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Old 26th October 2014, 02:39 AM   #1
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Default comments on Sanders Sound systems White Paper

On Sanders Sound Systems website, Roger Sanders has white papers explaining, among other things, why large flat panels provide better imaging and sound than curved panels.
Also according to this white paper, the beaming produced by a large flat panel will give a more focused sweet spot, and the larger sweet spot of a wide dispersion speaker is just a small sweet spot with a smeary sweet spot around it (not his words).
His (expensive) esl speaker is 15 " wide.
I will agree that I've not heard a speaker that has front to back imaging as good as my Acoustat 2 + 2 's, which have 2 9" panels but are angled.
According to his white paper, his flat panel would be better than my 2 angled panels.
Sanders Sound Systems - Dispersion White Paper

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Old 26th October 2014, 04:14 AM   #2
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A white paper by Dr. Earl Geddes, GedLee LLC. ... Constant Directivity or Controlled Directivity (CD) has become a common buzz word these days. .... ideal CD vs. realistic CD discussed

From what I have learned with my Apogee Full Range LineSource ribbon speakers, I would design a full range ESL with one narrow(~1") tweeter panel, directly next to one wider(6") midrange panel, directly next to a line array of a few 12" dipole woofer dynamic speakers. Some panels cover Tweet+Mid by having a separate Tweet circuit and a separate Mid circuit.

OR I would mimic the QUAD ESL63 with time managed concentric rings of high-to-mid-to-low frequency areas.

===========Comic Relief===Why Diversity is Good in Speakers and Humanity======
"Do you feel lucky Punk?"

Everytime I purchase a new CD I remember this line from the Dirty Harry movie.
Stereo recordings are only a BIG FAKE ILLUSION.
The sonic quality and stereophonic presentation of each recording is a gamble.

When you bring questionable recordings and fake audio illusions into your home, your selection of speakers and room conditioning offer several very different options for the presentation.

1) Do you want to hear what the microphones hear? Horn speakers, especially converged entry unity horns, are good for this presentation. Many classical recordings use just two orthogonal mikes which match well with controlled polar pattern horns.

2) Do you want to add some auditorium ambience? Box monopole speakers with flat frequency response and controlled directivity can do this. Most of the 80-1100Hz vocal range can be covered by one speaker propagating into 180 degree 2-pi space. ENERGY into the room which generates new reflected "you are there" ambience illusions.

3) Do you want the illusion of the musicians playing in your room? Dipole and caridiod speakers can do this. Adding diffusion panels on the front wall behind the speaker improves the "they are here" illusion. ... most POP recordings are MIX'ed in close mic'ed small recording studios, and heavily compressed to generate hormones with IPOD earphones. 4-way dipoles are getting love because they add some realism to compressed POP.

4) Do you want to play conductor? Nearfield listening of large linesource dipole planars like BG75, ESL, Magnepan and Apogee blend the microphone directness with stage ambience, similar to what a conductor hears.
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Old 26th October 2014, 07:18 AM   #3
Calvin is offline Calvin  Germany
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the beaming produced by a large flat panel will give a more focused sweet spot, and the larger sweet spot of a wide dispersion speaker is just a small sweet spot with a smeary sweet spot around it (not his words).
I agree with that, but from a certain point on, the focus becomes so narrow that You'd have to have Your ears nailed to a fixed listening position.
The variations in highfrequency amplitude response may reach ~10dB for just 1 off of axis.
Practicality demands a sweet spot widened at least so far, that at minimum one person may comfortably enjoy music
Also HiFi already differs from reality, as even wide dispersion speakers display a sharper focus than one experiences in a concert hall.
We've got used to and like a sharp focus and it certainly makes up for the missing optical focus in a life situation, but it certainly differs from the reality.
Said that, the Q arises wether a extreme narrow focus increases the impression of realism or of artificiality.
Imho, Sanders's postulations lead to a impractical uncomfortable listening situation and a artificial 'overrealistic' presentation of music.

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Old 26th October 2014, 09:12 AM   #4
tyu is offline tyu  United States
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After 30 years of With Acoustats an any other ESL i could get my hands on.....My Acoustat setup to day is 3ea 9" panels Flat 15" off the yes the sound is the best i have had yet....
Sure i have ML an the 9" an 12" wide panels are Fun but...It like surround sround all the time....hehe... i can see were some think this is a good thing...
Till thay hear a good flat speaker old quad 57s... Apogee ribbons...even Magenpans....All flat....down side a 1/2 movement can make these flat panels sound get them setup a good room...
Acoustats...most say that there best speaker... is the 1+1...
But the wider ones have better mids an bass....Thats why i went with a 3panel wide i dont get the small sweet spot .... Roger Sanders has go it right..
Hell any bose speaker an a $100. Surround recever well give big unreal sound... that i have even heard out of Soundlab ESLs....thats is if you can get a Amp to drive them hehe.............
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File Type: jpg acoustat 001.jpg (894.9 KB, 232 views)

Last edited by tyu; 26th October 2014 at 09:23 AM.
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Old 26th October 2014, 09:37 AM   #5
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At RMAF, Sanders' speakers did provide excellent imaging as long as one stayed in the sweet spot (dead center left-right, and inside the front-back spots where the projection of the speaker areas intersect.)

With control of dispersion and reflections, the Floyd Toole method works fine too, but will have a slightly more diffuse sound (though possibly more pleasing, and certainly less dependent on the sweet-spot for acceptable sound.) Sanders' approach certainly has advantages under show conditions (unknown room, usually terrible, and fixed seating positions.)

Last edited by thune; 26th October 2014 at 09:44 AM.
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Old 27th October 2014, 01:20 AM   #6
AVWERK is offline AVWERK  United States
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If your going to push the microphone diaphragm in and expect to get this information to your ears with the least amount of corruption than that information should be preserved as much as possible.
Wide dispersion speakers distort this idea
If the venue that was recorded includes the ambient information in the mix, than you still want the speakers to replicate that dimension without anything added along the way.
Wide dispersion speakers corrupt the input information. They add material distortion ( walls ,floor,ceiling, etc that was never part of the recording.
So all you can do in the real world is try to minimize this first arrival event as much as possible for as long as possible.
I find no uncomfortable event happening at all in my listening to directional speakers and don't care about others outside of my moment.
Moving my head around while listening to his speakers doesn't change the sound field whatsoever.
All I hear is amazing clarity that no other ESL can deliver to this point.
And the bass is incredibly integrated. You are unlikely to do much better with separate amps and placement like I try to do all the time. Here you have a total system that works...

Wide dispersion after the event, baffles, horns, walls etc is distortion that was never there if your interested in the real recording information.
His white paper is really not controversial at all, simply the truth. He has built both curved and flat. His results just eliminate the gross imperfections

Anything you can do to limit what your listening room is doing to your experience just brings you one step closer to the ones recording and delivering the info.

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Old 27th October 2014, 07:39 AM   #7
Calvin is offline Calvin  Germany
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His white paper is really not controversial at all, simply the truth
Loool, that was a good one.
You know a white paper is promotional flyer with more or less 'technical' colouration.
As such it doesn't need to be as precise or correct as a technical bulletin or a scientific article.
Sanders's papers contain alot of worthy information and trueths, but certainly not only and simply The trueth.
For example does he say that the effects of comb filtering sound "awful" and he's referring to cancellation due to delays of early reflections and he's right about it.
But at higher frequencies wide flat panels are comb filter generators par excellence in themselves.
They don't even need nearby reflective walls.
Does Sanders explain this contradiction?
No, of course not, because its a white paper he wrote, not a scientific review.
In contrary a curved panel widens the sweet spot only at higher frequencies and to a much lesser degree than ML's claims of a wide and rather constant dispersion of 30.
That is long proven wrong and plain marketing BS and Sanders knows that also.
Still he talks of wide dispersing curved panels.
Fact is, that curved panels are highly directive too and that they only differ in directivity to flat panels in the highest one or two octaves.
Here they reduce the 'awful' comb filtering effect due to the slightly widend sweet spot.
And to be clear, slightly widened means something like the difference between 1" and 4" not 1" and 40".
Only within the sweet spot area remains the amplitude response rather constant.
Outside that area comb filtering related amplitude ripples spoil the 'trueth'
Now if it requires a head movement of just an inch to leave the sweet spot this is neither a comforting nor practical listening situation.
I don't think that people really enjoy sitting still like a mummy for hours.


btw. this is just another view to the Trueth *gg*

Last edited by Calvin; 27th October 2014 at 07:44 AM.
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Old 27th October 2014, 08:09 AM   #8
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Hi Guys. Time I stopped lurking & contributed. Jazzman very kindly told me how to configure the diaphragm stretching table for my own ESL build.

I have Sanders 10c speakers (presently not used now I have my DIY hybrids) which I bought for their directivity in a room that would be very challenging for wide dispersion speakers. His white paper is supported by the result - they do what it says on the tin, refreshingly rare in these days of marketing claims. They image beautifully and I could care less how many others are in the sweet spot.
Sanders does explain that the set up is crucial and covers this at length in the manual - I found a laser measuring device invaluable. Tiny changes to toe-in/out, distance and 'lean' make large changes to the presentation and countless hours can be had tweaking this.
Ultimately, however, the constant need to be 'in the zone' detracts from listening and drove me to a flat, multi panel, vertically segmented design that provides 90% of the image without worrying about being 20mm off axis after picking up a beer.
It's worth mentioning that the panels on the 10c are mounted fairly high - 73cm (to 180cm). Casual listeners need to careful about sitting or standing.

In short, for me CD ESL is close to perfection but in this specific implementation, a flat panel from 170Hz, is tiring for longer listening.
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Old 27th October 2014, 02:50 PM   #9
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I'd say the essential issue is room acoustics. Over-simplifying what I think is this years' point of view, you need lots of house-curved direct sound coming right at you, avoidance of early reflections (I forget this years' timing recommendation), and good later reflections for ambience.

In light of that requirement, any technology or shape of ESL can potentially work right in your music room (or could be awful). My recent experience is that it is important for imaging to avoid having ESLs too close to the side walls in order to limit early reflections*. In turn, curved or flat will work differently depending on distance to side walls, etc. in your room.

BTW, putting a flashlight on your head so as to see the bright spot reflection centred in the mylar is real easy way to aim an ESL right to you.

*Assuming everybody has the good sense to have wall-to-wall carpeting with a felt underlayer
Dennesen ESL tweets, Dayton-Wright ESL (110-3200Hz), mixed-bass Klipschorn (28-110), and giant OB using 1960's Stephens woofer (18-110); Behringer DSP. HiFi aspirations since 1956

Last edited by bentoronto; 27th October 2014 at 02:53 PM.
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Old 28th October 2014, 01:38 PM   #10
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I've not had an opportunity to hear Roger Sanders' speakers but I'm a huge fan of his and I borrowed heavily from his concepts when building my own flat panel hybrid ESL's. I think Roger mostly has it right insofar as flat panels give magical imaging on-axis and they have great slam. But, as any business man might, I think he downplays the downside to sell his speakers. My flat panels don't sound "just fine" or "like ordinary speakers" outside of their sweet spot, as one of Mr. Sanders' video states; nor is the downside as bad as some others suggest. With my flat panels, I find that the highs fall off a cliff as I move even slightly out of the sweet spot-- until I move far enough away from the sweet spot that room reflections begin to dominate and the frequency balance is restored. I love them but they do have their limitations :-)
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