"They are here" vs. "You are there"

A brief interruption to say a few words about the nature of this thread...

As Al pointed out several posts back, this thread is full of speculation. I myself have speculated at a furious rate. I just want to say that I do not regard speculation as great way to reach reliable conclusions. I regard carefully controlled TESTING as a great way to reach reliable conclusions. In that sense, I am an empiricist.

Unfortunately, I cannot currently afford to build a highly customized listening room, like some of the ones posted here on A’gon. In light of that, I am left to speculate on the basis of my experiences with (1) customized listening rooms for professional mixing; (2) customized listening rooms at audio dealers; and (3) my own quite humble listening room.

The purpose of this post is to explicitly acknowledge that I do not believe that speculation can ever be an adequate substitute for carefully controlled testing. Having said that, not all speculation is groundless. Speculation can be grounded on prior experiences, theoretical knowledge, and sound reasoning. I have made an effort to ground my speculations, though that may not always be apparent, which is my own fault. My thanks to other posters who, it seems to me, have made an effort to do likewise.

It would be nice if some folks with extensive experiences with customized listening rooms or expertise in acoustics would chime in, as it would elevate some of our speculations to the level of highly informed or even expert opinion.

Until that happens, let the speculation continue.

Hi Bryon - once again, you and Al and Cbw and Dgarretson have provided some excellent posts with much food for thought! Let the speculation continue, indeed! I have really enjoyed reading all of it, and you are certainly correct that although very few of us can design and build the rooms we might wish, there are many low cost ideas that can greatly improve any room. I envy all of the folks on this site who have a dedicated room, I don't even have that myself. Maybe in my next house!

Cbw – I have been giving more thought to your theory, and I have some fresh speculations…

You mention two parameters that determine whether a playback space creates the illusion that “you are there” or “they are here,” namely whether a recording has ambient cues or not, and whether the listening room is “live” or “dead.” To these, I think it’s useful to add a third parameter, namely, whether or not the listening space is acoustically similar to the recording space. With that in mind, I think there are…

FIVE SIGNIFICANT CATEGORIES:

(1) reactive room, ambient recording, acoustical similarity

(2) reactive room, ambient recording, acoustical dissimilarity

(3) reactive room, non-ambient recording

(4) unreactive room, ambient recording

(5) unreactive room, non-ambient recording

SOME DEFINITIONS TO GO WITH THEM:

-“reactive room” is a listening space with significant ambient cues. Hence a listening space that significantly interacts with the ambient cues of the recording during playback. A.k.a., a “live room.”

-“unreactive room” is a listening space with insignificant or no ambient cues. Hence a listening space that minimally interacts with the ambient cues of the recording during playback. A.k.a., a “dead room.”

-“ambient recording” is a recording that contains ambient cues of the recording space.

-“non-ambient recording” is a recording that does not contain ambient cues of the recording space.

-“acoustical similarity” refers to the acoustical similarity of the listening space to the recording space, as discussed in my second post from 9/14.

Each of the parameters that define the five categories is a continuum. A room is not either reactive or unreactive. Reactivity is a continuum, with maximally reactive rooms at one end and minimally reactive rooms at the other. Likewise for ambient cues on recordings. Likewise for the acoustical similarity of the listening space to the recording space. Since each parameter is a continuum, the five categories that they define are each idealizations, in the sense that actual members of each category will APPROXIMATE its idealized description.

Taking the five categories one at a time…

(1) reactive room, ambient recording, room similarity =

…YOU ARE THERE...

In my view, this maximizes the illusion that “you are there,” as I have suggested in earlier posts. I acknowledge, however, that this is not the most practical approach to building a listening space, since the greater the acoustical similarity the listening space has to the recording space, the LESS acoustical similarity it will have to different recording spaces, and the more your listening space will be “recording-specific.”

(2) reactive room, ambient recording, room dissimilarity =

…YOU ARE CONFUSED…

In my view, this would be the “mess” that Cbw was describing in his last post. To the extent that the ambient cues of the listening space are different from the ambient cues of the recording space, it could result in a confused, contradictory, or paradoxical set of ambient cues at the listening position. In other words, “you are confused.”

(3) reactive room, non-ambient recording =

…THEY ARE HERE…

In my view, the absence of ambient cues in the recording combined with a reactive listening space is what creates the illusion that “they are here.” This is perhaps the most straight forward of the five categories. And in some ways, it is the easiest type of illusion to create. Of course, if you don’t like the sound of your listening room, then you won’t like the way “they” sound when “they are here.”

(4) unreactive room, ambient recording =

…YOU ARE “ALMOST” THERE…

This is the trickiest of the five categories, I think. As I have argued in previous posts, I don’t think that you can fully create the illusion that “you are there” without omnidirectional ambient cues at the listening position. So, as a listening room becomes less and less reactive, I believe it will sound less and less like “you are there.”

Having said that, I should acknowledge that this comes close to creating the illusion that “you are there.” The bidirectional presentation of the ambient cues of the recording provides some significant information about the recording space, though as I have argued, it doesn’t present that information with the correct DIRECTIONALITY, which limits the illusion that “you are there.”

Of course, all this assumes that the playback is stereo. If playback were multichannel, then an ambient recording played back in an unreactive room could, in theory, create the illusion that “you are there." I say “in theory” because, as other posters have pointed out, most multichannel music mixes leave much to be desired, and hence typically fail to create the illusion that “you are there.” Nevertheless, the multichannel playback of ambient recordings in unreactive rooms to create the illusion that “you are there” is the prevailing methodology in movie sound, where it achieves some success, I think.

I should also acknowledge that there is a significant advantage to a SOMEWHAT UNREACTIVE listening room when playing back ambient recordings, namely, that it prevents your listening room from being “recording-specific.” But I don’t think that’s the ONLY way to prevent your listening room from being recording-specific (More on that in a future post).

(5) unreactive room, non-ambient recording =

…YOU ARE NOWHERE…

In my view, the absence of ambient cues in both the recording and the room creates an otherworldly “you are nowhere” effect, like you’re listening in outer space (yes, I know that’s impossible).

This may seem like a revision to what I said in my last post, when I agreed with Cbw that the category of “weak recorded cues + dead room” would result in the illusion that “they are here.” But I suspect that, when Cbw was referring to dead rooms, he was not referring to COMPLETELY dead rooms. Hence my earlier agreement with him that partially dead rooms (thus partially reactive) could create the illusion that “they are here.” I am now saying that, to the extent that a room is unreactive, non-ambient recordings will create the experience that “you are nowhere.”

Bryon, I agree that experimentation is really the only way to answer some of these questions and likely the only way to find an ideal listening environment for a person’s particular taste (aside from hiring someone who has the experience to design a room based on your expressed preferences -- though even that might take a few iterations or adjustments since it is unlikely that it will be right on the first pass (unless you’ve already heard exactly what you want and can point to it and say “I want that.”))

My point was mostly about the difficulty of getting the cues on the recording to be omnidirectional. If you achieve it, I think you also get a whole bunch of extra stuff from your room that you probably don’t want and would likely swamp the recorded cues. And even then, to the extent that the cues on the recording are omnidirectional, they’ll be mistimed and out of phase. I’m not sure it’s physically possible (outside of electronic intervention) to get the cues *on the recording* to be both omnidirectional and sound realistic.

The various kinds of room colorations you mention, what you are calling “source distortion,” “echo distortion,” and “temporal distortion,” are definitely things to be addressed. But it seems to me that these are precisely the kinds of things that an acoustically treated room DOES address. “Source distortion” is typically addressed by absorption or diffusion at the first order reflection points on the side walls and the ceiling. “Echo distortion” is typically addressed with diffusion behind the speakers. “Temporal distortion” is typically addressed by balancing the ratio of absorption to diffusion to achieve a specific reverberation time.

Right, I agree. But my point is again about the ambience cues in the recording. The primary signal in the music is generally going to dominate, and the cues are softer, lower SNR, and more diffuse. So, if you succeed in taming the distortions I mentioned for the primary, you also greatly diminish the omnidirectional nature of the cues -- probably completely out of existence. If you don’t succeed in taming the primary reflections, then they’re likely to overwhelm the reflected cues. But this is an argument from theory, and there may be some middle ground where it could work.

My view is that omnidirectional ambient cues are more valuable than strictly accurate ambient cues for creating the illusion that "you are there." Having said that, I guess I’m not as skeptical as you, Cbw, about the possibility of constructing a listening space whose acoustics allow for omnidirectional ambient cues that are REASONABLY ACCURATE to the recording.

If I understand you correctly, I think you are saying that one can, effectively, simulate ambience cues that approximate the cues on the recording, but are not sourced from the cues on the recording. If that’s the case, I agree (with the caveat that if the cues on the recording are strong and not well-matched to the room, you are likely to get a mess). To achieve this, you will be structuring your listening space to create a certain ambience. If that matches well with your music, you may have a very pleasing “live” sound. If it doesn’t, well, you’ll have to learn to live with it (or maybe have some movable absorption panels that can deaden the room effect when it’s not desirable).

I think, though, that purists will not like this approach. To the extent that you are creating ambience cues from the listening room, you are obscuring information on the recording. Learsfool, for example, might not like this approach for his listening, since he’s expressed a strong preference to hear precisely what is on the recording down to the differentiation of concert halls on fifty-year-old records. That probably wouldn't be possible in a room that was not very dead, or with a soundfield that was not very focused.

Bryon, I agree with most everything in your recent post. I would like to point out one detail that I tried (probably unsuccessfully) to make in my most recent post. You say:

-“reactive room” is a listening space with significant ambient cues. Hence a listening space that significantly interacts with the ambient cues of the recording during playback. A.k.a., a “live room.”

My point is that a reactive room reacts to everything in the signal, not just the ambience cues. Thus, with the drum hit I was talking about the direct wave reaches the microphone first* as a primary signal, then come the echoes, reverb, etc. in its wake. The cues come later, smaller in amplitude, and more stretched in time than the primary signal. So a room that reacts to the cues will always react also to the primary signal, and that signal will generally be stronger than the cues.

*While it is technically possible for a signal to reach the microphone before the direct wave, I don't think it is a big factor in most recordings.