are room treatments the key to a holographic soundstage?

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drphoto

Are room treatments the key as well as the equipment? I have Merlin TSM-MMe which are pulled out a least 6 ft from the wall, and 4 ft from the sides. Upstream they are driven by a Stan Warren Aiwa XC-35/MSB DAC>Odyssey Tempest SL>Stratos Monos. IC are Gronenberg TS and speaker wire is Reality. Bass is handled by 4 GR servo OB subs.

While the speakers disappear, the sound stage really isn't wider than the speakers or particularly deep.

Right now I have 2 GIK 242 at first reflection points on the side wall, and one across a rear corner as a bass trap. Would adding a lot more broadband absorption help w/ sound stage?

I should think imaging from the Merlins would be excellent.

zybar

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Re: are room treatments the key to a holographic soundstage?
« Reply #1 on: 17 Aug 2009, 10:41 pm »
Room treatments absolutely help sound stage depth and width (assuming it is in the recording and your setup is capable of producing it).

I know that when I added Realtraps RFZ panels at the first side reflection points, it cleaned up the imaging and sound stage.

George

keenween

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Re: are room treatments the key to a holographic soundstage?
« Reply #2 on: 17 Aug 2009, 10:56 pm »
In addition to the original question, what treatments have the most potential to create this? I would assume first reflection points...but then, something next?

I would like to treat my room, but will probably be limited to a few non-permanent panels...i.e. only installed for my more serious late night listening sessions. From all the reading I've done in this forum, I've obtained that the more room treatments...the better. I've read that broadband absorption and heavy bass trapping will in effect provide greater clarity. I've also not yet read of someone over-treating a room. I'm interested in how to obtain more holographic soundstage with less or restrained treatments. Obviously a well treated room would be ideal, but not possible for me. I think depth of soundstage is what really bowls me over, if there are specific treatments better suited for depth, I'd like to know!

rhyno

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Re: are room treatments the key to a holographic soundstage?
« Reply #3 on: 18 Aug 2009, 12:02 am »
1st and foremost, get your speakers positioned properly. if they're not set up optimally, forget about a holographic stage.

(monkey coffins respond very well to the "WASP" (wilson audio setup procedure) method, which uses such aggressive toe-in that it reduces the influence of side wall reflections. search online as i think a web site covers how to do it).

i've no diffusion in my room, just absorption (and absorbing bass is huge for clarity, of which stage cues depend), and get great staging.

oh btw, if you've not addressed vibration throughout your rig (from electronics to speakers to cables!), you'll never get the best stage you're capable of.

rhyno

richidoo

Re: are room treatments the key to a holographic soundstage?
« Reply #4 on: 18 Aug 2009, 01:46 am »
Reducing phase distortion throughout the system is what improves soundstage imaging.

Make the speakers same distance from tweeter to ear in the listening position, and same toe angle. If your room is large enough get the speakers and yourself as far away from the walls as possible so early reflections are minimized. Then toeing out a little helps ambience. If the echos arrive at your ears long enough after the direct sound from the speakers then the added echo does not detract from soundstage. In a small room treatments like absorbtion or diffusion can work better because you can't get far enough away from the walls. The front wall should be hard and flat with nothing placed between the speakers. No soft stuff anywhere on the front wall for best soundstage.

Amplifiers (pre and power) should have linear phase through most of the frequency range. Tube amps are naturally good at this, but a good SS designer can do it. Speakers should have linear phase crossover which is a lot easier to achieve with 2nd order than 4th order passive filters. Drivers should be time aligned at the listening position. Reduce digital jitter, clean AC power, no ringing in signal wires. Presto! excellent imaging. But imaging is just a parlor trick compared to clean flat satisfying bass response in the room and accurate timbre and PRAT from the amps and source.

poseidonsvoice

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Re: are room treatments the key to a holographic soundstage?
« Reply #5 on: 18 Aug 2009, 02:01 am »
Reducing phase distortion throughout the system is what improves soundstage imaging.

Make the speakers same distance from tweeter to ear in the listening position, and same toe angle. If your room is large enough get the speakers and yourself as far away from the walls as possible so early reflections are minimized. Then toeing out a little helps ambience. If the echos arrive at your ears long enough after the direct sound from the speakers then the added echo does not detract from soundstage. In a small room treatments like absorption or diffusion can work better because you can't get far enough away from the walls. The front wall should be hard and flat with nothing placed between the speakers. No soft stuff anywhere on the front wall for best soundstage.

Amplifiers (pre and power) should have linear phase through most of the frequency range. Tube amps are naturally good at this, but a good SS designer can do it. Speakers should have linear phase crossover which is a lot easier to achieve with 2nd order than 4th order passive filters. Drivers should be time aligned at the listening position. Reduce digital jitter, clean AC power, no ringing in signal wires. Presto! excellent imaging. But imaging is just a parlor trick compared to clean flat satisfying bass response in the room and accurate timbre and PRAT from the amps and source.

Agreed. And very nicely written. From one Carolinian to another.

Anand.

Mag

Re: are room treatments the key to a holographic soundstage?
« Reply #6 on: 18 Aug 2009, 02:08 am »
In my experience which is rather limited. Having a good acoustic room to start with is the key. You don't want a room that is dead sounding or too lively, but middle ground. Room treatment then helps focus the sound increasing clarity and details.

I can think of 3 types of holographic imaging, there may be more I'm not aware of at the moment.

There are speakers along with certain amps that have a bloom imaging. Which in my interpretation could be considered holographic. My speakers don't have this bloom or I don't notice bloom being acustom to them.

Then there is an omni-directional holographic imaging that comes from higher or low freq.. usually at higher volumes, interacting with the room. I find this effect to be mesmerizing.

Then with better equipment the holographic image changes to one of 3D depth & weight, the sound may contain the omni-directional imaging as well, depending on musical content.

drphoto

Re: are room treatments the key to a holographic soundstage?
« Reply #7 on: 18 Aug 2009, 02:20 am »
How do you reduce ringing and/or vibration in signal wires? I know Sonoran touts this concept w/ their top of line cables by using a filler they call 'micro-bearings'. They are great sounding cables but they are ridiculously expensive.....at least to me. I mean the speaker cable length I'd need would cost more than my speakers.

My transport is on Mapleshade tri-points, and the Odyssey stuff have their supposedly anti-vib footers. However my rack (a DIY Flexi) is not spiked to the subfloor.....maybe that would help.

I guess this phase distortion thing is why way back in the day when I first got into this people told my conventional tone controls wrecked imaging, and why real hi-end pre amps did not have them.

3D imaging might be a parlor trick, but I like it. Other wise the system sounds pretty darn good, especially w/ the addition of the OB subs.

rhyno

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Re: are room treatments the key to a holographic soundstage?
« Reply #8 on: 18 Aug 2009, 01:18 pm »
cheap tweak for signal cables to reduce vibration: add clothespins to them (the old spring loaded wooden type).

cable vibration is less important than A) front baffle vibes, B)source vibes, and C) remaining electronics vibes, in that order.

rc

jimdgoulding

Re: are room treatments the key to a holographic soundstage?
« Reply #9 on: 18 Aug 2009, 01:54 pm »
Are room treatments the key as well as the equipment? I have Merlin TSM-MMe which are pulled out a least 6 ft from the wall, and 4 ft from the sides. Upstream they are driven by a Stan Warren Aiwa XC-35/MSB DAC>Odyssey Tempest SL>Stratos Monos. IC are Gronenberg TS and speaker wire is Reality. Bass is handled by 4 GR servo OB subs.

While the speakers disappear, the sound stage really isn't wider than the speakers or particularly deep.

Right now I have 2 GIK 242 at first reflection points on the side wall, and one across a rear corner as a bass trap. Would adding a lot more broadband absorption help w/ sound stage?

I should think imaging from the Merlins would be excellent.

What is the distance your speakers are separated from one another (centerpoint to centerpoint) and the distance from them to your listening chair?  Your speakers are out from the wall behind them.  What is the distance out of your chair (head) from the wall behind it?  And what are the dimensions of your room?  This might be helpful to know.  Thanks.

Ethan Winer

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Re: are room treatments the key to a holographic soundstage?
« Reply #10 on: 18 Aug 2009, 04:14 pm »
In addition to the original question, what treatments have the most potential to create this? I would assume first reflection points...but then, something next?

Absorption at the side-wall and ceiling (and floor) reflection points are the key. Bass traps are very helpful, but they solve a different problem. Imaging and sound stage etc is mainly a mid/high frequency issue. If you can't treat your room permanently, panels on stands are a good solution because you can take them out to listen, and put them away when company visits. The (older) photo below of George's setup shows his side-wall panels on stands:

--Ethan


TRADERXFAN

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Re: are room treatments the key to a holographic soundstage?
« Reply #11 on: 18 Aug 2009, 04:19 pm »
Alternatively, you can try a controlled directivity speaker, like Gedlee's.  Stops the problem at the source. No need for sidewall treatment, you can put that back in your equipment budget...
  aa

-Tony

woodsyi

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Re: are room treatments the key to a holographic soundstage?
« Reply #12 on: 18 Aug 2009, 04:57 pm »
Unless you are out in your backyard, you are going to have  reflective bounce form the walls.  I don't see how Gedlee makes sound waves disappear.  Are you saying that his speakers beam right at the listener and has no dispersion that will strike the side walls? :o

TRADERXFAN

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Re: are room treatments the key to a holographic soundstage?
« Reply #13 on: 18 Aug 2009, 05:04 pm »
Yes "beamed" at you, if you want to use that word. Not exactly on axis, but that is just a finer point based on the designed response.

No smearing. Every detail is clearly heard. This also due to efforts expended to minimize diffraction on the speaker itself.

Don't be afraid. This is a good thing!  After the small window of time, <20 milliseconds, (when a reflection will cause smearing in our hearing) the reflections do come back around and everything sounds natural.  --Oh should add, the layout is to have the reflection strike the opposite ear, as we psychoacoustically process this differently from the direct sound to the "same side" ear.

http://www.gedlee.com/downloads/Cum%20laude.pdf
page 6

 :thumb:

JackD201

Re: are room treatments the key to a holographic soundstage?
« Reply #14 on: 18 Aug 2009, 06:57 pm »
Clearly I'm no flat earther but as far as I can remember 3D imaging was why stereo was invented in the first place. I mean it couldn't have been the other stuff on the audiophile checklist because mono sure as heck did all the other stuff well when stereo made it's entry. Further, stereo in its beginnings was nasty in the way engineers were going bonkers with the pan controls and the lack of user knowledge about ideal set up. Those were the days when bookshelf speakers were really put on bookshelves  :o

Having said all that here are a few things that dictate good soundstaging.

1. Left and Right Channels that are properly matched in amplitude. Mismatched amplitudes are the primary cause for stages collapsing, hence usually the first sign of a weakening power tube for tube lovers without autobias.

2. Speaker set up that takes into account the dispersion patterns of the said speakers and how their off-axis peaks and nulls interact (phase as richidoo said). When in doubt check with your speaker manufacturer or dealer for good starting points when setting up.

3. A room that neither keeps everything bouncing around (reverberation time too long) or sucks the life out of the music (way too short)

So yes, I would say room treatments could very well be the key to enhancing a system's ability to produce a believable soundstage but the first two conditions must be met else any other effort be in vain. Some folks I know have been lucky in that their rooms by pure chance needed no treatments at all. Sadly this is not the case the vast majority of the time. Speaker dispersion characteristics also dictate to some degree where treatments should be placed as is the case for dipoles or super cardioid types. As with all things in this hobby a few things are musts and a much more depends on tastes. Judicious use always betters wanton excess.

Good Luck!

kenreau

Re: are room treatments the key to a holographic soundstage?
« Reply #15 on: 18 Aug 2009, 07:07 pm »
At risk of stating the obvious, dont' forget the recording/software.  All this quest and effort of fine tuning the room and hardware (which I am an advocate of) will only reveal to a further degree how well the performance/recording was to begin with.  G.I.G.O.  Some songs/albums have it, many do not. 

DougSmith

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Re: are room treatments the key to a holographic soundstage?
« Reply #16 on: 18 Aug 2009, 07:22 pm »
I second the comment about the Geddes waveguide speakers.  My Abbeys image great when toe'd in ~45 degrees in my room.  At that angle you get essentially no high frequencies bouncing off the near side walls since the cone of dispersion is ~90 degrees on axis (and the directivity is relatively constant within that cone).  My room has no treatments at all, which is probably not optimal since there is a bit too much clutter up front, and I have a 5'x7' plate glass window right behind the listening couch.  But the imaging is excellent nevertheless. 

-Doug

nrenter

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Re: are room treatments the key to a holographic soundstage?
« Reply #17 on: 18 Aug 2009, 08:11 pm »
Speakers should have linear phase crossover which is a lot easier to achieve with 2nd order than 4th order passive filters.

Sorry, guy, but anything other than mirrored first-order crossovers smear the time domain of the signal. Doesn't matter if it's second-order or fourth-order, the both don't work. And this is only if the speaker is behaving with rigid, pistonic action. This second point explains why single-driver crossoverless speakers are not time and phase-aligned.

Russell Dawkins

Re: are room treatments the key to a holographic soundstage?
« Reply #18 on: 18 Aug 2009, 08:24 pm »
Over the years I've said it before a couple of times to no response, but I can't help saying it again - you are shooting in the dark unless you check your progress by the quality of the mono image your setup is capable of generating. The tighter and more focussed the mono ("phantom") image, the more valid the stereo image. If the mono image is laterally smeared, you can bet your stereo image is as well, no matter how much you like it or how pretty it sounds - it is not what was intended by the mixing or mastering engineer. The more distortion in playback, no matter what the source of the distortion, the sloppier the mono image.

It must be said though that is the real world a little de-focusing of the image can make "pan pot stereo" (mono mic sources panned left, right and in between) easier to take, if that's your main fare.
As to achieving good imaging, my approach is to
1. favor live-end-dead-end configurations, where the speaker end is dead
2. try for a laterally symmetrical environment for the speaker end of the room
3. absorption at the first wall, floor and ceiling bounce areas
4. toe in so the speaker axes cross in front of the primary listening spot

Finally, controlled dispersion in the manner of Geddes, Audiokinesis, SP Tech, Emerald Physics does help in controling first reflections, which are a major culprit.

JackD201

Re: are room treatments the key to a holographic soundstage?
« Reply #19 on: 18 Aug 2009, 08:41 pm »
I totally agree about the mono part. My set up ritual invariably begins with a mono recording and getting the instruments to stack up accordingly.

I personally go for EFZ rather than LEDE and favor loudspeakers with linear off axis response. Speakers that fit this profile just end up floating my boat more because the experience, for me at least, is more immersive rather than voyeuristic. These type of speakers just happen to need less toe in not that I don't employ it when in search for a tad more focus. Wider linear off axis radiation also allows me to enjoy a soundstage that extends far front as well as far behind the speaker plane. Again this is a matter of taste as I know many folks whose holy grail is to have the soundstage as far back as possible. Width is not so much an issue for me as breadth. In EFZ I find I get room boundary support while enjoying reflected energy way outside the Haas window. The downside is that you can throw WAF out the window and a dedicated space is a must.