How NOT to set up speakers and room treatment ( Goldensound)

amirm · May 31, 2023

tuga said:
Early reflections improve LIVE speech intelligibility, maybe also close-mic'ed recorded speech but once you create depth/space in a stereophonic recording that is no longer true.

The research was not done "live." A speaker was placed in front and another representing the side reflection. The level of the speaker on the side was varied and detection threshold/preferences assessed. The reason for improved intelligibly is that overall sound energy increases with reflections. Suggest reading my published article:

Perceptual Effects of Room Reflections

https://www.audiosciencereview.com/...ds/perceptual-effects-of-room-reflections.13/

“Measuring Audible Effects of Time Delays in Listening Rooms, ”Clark, David, AES Convention: 74 (October 1983)

"In scenario #1, the addition of a second speaker was considered to have “moderate and pleasing effect.“ This, despite the fact that comb filtering was generated as a result of the second speaker. Clearly the listeners liked the effect more than they were concerned with any frequency response variations."

Room reflections are also not sufficiently delayed to create the effect you are talking about "depth/space." For that, you need multichannel recordings. What happens is image shift, not what you imagine in your head.

Please folks, don't opine unless you have read the research.

tuga · May 31, 2023

amirm said:
The research was not done "live." A speaker was placed in front and another representing the side reflection. The level of the speaker on the side was varied and detection threshold/preferences assessed. The reason for improved intelligibly is that overall sound energy increases with reflections. Suggest reading my published article:

Perceptual Effects of Room Reflections
https://www.audiosciencereview.com/...ds/perceptual-effects-of-room-reflections.13/

“Measuring Audible Effects of Time Delays in Listening Rooms, ”Clark, David, AES Convention: 74 (October 1983)

"In scenario #1, the addition of a second speaker was considered to have “moderate and pleasing effect.“ This, despite the fact that comb filtering was generated as a result of the second speaker. Clearly the listeners liked the effect more than they were concerned with any frequency response variations."

Room reflections are also not sufficiently delayed to create the effect you are talking about "depth/space." For that, you need multichannel recordings. What happens is image shift, not what you imagine in your head.

Please folks, don't opine unless you have read the research.

I did write close-mic'ed speech for that reason. But my point is that a music recording has either real or fabricated spatial cues, and once you start reflecting these things get messy.
I am not saying that room reflections are suffiently delayed to create a spatial effect (unless the speakers are dipoles), what I mean is that the recording has spatial an localization cues and reflections of those cues clash with the direct sound.
Stereo is a trick, localization in a recording cannot be compared with localization in nature/live.

A couple of snippets from "Acoustics  Of  Small Rooms" by Kleiner & Tichy:

Spaciousness and diffusivity

Localization of externalized single sound field components was shown to be fairly straightforward but dependent on many factors. Localization of sound field components that have identical sound levels at the ears will depend on further factors such as phase difference.
When sounds are correlated, such as a monophonic signal that is presented binaurally, the auditory event occurs inside the head, inside head localization (IHL). If the sounds at the ears are fully uncorrelated, such as two separate noise signals that are presented binaurally, there will be two auditory events, one at each ear.
An interesting effect can be heard when presenting a monophonic wide bandwidth noise signal in stereo (over loudspeakers or headphones) if the stereo signals are out of phase. The noise frequency components below 2 kHz are then perceived as spatially diffuse—having spaciousness— whereas those for higher frequencies are perceived as located between the loudspeakers (or for headphones, IHL occurs). The time difference in the low-frequency components provides phase cues that are ambiguous thus providing apparent sound field diffuseness, whereas the high-frequency sounds are analyzed by their envelopes and those will be identical at the two ears causing a located auditory event.
Similarly, when a wideband noise signal is provided over headphones to a listener and one of the headphones is fed with the signal delayed by a millisecond or more, the sound is perceived as diffuse.
What constitutes a diffuse sound field is thus different in the physical and psychoacoustic domains. In the latter, a diffuse sound field is that that provides non-locatedness of sounds or, alternatively phrased, that provides a sound that is located over all spatial angles (or rather upper hemisphere in a concert hall that has sound-absorptive seating).
In physics on the other hand, a diffuse sound field is defined as a sound field where all angles of sound incidence have equal probability, where the sound from each spatial angle is out of phase, and where the energy density is the same everywhere.
Obviously, the two ideas of what constitutes diffuseness are different in the two sciences. A physically diffuse sound field will also be psychologically diffuse but not necessarily the reverse. From the viewpoint of listening, it is of course the psychoacoustic properties that are of importance, not the sound field properties.

Auditory source width and image precision

As we listen to sounds, the apparent width of the auditory event, often called the auditory source width (ASW), will depend on many issues. To those listening to stereo or multichannel recordings of sound, it is quite clear that the width of the array of phantom sources treated by the recording or playback is determined by not only the layout of the loudspeaker setup in the listening room and the directional properties of the loudspeakers but also on the listening room itself. The more reflections arriving from the sides of the listening room, the wider will the ASW be. However, the ASW will be frequency dependent above 0.5 kHz and a 2 kHz sound arriving at ±45° relative the frontal direction will produce maximum ASW [38,39]. This is to be expected since the masking by direct sound is the smallest for this angle of incidence of early arriving reflections [16]. The ASW also depends on the low-frequency content of the signal, more low-frequency energy increases ASW [38,40,41]. Psychoacoustic testing shows that the spatial aspects of the early reflections are primarily determined by the reflection spectrum above 2 kHz [33].
Reliable data for sound reproduction in small rooms are difficult to find. A single omnidirectional loudspeaker judiciously placed close to the corner of a room may well create as large an auditory image as a conventional stereo loudspeaker setup placed out in the room as discussed in Chapters 9 and 11.
Using digital signal processing, the ASW can be made to extend far outside the bounds set by the stereo baseline. Sound field cancelation techniques

Symmetry

Early reflected sound will confuse hearing and make the stereo stage and its phantom sources appear incorrectly located or even blurred. As explained in Chapter 8 the listener’s placement of the phantom sources is dependent particularly on the transient nature of the sound that comes from the loudspeakers so it will be affected by the early reflected sound from the room surfaces. The early reflected sound will also affect the global auditory source width for an orchestra for example and may make it extend considerably beyond the baseline between the loudspeakers.
In asymmetric rooms where the walls on the left and right of the listener have different acoustic properties, the stereo stage may become biased towards the wall that reflects the most. The curve in Figure 8.23 shows the dependency more clearly for different levels of unbalance as applied to the center phantom source in a stereo loudspeaker system. The intensity will then be higher at that ear and the sound stage distorted. This distortion is usually compensated by changing the balance in amplification between the stereo channels.
At low frequencies in the modal region, symmetry may not be desirable since someone sitting in the middle of the room may be on or close to modal node lines. One way of avoiding such node lines is to make the room asymmetric in the low-frequency region.
This can be achieved by having an asymmetric rigid shell surrounding the inner room which is symmetric for mid- and high frequencies by suitably reflective side walls, ceiling, and floor. The inner room must be open acoustically to the outer shell at low frequencies, for example through ventilation vents, and similar large openings, for example at corners. In this way, one can have the desired listening position sound field symmetry for mid- and high frequencies while at the same time have asymmetric conditions in the modal frequency range. Bass traps to control the damping—and thus the reverberation times—of these modes can be placed between the outer and inner shell. It is important to remember though that noise transmission to the surrounding spaces will then be dependent on the sound isolation of the outer shell that must be physically substantial.

Acoustics of Small Rooms
Mendel Kleiner & Jiri Tichy
https://www.amazon.co.uk/Acoustics-Small-Rooms-Mendel-Kleiner/dp/1138072834/

amirm · Jun 1, 2023

gnarly said:
Must also say * Early reflections improve speech intelligibility * runs completely opposite to anything I've ever heard or measured, or seen recommended..
I think proaudio install for speech reinforcement, would roll their eyes on this one.

Their impression of what is wrong is based on late reflections and likely in large spaces. We are talking about early reflections. The research into intelligibility is solid as a rock there. See for example J. AES paper: Audio Engineering and Psychoacoustics: Matching Signals to the Final Receiver, the Human Auditory System* EBERHARD ZWICKER AND U. TILMANN ZWICKER

Zwicker by the way is as close to "god" we have in psychoacoustics.

On the last bit, the reason we don't want to go past 0.5 seconds is that. Consonant-vowel distances in western languages last about that much in cadence.

tuga · Jun 1, 2023

gnarly said:
I think that list of attributes for reflections 'reflects ' .........a vantage from a particular type of preference.
Granted it may be the majority preference...and rightly so....but that still seems like a big so what.

Must also say * Early reflections improve speech intelligibility * runs completely opposite to anything I've ever heard or measured, or seen recommended..
I think proaudio install for speech reinforcement, would roll their eyes on this one.

Toole's book is very dense and requires several readings. And once you do so, some things start not to make as much sense as they should.

amirm · Jun 1, 2023

tuga said:
I did write close-mic'ed speech for that reason. But my point is that a music recording has either real or fabricated spatial cues, and once you start reflecting these things get messy.

They only get "messy" in one's lay intuition. Research strongly shows otherwise.

gnarly · Jun 1, 2023

amirm said:
Their impression of what is wrong is based on late reflections and likely in large spaces. We are talking about early reflections. The research into intelligibility is solid as a rock there. See for example J. AES paper: Audio Engineering and Psychoacoustics: Matching Signals to the Final Receiver, the Human Auditory System* EBERHARD ZWICKER AND U. TILMANN ZWICKER

View attachment 289459

Zwicker by the way is as close to "god" we have in psychoacoustics.

On the last bit, the reason we don't want to go past 0.5 seconds is that. Consonant-vowel distances in western languages last about that much in cadence.

I dunno Amir...seems to me all he is saying is increased loudness improves speech intelligibility.

I mean really, it doesn't even pass the smell test, that multiple sources can increase speech intelligibility.

tuga · Jun 1, 2023

amirm said:
They only get "messy" in one's lay intuition. Research strongly shows otherwise.

Did the research stereo music recordings reproduced by two speakers?

tuga · Jun 1, 2023

gnarly said:
I dunno Amir...seems to me all he is saying is increased loudness improves speech intelligibility.

I mean really, it doesn't even pass the smell test, that multiple sources can increase speech intelligibility.

Deflectors are used in large halls to direct sound to the rear of the audience. But that is for live sound, not recordings.
If I am not mistaken line arrays are used for the same purpose in PA'd live gigs.

theREALdotnet · Jun 1, 2023

tuga said:
Did the research stereo music recordings reproduced by two speakers?

Of course not. The researcher doesn’t believe in stereo and thinks it’s a distraction. Mono or multi-channel is where it’s at. I found very little relevance in all of the quoted snippets to the listening of recorded stereo music and the reproduction of a 3D soundstage. NB, the width of the soundstage is of fairly little concern. It is the ability to localise performers and instruments within the soundstage that counts, including its depth front to back. If you desire a wide soundstage you don’t even need to put polished concrete on the sidewalls, an AU/VST plugin with a stereo width slider will do that, neutral position right in the middle.

juliangst · Jun 1, 2023

Are big rooms always better than small rooms?

I recently watched an acoustics insider video on this topic and he said that reflections in large rooms (like 30x50 meters) are so much delayed and lower in amplitude compared to the direct sound that they don't matter anymore and also don't need treatment.
Is this comparable to a heavily dampened room (like Goldensound's)?

Axo1989 · Jun 1, 2023

amirm said:
Their impression of what is wrong is based on late reflections and likely in large spaces. We are talking about early reflections. The research into intelligibility is solid as a rock there. See for example J. AES paper: Audio Engineering and Psychoacoustics: Matching Signals to the Final Receiver, the Human Auditory System* EBERHARD ZWICKER AND U. TILMANN ZWICKER

View attachment 289459

Zwicker by the way is as close to "god" we have in psychoacoustics.

On the last bit, the reason we don't want to go past 0.5 seconds is that. Consonant-vowel distances in western languages last about that much in cadence.

Preferred it louder, eh ... so, not level-matched?

Ah ninja'd by @gnarly

Edit: I think invoking the speech research in this manner may be drawing a long bow (or clutching at straws, I can never remember). Do we want our own room's reflections to be more intelligible? Do we always want to widen the apparent source width? May bring us back to the observations upthread that this is somewhat genre-dependent. We may enjoy greater global source width (overall breadth of soundstage, aka envelopment) for an orchestra, but prefer more focus (less impact on apparent source width for individual sonic elements) for electronic, and so on.

amirm · Jun 1, 2023

tuga said:
Symmetry

Early reflected sound will confuse hearing and make the stereo stage and its phantom sources appear incorrectly located or even blurred.

Do you own the book and on purpose mis-quoted this excerpt? Herer is the full heading:

He has specific sections in the book for control rooms and home listening rooms. For control rooms, he is stating the usual assumption that such reflections may not be good. But as I post, recent research shows this may not be the case.

amirm · Jun 1, 2023

gnarly said:
I dunno Amir...seems to me all he is saying is increased loudness improves speech intelligibility.

I mean really, it doesn't even pass the smell test, that multiple sources can increase speech intelligibility.

You are making the wrong assumption about those reflections. Likely you think they are "echoes" and hence disturb the main signal. In reality due to Haas effect and shortness of the delay, psychoacoustical they do not act that way. Instead, they help to bring more energy to the listener, same as if you cupped your hands around your mouth.

How our two ears interact with each other and the brain interpreting the conflicting information is very complex and doesn't lend itself to simple intuition. See this excerpt from Dr. Toole's J. AES paper I quoted before:

"It is interesting to note, at this stage, prescient comments by some early workers in the field. Gilford, in 1959 [3], studied how well recordings of speech made in different BBC studios survived the transition to different broadcast monitoring environments. Observing that they survived very well, he concluded: “The fact that the listening room does not have a predominant effect on quality is very largely due to the binaural mechanism.” In contrast, he showed that test sounds generated in a recording studio, picked up by a studio microphone, reproduced in a listening room, and then quantified using a microphone at the listening position in the playback room, showed that the listening room “had the principal effect.” Conclusion: we measure differences that we seem not to hear. His colleague, James Moir, added in discussion: “Finally, in my view, if a room requires extensive treatment for stereophonic listening there is something wrong with the stereophonic equipment or the recording. The better the stereophonic reproduction system, the less trouble we have with room acoustics.”

The last sentence is why I always say the speaker is most important. Not the room!

TheZebraKilledDarwin · Jun 1, 2023

amirm said:
The solution to more than one location is multiple subwoofers plus EQ. You have a small version of that in stereo with common bass in both channels but you will only benefit in width. For other dimensions, you need to use subs. Combine this with proper DSP (e.g. soundfield management from Harman) and you get very even response across multiple seats.

@amirm
Without acoustic treatment and long decay times, how do you achieve it to hear less of the room you are listening in, and more of the carefully crafted ambiences, rooms and delays in any mix?

Claiming studio acoustics was old methodology and not necessary anymore, I find strange and it does not fit to your CV with a solid technical background.

TheZebraKilledDarwin · Jun 1, 2023

amirm said:
“Finally, in my view, if a room requires extensive treatment for stereophonic listening there is something wrong with the stereophonic equipment or the recording. The better the stereophonic reproduction system, the less trouble we have with room acoustics.”

I start to wonder, what the hailed Mr. Toole is understanding as "listening"?
Hearing the ambience used for the voice in the mix, if its a plate or a hall, with or without predelay, with some slapback or not, seems not to be part of his understanding as listening.

If such important details in a mix do not matter for listening, I am wondering what objective criteria are used to make a judgement about a mix? Or the sound quality of the setup?

gnarly · Jun 1, 2023

amirm said:
You are making the wrong assumption about those reflections. Likely you think they are "echoes" and hence disturb the main signal. In reality due to Haas effect and shortness of the delay, psychoacoustical they do not act that way. Instead, they help to bring more energy to the listener, same as if you cupped your hands around your mouth.

Nope. I don't perceive them as echoes at all. I see what we are discussing as simply later reflections that fall within well studied masking and integration time windows.
But they still definitely detract from speech intelligibility ime. (and all pro install advice I've ever encountered)
I work on this alot, and rank speech/lyric/vocal intelligibility in music as a prime success factor, when it come to speaker design and tuning.

amirm said:
How our two ears interact with each other and the brain interpreting the conflicting information is very complex and doesn't lend itself to simple intuition. See this excerpt from Dr. Toole's J. AES paper I quoted before:

"It is interesting to note, at this stage, prescient comments by some early workers in the field. Gilford, in 1959 [3], studied how well recordings of speech made in different BBC studios survived the transition to different broadcast monitoring environments. Observing that they survived very well, he concluded: “The fact that the listening room does not have a predominant effect on quality is very largely due to the binaural mechanism.” In contrast, he showed that test sounds generated in a recording studio, picked up by a studio microphone, reproduced in a listening room, and then quantified using a microphone at the listening position in the playback room, showed that the listening room “had the principal effect.” Conclusion: we measure differences that we seem not to hear. His colleague, James Moir, added in discussion: “Finally, in my view, if a room requires extensive treatment for stereophonic listening there is something wrong with the stereophonic equipment or the recording. The better the stereophonic reproduction system, the less trouble we have with room acoustics.”

If our perspective is always from that of a listening room, we are missing a bigger picture in understanding audio, imho.

amirm said:
The last sentence is why I always say the speaker is most important. Not the room!

Yes !!! The speaker is the most important. Yes !! !
Why turn it into a multiple source, non minimum phase device, by mucking it up with reflections???

amirm · Jun 1, 2023

gnarly said:
Why turn it into a multiple source, non minimum phase device, by mucking it up with reflections???

Because you can't snap your fingers and turn your room into an anechoic chamber. And even if you did, it would sound awful.

Fact is that spaciousness is captivating to audiences. It is what they want and up to a limit, the more the better. I was at a live session at an audio show a few weeks ago organized by a boutique label. The performance finished and I asked the singer if she liked the "dry" version we heard there, or the "sweetened" one that is on the recording of it released. She got all excited and said dry! And went on to say she couldn't believe audiophiles liked it with reverberations. I asked the producer what she thought and she said she added reverb because that is what people like to hear. A quick poll in the room showed everyone agreeing with her.

Why do we like it that way? Because we associate that with realism. From the book above:

"The most neutral sound reproduction is usually not the goal of sound reproduction except in the control rooms of sound recording studios. In homes, both for music appreciation and home movie theater, the goal for many listeners is rather suspension of disbelief a term used in presence research.

Kleiner, Mendel; Tichy, Jiri. Acoustics of Small Rooms (p. 275). CRC Press. Kindle Edition. "

You can't sit there and keep telling yourself that a dead room is better when you prefer otherwise.

thecheapseats · Jun 1, 2023

TheZebraKilledDarwin said:
@amirm
<snip> ...Claiming studio acoustics was old methodology and not necessary anymore, I find strange and it does not fit to your CV with a solid technical background....

huh? - when was that said?... I've been following this thread (mostly) out of morbid curiosity and I don't recall that statement... perhaps you're referring to D'Antono's quotes from earlier in the thread... from here...