Eureka or bust... Stereo experiments.

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Are you talking about Stereo or Mid/Side? They are not the same indeed...

I was referring to stereo represented in MS format as opposed to LR format. Their relationship via energy preserving coding/decoding means they are the same thing information-wise.

But reproducing only an M channel over two loudspeakers merely introduces some of the deleterious artefacts of conventional stereo. Comparing "apples to apples" is then not so straightforward.
 
I was referring to stereo represented in MS format as opposed to LR format. Their relationship via energy preserving coding/decoding means they are the same thing information-wise.

But reproducing only an M channel over two loudspeakers merely introduces some of the deleterious artefacts of conventional stereo. Comparing "apples to apples" is then not so straightforward.
Thank you for your reply. M/S is an interesting topic. I've been looking into to it today, the interchangeability is fascinating. The artefacts you speak of, would they exist if playback was over a single loudspeaker, in other words are you talking about comb filtering artefacts?


Well, If you happened to chew a Juicy Fruit at the time of the original event but didn't at reproduction - and felt "I miss something" - I cant help you ;)

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Agreed. We can look into possibilities of injecting secundary signals during playback.
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A more serious post today...

YouTube
A YouTube video titled "Hear the first stereo ever, Blumlein's original recordings from 80yrs ago"

I've watched it on the setup with 4 monopole speakers as per the first experiment.
The narrating voice clearly audible as if coming from the front speakers.
The recordings made by Blumlein: coming from all around.

Another original:
YouTube
This 'walking and talking' video demonstration of channel seperation:
I obviously can hear who is talking in the video, left or right, sound coming in from the front. But when the 'clapper' is shut with force at 1:22 I can hear the reflections of the sound coming in from behind as well.

Anybody else testing this?
 
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IMAGE.whatformatisthis

Don't be afraid to criticize something. I don't take any of it personally...

Changes:
The couch moved back from the middle of the room towards the backs wall.
I can now enter and leave the room without obstruction, like before.
LP has changed, and I've been retrying to get imaging with moderate succes.

All this time I've been using a mix of DIY fronts and Mission M32 rears.
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I want to test if this is a problem by eliminating it. 2 of the speakers should be replaced by others, to sum up to 3 identical pairs.
Any change in perception will be reported and discussed.

During the adjustment of time alignment of front and rear,
it seems I'm relatively sensitive voor imaging in the midrange.
Just aligning low or high frequency, does not create the image like the midrange is able to. Therefore current time alignment is based on midrange frequencies, other frequencies are being filtered out at the rear speakers, limiting their distortion on the image effectively.
However, now the sense of spacioussness has decreased. The low pass filter in the rear speakers was replaced with a high shelf filter, of which the gain was adjusted at the most comfortable compromise betweet sense of space, and image clarity.
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When listening to only the front pair of speakers, I enjoy the reflections of the rear wall. When listening to the double pair, rear wall reflection distorts the image. A very large pillow is placed centrally against the rear wall, effectively removing reflections that travel from front speakers->rear wall->LP. Image has become less distorted. Compared to only the front speakers, the size of the perceived space has grown and the image is more clear. I am conflicted about the space. Should it realistic in comparison to the listening room, or should it be whatever is in the recording? For now it seems to be more comfortable to let the space be what it wants in stead of conflicting with the room. The perceived central image does not feel very connected to the perceived space yet.

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About the time alignment:
The attached shows that delay to the rears is quite low, especially considering that both front channels have to pass through more external DSP.
I was expecting more delay was needed because of physical positioning.
With some albums, delay settings have to be changed to get the maximum effect.
The sound card has a seperate board for the surround channel ouputs. The DAC's on there are different from the main 2-channel output.
An internet search revealed that there are users who report a delay of the rear channels. I will need to measure the difference in delay of the stereo ouputs, the surround ouputs and the digital output+dsp/dac for a comparison.


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Lastly, attached is a picture of my broken TV.
I wonder how it can break in this weird way.
It looks like it has some interlaced artefacts, I was suspecting a driver or DSP fault, but I found that the screen uses "phased array" to drive the pixels that render the image. So it could be a hardware problem as well, like a signal trace gone bad. Interesting to see that in this distorted area, you can see noise that is related to what it is displaying down below. Sometimes you can even read text in this area that isn't supposed to be there. If wanted I can make more pictures of it.

Phased array sounds interesting...
And UltraSonic Imaging too.
Is knowledge of other types of imaging useful for sound image reproduction?
 

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I always thought a Blumlein mic arrangement was for convenience when recording Grateful Dead shows...Only one stick to hold, no buddy / other stick needed, no extra mic cord to get trampled upon.

Seems to me 4 FR drivers in a standing 4 sided pipe TL would spit back the point in space this Blumlein arrangement captured. Might be a little impractical having such right in the middle of the widescreen display... But this is experimental, so, who cares - solve that detail later!

What to do with the EQ on the (-) pair of such an arrangement, so the TL cabinet can make some bass. Dial those into midrange only with the DSP based EQ?

Anyway...maybe you'd just end up with a sort of quasi-monaural soundfield from such an arrangement, which - not to judge without direct experience - might be better than true monaural (L+R) in some perceptible ways.
 
@wiseoldtech: thanks. I'll have a look inside to see if the ribbon cable is visible/repairable before I buy something else.

@jjasniew: it's at least as interesting as it is impractical :) a few compromises here and there and we could try. For a monaural build I'd want to keep it simple as possible at first.
 
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I've been working on a little something special. (second experiment)
Have some Full-Range drivers to go in the baffle.
This means I will have to modify the drivers a little bit because they are too deep, the accoustic offset is problematic.
It's not much, but it might be the kitchen-sink project that could change my experience drastically.
Think of it: when a bass note is hitting the cone of the driver in one direction, the high frequency stuff that's modulated on top of that wave, will be thrown into the same direction. Isn't it logical?
 

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