..and a cite I can find and actually read that's directly on point?
BTW, I would never describe even an acoustic source (let alone a reproduced source aka "image"), as being spacious or having spaciousness. That it has spatial properties - yes, but not as having spaciousness.
Hello Earl
Hmmm?? Well I think I can see your point. May be not. The space is artificial and created by electronic means and it's mastered in stereo. Then yes stereo would be the most "accurate" recreation method.
That said I still think a surround system does a better job of recreating a sense of space and envelopment than a 2 channel system. Problem is with 2 channel media the limiting factor is the media. Take a movie as an perfect example of artificial space. From the rain forest to a city street in 30 seconds.
From a live music perspective as in a concert then surround is the way to go. I have plenty of material where I have a surround DVD and a stereo CD of the same show. The surround version is much more convincing and more realistic of the two.
As far as the original topic I like CD systems they make the most sense to me even if there is no clear preference in Tooles work.
Rob
I think we can speak about a sense of the spaciousness of a listening space (multichannel can convey it) but that is something different from the spaciousness of virtual sound source which is about their lifelike, palpable 3D quality
The latter is NOT just the ASW, it is height and depth as well, and robustness ("The degree to which the perceived location of a source changes with movement of the listener"), and locatedness ("Spatial distinction of a source." (Definition according to Blauert, 1997): "The degree to which an auditory event can be said to be clearly perceived in a particular location.") too .
For my part by spaciousness in the context of sound reproduction I mean an illusion of virtual sound sources having realistic spatial qualities
the following glossary of spatial terms comes from Wittek IIRC:
If we can point to hundreds of different speakers that reviewers have raved about over the years and find that they have widely differing characteristics wrt directivity (and some of them seem to violate 'the principles' quite egregiously) does this mean that some reviewers don't know what they're talking about or that directivity is not a crucial parameter?
if only it was just the matter of reviewers, cause why would anobody care about reviewers and what they say?
but it's not just the reviewers
it's more than that, it's more like PMC BB5 vs JBL M2 vs Dynaudio Air25 vs Genelec 1039 vs Klein-Hummel O410 vs sound professionals that use audiophile speakers in their studio work and so on
for me it's obviously the latter
for what is the crucial parameter is the speaker-room interaction, the room is a physical extension of the loudspeaker
I am glad that you do see the point because the vast majority of music is done this way - on 2 channel for 2 channel.
I have nothing against multichannel, it works great when the source is mixed that way. But almost nothing is (movies excluded). When it is "stereo" (as this thread is about) then multichannel is not the solution to anything, let alone being a global solution to the problem.
I spent a little time last night looking back at some of his work.. from what I can tell he is pulling references from other work that are pulling references from concert hall work - specifically ASW (Apparent Source Width). See one of his references and how that author introduces the topic. Reference here (page 113):
http://www.tnw.tudelft.nl/fileadmin...ons/Ph.D._thesis/doc/Evert_Start_19970624.pdf
Note that ASW should NOT have ever been characterized as "spaciousness" - it's just plain wrong. (Spaciousness concerns an area that might contain things - ie. "the room has a high degree of spaciousness." A virtual source presumably doesn't contain anything - it doesn't have spaciousness. Ex. that reproduced cello has a high degree of spaciousness? Or the reproduced venue has a high degree of spaciousness? The later, not the former.
) I suspect this SNAFU is the result of non-English speaking researchers (..probably Japanese) looking at the prior work of English speaking researchers (likely Marshall) and using the word improperly. From there you've got that "sheep" mentality with respect to precedent (no matter how improper) that evolves a new meaning that most lay people would be utterly confused by.
Here is an interesting abstract that actually makes some reference to this problem:
http://epubs.surrey.ac.uk/7050/2/2004 Room Acoustics Design Symposium.pdf
To me Markus's example is presence.
What is "Spaciousness"?
It's common to use a phrase like: "that vocal has presence" - and it specifically relates to the vocal's interaction with the room (..ie. the vocal and its reflections within the room in the way it alters that vocal).
It's also common to say that "the room has presence", which is still in respect to sound in that room and altered by that room (even if only low level noise).
And both uses have likely been common for a very long time, probably before recorded sound. They certainly have been used that way in broadcast transmission and recordings, and of course film - from very early-on.
This brings up something more on-point for our thread..
Beyond the use of "Spaciousness" in Markus's web page he makes two other distinct claims:
1. "Reflections coming from the side walls of a room (lateral reflections) have the biggest impact on perceived *spaciousness."
2. "Although *spaciousness is desirable for certain music genres, it can be detrimental to localization of (phantom) sound sources."
*..again, he is referring to "spaciousness" within a very narrow context that I call presence.
#1: Is this correct in the context of loudspeakers - specifically for STEREO? Are they generating an increase in presence (or "spaciousness") for all reproduced sources (or "images")?
Remember this isn't simply one speaker reproducing sound from one point.
Further, it's a broad statement - it's not suggesting any spl/intensity dominance on the part of the grouping of reflections vs. that of the direct sound.
#2: IF #1 is true that the room is altering images by enhancing their presence (or "spaciousness"), can or will this become detrimental to localization of those images, and if so - in what manner? While the statement is prefaced with "can", its context suggest that it will (at least to some audible degree).
From my own experiments I'd say neither statement is correct - so long as the loudspeakers are kept a reasonable distance away from walls in relation to freq. and have dominating direct sound at higher freq.s (relative to reflections).
Even when the loudspeakers are clos(er) to the walls, I'm not sure I detect any additional presence (or "spaciousness") from "images", or that it's detrimental to localization as a by-product.
This is not to say that I don't have problems (even localization problems) with the side-wall interaction when in close proximity to each loudspeaker's near side-wall. Rather, that I don't think these problems arise from an enhancement in the subjective result of increased presence (or "spaciousness").
I'll skim through Toole's book tonight to see if he has something contextually "on-point".
Last edited:
I believe that:
is indeed necessary for any realistic presence/extension to appear.
I have never experienced it with any conventional stereo system under any circumstances. The first time I experienced it was with my stereolit-like bipole speaker, the second with my flooder (FCUFS).
The difference between the two types of presentation - conventional stereo and those unconventional systems - makes conventional stereo no option for me as far as realistic sound reproduction is concerned.
Of course I can understand that one can prefer accurately (?) unrealistic over realistic. That's a question of goals.
Yes, when you get reflections that are higher in level than the direct sound, it can sound more realistic.. but you can also "over do" it as well and it can make the image sound more diffuse.
Another method is utilizing something that breaks the spl gradient (or basically something that is directly in front of the loudspeaker that causes the sound to diffract around it before it reaches the listener). This can even be as "simple" as horn loudspeaker rotated just far enough so that you can't see the compression driver exit.
Another method is utilizing something that breaks the spl gradient (or basically something that is directly in front of the loudspeaker that causes the sound to diffract around it before it reaches the listener). This can even be as "simple" as horn loudspeaker rotated just far enough so that you can't see the compression driver exit.
Sounds like there's a specific "spl gradient" that makes the presentation either more or less realistic. Are there any detailed informations or references on how "spl gradient" influences perception? Care to elaborate?
I looked over several sources of research and Toole's book.
From what I can tell all of it is derived from ASW, and it's not describing presence (or "spaciousness").
ASW relates to the source becoming broader, NOT shifting position (and NOT becoming broader).
Moreover while ASW has been prefaced as a condition as the result of time delay in reflections, from what I've read this is still very much a questionable result (one that's still being questioned 50 years later). Instead, ASW seems to be more a product of intensity (with respect to freq.) vs. angle with those reflections.. the time delay seems to be almost incidental (..and you'll get wildly varying delay conditions depending on the paper - from milliseconds in the 'teens, to up to 80 ms. You'll also find wildly different freq.s that are postulated as being "important" to this attribute, but the median "split" seems to be around 500 Hz or so, with a few that simply argue it's a full bandwidth effect.)
Toole makes comments directly at the start of his section on "First Order Reflections" in chapter 8 that coincide with Markus's statements, but aren't entirely on-point.
Toole generalizes (from Ando and Kishinga) that:
"..reflective sidewalls resulted in a "broadening of the sound image"."
and
"..absorption to the front walls, behind the loudspeakers, reportedly improved image localization and reduced coloration."
And while the backing research does do IACC measurements, it's not arguing that delay had much if anything to do with the results. In fact Kishinaga's was done in a small room with what couldn't have been much of delay from most angles, certainly not 30ms as in Markus's examples.
Nor did Toole describe the conditions for treating the front wall behind the loudspeakers that reportedly "improved localization and reduced coloration". Presumably it was most, if not all of the front wall, which led to higher IACC or increased correlation.
****Note: IF however that absorption had been limited to within about +/- 15 degrees of the listener's "0 axis" - or essentially about 3rd of the front wall centered on that wall, then it's quite likely that IACC would have similarly low to the non-treated wall, or perhaps even lower by lowering the mono-phonic emphasis (and thus the similarity of sound reaching left and right ear).
Moreover the front wall behind the loudspeakers (couldn't have been more than few ms) - so a longer delay (more characterized in ASW research) from reflections off of that wall is NOT responsible for poorer localization or increased coloration.
From what I can tell all of it is derived from ASW, and it's not describing presence (or "spaciousness").
ASW relates to the source becoming broader, NOT shifting position (and NOT becoming broader).
Moreover while ASW has been prefaced as a condition as the result of time delay in reflections, from what I've read this is still very much a questionable result (one that's still being questioned 50 years later). Instead, ASW seems to be more a product of intensity (with respect to freq.) vs. angle with those reflections.. the time delay seems to be almost incidental (..and you'll get wildly varying delay conditions depending on the paper - from milliseconds in the 'teens, to up to 80 ms. You'll also find wildly different freq.s that are postulated as being "important" to this attribute, but the median "split" seems to be around 500 Hz or so, with a few that simply argue it's a full bandwidth effect.)
Toole makes comments directly at the start of his section on "First Order Reflections" in chapter 8 that coincide with Markus's statements, but aren't entirely on-point.
Toole generalizes (from Ando and Kishinga) that:
"..reflective sidewalls resulted in a "broadening of the sound image"."
and
"..absorption to the front walls, behind the loudspeakers, reportedly improved image localization and reduced coloration."
And while the backing research does do IACC measurements, it's not arguing that delay had much if anything to do with the results. In fact Kishinaga's was done in a small room with what couldn't have been much of delay from most angles, certainly not 30ms as in Markus's examples.
Nor did Toole describe the conditions for treating the front wall behind the loudspeakers that reportedly "improved localization and reduced coloration". Presumably it was most, if not all of the front wall, which led to higher IACC or increased correlation.
****Note: IF however that absorption had been limited to within about +/- 15 degrees of the listener's "0 axis" - or essentially about 3rd of the front wall centered on that wall, then it's quite likely that IACC would have similarly low to the non-treated wall, or perhaps even lower by lowering the mono-phonic emphasis (and thus the similarity of sound reaching left and right ear).
Moreover the front wall behind the loudspeakers (couldn't have been more than few ms) - so a longer delay (more characterized in ASW research) from reflections off of that wall is NOT responsible for poorer localization or increased coloration.
Last edited:
Almost nothing.. that I've found.
Even Griesinger only seems to mention it in relation to phase fluctuations on that low-freq. paper of his.
I do vaguely remember several sources that suggest that we are "to" sensitive to directional ques in that typical 2-5 kHz range that make fundamental stereo in-accurate (with reality - which is monophonic as a source instead of a generated "image" from two sources: the loudspeakers).
Here is very imperfect example that starts the effect about 40 seconds in:
JBL 4428 compact 3 way studio monitor - YouTube
Of course freq. response is skewed as a result, and you have a substantial emphasis on one channel vs. the other.
Last edited:
Or would this be akin to a vane either horizontal, vertical or both bisecting the driver where it's radial length is = the wavelength at crossover point, suffice?
The combination of both would be a quadrature (?) corner reflector of sorts
interesting, an example of something mounted in front of the driver to improve stereo is Prof. Manger's "Holoprofile":
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.