Impact of Reflections: In-Room Speaker Recordings

[Drengur]

It's funny I regularly see people asking for headphones with a more spatial sound (they hate my HD600s), never the other way around, and now we suddenly see people prefering a narrower image.

I'll try with my DC Noires later tonight and see if I feel it differently. Unfortunately I don't have any open back headphones at the moment. I do not, generally speaking, prefer a more narrow image, quite the opposite. That tells me there is more at play here.

 

[goat76]

The recording of the first one with the speakers in the vertical position is a little bit unbalanced to the right channel, it also sounds wider but at the same time a bit less "coherent" between the channels as if the speakers are positioned too far apart from each other. I fully understand what people mean when they say that the second one with the speakers in the horizontal position sounds more realistic, as it sounds more like the orchestra is on a scene in front of the listener.

I listen to the sound files on my Airpod Pro II.

 

[Deleted member 21219]

I was interested in this, because I have a slightly different speaker setup compared to most listeners. (I have always liked closefield listening, which minimizes the sidewall reflections.) However, I started on headphones.

Sideways ..... clearer bass. Woodwinds slightly left of center.
Normal ..... more spacious. Woodwinds slightly right of center.

These generally agree with what @goat76 has mentioned. I listened on Audio Technica ATH-M40x.

I also listened on my speakers, in order to compare my speaker setup with headphones. There's a marked difference in lateral extension, but otherwise, not anything humongous.

Jim

 

[Thomas_A]

The instruments in 1 is more spaced and you are in a hall. In 2, details are better and focused but there is "no room". Just a tunnel to the event. As I would expect.

A comparison to a more "envelopment (upmixed)" binaural recording I made some time ago.

o helga natt.wav

Shared with Dropbox

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[goat76]

I was interested in this, because I have a slightly different speaker setup compared to most listeners. (I have always liked closefield listening, which minimizes the sidewall reflections.) However, I started on headphones.

Sideways ..... clearer bass. Woodwinds slightly left of center.
Normal ..... more spacious. Woodwinds slightly right of center.

These generally agree with what @goat76 has mentioned. I listened on Audio Technica ATH-M40x.

I also listened on my speakers, in order to compare my speaker setup with headphones. There's a marked difference in lateral extension, but otherwise, not anything humongous.

Jim

I just did another comparison between the recordings and this time I used my DAW (Reaper) to be able to make faster changes between the sound files and listen with my Audeze LCD-X, and I still prefer the more coherent sound of the second file. I don't find it sounds like mono, just more like an orchestra on a stage in front of me.

I don't think my preference has much to do with the horizontal vs the vertical position of the speakers, it's possible that I would have preferred the sound of the speakers in the vertical position if they were positioned closer to each other and reproduced a more coherent stereo sound.
I would like to see pictures of the setup of the speakers with some measurements of the distance between them and how far away the microphones were placed.

 

[sarumbear]

I have posted before about a small nested line-array speaker that I designed and built, which I call the Skylarks. These speakers are typically listened to vertically, where they have wide horizontal dispersion, but limited vertical dispersion. However, they are sufficiently small that they can be turned on their side as well. In the sideways orientation, they produce wide vertical dispersion and limited horizontal dispersion. I have done sighted listening tests where I have rotated the speakers back and forth. This isolates for a lot of variables since it's the same speakers in the same place in the same room, with the same frequency response, the same crossover parts, the same dynamic range and distortion profiles. Everything is the same except the dispersion pattern. I have repeated this test for a very limited number of people.

I have also been working on a microphone array using 5 cardioid mics arranged equally around a circle. It's my intention to couple that design with significant post-processing to allow fairly narrow spatial filtering. As a proof-of-concept, I wanted to see if the mic array could capture the difference in sound of the skylarks in their normal (vertical) orientation as compared to in their sideways (horizontal) orientation. I recorded the same song with the same array in the same spot, played a the same level, and only changed the speaker orientation. Although I'm still working out some issues that are preventing me from finalizing the post-processing, I determined that simply mixing the forward three mics into a stereo recording is fairly demonstrative of the impact.

I have attached 2 diagrams showing the speaker orientation change. I have also linked 2 recordings (flac). I have time aligned them sufficiently so that an abx plug-in can be used to switch back and forth between the two in real-time. I roughly level matched them by reducing the level of the recording from the horizontal orientation by 2dB. The reason for this is that the floor and ceiling are closer than the sidewalls, and thus the vertical reflections add more reinforcement than the horizontal ones. Feel free to do a better level matching if you find it necessary.

If you're interested, take a listen and post your impressions comparing and contrasting the recordings. What I'm most interested in are the implications for how speakers ought to radiate sound into a room. Your listening should be done with headphones since there has already been one set of speakers and a whole room added to the chain.

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Skylarks_Sideways_3mics_mix_245.flac | Powered by Box

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Am I missing something or do you consider the pinna, concha, and the helixes are not part of our hearing mechanism?

 

[fieldcar]

 

[617]

No comment on the sound as I don't have time to listen, but @BenB really nice to see you keeping the tradition of DIY innovation alive. Really cool to see.

 

[STC]

D

View attachment 302640View attachment 302641

both skewed towards right…. Thanks for the confirmation.

 

[AndreaT]

It could be that those who found it more real did not find it to almost sound mono. It could also be that realism is judged by other factors than stereo vs. mono. In my case I am not sure what caused my brain to feel as if I was within the room with the orchestra as opposed to the first recording where I felt I was in the room with the speakers.

It is highly dependent on your seating position in the symphony hall. From personal experience, moving up from center row 31 to center row 13 in Symphony Hall in Boston allows a wider soundstage and more "stereo" (in its original Greek root: tridimensional) sound with more separation of the sound signal from different group of musical instruments. Some composers do achieve more tridimensional (or multidimensional sound, I should say) than others: I venture to say the chromatic contrasts of Mahler and Strauss large symphonic ensembles are way more multidimensional in the music sound generated than Haydn and Handel. The upgrade in the seating was money well spent.

 

[DanTheMan]

In general, the first recording is overly wide, diffuse and spacious while the second sounds like it’s coming from my forehead with Apple EarPods in. Very cool experiment and thank you for sharing and allowing us to participate.

 

[Anthony LoFi]

As directed by Ben I have listened to both tracks with the cloud audiofile played real time from my mac by USB to an Avid 003 rack D-A to a pair of Sennheiser HD 25 and strain my ear/brain receptors to hear any consistent differences.
I guess Im the odd one out here.
It is stereo but as others have indicated either a narrow sound-field or the microphones placement could have reduced the original stereo effect.

I wonder if a re-recording using one microphone and one speaker only could highlight a pronounced difference?

 

[Dave Tremblay]

No contest for me. I prefer the second recording. It is narrower, but the first recording sounds diffuse and unfocused.

However, I’m not sure your mic technique here would correlate that strongly to preference in the actual room. Because reflections are coming from different directions, they undergo a different HRTF, which helps our brain separate them somewhat. When you’re recording with cardioid mics, that information is lost. What you’re capturing here is a recording with delays, not a spatial recording.

 

[BenB]

Later on it would be interesting to hear the original recording, so we could assess to what extend room reflections increased the width of the stereo image, or the horizontal speakers narrowed it down.

Listening to the original recording back and forth with the in-room recordings is pretty jarring. In order to lessen the differences, I added 2 sets of EQ. One for the Harman Room curve (with picture attached), and the other for a simple frequency roll-off associated with the skylarks (sealed) which are supposed to be used with a sub. I didn't use the sub in this case, because I wanted all the sound originating from the 2 speakers. I know people will have differences of opinion on what the Harman curve truly consists of, but I am being transparent by showing the EQ I used, right or wrong.

Here's a link to the EQed and (somewhat) level matched audio from the CD. There are still spectral differences I'm sure. No room is average, no speaker is perfect, etc, etc.

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Here's the Harman EQ.


Here's the bess extension EQ.


I understand that the EQs offset each other significantly in the bass region.

 

[Madlop26]

Revel 126Be, oversimpliying first stereo, second mono. What really surprised me is that some prefer the second, we are animals of different taste, aren't we.

 

[Geert]

Here's a link to the EQed and (somewhat) level matched audio from the CD.

As I thought, the original has an even wider stereo image than the first recording. You can perfectly locate the instrument groups. How I knew? Every recording of classical music I own has a wide stereo image that the second recording.

I'm also surprised no one else noticed the comb filtering I heard, and the muddy low mid in the second recording. I looked at the spectrum of both recordings and the response of the second one is clearly more jagged than the first, including an ugly low mid bump.

So half of the audience prefers a speaker setup that detoriates the sound of recordings? They even call it 'more real', while no other recording sound like this. I would say I'm shocked, if it wasn't the first time this happened in a test like this.

 

[tmuikku]

Jeah pretty big fundamental difference what people prefer. Some prefer to listen whats on the recording, some prefer "local room", or some other notion, basically to transform the recording to their liking or to reality or something. Or compare to reality at least. It seems that some people just do not like to hear what is on the recording, but prefer some "reality".

Regarding stereo loudspeakers and setups one should definitely know which one they like, and how to maximize that. Or be able to adjust between multiple.

If one likes to listen what is on the recording, please shrink your listening triangle and that's it, local room is mostly out of perception as long as speakers are good enough and brain locks in to phantom image. If one prefers something else, "a reality", please make sure your room corresponds to your reality and you listen far enough so that the reality happens in reality. It would be better if each instrument had their own sound loudspeaker, preferably similar DI as the real instrument has, recorded close micing. This is to mimic real instruments and an ensemble that radiates sound from various spots in room and individually to all directions with various frequency responses. Now you have reality Stereo speakers and recordings lend poorly to this I think. Well, at least listen far enough to have some of it, maximum local room involvement, at least avoid to let your brain lock in to the sound in the recording, that's not what you want to hear.

Interesting bit on the listening test to me was to hear how the strong early reflections affect perception of the sound and how it relates to my situation. I'm adding this to pool of information I'm using to reason how to improve my system. So, its not very important to fight over who likes what. People like different things and best thing one can do is to understand what you like, and to be able to contrast to some other options and why would they matter to some. Perhaps I don't know what I like, perhaps I think I like something but turn out prefering the opposite. Its all just a tool to explore around, know the options, figure out what works for you.

For forum discussion, its absolutely necessary that this context is known. Giving or taking advice on early reflections or DI for example, could be wrong if everyone with the discussion are not aware or not communicating about the context. I mean, listen the samples on opening posts, people are split between the two!

 

[Geert]

shrink your listening triangle and that's it

Funny, I was just thinking if the people who prefered the more focused sound indeed have their speakers closer together or have taken other measures (like using horns speakers).

Personaly I use coaxial speakers at home, delivering a great phantom image without reducing spaciousness.

 

[tmuikku]

Yeah, and there is, or at least seems to be to me that there is, quite simple listening test to figure this out which ought to work with most speakers and rooms. I do not know though, I just assume since it happens with my setup

There appears to be quite distinct transition between two very different "stereo sounds", at some listening distance to speakers perception of stereo sound seems to shift. Kind of on/off phenomenon, brain seems to lock in to the sound in recording quite suddenly and it feels literally like stepping inside the sound of recording, or stepping out to local room. I've been writing about this lately a lot on various threads trying to lure people write if they hear it too and what do they think about this. I'm hobbyist and figuring this out by my self so kind of need the community to figure out whats going on.

What is nice about the audible critical distance is that it's quite easy to hear (I think), and as it's such a on/off transition everyone should be able to pick it up without confusion, a common point of perception that separates sound of recording from sound of your room. If everyone knew about this, how each of the sides of this critical distance sounds like and which one they prefer, there would be a lot less confusion about communication on stereo image stuff and about speakers and hifi hobby in general, what kind of speakers would work better for ones liking and room for example.

To me, hearing the transition my self has basically been a revelation, especially after finding out it correlates with David Griesinger work. It has been a way to root my perception of sound to written concepts like what is envelopment or spaciousness and when I can hear them, and means to reason how can I adjust them, and which one I like better, and so on helps to make sense of conflicting advice, both could be true if they are for opposite sides of the critical distance for example.

Read more on this on another thread if you find it interesting: https://www.audiosciencereview.com/...dstage-and-imaging.46259/page-11#post-1668327 then go and find out David Griesinger studies and papers, they seem to make a lot of sense and basis for what I'm trying promote. Everyone should know about the audible critical distance and what is their relationship with it. Having personal perception of the transition at critical distance, and then holding Griesinger paper(s) at your hand feels like having a map to get better sound. At least it gives better understanding of what I'm hearing and what I'm supposed to be hearing, how to get the sound I think I should be getting. How my room affects the sound, relative magnitude of things and so on.

 

[maty]

Sealed: much better now.

After, again, Skylarks normal -> Wider, too much bass