Question for the mega minds.....

SDA1C

What cancels the inter aural cross talk in live sound? Surely the instruments sound is being heard in both ears at different times. What is the phenomena and how does it work in relation to the live performance being separated naturally and needing to be compensated for with reproduction. If the answer is big sound in a tiny room then I get it but do try to be more technical if possible.

Speedskater

You might read some of David Griesinger many papers on the subject:

http://www.davidgriesinger.com/

or maybe JJ Johnston's

blog:
http://audioskeptic.blogspot.com/2012/03/why-we-hear-what-we-hear-part-1.html

PowerPoints:
http://www.aes.org/sections/pnw/ppt.htm

SDA1C

Speed skater,

Thanks for your reply.

The majority of the links you provided are related to the anatomy of the ear, the audience perception of tonal qualities in a multitude of rooms and the ability to -tune- out of tune to make the sound more pleasant to the audience as affected by the size and shape of the hall. The compensation of the time alignment before it gets to the ear is what I am investigating. Once the sound is in the ear thare is no longer the ability to modify it's delivery.

What is your take on the time differences noted in Scotts review and how do you equate its relevance to the inter aural cross talk?

Speedskater

Scotts review ???

heiney9

Reflections and multiple speakers and radiation points of a large auditorium, theater or arena. Although most arena sound stinks as far as instrument location, separation, tone, timbre, etc.

SDA1C

Speedskater wrote: »

Scotts review ???

Did you not reads your own links? Scott Meherns. The PP about the cellular phone. I am interested in the relevance to the op as you see it.

SDA1C

That's what I am trying to figure out Brock. It seems to me if the IA compensation is set by how far apart the speakers are then it stands to reason if they are farther apart than an intimate jazz setting, for example, it could possibly create issues of spacial effect and could magnified the sound stage beyond its desired result. I know the reflections are atrocious in a hall or auditorium but what about beyond the extreme with respect to the reproduced dimension. Could the SDA effect actually take it too far?

I base this on the fact that I do not really care for SDA for near field and much prefer the 5jr+ for that duty. The SDA in close proximity seem to get cloudy, especially for heavy separation like the left right sweeps in many of the Cars offerings. It seems, once you get close enough, the inter aural timing is exacerbated by the extreme angle of attack for the dimensional driver and causes issues with the effect itself.

treitz3

Live sound does not have two point sources.

Tom

headrott

SDA1C wrote: »

I base this on the fact that I do not really care for SDA for near field and much prefer the 5jr+ for that duty. The SDA in close proximity seem to get cloudy, especially for heavy separation like the left right sweeps in many of the Cars offerings. It seems, once you get close enough, the inter aural timing is exacerbated by the extreme angle of attack for the dimensional driver and causes issues with the effect itself.

I disagree. I think there is very good sweeping from one channel to the other in SDA's. It may depend on the rest of your equipment, however. I think there is very good imaging and soundstage properties from SDA's; particularly after fully moddifying them. It may be a combination of set up issues and gear issues that make your SDA soundstage sound muddy. MY SDA's definately don't have that problem.

Face

headrott wrote: »

I disagree. I think there is very good sweeping from one channel to the other in SDA's. It may depend on the rest of your equipment, however. I think there is very good imaging and soundstage properties from SDA's; particularly after fully moddifying them. It may be a combination of set up issues and gear issues that make your SDA soundstage sound muddy. MY SDA's definately don't have that problem.

HR, he did state "near field". I find that only coaxial or dual concentric speakers are able to image and throw a soundstage near field.

headrott

Face wrote: »

HR, he did state "near field". I find that only coaxial or dual concentric speakers are able to image and throw a soundstage near field.

I guess if "near field" listening is defined as less than the width of the SDA tweeters, then yes, it makes sense that the soundstage would be cloudy, narrow and not good. However, SDA's were never designed to be used this way, so I would say that that's the problem right there. Thanks for pointing that out though Face.

F1nut

treitz3 wrote: »

Live sound does not have two point sources.

Tom

Bingo!

BlueFox

treitz3 wrote: »

Live sound does not have two point sources.

Tom

F1nut wrote: »

Bingo!

Which is why a surround sound system has the potential to best reproduce an actual musical experience.

Face

BlueFox wrote: »

Which is why a surround sound system has the potential to best reproduce a cinematic experience.

Fixed!

SDA1C

treitz3 wrote: »

Live sound does not have two point sources.

Tom

Interesting. I see what you are getting at. Is that to say that live sound has multiple point sources or just one very wide one?

SDA1C

headrott wrote: »

I disagree. I think there is very good sweeping from one channel to the other in SDA's. It may depend on the rest of your equipment, however. I think there is very good imaging and soundstage properties from SDA's; particularly after fully moddifying them. It may be a combination of set up issues and gear issues that make your SDA soundstage sound muddy. MY SDA's definately don't have that problem.

Face wrote: »

HR, he did state "near field". I find that only coaxial or dual concentric speakers are able to image and throw a soundstage near field.

Yes indeed, Face, thanks for the clari. I only prefer the 5jr+ over the SDA for near field. Anything farther than about 6 feet (My SDA are 11 feet apart) and the SDA's win hands down.

Speedskater

SDA1C wrote: »

Did you not reads your own links? Scott Meherns. The PP about the cellular phone. I am interested in the relevance to the op as you see it.

No, my link was to "JJ Johnston's" papers. 'Scott Meherns' just happened to be on the same page.

F1nut

(My SDA are 11 feet apart)

That's too far apart, 6 to 8 feet is recommended.

tonyb

My SRT's were about 7.5-8 ft. apart and that seemed to be what they liked in a large 26 by 24 room. About 2 ft from the back wall and a good 3 ft from any side wall. Set up, the room, associated gear, all play their part as we all know. If your music isn't up to snuff, look at the speakers last is what I say.

SDA1C

Thanks for the heads up F1. (After I maesured and not guessing...)They are 10ft 1 inch center to center, 3ft 6in from the side walls equally and 23ft in to my listening ear. They are 2ft 3in from the wall to the face of the cabinet. They sound SUPURB! I am not missing anything in fact I am still picking up different background activities on the Use Your Illusion albums that I never knew were there. i.e. The pistol cocking and the bottle caps hitting the floor. I have no problems what so ever with the performance. I was asking the question from a technical point of view as to whether the effect is compensating for one point source or multiple sources. That is of "one band one sound" or many instrument sources being replicated by just two speakers. As soon as I find my matching set of speaker wires I will bi amp and not look back. Until I find another 425sig that is. I am really digging the 3.2 set up for movies. The explosions are epic.

SDA1C

Speedskater wrote: »

No, my link was to "JJ Johnston's" papers. 'Scott Meherns' just happened to be on the same page.

LOL Kinda wondered about the compilation as it were... What part specifically should I be noting in JJs work that relates to IA cross talk? His perception of an use of double blind has been argued until blue in the face. I am not sure that relates to the design of SDA or the time alignment properties associated with band size vs. speaker separation.

Speedskater

You might note that the original question was:

What cancels the inter aural cross talk in live sound?

Also note that 'SDA' only appeared later in post #7.

Both 'David Griesinger' and 'JJ Johnston' are scientists that write about live sound and human hearing.

Let me add 'Siegfried Linkwitz' to the list of scientists. He has page & pages of information and more pages of links.

http://www.linkwitzlab.com/index.html

SDA1C

You are correct. I was continuing a conversation, from another discussion, with other forum members about SDA. My apologies for not making the question more clear. I also made an assumption, based on location of post, and the fact that the way ears work is rather well known and need not be discussed on an elementary level, that the general audience of most of my posts are SDA enthusiasts and could have put the question into perspective based on that knowledge.

In light of the clarified intent of my topic, do you still feel the links are relevant?

ZLTFUL

Sort of as an aside, but wasn't SDA developed to assist in cancelling out inter-aural crosstalk? Thusly making the topics an extension of and compliment to each other?

zingo

heiney9 wrote: »

Reflections and multiple speakers and radiation points of a large auditorium, theater or arena. Although most arena sound stinks as far as instrument location, separation, tone, timbre, etc.

Agreed. I do not prefer the sound of most amplified, live music.

ZLTFUL

heiney9 wrote: »

Reflections and multiple speakers and radiation points of a large auditorium, theater or arena. Although most arena sound stinks as far as instrument location, separation, tone, timbre, etc.

Definitely. If you want to test this theory, record your next concert on a cell phone...the sound is outstanding in its horribleness.

George Grand

The way I see it, every instrument at a live acoustic performance is acting like a point source. There IS no inter-aural crosstalk. That doesn't happen with a pair, or four or five speakers in a living room.

SDA1C

George Grand wrote: »

The way I see it, every instrument at a live acoustic performance is acting like a point source. There IS no inter-aural crosstalk. That doesn't happen with a pair, or four or five speakers in a living room.

George,

This is where I am getting the disconnect in theory. If it is an acoustic presentation than I would certainly agree and i believe that would be one giant piunt source. If it is an amplified concert and the Mixmaster B is involved, hehe, does that not reduce the single instrument sources to distinct and mixed point sources? I wonder how the sound would jumble if it were simply each instrument amplified to its own channel and the stack was in the same position as the instrument? It would seem the mixer eliminates the multiple point source theory, no?

There was a wall of sound for The Dead shown here a few months back, would it be two point sources or just one big one or multiple sources all on the same plane? I do not see how the sound could be IA compensated if mixed. I also don't see how the sound could be balanced properly if each instrument were amplified separately with the instruments own channel. Seems like a one or the other sort of option.

SDA1C

ZLTFUL wrote: »

Sort of as an aside, but wasn't SDA developed to assist in cancelling out inter-aural crosstalk? Thusly making the topics an extension of and compliment to each other?

In my view they are not related as once the ear gets the signal, regardless of timing, there is no longer any manipulation that can be done. All SDA effect must have taken place prior to the reception, the ear knows and/or reacts to nothing until stimulated. The science of how we hear is vastly different than the science behind the time alignment and electronic manipulation of the sound prior to hearing it.

nooshinjohn

My take is this... if an amplifier and speakers are used to produce sound at a live event, it is still a copy of what the instrument produces and therefore I don't consider it to be anything more than a live concert. there is zero "Point-source" information there to begin with, and this would also hold true for much of the recorded rock music out there. It takes a brilliant recording engineer to sort out that mess and make a great recording of it.

A live acoustic performance without amplification, or minimal amplified electric guitars are the types of performance that you will find "point-source" imaging to be far more pronounced, and this is where the SDA really shine. The are also somewhat able to clean up a muddled recording, but if the recording is complete crap... well you cant polish a ****.

Imaging is one of the greatest attributes of SDA, and one that gets significantly better when the mods are done.

SDA1C

nooshinjohn wrote: »

My take is this... if an amplifier and speakers are used to produce sound at a live event, it is still a copy of what the instrument produces and therefore I don't consider it to be anything more than a live concert. there is zero "Point-source" information there to begin with, and this would also hold true for much of the recorded rock music out there. It takes a brilliant recording engineer to sort out that mess and make a great recording of it.

A live acoustic performance without amplification, or minimal amplified electric guitars are the types of performance that you will find "point-source" imaging to be far more pronounced, and this is where the SDA really shine. The are also somewhat able to clean up a muddled recording, but if the recording is complete crap... well you cant polish a ****.

Imaging is one of the greatest attributes of SDA, and one that gets significantly better when the mods are done.

I wonder if we are listening to recorded music from the "sweet spot" of the concert hall, if that even exists, or if we are hearing it from multiple points after being mixed. If the recording mic is in the sweet spot then the SDA effect would be more corrective it seems. I notice sometimes that one instrument is not as involved as others. It makes me think the recording level is lower on that particular instrument making the recording not as accurate as it could be.