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An Enticing Marketing Story, Theory Without Measurement?

Krunok

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There might be a way around it: use some ambient mics, artificial (electronic) reverberation and artificial background noise when the record isn't playing. I suspect the real problem with an anechoic chamber isn't what it does to the music, but the silence and what happens to ordinary sounds in the room.
Huh.. Were you the guy that suggested BMW to use loudspeakers to enhance engine sound in the cabin? :D
 

Cosmik

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Huh.. Were you the guy that suggested BMW to use loudspeakers to enhance engine sound in the cabin? :D
Not me, but I'm pretty sure they do it in various cars.
 
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Although we talk of the lower frequencies being omni-directional, a double bass or kick drum can be located when we listen to stereo it seems to me. Presumably this is because of the higher frequency harmonics?

I suspect the real problem with an anechoic chamber isn't what it does to the music, but the silence and what happens to ordinary sounds in the room.
I would guess that the reason we may not like listening to recorded music in an anechoic chamber is the unusual level of silence we have mostly never experienced. If that was somehow alleviated (hearing your heart beating etc.) perhaps it wouldn't sound so bad. We would be hearing only the direct sound from the speakers plus interaural crosstalk.
 

Floyd Toole

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Although we talk of the lower frequencies being omni-directional, a double bass or kick drum can be located when we listen to stereo it seems to me. Presumably this is because of the higher frequency harmonics?



I would guess that the reason we may not like listening to recorded music in an anechoic chamber is the unusual level of silence we have mostly never experienced. If that was somehow alleviated (hearing your heart beating etc.) perhaps it wouldn't sound so bad. We would be hearing only the direct sound from the speakers plus interaural crosstalk.
I've done anechoic listening and, yes, the profound silence and lack of reflected sounds are there. One can get used to that, but when the "play" button is pressed they go away. In stereo the acoustical crosstalk cancellation dip is easily heard in phantom images. A surprise was that some sounds were perceived to be inside the head, or too close, or even behind - strongly dependent on recording technique. This is what happens if all you hear is the direct sound. The direct sound is the most important component, but it benefits from some timbrally similar reflected sounds - or better yet, from multichannel audio (even upmixed stereo) that can deliver more persuasive spatial ambiance.
 

SIY

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I've done anechoic listening and, yes, the profound silence and lack of reflected sounds are there. One can get used to that, but when the "play" button is pressed they go away. In stereo the acoustical crosstalk cancellation dip is easily heard in phantom images. A surprise was that some sounds were perceived to be inside the head, or too close, or even behind - strongly dependent on recording technique. This is what happens if all you hear is the direct sound. The direct sound is the most important component, but it benefits from some timbrally similar reflected sounds - or better yet, from multichannel audio (even upmixed stereo) that can deliver more persuasive spatial ambiance.
"Illusion" is the operative word. Microphones/room/speaker/room is an entirely different animal than a DAC/amplifier.
 

Blumlein 88

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Not me, but I'm pretty sure they do it in various cars.
Yes they do that in lots of cars. VW and Ford may have been the first. Ford uses 6 cyl sounds on 4 cylinders, and 8 cylinder sounds on 6 and 8 cylinder models. Porsche does it too. Instead of speakers they have a tube with a cover that enters the cabin from the engine compartment. Under heavier throttle, the cover on the tube opens to let engine sound inside. I think most manufacturers do some version of this now. I seem to recall BMW has an accelerometer on the engine firewall, and it fires something similar to a sub voice coil attached the firewall to transmit amplified lower frequency vibrations into the dash and steering wheel so the owner feels the power.

Funny thing, everyone isolated vibration so much, they decided owners liked it better to put controlled amounts of it back in most cars. Yet when I drive a Tesla, the smooth magical power seems awfully nice.
 

Cosmik

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Yes they do that in lots of cars. VW and Ford may have been the first. Ford uses 6 cyl sounds on 4 cylinders, and 8 cylinder sounds on 6 and 8 cylinder models. Porsche does it too. Instead of speakers they have a tube with a cover that enters the cabin from the engine compartment. Under heavier throttle, the cover on the tube opens to let engine sound inside. I think most manufacturers do some version of this now. I seem to recall BMW has an accelerometer on the engine firewall, and it fires something similar to a sub voice coil attached the firewall to transmit amplified lower frequency vibrations into the dash and steering wheel so the owner feels the power.

Funny thing, everyone isolated vibration so much, they decided owners liked it better to put controlled amounts of it back in most cars. Yet when I drive a Tesla, the smooth magical power seems awfully nice.
Fifteen or so years ago, I got hooked on a 'purist' PC rallying simulator with force feedback steering wheel - I got pretty good at it. I was convinced that it was some finite fraction as enjoyable as the real thing. Even if only 20% (and I guessed it was somewhat higher than that), it was costing me about 0.01% of the price.

From the sound of it, the real thing is now turning into the simulator, complete with force feedback steering wheel :)
 
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Anechoic room listening must be of real theoretical importance but I don't have a handle on it. Not sure how that differs from out-of-doors listening or what that would mean. Why are the experiences so different?

Long ago, Jim West, keeper of the Bell Labs full-sized chamber (very rare) used to play a radio in the anechoic chamber when setting up stuff (prolly his newly invented electret mikes). As I vaguely recall, it sounded just like a table radio played in an anechoic chamber (I don't mean that as a joke). Other than my own instrumented testing (motional feedback), never thought to set up a stereo system (yes, we had stereo in those days).

Back to room soundscapes (if that term can be applied to the absence of a soundscape). The experience (including the trampoline floor mesh) is quite weird and disorienting. So, it's hard to think of the setting as a useful perceptual benchmark. You feel something is wrong with your hearing or like underwater pressure is on your ears.
 

scott wurcer

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A surprise was that some sounds were perceived to be inside the head, or too close, or even behind - strongly dependent on recording technique. This is what happens if all you hear is the direct sound.
I watched one of the latest THX encoded Star Trek films on an overnight waiting for a flight on a Kindle propped up in front of me. I was shocked at how well the 3D effects worked. Bob Adams demoed some of these "cheap trick" imaging tricks in the lab, they can be very convincing.
 
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Very interesting topic, one which I've spent hundreds of hours trying to make sense of. I've read Dr. Toole's excellent book, read most of his insightful posts here and watched several of these interesting discussions from afar. I'm not one to decide my beliefs over some philosophical thinking, I like to test theories myself - to the best of my abilities at least.

The first step I did was to buy the best speaker I could that suited my needs; the Kii Threes ended up being my choice due to different constraints.
Those are designed with the Harman research in mind, aiming for neutrality.
I placed them in the worst kind of conditions - a scandinavian home where furniture is illegal, walls are made of empty concrete or glass by law and no wall-to-wall carpet because we scandinavians die randomly when exposed to dust and germs.
On top of that, I placed them asymmetrically with one in a corner and the other with no side boundary for miles.

Surprisingly, this sounded nothing like neutral, dynamic, crispy, nice or comfortable. A revelation considering the claim that rooms are irrelevant, so I decided to take my speakers with me to different rooms. Both smaller and larger than my own. I could hear that it was my speakers most of the time, but the perceived sound quality was so much better when I placed them in a bigger room with far more space around the speakers.
Somebody somewhere lied about rooms being irrelevant!
I decided to experiment with a few absorbers behind my head and it sounded much better. Clearer, softer, snappier, warmer and more comfortable.
Frequency response remained the same, impulse-response/decay/RT60 and clarity did not.

It was clear to me that whatever happens in the time domain is important to my enjoyment of listening to music. Here's a selected few comparisons from before any treatment to how it looks now after placing 4 x 4 inch RPG Absorbors behind my couch and 4 inches insulation + Ecophon plates on the ceiling;

No treatment vs treatment- ETC.jpg

No treatment vs treatment - RT60.jpg


If anyone want to argue whether or not this kind of difference plays any role in perceived sound quality, go right ahead. If you think it doesn't, you're dead wrong. Same room, same speakers, same placement. Just different materials in the first reflections on the ceiling and back wall.

So for me, the first part of the equation is tried, tested and concluded with. Even with good speakers the room will affect your perception on sound quality. The next part of the equation is, of course, room compensation EQ, which is a more difficult topic IMO.
Being a nosy individual, I have tested quite alot, both before and after room treatments. I have the luxury to have both Dirac Live and Audiolense on my computer and can easily switch between the two, and I'm also using Minidsp 4x10 HD with parametric EQ only - and can buypass any EQ as I see fit.

So many hundreds of graphs have been made and analysed, so many different filters, target curves and cut-off frequencies have been tested and re-tested. Want my opinion?

- Audiolense is faster, simpler and have more fiddly-stuff so you can mess up everything in so many ways. More powerful software with more possibilities.

- Dirac really needs you to measure multiple points in space with sufficient distance, otherwise the correction will be way too much and will look like this;

Blue = Dirac single point measurement correction
Red = Dirac after room treatments with 9 point sofa measurement
Green = Dirac before room treatments with 9 point measurement

1/24 smoothing
Dirac before treatment vs after + Dirac single point measurement.jpg


- As we see, Dirac will not over-compensate when used properly. In the red graph I placed the microphone stand stupidly so that the high frequencies show alot of reflections from that. I fixed that mistake later on, but can't find the measurement for that. Notice how similar the red and green graph is, the green is before ceiling treatment. Placement is not the same, seating position shifted about 20 cm.

- Both Audiolense and Dirac can make your sound worse than no EQ if you try, but very difficult to make things worse under 250 hz.

- Both Audiolense and Dirac make very little audible changes over 500 hz compared to my PEQ-settings with Minidsp, but Audiolense sounds better full-range than limited to 500 hz. Dirac sounds flatter and less dynamic.

To those of you who suffered through all of this, thank you. All I wanted to say was that room matters and EQ can be good for you. But buy better speakers anyway!
 
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I've done anechoic listening and, yes, the profound silence and lack of reflected sounds are there. One can get used to that, but when the "play" button is pressed they go away. In stereo the acoustical crosstalk cancellation dip is easily heard in phantom images. A surprise was that some sounds were perceived to be inside the head, or too close, or even behind - strongly dependent on recording technique. This is what happens if all you hear is the direct sound. The direct sound is the most important component, but it benefits from some timbrally similar reflected sounds - or better yet, from multichannel audio (even upmixed stereo) that can deliver more persuasive spatial ambiance.
Thanks. I get the impression upmixed stereo is the way to go for me when or if I abandon stereo as I doubt most of the stuff I have is available in multichannel.
 
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Very interesting topic, one which I've spent hundreds of hours trying to make sense of. .......

- Dirac really needs you to measure multiple points in space with sufficient distance, otherwise the correction will be way too much and will look like this;

Blue = Dirac single point measurement correction
Red = Dirac after room treatments with 9 point sofa measurement
Green = Dirac before room treatments with 9 point measurement...

To those of you who suffered through all of this, thank you. All I wanted to say was that room matters and EQ can be good for you. But buy better speakers anyway!
But you never measured the right thing.

You were looking for sound quality and all you (side-tracked) did was measure certain acoustic properties. Better to assess sound quality which is human cognition.
 
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But you never measured the right thing.

You were looking for sound quality and all you (side-tracked) did was measure certain acoustic properties. Better to assess sound quality which is human cognition.
How would you like me to measure this for you? By time spent listening to music? By number of goosebumps per hour?

I presented measurements to back up my insinuation that I have real and not theoretical experience with perceived sound quality with good speakers in vastly different acoustical properties in the same room.

I can present measurements with and without Audiolense to demonstrate the differences, but I can't show you measurements to assess sound quality.
Maybe you can get some experience with the different properties shown in my measurements and then you can try to extrapolate that information to your subjective feelings?

Either way, here's with and without Audiolense;

With vs without Audiolense - config1.jpg


And here's the measurements with all listening seats in the couch (+- 1,5 meter from main LP)+ the average of all in red after Audiolense;

Config 1 - All Listening positions after Audiolense.jpg


If you compare that to raw measurement in-room of my speakers without any dsp, you can see that the notion that flat speakers with good off-axis measurements won't always be sufficient to achieve the desired in-room response;

No Dirac.jpg
 
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How would you like me to measure this for you? By time spent listening to music? By number of goosebumps per hour?

I presented measurements to back up my insinuation that I have real and not theoretical experience with perceived sound quality with good speakers in vastly different acoustical properties in the same room.

I can present measurements with and without Audiolense to demonstrate the differences, but I can't show you measurements to assess sound quality.
Maybe you can get some experience with the different properties shown in my measurements and then you can try to extrapolate that information to your subjective feelings?
I never thought of a goosebumpometer. Might work. Or pupil dilation.

ABX (blind testing) would be a good start.
 
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