Loudspeakers and room as a system

[MaVo]

Think of your surroundings as a pie. Traditional stereo cover a 60 degree slice of this pie, while the remaining 300 degree are room reflections. I dont know what Key wants to say with it, but thats what i think he meant.

[markus76]

If that is Key's view then he is under a misconception of what stereo is.

Talking about Wittek, here's what he concludes: "In general, the physical properties of the reproduced space do not necessarily have to be realistic or existent in any real situation." (Perceptual differences between wavefield synthesis and stereophony by Helmut Wittek, p. 4)

[el`Ol]

Originally Posted by Key

With conventional stereo you get 60 degrees of controlled coverage and 300 degrees of errors.

I can live very well with my "errors". Recently when a friend listened to my system she said this is "more than stereo".

[LineArray]

Originally Posted by el`Ol

...
So probably Olive is right when he says room correction is only possible up to 500 Hz and above it's only speaker correction (traditional EQing, just finer).

When looking at the curves from Olive's presentation that
show "spectral balance" judgements of the listeners i come
to a simple conclusion:

What mainly has been "balanced" or "equalized" above 500Hz
- where the room behaves statistical and not modal anymore -
is the narrowing coverage of the midrange driver,
especially around 1Khz up to the crossover frequency
of the tweeter.

When comparing the best RC (RC1) with RC4 (no correction) this
is rather obvious.

When crossing two transducers with very different coverage at
the crossover frequency, there will always be a compromise between
flatness of on-axis response (in a large and dry room) and the total
radiated power which is essential in more 'wet' and small rooms.

The optimum crossover alignment is then strongly dependent
from listening room, listening position (distance!) and the
loudspeaker's position.

Such a problem could more easily be corrected in the speakers
crossover itself, by providing different characteristics for different
listening positions and rooms, if the designer is aware of the problem
and willing to reduce it (outside of the room where the speaker has
been aligned).

It points me to the assumption, that a speaker having constant
coverage or at least coverage "only smoothly varying with frequency"
does not need "room correction", especially if the coverage is restricted
to a narrow angle.

So in the end there is no "room correction", but there is modal balancing
for the modal frequency range of the room or "room/speaker system" .

[graaf]

Originally Posted by Key

The problem is perceptual coverage. With conventional stereo you get 60 degrees of controlled coverage and 300 degrees of errors.

yeah, more or less, with conventional front firing multi-way speakers

not so with the flooder (ie. single driver or coaxial CFS) - no such "errors"

best,
graaf

[graaf]

Originally Posted by markus76

The time writing spectulative posts without gaining any knowledge is much better invested reading stuff like Witteks thesis or Toole's http://www.harman.com/EN-US/OurCompa...ions/13686.pdf. If you really want to learn something, it doesn't get any easier than this.

on the contrary - it does - trying something Yourself is easier

BTW Toole arguments in this article indirectly support the flooder concept:
Loudspeakers and room as a system

best,
graaf

[markus76]

Originally Posted by graaf

on the contrary - it does - trying something Yourself is easier

I don't see anybody here trying anything in a meaningful way.

[graaf]

Originally Posted by el`Ol

From my experience with the HX201 CFS I would say the opposite.

Sounds like a contradiction to me. An indirect sound with not-flat FR can colour the perceived result, but not correct it?

I would say the opposite as well

we never ever hear the frequency content of the direct sound as such

it is completely irrelevant as such

in terms of frequency content we hear a sum of direct sound and all reflections
therefore indirect sound can in a sense correct not-flat [direct] FR

and therefore actually it is easier to get a good frequency response with a CFS

Originally Posted by el`Ol

BTW,
is it a problem for you to use an additional pair of bass speakers? Heavy boosting is a torture for fullrange drivers.

not boosting as such but high volumes
anyway - in the near-corner placement of the flooder just 6 dB boost @50 Hz and below would make me happy
that is not heavy boosting, or is it?

Originally Posted by el`Ol

I can live very well with my "errors". Recently when a friend listened to my system she said this is "more than stereo".

lucky You!

BTW no Key's "errors" in case of the flooder

Originally Posted by el`Ol

Too many pages. Graaf?

I don't know
only two ocurrences of the word "transient" in the whole text

and music and speech = transients

I like this one more:
"Spatial Hearing with Simultaneous Sound Sources: A Psychophysical Investigation"
http://ses.library.usyd.edu.au/bitst...24302whole.pdf

best,
graaf

[graaf]

Originally Posted by markus76

I don't see anybody here trying anything in a meaningful way.

I am not sure what You mean by a meaningful way but I have a CFS here in my home and so has el'Ol and we have tried some options and some placements in room
I have also tried SLS (stereolith-like-setup) and I built three different versions of that stereolith thing

And You cannot read about it in Wittek, Toole or anywhere else

The only technical article I know that mentions SLS is Manger diskus patent description. I don't know any technical articles that mention CFS.

but I just have built it and it works

best,
graaf

[markus76]

Originally Posted by graaf

I don't know
only two ocurrences of the word "transient" in the whole text

and music and speech = transients

I like this one more:
"Spatial Hearing with Simultaneous Sound Sources: A Psychophysical Investigation"
http://ses.library.usyd.edu.au/bitst...24302whole.pdf

Now it's about what text you like more?? Virginia Ann Best speaks about natural sound sources. We are talking about phantom sound sources in multichannel sound reproduction.