Has anyone played with the Behringer VIRTUALIZER 3D FX2000? It has a "binauralizer" mode that says it widens the stereo field and does some crosstalk processing.
BEHRINGER: FX2000
Greg
BEHRINGER: FX2000
Greg
Looks like a 2 ch device, not so much a multi ch music processor. I would also bet the op amps used aren't the best, though the analog circuits could be replaced.
The PDF for the user manual won't open so I can't read about it in depth, but it would only be similar if the xtc is recursive. That's what R.A.C.E. is.
Regarding miniambio....I wish people would show more interest so they don't discontinue it. Maybe supporting their forum would help. I really wanted the minidigi-miniambio stack they promised me
Another note.....what do you guys think of the ambiophonics iPad app?
Only me and one other person reviewed it in the app store. We have to create a buzz for ambiophonics or it will never take off! Most audiophiles don't even know about this stuff, nevermind your average Joe.
Ok, I'm starting to rant now......sorry
Regarding miniambio....I wish people would show more interest so they don't discontinue it. Maybe supporting their forum would help. I really wanted the minidigi-miniambio stack they promised me
Another note.....what do you guys think of the ambiophonics iPad app?
Only me and one other person reviewed it in the app store. We have to create a buzz for ambiophonics or it will never take off! Most audiophiles don't even know about this stuff, nevermind your average Joe.
Ok, I'm starting to rant now......sorry
There are two issues with current x-talk cancellers that will have to be solved before it gains wide acceptance.
1- The higher frequencies.
A little barrier will cancel X-talk in this range but the Ambio4you ( the one I have spent more time with) will not. I believe this problem exists with all software implementations I have tried so far.
2- The more you apply recursion the more prominent the reverb in the recording will get. Reducing recursion will simply not give you all the magic an ambiophonic system is capable of. So a way must be devised to reduce reverb as recursion increases. This problem would of course not exist if recordings were made with ambiophonics reproduction in mind: just a matter of tilting the direct sound/reflections ratio more towards the former.
To me, #2 is the real problem. A llittle barrier does not scare me. I easily put it in place for a listening session and then put it away.
I found that Robin Miller and Howard Moscovitz´s implementation (over at elctro music.com) was more satisfying and it did include a 'space' control that reduced reverb somehow but cannot comment much on it because I long ago decided not to bother using the PC, converters and so on to listen to music.
So it seems feasible but I don´t think they are willing to comment much on that. I did ask them to consider offering their system in a little box such as Ambio4you.
1- The higher frequencies.
A little barrier will cancel X-talk in this range but the Ambio4you ( the one I have spent more time with) will not. I believe this problem exists with all software implementations I have tried so far.
2- The more you apply recursion the more prominent the reverb in the recording will get. Reducing recursion will simply not give you all the magic an ambiophonic system is capable of. So a way must be devised to reduce reverb as recursion increases. This problem would of course not exist if recordings were made with ambiophonics reproduction in mind: just a matter of tilting the direct sound/reflections ratio more towards the former.
To me, #2 is the real problem. A llittle barrier does not scare me. I easily put it in place for a listening session and then put it away.
I found that Robin Miller and Howard Moscovitz´s implementation (over at elctro music.com) was more satisfying and it did include a 'space' control that reduced reverb somehow but cannot comment much on it because I long ago decided not to bother using the PC, converters and so on to listen to music.
So it seems feasible but I don´t think they are willing to comment much on that. I did ask them to consider offering their system in a little box such as Ambio4you.
The barrier also prevents right speaker sound from hitting the left wall then entering your left ear.
I thought of a headphone ambio baseball hat. Instead of headphone drivers firing into your ear, they hang out in front of you (hanging down from the brim) but maybe the frames would be 2"-3" apart, probably sealed backs. That way your ear folds tell you that the sound is infront of you, the way you've heard it your entire life. The no front image of headphones drives me NUTS !!!
Norman
I thought of a headphone ambio baseball hat. Instead of headphone drivers firing into your ear, they hang out in front of you (hanging down from the brim) but maybe the frames would be 2"-3" apart, probably sealed backs. That way your ear folds tell you that the sound is infront of you, the way you've heard it your entire life. The no front image of headphones drives me NUTS !!!
Norman
The purpose of either the barrier or the Ambio4you is to restore the localization cues (ILD and ITD) inherent in virtually all 2 channel recordings lost when speakers are located 60 degrees apart. Note however, that neither ILD nor ITD can be used by humans to localize at frequencies above say 1500 Hz. Above this approximate frequency humans can only localize using their pinna. Thus it matters little whether you cancel crosstalk above this frequency or leave it as stereo as far as ITD or ILD is concerned.
The ambio4you and virtually all the other Ambiophonic RACE implementations have a control in them so you can decide at what frequency you want the crosstalk cancellation to end shift back to stereo. If you set it as stereo say above 4000Hz then you will have to endure the normal combfiltering (major peaks and dips) that is one of several problemf with stereo loudspeaker placement. However if you have moved your speakers closer together for Ambiophonics then the combing starts at several octaves higher than with the 60 degree placement, so it is hard to hear any difference if the high frequencies are left as stereo rather than crosstalk cancelled using the controls provided.
If you set the ambio4you (miniambio) for full range cancellation, it will do that but it is unlikely that your speakers will be so perfectly aligned or that you will have set the delay and attenuation adjustments so perfectly that you will actually accomplish cancellation at frequencies like 10kHz where half an inch can cause a polarity reversal. (Same for stereo) But again, nobody has been able to show that high treble, cancelled improperly, sounds any different than stereo with combing, and the similar phase shifts with real speakers in real rooms.
Finally, the barrier is perfect in this regard. The trick has been to get RACE to where it sounds as good as the barrier to most listeners. This has not been easy. But if you can hear differences in cables and can hear a difference between 48/24 and 96/24 then you must use a barrier. But if your ears are that good, how can you stand the stereo loudspeaker triangle with all its obvious reproduction errors not just in localiztion but also in frequency response?
Finally, It is unlikely that Ambiophonics will replace stereophonics any more than stereophonics has replaced monophonics. Think cellphones, AM radio, iPods, Droids, TV news broadcasts, old movies. Even those with stereo clock radios, stereo TVs, and car systems seldom hear any stage. Ambio was really developed for classical music listening for those who want a domestic concert hall or opera house, and okay a jazz or Bway show orchestra. If you just listen to a vocalist with a guitar or small combo or a rapper you don't need Ambio and in most such cases you don't need two speakers either.
Ralph Glasgal
www.ambiophonics.org
I have not found any correlation between recursion and a change in percieved reverb. The time constants involved are of course quite different. The ping pong of crosstalk cancellation, normally every 180 microseconds at each ear attenuated by some 3dB each cycle reaches inaudibililty rather quickly so in say 3 milliseconds there is nothing to hear. In listening rooms or studios, the first early reflection is usually a bounce off the floor or in concert halls from a seat back or head and is on the order of 1 millisecond per foot of extra distance. So humans always are hearing these kinds of very early reflections and they are ignored by the brain. But in the case of Ambiophonics, the energy left at 3 milliseconds is negligible compared to the energy of the first early reflections in a concert hall, home, or studio which may only be a few dB lower than the direct sound.
However, when you eliminate the crosstalk and move the speakers closer, there is a noticable increase in depth, clarity, presence, spaciousness, etc. and one could describe this as something that seems like an increase in ambience.
There is also the case where hall ambience has been sensed by the mics and mixed into the front channels. This reverb has directional cues in it since it is coming to the mics from the side and front walls of the stage or from the sides, ceiling, and rear of the rear hall. When that directionality is recovered by using one of the crosstalk cancellers, then most humans, react favorably to these directional cues just as they would if they were at the microphone position during the session. Thus Ambio will not sound like stereo, but normally that is the idea. Changing the recursion parameters will not change this effect unless the cancellation becomes so poor that you essentially have mostly stereo again.
Most stereo recordings are relatively dry because if you have too much reverb coming from the front, humans begin to hear a sewer effect. Same with microphones that are exposed to the ceiling, the rear, and the sides of halls. If they are placed too far away from the performers, the result is again the sewer effect. The Ambiophone is a microphone array designed to prevent these effects, but in practice the overwhelming majority of existing LPs and CDs reproduce quite nicely using Ambiophonic reproduction systems.
Ralph Glasgal
Home Page
The original IMAX 3D system included earspeakers as you describe. The localiztion was great. The low bass was handled by woofers throughout the theater. You could not localize to the ear speakers. You just had this soundstage in front of you. They could not do direct sound from the rear or the extreme sides however. Panambiophonics can do this now but only for home viewing. If you use one or more Soundmatters foxl with RACE you can do the same IMAX thing at home for multiple viewers.
Ralph Glasgal
Home Page
That contradicts current psychoacoustics literature, e.g.
Introduction to Psychoacoustics - Module 08A
Introduction to Psychoacoustics - Module 08B
I follow you markus, long time ago, I have been surprised by a similar statement extracted from Understanding Ambiophonics
BTW, this removes nothing from the concept efficiency.
BTW, this removes nothing from the concept efficiency.
It is too bad that no more users of software xt cancellation are sharing their experience on this recursion/reverb issue. This is very obvious in my system, not subtle. I wish you could sit at my listening chair, Ralph, and tell me your opìnion. Don´t think it is a flaw in my ambio box. I have two and they behave exactly the same. Still much, much better than stereo
I think it's more efficient to use 3 real speakers than trying to remove crosstalk that was caused by moving the speakers closer together in the first place
Thanks these are very good tutorials on the subject. Everyone on this list should read these. The exact frequency at which the human ear shifts from one localization mechanism to another has always been a vague concept. It probably is different for each head. That is why I always say "about" or "approximate" when writing about this.
Long ago I decided that the only way to deliver a realistic soundfield to the human ear was to generate something at home exactly like the original sound field that would have reached each ear (mic) at the recording session without serious compromise Thus I would not rely on stereo sonic illusion phantom imaging quirks, or ignore pinna functionality (as is done in stereo and 5.1), would not ignore the directionality of the reverberant field, and so on. Technologies like Ambisonics and Wavefield Synthesis are similar in that they also do not require any knowledge of how the human ear works, do not try to fool the ear somehow using HRTF filters, or try to exploit some optical illusion-like quirk of the hearing mechanism like the stereo illusion. They just concentrate on delivering a true binaural soundfield as does Ambiophonics.
I did think that Ambio would be of interest only to classical music lovers and audiophiles. Also to make it practical, it would only apply to homes and one or two listeners (as is really the case with almost all quality stereo) and be more than reasonably applicable to the existing library of LPs and CDs.
As it turns out, the real interest in Ambiophonics and its competitors is movies and iPad/iPod/Android applications with games likely to follow.
Natural binaural-like localization is obviously more important in movies/video and games than it is in pop vocal-combo audiophile-like situations. Ambio also does not apply to large group listening situations like parties and auditoriums and so has this marketing limitation.
Ralph Glasgal
Home Page
I agree but you said "neither ILD nor ITD can be used by humans to localize at frequencies above say 1500 Hz" - perhaps it's just a typo?
All those technologies have their own drawbacks and multichannel might present the least limitations. Trying to present a realistic soundfield to the human ear does not necessarily result in a realistic perception. From Toole: "The author has heard the system several times in different places, including a precise setup in the NRCC anechoic chamber in which he participated. There, theoretically, it should have worked perfectly, since there were no room refl ections to contaminate the delivery of sounds to the ears. [...] So what did it sound like in the anechoic chamber? It sounded like an enormous headphone; the sound was inside the head. When the setup was moved to a nearby conventional listening room, the sound externalized, and all previous comments apply."
The source material is still stereo/multichannel and those recordings are mixed in acoustically treated dubbing stages and control rooms with conventional speaker setups. That's probably not going to change anytime soon.
I think it's more efficient to use 3 real speakers than trying to remove crosstalk that was caused by moving the speakers closer together in the first place
In stereo, as you move the speakers together, the stage just gets narrower and the frequency at which the combing begins rises. The crosstalk can even decrease. Imagine the speakers are laser lights. It the speakers are headspaced in front and beam at each ear there is no crosstalk. But if they are at 60 degrees then the beam can go around the head and cause crosstalk.
Unless the center speaker is mono, as in dialog for 5.1 movies, the use of a center speaker to do anything is counterproductive. The stero illusion is difficult enough to maintain without increasing the complexity of the crosstalk by using three speakers or worse by having offside stereo stages.
If you want to see why using a center speaker for a real three channel three mic system is counterproductive, just play your favorite CD but place two speakers 30 degrees apart and face one of them while you listen. I don't think you will hear much that you will like. It is simply not possible to generate a stereo stage between a center speaker and a left speaker and a center speaker and a right speaker that sounds like anything normal. So in most LCR recordings, either the center channel has no correlation with the sides, that is, it is a mono soloist or dialog or the outer speakers have a normal stereo signal with some mix of the two applied to the center. Thus a center speaker cannot constructively influence the crosstalk from the side speakers unless it is computer programmed to do this somehow which is not a bad idea.
Ralph Glasgal
Home Page
If the speakers were laser lights then there is less light from the right speaker at the left ear (and vice versa) the further the speaker moves to the sides.
A center speaker solves a very important issue: wrong pinna cues for the most important direction, the center. There's also the nice side effect that we finally escaped the head-in-a-vise scenario to a certain degrees. Something that's impossible with Ambiophonics and also with stereo (unless speaker directivity supports crossing in front of the listening position to achieve some trading).
I don't follow why a phantom image between C and L should sound worse than the same phantom image generated by L and R?
It would be enlightening and entertaining to have more people seriously putting together an ambio system and commenting on what they are hearing on top of all the theorizing.
Are you talking to me? I did test-drive Ambiophonics extensively and what I write is far from being theoretical.
Yes but that is not quite correct. If the laser speakers are directly in front and head spaced then there is no crosstalk at all as the sound just grazes the ears in passing. As the speakers begin to be separated the crosstalk increases since now sound can actually go around, over and under the head. At the far side the level at the far ear may decrease from some maxima but not by that much. So in general for a perfect laser speaker, the crosstalk does increase as the angle increases with some slight decline at extremes maybe.
The Soundmatters speakers are four inches apart and are the closest I have ever seen to being laser-like. With RACE they do produce a remarkably wide stage and are fun to play with but you have to listen to them in the near field. You can hang one around your neck.
Ralph Glasgal