Properties of speakers that creates a large and precise soundstage

[jim1274]

Some years ago I tried setting up a 7.1 with my Yamaha DSP a-1000. I was actually quite impressed by how much engineering had been put to this and the various effects it offered. The sound was truly immersive on some tracks, especially live performances. On majority of other tracks the effects were less then enjoyable and convincing. Reverted to 2.1 and never looked back.

Well, I cycled through all the DSP settings, a worthwhile experiment. I found all the hall/church/club settings had too much reverb, but the “9 channel stereo” setting was another story, a real eye opener. It eliminated the excessive reverb, actually sounding pretty darn good. The “9 channel stereo” DSP significantly attenuates the level on all the surround channels such that you don’t hear them as a sound source from the center listening position. The soundstage seems deeper and extended in the forward plane, I suspect from the side surrounds “pulling” it more towards the listening position. I have a friend who swears by this vs 2 channel stereo, and now see the allure. I’m certainly no where near saying it is preferable to 2 speaker stereo, but well worth further comparisons.

I’m definitely going to do some comparisons now on a wide range of recordings, both live and studio. The only one tried so far was a live recording—not sure what the effect will be on studio recordings.

I would encourage anyone who has a surround system to try this 9 channel stereo mode and compare to 2 channel. I’d be very curious to get others take on the comparison.

 

[audiofooled]

But in my opinion, an equilateral triangle is the way to go if we want to approach the most common studio standard, which in turn will most likely give us the intended width of the mix as it was heard by the engineer in the studio. So when we have figured out what distance works well for our speakers to get that distinct sounding phantom center, we can almost be sure that 'about' the same listening distance will also work pretty well (as in an equilateral triangle). So now that we approximately know how large this listening triangle should be, we can move this triangle around inside the space of the listening room to find the best compromise when it comes to both the listening position and the placement of the loudspeaker's distance to the walls.

Studios would usually have an ample amount of acoustic treatment. In a normal room, if you set things right, the soundstage width and imaging precision far to the left and right would not at all be limited to how large of a triangle you have, or how far apart the loudspeakers are spaced, if you will. In the video I posted earlier, Earl Geddes explains how, by using toe in or bringing the speakers closer together, you get a wider sweet spot. That is, if the loudspeakers are well behaved off axis and you delay the lateral reflections enough.
A wider sweet spot IME does not only mean a wider area in which you get good imaging, but also a soundstage width that isn't any smaller than if it were an equilateral triangle, if that's what you're aiming for. It's just that the sonic images would be localized more farther to the left and right than the loudspeakers are located.

 

[jim1274]

Big thumbs up on this suggestion. As good or better on soundstage size of any recording of its type I’ve come across. I found the exact one you referenced on Tidal—didn’t show up in initial search but noticed when scanning all the CSO albums:

View attachment 349509

I just tried this for soundstage comparison of 2 speaker stereo vs “9 channel stereo” DSP. This is opening a big can of worms, at least for me. On this recording, both sound really good and almost a coin toss on which I prefer after just a quick first listen.

 

[jim1274]

I just tried this for soundstage comparison of 2 speaker stereo vs “9 channel stereo” DSP. This is opening a big can of worms, at least for me. On this recording, both sound really good and almost a coin toss on which I prefer after just a quick first listen.

That was interesting (though at sometimes a bit rushed IMO)...

Griesnger's talk about "proximity" of sound being "engaging" meshes pretty well with my experience or tastes. Though his specific talk wasn't exactly concerning the following, it does remind me of the point made about advantages I get from my 2 channel speaker set up vs surround:

I think it's quite common that, as in my own case, for sheer practicality surround systems are often not placed in the positions many audiophiles prefer for 2 channel listening.
So my surround speakers are on the walls, my L/C/R speaker flank my projection screen, whereas my 2 channel speakers are pulled out "audiophile style" in to the room to form the perfect listening triangle.

One of the benefits of the closer positioning of the stereo speakers is "proximity" to the sound, IMO. The speakers are capable of casting a VERY deep soundstage that can seem to go waaaay back beyond the room borders, for sounds in a soundstage that are placed in the distance. But on the other hand, sounds that are mixed right "up front" occur at the front plane of the speakers, and so their "proximity" is very close to me, and attention grabbing. This means that not only is there a wide variety of depths and layers of imaging that happens when switching between recordings, but recordings that contain a wide layering of sound - e.g. from right up close say sounds panned left and right at the speaker plane, to sounds waaaay back in the soundstage, can therefore create a tremendous impression of layering and depth, from "really close right next to me" to "very far away."

I don't get this from my surround system if only because, of necessity, the L/C/R speakers are significantly further away and even the closest mixed sounds start at quite a distance from me, and thus are never as attention grabbing and I don't get the same sense of the whole room opening up in space, from close to me to far away.

(And that's also why, despite having heard plenty of surround music, I still find my 2 channel set up can sound more convincing and enveloping in some respects. For some live performances the imaging actually feels more like being among the audience, hearing through a real acoustic space, to the performers. Where there are other times, other tracks, where I might prefer the surround immersion of the surround system).

The thread kinda shifted gears more to soundstage using a multichannel DSP scheme on 2 channel sources, so this seemed like the best point to go back to 2 speakers.

After abandoning the surround sound rig experiments, I focused on dialing in the “box” speakers for best soundstage. First, I moved some obstructions out of the way and systematically (and as smoothly as possible) moved my listening position back and forth (testing different width spacings too), noting the changes. Well, I never quite fully realized how profound an effect that has, not only in the soundstage, but maybe even more so in clarity. The increase in clarity actually was more than previously realized by just leaning forward and back a few feet. When finished fine-tuning the speaker placement for best soundstage size and instrument localization precision (along with clarity, timbre and such as well), I ended up with an equilateral triangle. That ended up being 8’ from the front wall, 3.5’ from side walls, and 8’ “legs” on my equilateral triangle to listening position. The soundstage presented after speaker position tweaking then became a function of the specific recording played. This is where things got more interesting…

So, now that the box speakers were optimized, so to speak, let’s compare to the Omnis. I did the same back and forth listening distance with the Omnis, and didn’t notice as much increase in clarity as the box speakers when moving closer. Then I did an A/B of box and Omni at the 8’ triangle position, noting the big penalty in clarity on the Omnis, enough that any soundstage advantages were not nearly enough to offset clarity loss. I was about ready to eat crow for over-selling the Omnis when it crossed my mind to move Omnis in a lot closer. Theory would suggest that will increase the direct to reflected energy ratio, having a positive impact on clarity. Well, that was a game changer, more than just some increase in clarity.

I now cut my equilateral triangle size in half for the Omnis down to 4’ between the Omnis and 4’ to my listening position (which also moved them a couple feet further from side walls) First off, the increase in clarity was so much that it was now very close to the BMR box speakers in that characteristic. What surprised me just as much was literally no soundstage penalty. The Omnis still completely disappeared, their soundstage still deep and wide, sometimes sounding like it started well behind the speakers and extending back to the front wall. This varies by recording, just like the BMR box, but had much more depth and no noticeable penalty on width. The soundstage depth with the box speaker was not even close, on some recordings sounding like mostly sound coming right from the speakers and on the same plane.

I was just about to conclude that the Omnis loss in clarity when compared to the box was maybe a deal breaker, but no longer. I’ve done A/B on several dozen songs now and find the Omnis preferable on most songs so far.

 

[jim1274]

This made me think of the Hughes unit from back in the 80’s:

https://gearspace.com/gear/hughes/ak-100

Not what you describe, but still a soundstage “enhancer” gizmo.

Earlier today in the Omni thread, xschop posted a thought about trying Omnis near field on a desk, making me think of another “Omni like” portable speaker that is in this “enhancer” category. I use one currently as an external speaker for a kitchen TV due to its stereo “effect” and compact size. They are no longer in production, but still available on a fire sale close-out:

Mass Fidelity Core | Periodic Audio

Core Bluetooth Speaker with Wavefield Synthesis NOTE: International shipping will be QUOTED AFTER ORDER - due to the size and weight of this product, we

periodicaudio.com

They got some glowing reviews, a bit over-stated IMHO, but pretty good sound given the small size and also portable battery powered and now under 100 bucks. They originally were a lot more $ ($599!!) but for under a hundred delivered, a more compelling buy. I am considering grabbing 3 for mounting on the 3 garage walls at standing ear height to try as garage “work tunes”.

Some reviews describing what they are about:

Mass Fidelity Core Multiroom Bluetooth Speaker

Performance Features Ergonomics Build Quality

www.soundandvision.com

Mass Fidelity Core Review - HomeTheaterHifi.com

The Mass Fidelity Core is an attempt to bring holographic, stereo sound from a single, small speaker that connects to Bluetooth sources.

hometheaterhifi.com

Mass Fidelity's Core Is a Tiny Wireless Speaker That Puts Out Huge Sound

It uses wave field synthesis to produce a wider soundstage.

www.wired.com

Mass Fidelity Core Review

The innovative Mass Fidelity Core delivers excellent audio quality you'd expect from a wireless speaker twice its size.

www.tomsguide.com

 

[richard12511]

I'm not the one making the claim that others are asserting "the soundstage should come from the room and speakers and not from the recording."

Again, I invite you to show me a post that makes this claim. It may well exist, I'm not saying nobody ever said it, but I don't recall THAT assertion being made in this thread.

Having just read through this entire thread up to this point in the past couple days, I don't think I saw anyone make that claim either, but perhaps I missed it.

 

[BrokenEnglishGuy]

One of the widest soundstage i've hear is the Concept 500, apparently not only wide dispersion have to be wide but also the tweeter have to not beam too early, cymbals sounds much more convincing because the tweeter start beaming it's 70° at 12~15khz
A lot of people call this speaker '' holographic '' '' very wide soundstage '' '' huge soundstage '' etc

 

[dualazmak]

Although quite belated, I read through this interesting thread.
I well know and understand that "properties of speakers" and "room acoustic environment" are greatly depending with each other for nature of "sound stage/image".

Let me share with all of you my own present series of audio experiments mainly relating to "sound stage/image" by dispersion tuning of my super-tweeters which are of rather narrow-directivity highly-efficient metal-horn FOSTEX T925A (covering ca. 8.8 kHz - 23 kHz) singing together with reasonably wide-directivity Beryllium dome tweeters (covering ca. 6 kHz - 14 kHz).

I presently test wide-3D reflective dispersion of the super-tweeters T925A using heavy-thick random surface crystalline-cut-glass, and found (subjectively in my room acoustic environment) that such wide-3D dispersion of super-tweeter sound gives not only more stable and robust "sound stage/image" but also wider/larger sweet spot/sphere around the center of my listening position which is at 3.2 m from the surface of the SP system.

If you would be interested in the details of my present on-going experiments in this regard, please visit my posts on the thread of multichannel multi-SP-driver multi-amplifier audio project;
- A new series of audio experiments on reflective wide-3D dispersion of super-tweeter sound using random-surface hard-heavy material:
Part-1_ Background, experimental settings, initial preliminary listening tests: #912

Part-2_ Comparison of catalogue specifications of metal horn super-tweeter (ST) FOSTEX T925A and YAMAHA Beryllium dome tweeter (TW) JA-0513; start of intensive listening sessions with wide-3D reflective dispersion of ST sound: #921

Part-3_ Listening evaluation of sound stage (sound image) using excellent-recording-quality lute duet tracks: #926

Part-3.1_ Listening evaluation of sound stage (sound image) using excellent-recording-quality jazz trio album: #927

 

[audiofooled]

There are some similar threads about what imaging and soundstaging even is, and some threads about how to measure it (we're not great at that). In this thread I thought it would be interesting to have a look what properties is likely to enable a speaker to be good at this.

My (!) definition of "good" would be to be able to present a large soundstage. With "large", I mean the experience of sound being presented well beyond the speakers in all dimensions. Width, depth, height. I also mean the experience of a clear perception of where within this space different sounds are located. Finally, this also results in an experience of the music just being present in your listening space, not coming from the speakers. Often explained as speakers "vanishing" in subjective speaker reviews.

Commercial disclaimer: Imaging & soundstage are qualities I find important, so I strive to achieve this in my designs. You will therefore necessarily find that the list below matches well with our designs. My intent of this thread is not to discuss our designs specifically, but to discuss the technical properties enabling this quality from a general perspective. Possibly also going into detail on what is likely most important, how much the implementation matters (can you check the boxes on this list and still fail?), and wherever else this thread may lead us. Personally I think this is a very interesting topic, hopefully others agree.

Below is a list of important factors (not necessarily in order of importance) based on my experience.

1. Point source. I don't think this is controversial, and I think this is almost a prerequisite. Coaxial drivers are of course the easy approach to this. There are speakers with traditional drivers that sound big too, but interestingly it's often 2-way speakers with relatively small drivers and/or with at least the midrange and tweeter placed pretty close to each other. Exactly why this elevates the quality of soundstage and imaging I'm not sure.
2. Even off-axis response / controlled directivity, so that reflections feel like a natural addition to the direct sound as opposed to being perceived as a distraction or noise.
3. Linear phase crossover between the tweeter and midrange.
4. Less late reflections. So a well damped room, speakers not too far away, and/or cardioid speakers.
5. Enough level and capacity in both the deep bass and the midbass. This I think is another relatively well known thing, that well defined, deep bass can often add to the sensation of space.

EDIT: Additions to the list based on the discussion, with my comments (will edit again as the discussion progresses):
6. Placement and toe-in naturally affects this quality.
6b. Many argue that the speakers have to be well away from the front wall for good three dimensional, especially in the depth plane. I find this to partially true, but suspect there is one area where the mind plays some tricks on us. Seeing a speaker close to the wall, makes it harder to accept depth cues.
7. Sidewall reflections. This definitely affects this quality, but personally I've had varied results which make this a somewhat confusing one. In several rooms I've ended up not dampening the sidewalls for the best soundstage, while in others the opposite was true.
8. Directivity (also mentioned in point 2) - I'm not sure it's entirely clear what works here. My own designs are I guess somewhere in between wide and narrow directivity, and that subjectively works very well, but that's not to say that a different approach can't work well too.
9. Well tamed low-end (so good extension with smooth response) has also been suggested. I'm not sure if that is true directly, or perhaps indirectly due to the fact that uneven bass takes away our attention from the rest.

EDIT #2:
Adding an interesting quote from @Duke that I think perhaps quite precisely describes what we are after: "The spatial cues on the recording are perceptually dominant over the spatial cues of the playback room."

General reflection: We could perhaps form the theory that there are a number of elements that need to come together to create this magic, and the exact combination of ingredients may not be the same for each room(?). Which may be one reason why it's a bit elusive. The same speaker definitely doesn't present the same level of soundstage across rooms, so the room + placement is a significant factor.


What else? Agree/disagre? Any reflections (pun intended) to share on the subject?

As I can see, this interesting thread has now matured quite well. Thank you @sigbergaudio for starting and summing this discussion.

At the moment, I would like to add some comments which are normally absent from these discussions, sometimes because they are too complex and deserve a thread of their own (and they have), but are rarely integrated and recognized as potentially important ingredients for how we perceive sound stage and imaging. You may find my thoughts presented as a bit incoherent, but my intention is exactly that people take a bigger picture and draw their own conclusions with regards to their own experiences:

- Spectral tilt vs. spectral variance. Besides ITD and ILD, which are in the recording, our hearing relies on spectral cues as well. In room, loudspeakers can have varying degrees of success with regards to this which IME is directly proportional to directivity control, or a lack thereof. Spectral tilt is natural, caused by air absorption and gives us clues about how distant sounds are. Spectral variance is usually a consequence of lack of directivity control. Loudspeakers with uneven off axis response will suffer from spectral variance in the reverberant field, which will make it sound unnatural and give conflicting information about sound localization. This will result in loss of clarity and imaging precision. Depth perception will mostly suffer giving us perception that everything is equally distant. Something we may describe as a "wall of sound".

- Phase summation, phase offset and phase delay. This is hard to imagine and not always understood from steady state measurements. I won't say a lot, but I think that important properties to our discussion are that the "phase wheel" if described as such, has 360 degrees (for each frequency, so how quickly it turns is frequency dependent), once it reaches 0 degrees it turns again.

What's important to us is that phase summation at a given measurement point, with regards to sound pressure level, gives us full 6 dB of summation for correlated signals that are arriving fully in phase. Also about 3 dB of summation for less than 90 degrees of phase offset. At 120 degrees offset we are at 0 dB (nothing to gain, nothing to lose). 120 - 180 degrees we get the opposite (180 being full cancellation). Phase delay would be propagation with equal phase offset. but adding 360 degrees for every full cycle.

If we can setup our systems as such that we get hopefully less than 30 degrees offset, we are gaining efficiency, because it would mean that correlated signals (mono bass, phantom center) would gain anywhere from 5,7 dB to a full 6 dB boost. Uncorrelated signals would be more complex, but for the moment, let us at least be able to see the benefits in fixing phase summation for the phantom center, also at the crossover region for subs.

Brain works on loudness, but there's a threshold of time within we are able to fully integrate loudness and then compression kicks in so otherwise dynamic signals with sharp envelope onset suddenly sound compressed and equally loud. Considering above, we may conclude that time and phase aligned system can be perceptibly more dynamic. The opposite is true weather the signal is too compressed, or the loudspeakers suffer from compression. Either way what may result is listening fatigue.

What may also not be so obvious, but such loudspeaker and setup qualities may have a great influence in room over a direct to reverberant sound ratio.

Can we have directivity control over the low frequencies as well? Yes we can. But again, we must consider wavelengths and phase summation at the desired listening position. Wavelengths we must consider in every direction for omnidirectional signals, primarily how we position the LF sources with regards to each other and walls. Also we must consider crossover. We can have enough control so that the transient bass is considered as a coherent part of the soundstage, (at least for a short amount of time required) and very distinguishable from sustained bass which is enveloping.

 

[LevityProject]

As a psychoacoustic Effect ... it's still an electrical phenomenon.
Perhaps a better way of understanding audio is as an electro-acoustic phenomenon. The psyche part doesn't happen until after the acoustic and electrical part - on all counts (the equipment, our ears, our brains receiving and transmitting to our frontal lobes and other areas from our ears). Once all of the receiving and transmitting is done, we then (and only then!) make decisions based on what we hear (I like it, I hate it, I don't hear anything, I want more bass, the vocalist is out of tune, there's too much reverb etc etc etc).

Soundstage
It's tough to define, but I tend to think about it as the width of a recording, set of speakers, or set of headphones. And it's very possible to fundamentally change the soundstage of audio equipment by manipulating the sides of an audio signal. The Mid of an audio signal is it's mono source. So you can widen the perceptual soundstage of a recording by increasing the gain on the side channels.

I've used Mid-side processing for a while and I know what it sounds like. But I have no idea how it internally works. So, this article was interesting in explaining how side channels can be isolated. https://www.soundonsound.com/sound-advice/q-how-does-mid-sides-recording-actually-work

Mid-side processing
This is quite different from processing a stereo signal. The side channels contain FX dispersion, room noise, phase shifts etc. The Mid channel is the direct mono signal from all sources within a recording.

So if you widen a stereo recording to 300% using something like Waves S1 Stereo Imager or the Stereo width plugin that comes with Logic, it will sound like everything in the recording is coming from outside your speakers or headphones and the reverb will be insane. But when you switch to mono, everything will sound relatively "normal" and direct (unless the recording engineer didn't balance things well, in which case you might lose too much of the FX and certain instruments like electric guitar).

Let's Split Another Hair
The sides of a recording can be boosted without doing specific mid-side processing by simply boosting the upper mids using a generic stereo EQ. Why? Becasue 2-5khz is where a lot of the spatial sound of a recording lives. Mono recordings don't typically sound harsh here unless they've been wildly pushed in those upper mids. Another area where the sides can get some excitment is in the top end of the frequency spectrum.

Now this can get a little bit crazy because everyone hears top end differently due to age and exposure to overly loud music above 86db SPL (A-Weighted, Slow) for longer than 1hr at a time. That alone could turn into a whole side thread

Why do some IEMs sound "Wider" than others?
My good friend's JH Audio Custom (newer than what is reviewed at ASR) In-ears have an impressive soundstage. They are naturally spacious. Soundstage in headphones particualrily has something to do with how the driver combined with its housing design recreates the electrical audio signal. Over-ears tend to have a larger sound stage due to the nature of their design. On-ears can have a bit of a narrower sound stage, while In-Ears typically have quite a narrow sound stage due to the fact that they are shoved directly into our ear canals. But Some in Ears have a wonderfully spacious sound stage, like my friend's JH customs. What's up with that?

Soundstage in headphones is a fickle beast, since the typical "equilateral triangle" one would use to set up a set of loudspeakers (equal distance from the lister to the speakers and between the speakers) doesn't apply with headphones. They are on or in your ears, and effectively Panned hard left and right! So we need to use processing to widen or narrow the perceivable stereo width of headphones until we can get something that resembles a natural-sounding listening position with a solid "phatom middle".

That's about as far as I can go, but the best headphones i've tried at least re-create a realistic soundstage. Not too wide, not too narrow, but they allow for very wide elements if a mixing engineer puts that into the recording (like hearing the top row of a crowd around an arena at a concert, or a saxophone that is playing to the far left of a singer, or in Film when a voice is calling from the right at a far distance, and echoing off some buildings to the left). Indirect sound is vitally important for having a pleasant stereo spread in a recording. Again, not too much and not too little.

Soundstage in speakers has a lot to do with how far apart they are placed and how close the lister is to them. Put two speakers next to each other, and you'll have a very narrow sound stage. Pull them apart to the corners of a room and you'll have a massively wide sound stage.

 

[Emlin]

Soundstage
It's tough to define, but I tend to think about it as the width of a recording, set of speakers, or set of headphones. And it's very possible to fundamentally change the soundstage of audio equipment by manipulating the sides of an audio signal. The Mid of an audio signal is it's mono source. So you can widen the perceptual soundstage of a recording by increasing the gain on the side channels.

What are the sides of a sinewave?

And it's mostly about accurate reproduction of reverb.

Not what you are claiming.

 

[LevityProject]

What are the sides of a sinewave?

Good question!!

Sine waves will be the same in the mid and side channels (no tonal variances). However, use a daw like reaper and keep the sine wave panned up the middle, add a stereo reverb to the sinewave. Add a midi region and play a few notes with it, and then you'll hear the reverb only in the side channels, some combination of the reverb and sine wave in the mono channel, and the sine wave with stereo reverb in regular stereo. (I'll add a file - free tools so it should work as long as you have reaper, which has a limitless free trial)

To make it more apparent, hi-pass the reverb to 500hz

A single sine wave, even with reverb will sound the same in mono and stereo because there is no variation in the audio signal between the left and right channels (that doesn't mean there is no side signal, just that it's impossible to differentiate from the source). You'll hear the difference though on stopping!

This broke my brain! When I used a sinewave and added reverb, or a synth and added reverb, the side channels shifted to the left as I increased the reverb!

DSP is FICKLE.

I noticed that when I added reverb and a side-widening plugin, one channel got boosted. This might be a DSP processing issue with Reaper's user-created JS effects. For me, this is helpful to know because I have relied on them in the past, and it may be why some of my mixes were wonky

 

[Emlin]

Good question!!

Sine waves will be the same in the mid and side channels (no tonal variances). However, keeping the sine wave panned up the middle, add a stereo reverb to the sinewave and then you'll hear the reverb only in the side channels, some combination of the reverb and sine wave in the mono channel, and the sine wave with stereo reverb in regular stereo.

If you take away the reverb and pan the pure sinewave to the left, you'll hear it a little more loudly in the left as you maximize width. But it will just be mono if you switch from stereo to mono

Stereo means 3D. I don't know what you are talking about, and I don't think that you do either.

 

[Axo1989]

Stereo means 3D. I don't know what you are talking about, and I don't think that you do either.

Hmmm, mid-side as a microphone recording method can produce stereo, as can many other methods. You can indeed adjust the balance, and thus apparent width. Mid-side manipulation doesn’t define stereo, obviously.

 

[Emlin]

Hmmm, mid-side as a microphone recording method can produce stereo, as can many other methods. You can indeed adjust the balance, and thus apparent width. Mid-side manipulation doesn’t define stereo, obviously.

You are talking about recording techniques. We were talking about reproduction. As per the thread title.

 

[Axo1989]

You are talking about recording techniques. We were talking about reproduction. As per the thread title.

Well, a recording and production technique. I was wondering why @LevityProject is proposing mid-side as a playback manipulation? Most any effect applied to production can be applied to reproduction I guess (depending where we think creativity should be applied).

 

[LevityProject]

You are talking about recording techniques. We were talking about reproduction. As per the thread title.

Mid-side processing is a mixing technique that separates the mono signal from everything else. DSP amplifiers use it all the time. And it is possible to use DSP to increase the apparent soundstage of a pair of speakers without changing speaker placement. Not that you would want to do that, but it's a solution for if not enough room to physically move speakers around.

Mid-side recording is something different

Soundstage is related to mid-side, since widening with DSP (or pulling your speakers further apart) effectively increases the gain on the side channels and/or decreases the gain on the mid channels.

For speakers, the further you have them apart, the wider the sound stage will feel. In contrast, put two speakers right next to each other and you'll have a narrow sound stage. Getting an accurate soundstage out of speakers is mostly a matter of having a decent set of speakers (anything recommended here) and doing a thoughtful setup.

To start:

• Create an equilateral triangle between you and each of your speakers with your listening position at one point, and each speaker at the other two points on the triangle.
• In a setup that contains two speakers each with 1 woofer and 1 tweeter, you would measure according to the middle of the woofer. This means your ears are at the height of the middle of the woofer. This supports the Mid (mono) signal.
• The larger the triangle, the more width you'll perceive.

The sine wave thing was odd and I'm a bit baffled about why it didn't behave like I thought it would. I suspect isolating the sides of a reverberating sine wave could illustrate the reverse of how mid-side works. But it's a little bit mind bending, which is why I am stumbling over words ...

 

[LevityProject]

Hmmm, mid-side as a microphone recording method can produce stereo, as can many other methods. You can indeed adjust the balance, and thus apparent width. Mid-side manipulation doesn’t define stereo, obviously.

The sides are what makes stereo ... stereo. If you remove the sides (either by processing them out with DSP or physically changing speaker placement, recording techniques, whatever), you're left with mono.

 

[Axo1989]

The sides are what makes stereo ... stereo. If you remove the sides (either by processing them out with DSP or physically changing speaker placement, recording techniques, whatever), you're left with mono.

Your attempted definition is circular. Mid-side is a recording and production technique. Typically, you record M-S (using an approximately coincident figure-8 and directional microphone pair) for the purpose, and adjust the relative levels of each in the mix to influence the spread of the stereo image. But L-R stereo can be matrixed to M-S stereo without loss (and vice versa). So you can mix as M-S without necessarily recording that way (recording M-S has certain advantages, but all microphone techniques have pros and cons). M-S is one way of managing and manipulating the stereo image, and can also be used as part of a mix together with L-R and mono elements. And M-S isn't essential for stereo. Accordingly, M-S isn't the definition of stereo.

 

[LevityProject]

Your attempted definition is circular. Mid-side is a recording and production technique. Typically, you record M-S (using an approximately coincident figure-8 and directional microphone pair) for the purpose, and adjust the relative levels of each in the mix to influence the spread of the stereo image. But L-R stereo can be matrixed to M-S stereo without loss (and vice versa). So you can mix as M-S without necessarily recording that way (recording M-S has certain advantages, but all microphone techniques have pros and cons). M-S is one way of managing and manipulating the stereo image, and can also be used as part of a mix together with L-R and mono elements. And M-S isn't essential for stereo. Accordingly, M-S isn't the definition of stereo.

Well, I'm not really attempting a definition. Just pointing out the practical ways mid side processing shows up. Even when we *think* we're just working in stereo, we are in fact manipulating both the mid and side aspects of a recording at the same time.

If you take a stereo recording and remove the side channels, all that's left is THE mono signal.

Boost 3k with a stereo eq and suddenly reverb and guitars in the left and right channels jump out.

That's just how it works.

Measuring the sides (or soundstage depth) of a set of speakers would be a feat, because it's a function of how the speakers are set up.

I feel like a lot of this is obvious, but maybe it's just my experiences talking.