|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
24.149.197.165
In Reply to: Re: What happens when you expose yourself to loud noise without hearing protection? posted by morricab on August 25, 2006 at 16:45:54:
"From my experience it is possible to get a sound very close to what is heard in a concert hall AND what would be heard in a small room. The key to the concert hall is low level resolution of the entire reproduction chain."The key to reproducing what the concert hall does is duplicating hundreds of reflections resulting from each note arriving at you uniformly from many different directions in rapid succession over a period of a second, two seconds, or more where the high overtones die out nearly twice as fast as the lower and mid range tones. There are few if any sound systems in the world other than highly experimental ones which can do that. I have one such system. It is extremely difficult to set up, calibrate, and operate properly especially with different recordings. Try a binaural recording instead of a stereophonic recording made around Row "M" or Row "R". Listen to it through headphones. You'll hear two scalar fields so you won't get the spatial aspects of a true vector field but you will get the right musical tone of the instruments at least. That's better than what you normally get from other recordings.
Follow Ups:
"The key to reproducing what the concert hall does is duplicating hundreds of reflections resulting from each note arriving at you uniformly from many different directions in rapid succession over a period of a second, two seconds, or more where the high overtones die out nearly twice as fast as the lower and mid range tones"Yes this is why low level resolution is of the utmost importance because each successive reflection from a single event gets lower and lower in level, especially in higher frequencies which provide more spatial clues.
In addition, it requires an electronics chain that will not smear the time information of that low level signal. As you noted implicitly it is not just frequency repsonse but timing and low level resolution.
"I have one such system. It is extremely difficult to set up, calibrate, and operate properly especially with different recordings. ... but you will get the right musical tone of the instruments at least."
I simply don't believe you sounndmind. I don't think your system will do a credible job, not with the speakers you have and not with the electronic you are using. I can't put it any plainer than this. As to instrument tone, my system sounds very right to me, my fellow audiophiles and my girlfriend and her musician friends all seem to think so as well. Since I can't get to hear yours nor you mine then I guess we will have just not believe each other.
First of all, the sound associated with the acoustics is NOT on the recording.Secondly, there is no known and likely no possible way to record it if for no other reason than the sound due to the acoustics cannot be separated from the sound directly from the source instruments at the microphones.
Third, it would require at least 4 more channels in addition to the two stereophonic channels to record them if it could be recorded at all, channels only multitrack recorders have.
Today, the only method avialable is to process the existing channels through electronics based on mathematical algorithms designed to emulate the physical relationships of the acoustic itself in order to recreate the kind of field the listener hears at a live concert. This takes many speakers strategically placed around a listening room. This is not the same as quadraphonic or home theater systems and it doesn't sound like them.
There are no special requirements in the sense of "low level resolution" whatever that means for these "auxilliary" sound channels. You can believe whatever you like to believe and fool yourself into whatever you want to fool yourself into but to anyone with normal hearing who is honest, there isn't even a remote comparison between what you hear at a live concert and what you hear from a stero system....any stereo system. While fools waste their time tweaking amplifier circuits, wires, cd players deluding themselves that they are actually doing something valuable, acousticians are tweaking the architectural shape, materials, and baffles in concert halls to mold sound to their conception of ideal. Their supporters contribute millions, even tens of millions of dollars on often dubious expectations of improvement while the audiophile tweakers proclaim every change as a major breakthrough. I've offered this link in the past but nobody has taken me up on it even once, however if you want to actually learn something instead of just your usual yammering and what you get from ad copy, listen to Leo Beranek's lecture on the link below. He was a founder of Bolt Beranek and Newman, the leading architectural consultant in the US, probably the world and his lecture deals specifically with concert hall acoustics.
"I simply don't believe you sounndmind. I don't think your system will do a credible job, not with the speakers you have and not with the electronic you are using."
What do you know about it? You never saw it, you don't understand it, and you aren't really interested in it anyway. OTOH, the US Patent office was interested enough to grant me a patent and at least one company was interested enough to steal it. Funny, even though it offers real hope, few have even bothered to explore what possibliities it offers.
Here's the link to real knowledge nobody will use anyway. Go back to your ad copy, your stereo system, and your delusions.
"First of all, the sound associated with the acoustics is NOT on the recording."Can you actually be serious?? The acoustics and decay of instruments in a real space is easily heard on recordings. How is possible that this information is NOT on the recording?? This information comes to the microphone in the same manner as the direct sound, just softer and shifted in frequency balance. The microphone doesn't care when it arrives nor does the recorder. On the playback if your gear and speakers preserve the phase realtionships between direct and reflected sound and preserves the lowest level signals then your brain does the same thing to separate the reflected from direct just as it would in a real concert hall. I can clearly hear reflected sounds in the hall as well as the settling of instrument decay. It is a pity that you don't even reailze this information exists on the recording.
"There are no special requirements in the sense of "low level resolution" "
Of course there is. Do you deny that reflected sound and room decay are not much lower in level than the main signal? Sometimes more than 50db below the main signal. Information retrieval is crucial to creating an accurate acoustic space of the original recording, whether you have 2 or 10 speakers.
"acousticians are tweaking the architectural shape, materials, and baffles in concert halls to mold sound to their conception of ideal."
Again and again you are confusing the real thing with reproduction. No one here is doubting the benefit of a properly prepared room, whether for listening live or listening reproduced. The only way to have a truly correct reproduction of a venues acoustic is to have zero contribution from the room you put the stereo system into. IMO, puttnig more speakers all around the room could possibly exaccerbate the problem by exciting more room modes and generating even a greater contribution of the listening rooms own acoustical properties. Either way you haven't taken the listening room out of the equation so the soundfield is still a convolution of the recorded space and the actual listening room space. Nobody follows up your link because it is simply irrelevant to reproduced music. It is great if one wants to make their own music hall for live concerts but the criteria are most certainly different.
"What do you know about it? You never saw it, you don't understand it, and you aren't really interested in it anyway."
I know AR speakers from the past (and they were off the pace even in the 1970s with the exception of good bass). So you tinkered and added a better tweeter. I bet the integration between the drivers is less than ideal. Did you at least use a good active crossover? It might interest you though to know that I find 90+% of the things I heard at shows to be less than convincing. Many designers have crap for ears or don't really care about sound. That doesn't mean that the SOTA hasn't improved, it has in many ways, especially in electronics (I too have older speakers...from the late 80s early 90s).
"Funny, even though it offers real hope, few have even bothered to explore what possibliities it offers."
Well, soundmind it can mean only two things: 1) it was ahead of its time and maybe if you are lucky it will be rediscovered and used or 2) No one cares because it is not all you think it is and others dismiss it. Care to give the patent number so I can look it up?
"The acoustics and decay of instruments in a real space is easily heard on recordings. How is possible that this information is NOT on the recording??"Only a small percentage of the reverberation heard in the audience gets on the recording, what is there is inseparable from the direct sound from the instruments and, very importantly it is missing at least one of its most critical aspects, vectorization. In the audience, 90% of the field or more comes from the acoustics. On a recording it's usually far less than 50%, even far less than 25%. This is because the microphones are much closer to the instruments than the audience sits in a live performance and are often highly directional having a cardiod pattern and pointed directly at the musicians. If this weren't true, playing a recording which actually had that much reverberation such as a binaural recording made in the audience through one pair of speakers would make it sound like the performers are inside a tunnel. Most important of all, the recording contains reverberation in two scalar fields, the real reverberation is a vector field. My experiments show that humans are relatively but not completely insensitive to percepion of vertical differences in direction as opposed to horizontal differences to which they are very sensitive. If this were not true, the minimum criteria for reproducing reverberant fields would be eight auxilliary channels, not four and the minimum number of speakers would be 16, not 8. My current setup uses 16 auxilliary speakers in 4 lateral quadrant channels, a previous prototype used 20. The radiating patterns for the reverberant field are very different from the direct field in order that their source be undetectable. (Your friends can't help you out on this one, I literally wrote the book on this problem...so far only a small part of it has been published as part of my patent.)
"Information retrieval is crucial to creating an accurate acoustic space of the original recording, whether you have 2 or 10 speakers."
Most of the information just isn't there on the recording, there's nothing to retrieve. As for playing sound softly, most audio systems can do that. That's not the hard part.
"Again and again you are confusing the real thing with reproduction"
And again and again you are clueless.
"The only way to have a truly correct reproduction of a venues acoustic is to have zero contribution from the room you put the stereo system into. "
That's not possible...unless you live in an anechoic chamber. NOBODY DOES.
"IMO, puttnig more speakers all around the room could possibly exaccerbate the problem by exciting more room modes and generating even a greater contribution of the listening rooms own acoustical properties"
Wrong again and if you don't, you cannot duplicate the concert hall's critical function of directing multiple reflections at the listener from different directions. This is so critical that special architectural techniques are used to diffuse them by providing many convex surfaces as one example of many critical aspects of good acoustics.
"Nobody follows up your link because it is simply irrelevant to reproduced music"
Nobody here listens to Leo Beranek's lecture because they are morons. They have the opportunity to actually learn something from one of the greatest acousticians in the world who studied and designed concert halls over a lifetime and they pass it up preferring instead to yammer on about their imbecillic nonsense about wires and vacuum tubes. They reveal not only their ignorance but their determination to stay that way. Me? I've heard this lecture at least 10 times and learned something new about concert halls every single time.
"I know AR speakers from the past...."
This is a non sequetor. This has nothing to do with AR speakers or anyone elses. In fact this invention was born, experimented with, and patented many years before I even owned an AR speaker.
"it was ahead of its time and maybe if you are lucky it will be rediscovered"
Yes it was far ahead of its time. When I discovered the principles behind it and invented it, the technology to fully exploit it was beyond the cutting edge of technology as digital audio processing was still far too primitive and expensive to take advantage of it. The earliest prototypes used multiple tape delays and analog mixers. At this time, nobody is particulary really interested in it anymore. This is an industry which has died not only from lack of any new ideas but from a loss of interest in and knowledge of music itself. It will likely remain nothing more than a curiousity for those who know me personally and get a demo of whatever prototype I care to show them. I've decided that's the way I want it to stay, at least for the time being. There is a certain satisfaction in having something in this world than nobody else can have.
"Most of the information just isn't there on the recording, there's nothing to retrieve. As for playing sound softly, most audio systems can do that. That's not the hard part."Completely false and it is at the soft end of the spectrum where most systems fail utterly. This is why there is so much talk about having to turn up the volume in order to "wake up" the speakers. There is plenty of low level ambient and acoustic field information on better classical recordings. Most systems play well only in a very small loudness window, usually between about 70-90 db. Below that they lose the ability to keep complicated passages clear and above they start to suffer audbile compression and/or distortion. The better a system can play soft often the more realistic it sounds.
An example:
I have a recording made with a single stereo ribbon microphone (from Royer labs) that uses a blumlein configuration. The recording is of a full orcehstra playing Prokofiev's Romeo and Juliet. The microphone was placed 6 meters from the front of the stage. It sounds very similar to live in a very good system and a disaster in most systems. It has TONS of acoustic information and has such a wide dynamic range that unless your system excels at low levels you have to turn it up way too loud for the peaks (classic problem in a car with classical music). It does not sound like its in a tunnel, it sounds like a concert hall. I would argue that until you have made or heard recordings of this sort yourself then you are merely speculating about the result. I can hear the results and to me it sounds much more realistic than a multimiked session.
This post is made possible by the generous support of people like you and our sponsors: