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Perceptual Effects of Room Reflections

RayDunzl

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The head devices give "direct sound" only, which I should think is what speakers would provide (with some intra-aural crosstalk) if played in an anechoic environ.

I have not had the opportunity to listen to speakers anechoically, but don't understand the problem. Certainly the result would be different, and differences are subject to arguments over better or worse.

My panels seem to have a measurably lower reflection power in this room than the little JBLs, and I much prefer their presentation when listening attentively.

Red - panels

1579359550341.png


I interpret the above as a ratio of direct (at time 0) to reflected (the rest of the time) acoustic energy.
 
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Krunok

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The head devices give "direct sound" only, which I should think is what speakers would provide (with some intra-aural crosstalk) if played in an anechoic environ.

I have not had the opportunity to listen to speakers anechoically, but don't understand the problem. Certainly the result would be different, and differences are subject to arguments over better or worse.

My panels seem have a measurable 10 to 15dB lower reflection power in this room than the little JBLs, and I much prefer their presentation when listening attentively.
Aha, I see what you mean. IME it is not only about direct sound without reflections but more about absorption that gets more intense as frequency is rising, and that is why I suggested to put ear plugs half way. As a result LF didn't sound half as bad to me as did voices, especially female ones, cymbals etc. Vast majority of my coleagues shared that impression.
 

RayDunzl

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Aha, I see what you mean. IME it is not only about direct sound without reflections but more about absorption that gets more intense as frequency is rising
Direct sound is not absorbed by the room (anechoic or normal) between you and the speaker, though cancellations will occur with the reflections, which is how I interpret this unsmoothed SPL comparison:

1579359975850.png


The major dips in the red at 210 (and multiples) is the dipole off the wall behind cancellation, and that is the worst of the dips above the woofer range.

I just find the "imaging" much less refined with the wide-dispersion speakers in this relatively untreated living space..
 
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Krunok

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Direct sound is not absorbed by the room, though cancellations will occur with the reflections, which is how I interpret this unsmoothed SPL comparison:
I'm aware of that, otherwise it wouldn't be called "direct". :)

My wording was probably wrong, what I wanted to say was ".. it is not only about presence of direct sound without reflections but more about absorption that gets more intense as frequency is rising".

Btw, lack of early reflections contributes to the "dull" and lifeless sound but lack of late reflections was even more "strange" to me.
 

RayDunzl

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Btw, lack of early reflections contributes to the "dull" and lifeless sound but lack of late reflections was even more "strange" to me.
Without disagreement there isn't much to say...

If extremes are permitted, which would make a better listening room: anechoic or an echo chamber?

I'm too deaf to argue anything about high frequencies, so I'll let you have whatever you have in that area.
 

Krunok

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Without disagreement there isn't much to say...
LOL So true.. :)

If extremes are permitted, which would make a better listening room: anechoic or an echo chamber?

I'm too deaf to argue anything about high frequencies, so I'll let you have whatever you have in that area.
I'm probably equally or even more deaf as you - my ears roll of pretty sharply above 11kHz. :D

I've never been to echo chamber so hard to tell. But I've been relatively often to recording studios and slightly more often to my (quite reflective) bathroom and if I have to choose between those two I would definitely choose the bathroom. :D
 

dshreter

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[
But then, thinking a bit more, I wondered if there wasn't another problem. An anechoic room is designed not only to have no reflections but to keep sound from outside out. It has no ambient noise like we get in a normal environment.
I have been in an anechoic room, and you’re absolutely right that the experience is incredibly strange even without speakers playing. It’s similar to the feeling I had the very first time I wore noise canceling headphones, which is a disorienting sense of pressure or vacuum but more intense. I no longer get that feeling from headphones though.

so maybe it’s a poor baseline since even your heartbeat sounds strange in a room like that. It is hard to separate the sound of a room and the sound of speakers in that room as concepts.
 

Krunok

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I have been in an anechoic room, and you’re absolutely right that the experience is incredibly strange even without speakers playing.
When there is a silence in the anechoic room for more than 1 minute you start to hear not only your heartbeat but also a sound coming from a blood running through your veins. Extremely unpleasant experience!

At that time there was a story that a cat was accidentally locked in an anechoic room for a night and that it was found dead in the morning for no apparent cause. I find that easy to believe.
 

DonH56

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My room is pretty dead and I prefer it that way. Ambience comes from the source material instead of the room adding its own signature. I am aware that I am in the minority but it is one of those "preference" things. Imaging is better (more stable, "tighter") and the room is small enough that the speakers do an adequate job of "filling the room" whether stereo or surround.
 

375HP2482

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While remodeling our house a few years ago, I had an interesting experience along these lines. This old shack, built ninety years ago, was thrown up with redwood siding on the outside and dark T&G on the inside -- an old cabin-like affect. My wife had moved in earlier, and wanted a modern, less cavelike (sheetrock) look and feel.

After the exterior had been reframed and renovated I demolished the main living room, removing the rest of the T&G on the ceiling (llittle insulation anywhere). First step: insulation -- R13 in the walls, and R19 in the ceiling attic space. We were living room-to-room during this work, and so for a month or so we set up some crates to sit on in the main room with the big RPTV. So, now we are staring at insulation-paper everywhere we look (besides the floor). The acoustic effect was novel, about the deadest domestic space I've experienced. My wife's voice was quite a bit softer now (not a bad thing) but I could hear her very clearly without any wall reverb. But if she turned and faced away from me, her voice almost disappeared. And the sound of the modest TV speakers was, to my ears, now more clear and distinct than any TV I've heard since. I made a note of all this when it came time to build a sound room in the basement.
 
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It's really disappointing to see all the red herrings, and even an insulting tone, from someone like Amir. And to call an article showing numerous detailed graphs "reference free" is even sillier. Amir has lumped together three different rooms, trying to apply the response and waterfall graphs measured in a bedroom size space to my much larger living room and that even larger mastering room. As if the extensive treatment in the mastering room gives results like the bedroom. Even more disingenuous, and frankly stupider, Amir claims of my living room "He has covered every inch of wall surfaces" which is preposterous. Talk about unscientific! If you had read the articles I linked you'd have seen the detailed list of treatments in my living room, and known that they account for only 18 percent of the room's total surface. You are really grabbing at straws! :D

Amir also shows that he hasn't read my articles because he wrongly believes that EQ can reduce ringing decay times, and incorrectly uses a waterfall plot trying to prove the point. That's the wrong type of graph, as explained in my "Final" Dirac report linked earlier. He also misses the very important point that subwoofers typically operate only below 80 Hz, while the bass range extends up to 300 Hz. So no matter how many subwoofers you throw at the problem, you'll never improve the "speaking range" of bass instruments where clarity and minimal ringing are most important. Below 80 Hz is for the "weight" of music, and movie explosions. Amir, do you have any actual experience performing or producing music?

Then we have Krabbie refusing to say anything about his own preferences and treatment which would help me reply in a way he'll understand. So this is just pointless, and a waste of my time. You guys apparently have no actual experience, and so can only rely on "data" instead of music. Amir asked if I ever listened to Dirac, I guess assuming I'm like him and consider only "data." This again shows that Amir failed to read my articles because I included not only my own subjective impressions, but also those of a friend who's won five Emmy Awards as a TV and film composer. You guys are a hoot, and about as unscientific as it gets. Rule Number One in science is logic, and you both failed miserably. You demand that I read Floyd Toole's entire book, but refuse to read the few articles I linked. So I'm going to leave you with a rebuttal to Floyd's research on reflection preference from a past post, and say goodbye. You guys are literally like Trump supporters, ignoring facts and logic, steadfastly refusing to change your opinion.

The following explains some potential problems with Toole's research, which I'm sure you'll also ignore:
Sjeeez...
Just reading this. Great going guys you managed to chase away Ethan Winer :facepalm:

What a shame! While maybe not the easiest person to deal with on a forum he has more experience with acoustics and acoustical treatment than the rest of you combined.
And he's completely right in what he wrote on the subject too!

Again, what a shame and loss..
@amirm you're running a great forum but it's GREATLY lacking in its views regarding room acoustics and treatment. And even though many of you try to be "scientific" about it I feel you're mostly failing there. And people like Ethan are exactly the kind of people needed to lift this subject to a higher level.
I'd suggest, likely in vain, to try to make mence and make him feel welcome again here.
 

Eurasian

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This is interesting - my personal impressions are almost exactly the opposite. Most of my listening is classical, and most of that orchestral, and I'm always trying to listen through the system to some subjective notion of real instruments in a real hall. And I find that most systems tend to create, as an exaggeration, a loud, confusing, miniaturized orchestra in my room. Whereas sitting relatively close to directive speakers tends to create more of a sense of listening through a window into the hall - at least with decent recordings, which are much more prevalent in classical than in the dire wasteland of modern pop engineering.

But I may be a weird case. Before I had the Revels I owned MBLs. These were superficially the most impressive speakers I ever had. At the occasional party we would throw, I'd put music on in the media room and invariably I'd come around to find a few people sitting in the room absolutely mesmerized. They'd never heard audio like that and loved it. I loved it too - for a while. And for some kind of material - oh, say, some unchallenging Joe Sample jazz fusion - I'd still take it.

But after a while I got more and more disillusioned with a system that made every recording sound like MBL + Scott's room. That's when I went to a full Revel system - which was better, but still not fully satisfying for me. In some ways I still yearned for the sound that I got from my first real "high end" system in college, used Acoustat 3s driven by a Hafler DH250 kit I built (it was jointly financed by multiple roommates, I wasn't born with a silver spoon:) And so when I saw Robert E Greene's review of the Sanders 10E in TAS, I decided to go for it, knowing there's a 30 day money back. Done. These work for me, in spades, for 1 year+ now. The only thing I can imagine changing my direction is the advent of really good synthetic surround (QLS, you might have saved us had you only been born:)

But at the recent New Years day party my wife likes to throw, I didn't even bother to put on music in the media room - just had Roon send it to the living room Sonos. I knew nobody would be impressed with the way the Sanders sound on first impression. Or maybe the 100th impression, for a lot of folks. So I know my preferences are not those of most people. But having surveyed all of the literature, and tried a number the various options for myself, I'm at least confident that I prefer what I prefer.

Digression on Robert E Greene: he's a complete outlier on the TAS staff, an opinionated reviewer with an almost purely objective bent. He will allow that DACs or amps might sound very subtly different, but focuses on speakers, room, DSP or EQ, and especially recordings as the overwhelming factors. He's a math professor, and thus quite analytical about the differences in speakers, components, mic techniques, etc. He has a Yahoo Groups forum (yeah, I know!) called "regsaudioforum" that is worth joining if you want an interesting and opinionated perspective on audio recording and reproduction.

Scott
Hi Scott,,

If you can still find one, the JVC XPA1000/1010 was the best of the digital hall simulation processors. Wm. Sommerwork had a comprehensive review back in the day. BTW, I also use the Sanders 10s for serious listening.
 

tuga

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Is there room for a thread about ceiling vs floor reflections?
Do you mean this?





Floor and ceiling reflections close to the median plane are difficult for hearing to separate from direct sound by binaural means.
They arrive in about the same cone-of-confusion.
 
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Yet he doesn't advocate anything you say today.
strange assertion considering my comment you quoted above is simply a fact of a studio model. RFZ is literally a geometric (splayed walls) method to accomlish LEDE requirements. there is no "subjectiveness" about such a statement or anything to "advocate" - merely a fact of a design put forth for clarity/correction.

what he does or doesn't "advocate" is irrelevant to the clarification on your false claim that somehow these mix room models "from the 70s" somehow think "all reflections are bad" and thus strive to create anechoic/dead spaces. LEDE/RFZ is the exact opposite of that seeing as how it requires a very dense, reflection-rich lateral diffuse sound-field. to claim otherwise is simply not rooted in any reality and is spreading false information.
 
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It was but regardless, that was the background story. The real story today is that based on those types of designs and lay intuition that "reflections must be like echos," it has become the norm in many forums to tell people to a) run ETC and b) find anything that spikes in there and put an absorber on it. It starts with left and right walls. Then the floor. Then the ceiling. Then the wall behind you. Then the front wall. Then the lamp next to you. Then the shoes you are wearing, on and on. :)

Placebo effect and chasing graphs causes them to build completely dead and ugly rooms by the time they are done. Then watch some of them come back a year later and say, "I ripped out everything and the sound was so much better!"
attached photo: the bottom graph is an ETC (time-domain measurement) example of a "treated" LEDE/RFZ room. again, your insinuation that said spaces are "completely dead rooms" is factually incorrect. the "treated" room literally induces MORE reflections and a DENSER sound-field than a simple untreated (bare wall) room - it just does so in a controlled manner.

the repeated spreading of factually incorrect information on such designs that are well known and understood is bewildering.

user Bjorn's responses to you in that thread are spot on.
 

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If reflections are not good than is it safe to conclude that if the room is an acoustic nightmare with lot of hard reflecting surfaces than its better to get speakers with narrow dispersion window and point them to MLP?
 
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