The Advantages of Floor Coupled Up-Firing Speakers

[Colin]

Hi Earl

In your experience, does the corner problem for mid and highs still exist with Soffit mounting as shown here (under the Unity Horn- Finale link in the index)? This looks an elegant way to get rid of the usual hifi obstacle course that speakers seem to present.

[gedlee]

Originally posted by Colin
Hi Earl

In your experience, does the corner problem for mid and highs still exist with Soffit mounting as shown here (under the Unity Horn- Finale link in the index)? This looks an elegant way to get rid of the usual hifi obstacle course that speakers seem to present.

This idea has some merit and is the one preferred by Floyd Toole. To me it seems impractical and not necessary. What I have done is a little different. Put the speakers out away from the corners and hang some draps across the corners in front of the speakers. This hides the speakers and reduces the appearance issues, and then I put a lot of absorbing material to fill the corners (behind and arround the speakers but all behind the drape) to help damp out the LF modes. We both use a toe in of about 45°. We both taper off the high end a bit, he more than I. With flat Summas bhind a drape I get a nice gradual rolloff at the high end of just under -3 dB/oct.

I would use more subs (none are evident).

The room response seems questionable since there don't appear to be any subs, the room is very reverberant, but no LF modes are apparent. That goes against my experince.

[syntheticwave]

Originally posted by el`Ol
Hello Helmut!
I read that the Fraunhofer Institute is trying to switch to NXT speakers to keep the number of speakers lower without risking lobing. Recently I heard the Göbel at the Highend in Munich this year, and I find it does VERY well, apart from the instable imaging and the fact that it comes to its limits even before reaching full "room level".
Oliver

Hello Oliver,

by various occasions I was able to hear the Fraunhofer wave field synthesis loudspeaker rows around the listener. It is a huge step in the direction of realistic sound reproduction because it isn’t reliant upon the uncertain phantom source perception, like the conventionally procedures. But unfortunately the procedure isn’t able to bearing down the most audible disadvantage of all known loudspeaker reproduction procedures; the limitation onto the horizontal plain of the listener remain very disturbing.

Originally posted by graaf
[B]
imagine manufacturing process of a device comprising 1296 speakers, imagine cost of assembly, of shipment, complexity of the issue of installation if such a device at home (in a special dedicated room only?)
so yes, technically it is feasible but economically and commercially it will never be I'm afraid

You shouldn’t overrate the impact of the effort. No procedure in history was inhibited by that reason as far as the advantage for the user was apparent. Some multimillionaires would be purchase such gadget only because it would be too expensive for a normal millionaire . Unfortunately i am not among.

Originally posted by graaf
[B] in this thread we're discussing various solutions that take into account the issues of loudspeaker and room (normal living room) interaction to achieve much better results in terms of naturalness and realism of spatial presentation of sound than standard solutions

…o.k. I want not to enter the tread by my idea. Possibly we can discus the topic in this thread: Which amount of channels need the perfect rendition?
But the topic is loudspeaker and room as a system. The most of the errors in the frequency domain, that should concern the topic surely, caused by wrong superposition of reflected wave fronts in the playback room. Equalizing such comb filter effects in the frequency domain is the wrong way. Those errors are time related. It must become correct in time domain congruously as described on the website, not the frequency domain!

Originally posted by graaf

fortunately 1296 speakers with special electronics are not neeeded for that - in fact stategically positioned just two fullrange drivers without special electronics can do the job

best,
graaf

No, it doesn’t. We are far away from the goal of realistic reproduction by all phantom source based procedures. Only reason would be Ambisonics or wave field synthesis.

[graaf]

Originally posted by syntheticwave

No, it doesn’t. We are far away from the goal of realistic reproduction by all phantom source based procedures. Only reason would be Ambisonics or wave field synthesis.

by saying "do the job" I meant "do the job" "of being much better than what we have now"
I certainly didn't mean "do the job" "of wavefield synthesis"

in that sense surely it doesn't

but in a sense "much better" it does

and what about ambiophonics? "transaural stereo"?
http://www.ambiophonics.org/
what about binaural approach?
in words of Floyd Toole:

I am not sure what "the perfect sound" might be. If it is to transport a listener to a concert hall, then we have gone about it the wrong way - we should have focused our efforts on binaural recordings and playback

http://www.sonicdesign.se/tooleinw.htm

what do You think?
ambiophonics or binaural playack are perfectly technically feasible. And would be much more commercially feasible. Well, this doesn't change anything in reality. From the perspective of the industry these are and most probably will remain only curiosities
And "1296 speaker device" is even something more extreme, a real monstrosity

best,
graaf

[graaf]

Originally posted by syntheticwave

We are far away from the goal of realistic reproduction by all phantom source based procedures.

well, psychoacoustically the loudspeakers are perceived in stereo as early reflections of a sound whose direct version we missed

what is wrong with that? seems to me that nothing per se

what is fundamentally wrong is rather the positioning of these early reflections in a room
it is having these early reflections in a middle of the room what is higly unnatural and leading to lack of realism
try damping of the wall in front of the listener and Beveridge positioning where the loudspeakers are acoustically integrated into the side walls

what do You think?

best,
graaf

[Etienne88]

Hi Graaf,
Very interesting topic!

Originally posted by graaf

well, maybe it all boils down to a question how "pin point" is "pin point"?

to make myself clear - I don't know the experience of other contributors to this thread but loudspeaker and set ups I write about here give me precise imaging, not uncomfortably "diffuse" nor "vague" at all
not at all "un-pinpoint" in any negative sense

and absolutely more realistic the standard stereo - occupying a real space, 3D, very palpable images

best,
graaf

Jean-Michel Le Cléac'h wrote a document about phase distortion where he gives some numbers about the ability of the human been to localise point source in an horizontal field (the ability to localise in a vertical field is much less accurate). Between 100Hz and 10kHz, the human accuracy is between 1º and 3º, which is very precise! You can find the figures on page 23 of that document: Distortion de phase.pdf (7Mo). But he also says that parameters such as timing and intensity are not sufficient to pin point accurately a source. He doesn't say what else is needed to achieve the accuracy quoted earlier (1 to 3 degrees between 100Hz and 10kHz)...
He also says that the mechanisms of localisation are phase difference for the lower frequencies and intensity difference for the upper frequencies. Phase difference localisation is only possible up to 1500Hz due to the size of the head. See Stevens & Newman for the complete info. 3kHz tone are somewhat harder to localise. Above that, the intensity differences take over.

The room acoustic has always been one of my favorite subject. I myself consider the room as the weakest link in too many hifi set ups... Therefore your type of speaker combined with the appropriate positioning is quite interesting! Nevertheless, something catches my intention. Some of your requirements are high directivity for the high frequencies and early reflections coming after 5ms, 10 ms being much better. So far, so good! Then you place the driver firing upward. Since the later is directive in the highs you will have very little direct sound and mainly delayed reflected sound...
I don't get how this can lead to "absolutely more realistic than the standard stereo - occupying a real space, 3D, very palpable images" as you said yourself. I'm not questioning your feelings, I just try to understand the mechanism(s) behind!

I will try your set up myself and read the Carlsson white paper you linked to. This might help me understand better.

Regards,
Etienne

[el`Ol]

I just removed the inner walls of my open back boxes with the Ciare on top. The result is that the three-dimensionality is reduced and the imaging is more diffuse, while the delay time of the ceiling reflection is becoming uncritical.

[graaf]

Originally posted by el`Ol
I just removed the inner walls of my open back boxes with the Ciare on top. The result is that the three-dimensionality is reduced and the imaging is more diffuse, while the delay time of the ceiling reflection is becoming uncritical.

how does it look alike? can You attach some image of this set up? what Ciare on top and how? I can't figure it out from short description You have given

best,
graaf

[graaf]

Originally posted by Etienne88

Hi Graaf,
Very interesting topic!

Thank You!

Originally posted by Etienne88

(...)
he also says that parameters such as timing and intensity are not sufficient to pin point accurately a source. He doesn't say what else is needed to achieve the accuracy quoted earlier (1 to 3 degrees between 100Hz and 10kHz)...

probably what He refers to is head related transfer functions (HRTF) and especially the pinnae functions

Originally posted by Etienne88

Some of your requirements are high directivity for the high frequencies and early reflections coming after 5ms, 10 ms being much better. So far, so good! Then you place the driver firing upward. Since the later is directive in the highs you will have very little direct sound and mainly delayed reflected sound...

"high directivity for the high frequencies" and omnidirectional dispersion pattern are needed to make the individual loudspeaker in a two speaker stereo array harder to be distinguished from the side wall and harder to be localized as a distinct sound source and a real (and separate from the room acoustics) cause of virtual sound images
the aim is to acoustically integrate the speakers into the side walls just to make the room acoustics to be a carrier of left and right signals

by making the loudspeakers very short and positioning them next to the side walls I want to emulate (as close as is possible with dynamic cone driver) the Beveridge line sources

the additional advantage of high directivity in such a positioning can be less amount of detrimental high frequency "very early reflections" off the adjacent side wall

yes, in such a set up what we perceive in the highs is mainly sound vertically reflected off the ceiling arriving at the ears with about 10 ms of delay
but this is not a problem because the hearing mechanism is processing what the ears receive in "stages" or "phases"
the first stage is sound source localization and it lasts <1 ms counting from first wave front arrival at the ear, the second is sound source size assessment and it lasts for the next 1<30 ms, the third is sound source identification which begins with pitch recognition occurring between 10<30 ms

thus all sound source localization is done completely before the delayed reflected sound reaches the ears, no problem at all

moreover, in case of sound localization in reverberant space like a room hearing relies mostly on time difference mechanism - the law of first wave front and the precedent effect (Haas effect) and additionally on phase difference mechanism and in that regard most important are the spatial cues around 1 kHz at which my speakers are not yet that much directional

on the other hand the spatial cues encoded in a stereo recording are in most cases of the intensity type or at least they should be according to the original Blumlein stereo patent and a coincident stereo microphone set up invented by him for that application
this is simply how "stereo" should work
unfortunately this is often ignored diminishing the standard stereo ability of realistic spatial reproduction even more

Originally posted by Etienne88

I don't get how this can lead to "absolutely more realistic than the standard stereo - occupying a real space, 3D, very palpable images" as you said yourself. I'm not questioning your feelings, I just try to understand the mechanism(s) behind!

I am also nor completely sure about that I am only hypothesizing
and as I have already pointed to above in the thread the main problem with realistic spatial presentation of sound in audio reproduction at home is with the fact that we are listening to the speakers perceiving them as distinct sound sources, we are hearing the speakers – something that has no counterpart in nature

in spite we should listen to what the speaker do while staying unaware that this is done by the speakers
ambiophonics is trying to achieve that by the means of stereo crosstalk cancelling and making the listening room a little anechoic chamber
in that way the speaker themselves are made "invisible" to the hearing

but I believe that this can be done as well by integrating the speakers into the side walls instead of projecting the sound in the direction of the listener
in that way we can perceive that sound just occurs in the room like it would be if the room was attached through the wall in front of the listener to an original recording space (see image attached)

Originally posted by Etienne88
I will try your set up myself and read the Carlsson white paper you linked to.

I recommend to You the Beveridge white paper in the first place
http://www.bevaudio.com/White_Paper.htm
my approach is a sort of combination of the two ideas - of Carlsson and of Beveridge, and more precisely - while trying to emulate Beveridge loudspeakers’ radiation pattern I arrive at something resembling Carlsson speakers
it just happened that way - Carlsson was not my direct inspiration

best,
graaf

[el`Ol]

Originally posted by graaf


how does it look alike? can You attach some image of this set up? what Ciare on top and how? I can't figure it out from short description You have given

best,
graaf

Hello Graaf!

This was the setup (just destroyed to make place for an other experiment):

Driver is the Ciare HX201.
The next experiment in this direction will be a compression tweeter with narrow directivity, directed towards the ceiling.