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Properties of speakers that creates a large and precise soundstage

jim1274

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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

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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

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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

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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

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


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:


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:




 
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