakers emitting 'surround' signal of sort. Who really does it in practice? With stereo recordings, I mean. And the same improvement?
I cannot question that "it sounded like a radio" - unlocalizable and spacious sounding strange "radio" - at least that this is how You described it after two years passed by.
Question is if there is any room for improvement? Or is it really flawed by design?
So far I can't see any convincing reasons that it is flawed by design.
I really would like to see them if there are any.
can You elaborate on this? For example - was it a matter of the frequency response? Did You try to equalize it?
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When I placed my upward firing radio on the floor, it sounded like a radio on the floor.I cannot question that "it sounded like a radio" - unlocalizable and spacious sounding strange "radio" - at least that this is how You described it after two years passed by.
Question is if there is any room for improvement? Or is it really flawed by design?
So far I can't see any convincing reasons that it is flawed by design.
I really would like to see them if there are any.
I have no problem with the sound of the radio, but floor placement sounded "wrong" to my hearing.
If the goal of maximization of reflections is deemed a "design improvement" the primary design flaw I see with a floor placement is the direct sound from that source dominates the sense of where sound is coming from.
Sound coming from the floor is not a desirable attribute for any sense of realism, it is "really flawed by design" , if a sense of realism is part of the design goal.
If the floor mounted upward firing speaker has narrow enough high frequency dispersion, and the ceiling is fairly tall, percussive high frequency sounds reflected off the ceiling and walls arrive outside the fusion zone, which is as short as a few milliseconds for percussive HF sounds.
Those sounds are perceived as separate auditory images, coexisting with the direct sound, but as the direct sound is still perceptually dominant, this creates a "cognitive dissonance" of multiple locations of a single audio event, something that seldom occurs naturally.
Strike two against a natural sounding spaciousness.
Floyd pretty much sums up what I consider basic design flaws of the FCUFS concept here:
"Loudspeakers and Rooms for Sound Reproduction—A Scientific Review*
FLOYD E. TOOLE
(ftoole@harman.com)
2.1 Effects on Localization (Direction)—The Precedence Effect
Over the years the terms Haas effect and the law of the first wavefront have also been applied to this effect, but current scientific work appears to have settled on the term precedence effect. It has to do with the well-known phenomenon wherein the first arrived sound, normally the direct sound from a source, dominates our sense of where sound is coming from. Within a time interval often called the fusion zone we are not aware of reflected sounds as separate spatial events. All of the sound appears to come from the direction of the first arrival. Delayed sounds arriving outside the fusion zone may be perceived as separate auditory images, coexisting with the direct sound, but the direct sound is still perceptually dominant [6]. At long delays the secondary images are perceived as echoes, separated in time as well as direction.
It needs to be emphasized that, within the fusion interval, there is no masking—all of the reflected sounds are audible, making their contributions to timbre and loudness, but the early reflections simply are not heard as spatially separate events. They are perceived as coming from the direction of the first sound."
Yup.
Art
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but not all experimenters reported sound coming from the floor, in fact minority of them did, then how can we say that it is something that occurs inevitably by design?
and in the light of such established designs as Snell Type One or Keele's CBT it is hard to say what really causes this sound coming from the floor phenomenon
but no user which tested such configuration reported anything like that
so how can You say it is a flaw in the design??
well, yup what?? honestly I can't see any connection
Isn't the precedence effect a binaural mechanism researched for lateral reflections only?
Aren't psychoacoustic mechanisms for vertical localisation quite different, relying on spectral HRTF cues and on the first ground reflection cues??
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Graaf,
The precedence effect works in 3 dimensions, not just for lateral reflections, as can easily be determined by anyone who locates a chirping bird in the air, or a cricket on the floor.
What all the mechanisms are that determine why we can reliably point to a source of sound in three dimensions in a variety of acoustical spaces don't interfere with the fact we can.
Hearing the floor mounted speaker as located on the floor, I'm simply in agreement with Toole's statements in "2.1 Effects on Localization (Direction)—The Precedence Effect."
If you can't see any connection of the precedence effect to hearing something that is located on the floor as being on the floor, I certainly can't persuade you too.
If you or others hear the floor mounted speaker in some different location than the floor, I'm happy for your suspension of disbelief, or whatever you attribute the difference in perception to.
If you think floor localization is not a design flaw, so be it, it is not a design flaw to you.
I won't presume to know what you or others hear, but you either are ignoring or dismissing what I hear.
When I tried a more narrow HF dispersion speaker on the floor, I heard what I described, percussive high frequency sounds reflected off the ceiling and walls arriving outside the fusion zone, which is as short as a few milliseconds for percussive HF sounds.
Those sounds were perceived as separate auditory images, coexisting with the direct sound, but as the direct sound is still perceptually dominant, it created a "cognitive dissonance" of multiple locations of a single audio event, something that seldom occurs naturally.
I would expect others using narrow dispersion FCUFS to hear something similar, but their description of the experience may be positive, rather than negative.
Again, what I perceive as a design flaw is not a design flaw to you.
You don't agree with my assessment of the FCUFS, that's OK.
Have fun, good luck!
Art
...and:
"Figure 6.7 shows more data from Olive and Toole (1989), in which it is seen
that the thresholds for the side wall and the ceiling refl ections are almost identical.
This is counterintuitive because one would expect a lateral refl ection to be
much more strongly identifi ed by the binaural discrimination mechanism
because of the large signal differences at the two ears. For sounds that differ only
in elevation, we have only the spectral cues provided by the external ears and
the torso (HRTFs). Although the threshold levels might be surprising, intuition
is rewarded in that the dominant audible effect of the lateral refl ection was
spaciousness (the result of interaural differences) and that of the vertical refl ection
was timbre change (the result of spectral differences). The broadband pink
noise used in these tests would be very good at revealing colorations, especially
those associated with HRTF differences at high frequencies. On the other hand,
continuous noise lacks the strong temporal patterns of some other sounds, like
speech.
This makes the fi ndings of Rakerd et al. (2000) especially interesting. These
authors examined what happened with sources arranged in a horizontal plane
and vertically on the front-back (median sagittal) plane. Using speech as a test
sound, they found no signifi cant differences in masked thresholds and echo
thresholds sources in the horizontal and vertical planes. In explanation, they
agreed with other referenced researchers that there may be an “echo suppression
mechanism mediated by higher auditory centers where binaural and spectral
cues to location are combined.” (Toole, "Sound reproduction")
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By the way, here's the graph showing that the first 3 reflections in a "typical" room are already loud enough to cause image spread for speech:
(http://www.aes.org/e-lib/download.cfm?ID=13686&name=harman)
I did highlight the relevant parts just in case someone has a problem understanding what is shown
The above numbers are of course not representative for every room. In a normal livingroom there're also diffraction effects and reflections from nearby objects. One would need to measure to visualize the effects in a specific room.
(http://www.aes.org/e-lib/download.cfm?ID=13686&name=harman)
I did highlight the relevant parts just in case someone has a problem understanding what is shown
The above numbers are of course not representative for every room. In a normal livingroom there're also diffraction effects and reflections from nearby objects. One would need to measure to visualize the effects in a specific room.
Attachments
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No, I am not - not at all - all I am saying is that perhaps something was flawed in Your test, test conditions etc. rather than in the idea of the FCUFS itself
thank You so much, same to You!
Use of a delay on the direct radiators would solve this little issue, No?
Interesting that the few that could tell the sound was coming from the floor was so small.
With spectral adjustment of the critical hearing range of say 500-4k range while taking in account the directivity of both on and off axis at high freq even those whom originally could tell it's coming from down there, dissolves. My experience is that it takes alot of refinements beyond what's considered normal practice and thus because it's so unconventional is normally dismissed based on this or that theory. Pfff to that. Sitting down and doing some real science is what motivates me to go against the grain and find out the truth. Imagine this is true of so many of us. Being stuck in the theory rut doesn't get us anywhere... especially when we know probably less than half the facts... besides isn't that what DIYaudio is all about?
When my father was in school he did a report on space travel... Rockets, that lifted off slowly building enough speed to break out of earth gravity well. He was promptly laughed out of class by his professor, why, because at the time they thought the only way was to fire them out of a cannon. Just like my second grade teacher claiming no one on earth can imagine how big 1 million is! Pretty bad when your 7th grade teacher tells you that the wires you soldered on at home for some other class project was incorrect and got PO'd for goofing it. Yes teach, electrons must flow through the tungsten filament to work, moron! Oh Oh Oh (horshack) a little piece of foam can't hurt the shuttle... unless it's a couple pounds moving @ mach2, theories be damned!
Can imagine more than a few scientists crapped their pants over that one. Perhaps you can see my point, perhaps not, but that's ok
What listening test are you talking about?
What particular spectral adjustment are you talking about? How does the ideal directivity look like?
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Art, at least this portion is contrary to the Precedence effect.
While I have heard others mention that the sound is coming from the floor (or ceiling if ceiling mounted), I've never heard anyone mention anything like this.
The Precedence effect is basically "A" *or* "B", not "A" and "B". In the Precedence effect the "dominance" to direct sound is *utterly* dominate - you don't hear a secondary source at all, or "multiple locations".
As to the floor or ceiling-mount exception - there could be reasons owing more to the design of the experiment than simply placement. (..particularly diffraction effects that become more significant with a floor placement.)
Remember - most music isn't hard-panned to a loudspeaker. If it were, THEN you would expect the result where you point to the loudspeaker and say "it's coming from the loudspeaker" - or in this case: "it's coming from the loudspeaker down there".
With a traditional loudspeaker placement, better loudspeakers on better recordings tend to "float" an image above (and usually behind) the loudspeakers.
Note: I've heard many stereo and multi-channel ceiling installations, and sometimes yes - it sounds as if it's "up there". Other installations - perhaps somewhat elevated vs. a traditional setup, but not as if it were from the loudspeaker's position on the ceiling. (..Note - stereo ceiling installation isn't the same as a distributed ceiling installation you'll find in commercial venues.)
Using speaker manipulation to create spatial effects is very much the hard way to do things, the slightest variations anywhere are bound to play havoc with the subjective impression of what's going on ...
Far more satisfying and long term effective, to get the system electronics to behave themselves, and then the ear/brain will do all the hard work for you -- easily "floating" an image outside of the speakers, at all times, and with all recordings, with no special attention paid to speaker placement ...
I did, and you dismissed it as a poorly designed speaker without hearing or measuring the speaker itself(how a person who lives a country wide, and ocean wide distance from the listening place can come to this conclusion is beyond me). I mentioned quite clearly that a flooder in a room with a high ceiling sounded a mess to my ears. I heard it for myself in a room with a ceiling that was about 13-14ft high.
This is not correct. Anything coming solely out of left or right channel is hard panned. If it were not hard panned, it would not be coming from one channel or the other, it would be coming from both thereby centering it between the speakers. A stereo "spread" is a combination of hard panned and blended images. This is especially true with studio created recordings. So in the presence of hard left or right imaging, you can get "its coming from the loudspeaker down there" effect.
The idea for a floor (or ceiling) speaker is NOT to create a spatial effect that isn't part of the recording.
Rather it's a design idea to mitigate what is considered (by most authorities), the worst reflective offenses of room effects: Short-time "reflections", particularly the effect know as floor bounce.
The thing is - dumping a standard loudspeaker on the floor facing up introduces a lot of problems. It was never designed to be used that way. Putting a coaxial on the floor? Fewer problems. Putting a coaxial that has an integrated waveguide on the floor? Fewer still. A coaxial with an integrated waveguide and flush (inset) to the floor? Now we are getting somewhere..
(..though as a practical matter just who is going to do that?) Again, though - that's IF something like floor bounce is really causing a problem perceptually. Some sources say yes, others no. I guess it depends on the listener and the room + furnishings.
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And I would say it's the overall quality of the sound emerging from the speaker drivers that's key. Floor bounce ??? ... in all my years playing with audio I have never bothered with sound reflecting from the floor in front of the speakers causing problems - it's always been obvious that the sound at the actual interface of the cone to the air is where the issues are - simply put, there is far too much audible distortion output by the driver, well before the sound has a chance to bounce off any hard, or soft, surfaces ...