So, is it the major reason that the Sterelith shall be used against the wall? I mean, the listener hears the two side firing drivers mostly by the side wall reflections anyway (which are delayed), and the tweeter is physically delayed (pushed further away) to it's physical limit - the wall. (Sorry if this was brought up before. Been late to the party)
In this interview Schlupbach recommends at least 1 meter from the back wall, and the speaker free in the middle of the room. Reflections must have then some importance. I was missing it again. 
About "envelopment" (thx markus for the mention), this is what Blauerts-Lindmann said in 1986:
markus, please open your bag.
I did tests with big notches, band pass, subs added...all, but their effect is deadly robust an then not frequency dependent or seat dependent.
Just optimized stereo widening maybe.
About "envelopment" (thx markus for the mention), this is what Blauerts-Lindmann said in 1986:
Relevant here and interesting, but what with the phase shifts on the supras ?
markus, please open your bag
.I did tests with big notches, band pass, subs added...all, but their effect is deadly robust an then not frequency dependent or seat dependent.
Just optimized stereo widening maybe.
My bad, I just did the google translation, and they say 30 cm from the back wall and keep the sides clean.
Now, the question of the asymmetrical hearing properties (justification of the asymmetric tweeter) is very complex. Anatomically, the nerves give their infos to our both hemi brains, but it's not 50/50, the repartition is lateralized...and the 2 brains are specialized.
Almost all the authors agree now that on a right handed guy the right ear will more efficient for working on voices and the left one better for noises then music. But as it is a cognitive process, there is no general law, this depends of education, culture...
example: right handed musicians are supposed to hear music with the other side of the brain (more analytic than emotional), and for the japanese all is inversed.
I'm not a japanese musician, but I tried to move the tweeter, with a method allowing the control from the seat, closed eyes and so and on.
No difference at my level (never heard the difference between cables or other subtilities as the brand of a resistor).
joined pic, the exclusive remote control of the tweeter
Now, the question of the asymmetrical hearing properties (justification of the asymmetric tweeter) is very complex. Anatomically, the nerves give their infos to our both hemi brains, but it's not 50/50, the repartition is lateralized...and the 2 brains are specialized.
Almost all the authors agree now that on a right handed guy the right ear will more efficient for working on voices and the left one better for noises then music. But as it is a cognitive process, there is no general law, this depends of education, culture...
example: right handed musicians are supposed to hear music with the other side of the brain (more analytic than emotional), and for the japanese all is inversed.
I'm not a japanese musician, but I tried to move the tweeter, with a method allowing the control from the seat, closed eyes and so and on.
No difference at my level (never heard the difference between cables or other subtilities as the brand of a resistor
). joined pic, the exclusive remote control of the tweeter
Attachments
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Hello Radugazon,
I like the remote control! Very smart.
About the bass-mid driver: I understand you use Supravox because you had them? But Stereolith has 13cm side drivers whereas yours is 20cm diameter. Also as stated by Stereolith inventor the range of the most critical area for the 'effect' is around 1kHz. Now in this range 13cm driver has much wider dispersion than 20cm driver, and the direct sound to the listening position should be more than what you are having?
Also your room (I mean Hall) is very big and side reflections are much delayed, as you measured. *Maybe* Stereolith requires side reflections of shorter duration than what you are having. You know the summing localisation works only up to some specific time delay after which reflections are perceived separately and not contribute to the imaging.
- Elias
I like the remote control!
Very smart.About the bass-mid driver: I understand you use Supravox because you had them? But Stereolith has 13cm side drivers whereas yours is 20cm diameter. Also as stated by Stereolith inventor the range of the most critical area for the 'effect' is around 1kHz. Now in this range 13cm driver has much wider dispersion than 20cm driver, and the direct sound to the listening position should be more than what you are having?
Also your room (I mean Hall
) is very big and side reflections are much delayed, as you measured. *Maybe* Stereolith requires side reflections of shorter duration than what you are having. You know the summing localisation works only up to some specific time delay after which reflections are perceived separately and not contribute to the imaging.- Elias
Good remarks from the other side of the world. It' an eye opener.
I was not thinking that the size of the room could be an issue. But I noticed that listening from as far as 15 m was nice, this has to be tested seriously
.
In these conditions the shift direct/reflected is 6.5 ms vs 19, so the reflected is also integrated in the tune perception, not so much tweeter delay and for sure a better "global feeling". (and a very low head room ).
The dispersion & beaming is a native problem of the supras. Now I setup the EQ differently :
So, except error (I am a specialist in this domain), dispersion is not the big issue in its topography.
But as you mention, there is for sure an issue with it's content : the supra is under the "no filter" rule and makes still a little 12000 with the generator. I am not yet a full range maniacD) but it's like that that I got the best results. The more the tweeter does, the more the image narrows.
I have a ceiling HF diffusor of 3 x 1.5 m inclined at 45° just on the top of "the" speaker. This kills the ceiling reflections of the other system. Maybe it's too much for a single poor little dome. As the diffusor is controlled by cables, I will try to neutralize it.
I am very far from the Stlith behavior, my thing is more apparented to a Bose (that I respect) : wide range + reflect use + EQ.
PS : this cluedo game is very funny !
I was not thinking that the size of the room could be an issue. But I noticed that listening from as far as 15 m was nice, this has to be tested seriously
.In these conditions the shift direct/reflected is 6.5 ms vs 19, so the reflected is also integrated in the tune perception, not so much tweeter delay and for sure a better "global feeling". (and a very low head room
).The dispersion & beaming is a native problem of the supras. Now I setup the EQ differently :
- I make it flat on it's own axis
- the inter driver shift is integrated in the EQ
- I use low and high 6 db shelvings on the INPUT channel for voicing the response at the listening spot.
So, except error (I am a specialist in this domain), dispersion is not the big issue in its topography.
But as you mention, there is for sure an issue with it's content : the supra is under the "no filter" rule and makes still a little 12000 with the generator. I am not yet a full range maniac
D) but it's like that that I got the best results. The more the tweeter does, the more the image narrows.I have a ceiling HF diffusor of 3 x 1.5 m inclined at 45° just on the top of "the" speaker. This kills the ceiling reflections of the other system. Maybe it's too much for a single poor little dome. As the diffusor is controlled by cables, I will try to neutralize it.
I am very far from the Stlith behavior, my thing is more apparented to a Bose (that I respect) : wide range + reflect use + EQ.
PS : this cluedo game is very funny !
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Who knows but Mr Schupbach claims to the contrary:
"the "Stereolith" box diffuses sound in all directions without reflecting walls or surfaces. As it is independent from the place where it stands, it functions just as well in the open as in a very reverberating room."
best,
graaf
BS Marketing Semantics!
1) The invention doesn't "diffuse" anything. It has 3 rather traditional drivers that all become directional at higher frequencies. They point in different directions, and use that directivity and the acoustics of typical rooms to their advantage. 2) The ONLY way that the Stereolith can be "independent from the place it stands" is with the help of reflections. 3) Of course it sends "sound in all directions without reflecting walls or surfaces" . . . It has three small drivers pointing in different directions! That doesn't tell me anything about the path the sound takes to reach the listener.
In an anechoic chamber, I guarantee that the Stereolith would deliver a dominantly monaural experience, would have a significant response dip in the crossover region, and would present a soundstage about one foot wide.
It is a passive system. In the absence of room reflections, anything more is impossible without active signal processing and more exotic configuration of drivers.
I'm not saying the Stereolith is a bad concept. I love the simplicity. But let's not turn off our brains here when the marketer waves his pen. . . There are obvious limitations, contrary to the marketing hype. The Sterolith will never be able to present hard-panned images accurately, such as the imaging and pan test tracks on numerous Stereo setup discs. It is impossible to throw a sound leftward into an arbitrary space (not to mention simultaneously forward from the tweeter) and have the sound magically appear exactly 23-1/2 degrees left of center as the recording intended. Strongly panned signals will always stick to the speaker. The system relies on channel phase differences to create stereo impression, such as found on Symphonic recordings. Recordings made in a studio environment that rely on amplitude (pan-pot) differences for imaging will not "work" as well on the Stereolith as it would with traditional stereo triangle.
Any information in the stereo signal that is equal in both channels (ie panned center) is going to be monaural and quasi-omnidirectional (just missing some treble behind the speaker). The Stereolith will be fully omnidirectional for any wavelength significantly greater than cabinet dimensions and driver spacing.
I'm also sure that the midbasses run quite high, not XO'd anything like a front-firing 2-way, possibly fullrange. Otherwise there would be zero stereo presentation in the treble. Additionally, the sound off-axis would be too dull, and any treble info panned to the opposite side would be "lost", because the tweeter output will be considerably lower when playing a hard panned (and especially an out-of-phase) signal. Off-axis treble provided by the mids and room reflections fill-in the treble energy that would otherwise be lost off-axis.
All of this also explains why the Stereolith chose a smallish midbass.
The beauty of the arrangement is that it automatically shifts non-center information away from the tweeter and more toward the sides. The tweeter is only 100% "on" when a true center/mono signal is present. Likewise, a completely out-of-phase stereo signal (like early Dolby surround information) will turn the tweeter completely off.
If someone on this forum had the Stereolith sitting in their room right now, it would only take a minute with a couple test tones to verify all this.
Radugazon: Please try sending a monaural signal to your Stereolith with one of the speaker's polarity reversed. The image should appear everywhere-- completely detached from the speaker, and the tweeter should automatically turn off.
-- Mark
sorry but Your suggestions are rude and Your remarks are arrogant
Your only source of information is something that You name "BS marketing" yourself and yet You know so much...
on the other hand in this thread we are just discussing Schupbach's claims and our own experiments inspired by His designs and His "BS marketing", that's all
go in peace
Diffusion = "spread out", or spreading out sound in this context. (..not diffusion as a scientific term.)
Basically he is saying that it "spreads out sound without the addition of reflections".
Graaf's comment is correct - this design does NOT rely on reflections for the majority of it's performance "features". It only so happens that it *also* works well in a reflective environment, assuming these reflections are not very close in time.
With that in mind, try looking to its *direct* sound pattern for why it works. To help you with this: please DISREGARD the contribution of the tweeter.
(..btw, I suspect that any marginal lateral offset of the tweeter is purely an issue of amplitude integration with respect to diffraction and very early reflections from the "box" top.)
Perhaps my post looks much worse in print -- I don't mean to sound like a jerk at all, and sincerely apologize for that impression. Please note that I address marketing -- Never once did I mention Schupbach. I actually compliment the invention in my post! I simply pointed out (too bluntly it seems) that some of the marketing doesn't stand-up to reason.
Schupback is clearly too intelligent to literally mean what I interpreted from the text. If you can overlook the things that upset you, I hope you can see some merit in my thoughts.
My "only source of information" is much broader than this thread. It's not about what I do or don't know at all; It's about what is already known, thanks to years of cumulative knowledge from many individuals. I work in the field of acoustics. There is an awful lot that we collectively DO know. The basic behavior of cones, room acoustics, and passive circuits that apply here haven't changed in many decades. The knowledge base of psychoacoustics is improving every year. I have done a mock-up like others have. Please don't make it personal. I've never done that on any forum.
To be clear about my perspective:
1) I truly feel bad that I sounded rude and arrogant. This forum is a valuable place, and I cringe at the thought of being "one of those posters". I will choose my words more delicately.
2) I embrace the idea that people have different perspectives and preferences. I don't argue or defame anyone based on preferences.
3) Errors of fact or questionable published statements aren't preferences. Wrong or badly worded statements are harmful to our hobby, and should be addressed (perhaps more gently . . .
)4) My observations are speculative, but are also based on what we do know, short of actually buying the Stereolith and taking it apart. I don't see that any of the experiments shared by posters here contradict what I've shared.
We are all here to learn from each other, point each other to knowledge when it is available, and to share our ideas and experiences.
I ask you, and anyone that had the same impression, please forgive me.
-- Mark
Hello guys
I have to say two different things :
First, I was listening and testing my little speaker with faulty amps : + 1 VOLT DC offset on the 3 channels !!!. Because, last week I changed a lot of details in the input stage, good idea, but checked the offset with a multimeter having a dead battery. Skilled a lot .
Now, the pseudoSL makes everything much much better, including imaging, and my comments about the poor dynamic, nigh time speaker or very weak poor Supravox were justified only by the amps.
Second, about Tubamark...Hey, interventions like yours are absolutely welcome, necessary and mandatory, if not so each of us has better to stay in his corner.
I will not copy your text and adding my little comments in blue, because I agree almost with every statement. Laws of physic are one.
But there's a difference between what the speaker emits and what the listener feels, not because of any black magic, but because of the reflections, as you guessed, and :
PS: I am not a stereolith fan, just here to play with. But, OMG, it works really well.
I have to say two different things :
First, I was listening and testing my little speaker with faulty amps : + 1 VOLT DC offset on the 3 channels !!!. Because, last week I changed a lot of details in the input stage, good idea, but checked the offset with a multimeter having a dead battery. Skilled a lot .
Now, the pseudoSL makes everything much much better, including imaging, and my comments about the poor dynamic, nigh time speaker or very weak poor Supravox were justified only by the amps.
Second, about Tubamark...Hey, interventions like yours are absolutely welcome, necessary and mandatory, if not so each of us has better to stay in his corner.
I will not copy your text and adding my little comments in blue, because I agree almost with every statement. Laws of physic are one.
But there's a difference between what the speaker emits and what the listener feels, not because of any black magic, but because of the reflections, as you guessed, and :
- This thing is then perfectly able to reproduce a one sided pan potted signal, it's powered by the wall...and melts well with the speaker itself. Same for pink noise.
- The tweeter has naturally no duty in imaging (mine is actively summed R+L). It's just here for the tonal HF balance. I have to delay him for synchronization with the reflections and not with the "direct" sound. . Confirmation here of ScottG thoughts...Of course, 2 x 180°signals shut him off.
- And yes, youre right again about running inversed polarities, never heard such a psychedelic effect!!!
PS: I am not a stereolith fan, just here to play with. But, OMG, it works really well.
Hi Elias,
I vaugely remember you once suggested feeding some DC into VC on purpose (in one of the OB thread, quite a while ago...). Do you remember?
I haven't seen any further discussion on this. Any comments?
CLS
rather You have suggested that some people in this thread, especially me (as You commented my post) are "turning off their brains" "when the marketer waves his pen" - that was exactly "too blunt"
perhaps I am a bit oversensitive but for quite some time I am just fed up with arrogance of some people (especially dressing themselves as "experts") on this forum
but ok, I accept Your apology
believe me or not but I am also intelligent enough not to take "literally" anything Schupbach claims and to "overlook" anything, I also know some "abc", I only tell - "let's consider His claims"
therefore I started my post with "who knows" before quoting from His text
but Your only source of information on Stereolith is just this thread, isn't it? that was my point
oh yeah, so You are a pro acoustician?
Jeeesus, am I really to go through all this again??!! no way!
a couple of years ago on a Polish forum it took me perhaps a whole week to persuade a radio broadcast engineer to try some things stereolithically
before that happened His remarks had been waaaay more rude than anything I experienced ever on this forum - He just knew everything "what is already known, thanks to years of cumulative knowledge from many individuals" and I was called literally pathetic brainless lunatic and so on
but that was when I was younger, now I lost my patience for that kind of people, I have to save my patience for my kids, lots ot patience
3) Errors of fact or questionable published statements aren't preferences. Wrong or badly worded statements are harmful to our hobby, and should be addressed (perhaps more gently . . .
Let me tell You what I consider most harmful to our hobby - it's discouraging other people from trying new things themselves
such an attitude is understandable in pro activity which is about standards and so on but it is most hostile to the idea of DIY fun
oh well, perhaps I should be more gentle as well
my apologies in advance!
Hello...
After these emotions, let's go back to business. I've been checking if this lonely speaker can create a stereo field outdoor, without walls then and their very helpful reflections.
For this, my idea is to use Adobe Audition that has a lot of tools for evaluating all this
. After spending one day, either for making a good signal or for founding some "as flawless as possible" procedure, I've been measuring the speakers IN & OUT.
I was pretty sure of the opposite but : this lonely speaker produces a listenable and measurable stereofield outside.
Of course, it's not a PA system ! I've been keeping the EQ and delays used inside, so it's not very adapted to the outdoor use. To tell the truth, the best place for listening here is to have the nose under the tweeter.
Absolute nearfield.
The SL really needs the reflections, I will never tell something else.
But, no doubt, at 2 meters, I had many stereo effects, the soundstage is narrow, but it's correctly lateralized. A good exception, a Q sound demo, the jet taking off : the plane is really leaving far away on the right side, with normal stereo
I don't tell you all the details of this saga, but it has not been a piece of cake.
for watching the video report on "Audition real time" : here
the video that gave me the inspiration: here
joined pics :
could the background music remind something to Tubamark ???
After these emotions, let's go back to business. I've been checking if this lonely speaker can create a stereo field outdoor, without walls then and their very helpful reflections.
For this, my idea is to use Adobe Audition that has a lot of tools for evaluating all this
. After spending one day, either for making a good signal or for founding some "as flawless as possible" procedure, I've been measuring the speakers IN & OUT.I was pretty sure of the opposite but : this lonely speaker produces a listenable and measurable stereofield outside.
Of course, it's not a PA system ! I've been keeping the EQ and delays used inside, so it's not very adapted to the outdoor use. To tell the truth, the best place for listening here is to have the nose under the tweeter.
Absolute nearfield. The SL really needs the reflections, I will never tell something else.
But, no doubt, at 2 meters, I had many stereo effects, the soundstage is narrow, but it's correctly lateralized. A good exception, a Q sound demo, the jet taking off : the plane is really leaving far away on the right side, with normal stereo
I don't tell you all the details of this saga, but it has not been a piece of cake.
for watching the video report on "Audition real time" : here
the video that gave me the inspiration: here
joined pics :
- the wave used in the tests, 1000 Hz, rotation 180°
- one aspect of the phase analysis
- an other one (linear histogram)
- the 150 ms FR of the speaker : all that's missing is produced indoor by the reflections...a lot !
- The step, I believed it could have a better decay outdoor
- finally, a view of the operations, it's not a hoax
could the background music remind something to Tubamark ???
Attachments
glory to the brave!
I wonder what it would look alike with those delays. How does this outdoor measurements compare to indoor measurements without delays?
I seriously believe that under such conditions Your "stereolith" works like an ambiopole, according to the equation given by Bock and Keele:
my theory of Your "stereolith" was different than Schupbach's theory of His Stereolith
I thought that it acted like a sound projector with room boundaries acting like a screen
Your experiment shows that the truth must lie somewhere in between
I expected no soundstage with an exception of this ambiopolic absolute nearfield case in which I was expecting correct lateralization and all other elements - as evidence that the projector throws sound images in correct directions, faithfully
yet there is some soundstage, so there is also something in Schupbach's claims
on the other hand it is not fully developed, quite residual, so there is something in my understanding as well
interesting is the case of exception:
this suggests that there might be no inherent problem in the design as such which makes it not very suited for outdoor use, perhaps it is rather a problem of compatibility with recording techniques
in what way the recording of the jet can be different from others You have used?
with my stereolith-like boxes tested years ago I experienced very different reactions of it to various recordings
the best case was "no walls around - alternate space opened before me"
the worst was "no soundstage" - pure mono
my investigation lead me to conclusion that the decisive factor could be presence of distance/ambience cues in the recording - the more of them the more of a soundstage
in that sense my "stereolith" was very HiFi - it was showing me exactly what was recorded, nothing less nothing more
well, of course there are no distance/ambience cues in a 1 kHz test signal
impressive! great!
I wonder what it would look alike with those delays. How does this outdoor measurements compare to indoor measurements without delays?
To tell the truth, the best place for listening here is to have the nose under the tweeter.
I seriously believe that under such conditions Your "stereolith" works like an ambiopole, according to the equation given by Bock and Keele:
my theory of Your "stereolith" was different than Schupbach's theory of His Stereolith
I thought that it acted like a sound projector with room boundaries acting like a screen
Your experiment shows that the truth must lie somewhere in between
I expected no soundstage with an exception of this ambiopolic absolute nearfield case in which I was expecting correct lateralization and all other elements - as evidence that the projector throws sound images in correct directions, faithfully
yet there is some soundstage, so there is also something in Schupbach's claims
on the other hand it is not fully developed, quite residual, so there is something in my understanding as well
interesting is the case of exception:
this suggests that there might be no inherent problem in the design as such which makes it not very suited for outdoor use, perhaps it is rather a problem of compatibility with recording techniques
in what way the recording of the jet can be different from others You have used?
with my stereolith-like boxes tested years ago I experienced very different reactions of it to various recordings
the best case was "no walls around - alternate space opened before me"
the worst was "no soundstage" - pure mono
my investigation lead me to conclusion that the decisive factor could be presence of distance/ambience cues in the recording - the more of them the more of a soundstage
in that sense my "stereolith" was very HiFi - it was showing me exactly what was recorded, nothing less nothing more
well, of course there are no distance/ambience cues in a 1 kHz test signal
impressive! great!
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And its "narrow" perspective is a function of separation between the two sources relative to the distance from the listener. Move in close - and you'll get "wider". Move further away, and "narrower" results.
I remember the Bock and Keele paper, with the funny picture of the guys making the tests.
More seriously, here their equation can be grossly simplified :
by design H = D and T is just a little bit larger
So L = 2.2 X, kind of,
as X is very short, then, it's really "nose on the tweeter".
Grrrreat Discovery
...anyway, it's always nice to see an equation being confirmed by the facts.
Something I forgot to say : omni
in the experience and genuine French accent in the video.
More seriously, here their equation can be grossly simplified :
by design H = D and T is just a little bit larger
So L = 2.2 X, kind of,
as X is very short, then, it's really "nose on the tweeter".
Grrrreat Discovery
...anyway, it's always nice to see an equation being confirmed by the facts. Something I forgot to say : omni
in the experience and genuine French accent in the video.
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Er... I won't pretent I understand the phase analysis graphs... Looked up Adobe's site:
Adobe Audition 3.0
It says,
---- The white outline shows blah blah blah that are "reflecting the width of the stereo image. "
So... as I've seen in the video, in- or outdoor has very different (opposite) behaviors in near / far listening positions:
Indoor - widened when it's far away ; outdoor - widened when it's very near.
Or I mixed them up?
And that leads to:
When I visualize the projector-screen analogy, I think the room boundaries must be very important (like a screen, reflecting the images...).
If so, the room acoustics should be a key to the whole performace - its symmetry, reflections/diffusions/absorption... which can never be standardized but crucial to the final presentation.
However this seems very different from the 'image' (or feeling) that Stereolith wants to deliver -- easy going, simple, stereo sound everywhere... and so called "life style" sort of things.
hmmm....
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