Similar but not same. The benefit of measurement is that you can zoom in and see the difference in bigger margin, beyond what our ears can.
Rooms vary a lot. Once you account for the speaker behavior, it increases the variations beyond what our ears can decipher at once. This is when measurements come to aid.
Experience is what goes on in your head. Soundwave measuring tools can't get there. You would need brainwave measuring tool.
What we hear is what is real. Measurements might give the same results, but often they do not, especially with speaker design and placement. Also, in my experience, amps and preamps can measure reasonably well, yet sound lousy. It has embarrassed me over the decades when it happened to me. Almost anything can be fixed to sound pretty good, but you have to go beyond the measurements to get there.
I admire people who can design loudspeakers that both listen and measure well. I can only make speakers measure well. I have suffered a failure from then believing that the measurements were the only key to a good sounding speaker design. I don't design speakers anymore, because I lack the instinct to modify them from my initial design to sound their best. Others, like John Meyer have this skill.
I admire people who can design loudspeakers that both listen and measure well. I can only make speakers measure well. I have suffered a failure from then believing that the measurements were the only key to a good sounding speaker design. I don't design speakers anymore, because I lack the instinct to modify them from my initial design to sound their best. Others, like John Meyer have this skill.
A lot of control rooms of big recording studios are designed by specialists acousticiens, as near everybody knows.
They all had made the same kind of studies, use the same methods and the same measurements. Very few are able to achieve "magic rooms", that is a fragile balance between dump and live. The material of the reflective surfaces plays an important role (The wood or the brick, for example) ad well as the form of their surfaces.
In a surprising way, looking at this page: Bob Hodas - Acoustic Analysis we can see that the speakers in this mastering room, called by Jim Hannon (The Absolute Sound) "The Best System I’ve Ever Heard in a Studio" are siting... in the corners.
While lot of people think it is the worse place to put them ;-)
In France, the "Theatre d'Orange" is famous for being one of the outdoor theaters with one of the best acoustics in the world (I confirm and even for P.A.). However, it seems to me the Romans, who built it, did not have instruments of electro acoustic measurement.
Talking with one of the reputed acousticiens, specialists of studio acoustic design, he told me in confidence that, when he was hired to achieve the acoustic réalisation of an existing studio, he used measurements mainly to reassure its customers about the scientific seriousness of his work. But he could quite do without it. Experience and feelings.
Of course, that do not mean that, for us, less experienced people in this very difficult art, measurements are not of a great help.
My main job is part of a team designing control room and tracking spaces for major studios all over the world. While I do power/grounding/shielding, we have acousticians, cabinetmakers, mech. engineers, interior designers, lighting designers and architects on staff as well. I can tell you that designing good acoustics in today's studio market is a scientific endeavor involving spectral, RT60 and mode analysis, as well as considering direct to reverberant ratios and many other factors. It is a far cry from when I first designed studios in the 1980s using F. Alton Everest's (RIP) book Master Handbook of Acoustics...a 2nd edition of which is a prized well-worn tome in my library.
This being said, the most accurate rooms I have been in are LEDE (Live End Dead End), which quite frankly puts the operator in the near field for frequencies of 100 Hz and up depending on studio size. Sure there is reverberant contribution from the diffusors and reflective surfaces, but they are well out past the time of initial arrival. The percentage of direct to reverberant field and RT60 for each frequency band are specific to music of different tempos and style, so many of the higher end studios we design have variable acoustics in both the control and tracking rooms to meet this need.
We evolved as ground-based creatures, so our ears like our eyes are designed for greater horizontal beamwidth and accuracy than vertical. This means reflections from the sides are paramount to control, those from above and behind less so within limits. In general I always advise to put the speakers on the long wall if at all possible to delay the initial side reflection...this is a major contributor to poor imaging, as it can create a broad-band comb filter when combined with the direct sound from the speakers. Additional diffusion or absorption there can also be beneficial.
Referring to the picture posted by Tourney, although the setup apparently violates several guidelines for good speaker placement, one would have to evaluate much of the room which is unseen to predict it's performance. If the side walls were treated to absorb the initial side reflections, that would help, and if the rear of the room had diffusion that would help as well.
This subject is why there are so many opinions on different speakers...it is far more difficult to sell someone a room than a box to go in it...but even speaker placement is almost always a band-aid for the room's inherent acoustic problems. In an acoustically optimized space, equal path lengths from operator to apparent center of radiation is about all that is needed to sound as designed for serious mixing duty.
Just my 2¢ worth.
Howie
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Could-you explain how it works ? A micro mic ;-) that measures the sound pressure levels in your ears while you wear your headphones ?
Yes. And this what i have done in my room too (WAF inside ;-)
I don't remember many control rooms of studios so different from this principle apart those not acoustically designed at all. While the front 'dead' is often a little compromised by the window between the control room and the studio when the room is not specialized for mixing ? I do not like them so much: working in a box.
Thanks for your input, Howie.
1-Don't you think that our ears are, more or less, able to discriminate what is due to the source (Speakers) and the room ? At least in the medium treble ?
2- Never heard such a thing. Very interesting. Could you elaborate ? Are-you talking here of control rooms or theaters ?
May-be a topic that could help people (including me) to avoid mistakes in their listening room at home ?
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Hello, T;
All details of the how-to and the before and after results/graphs are shown in my Head Phone Ampfifier article for Linear Audio publication. .
You need the capsule from a Panasonic or other tiny electret microphone to measure inside/between the ear and the headphone cup. Alternatively, a small diam mic with a probe attached to it (also described in the art.)
THx- RNMarsh
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A precondition would be familiarity with the speaker. If this was not the case, I don't think many people could separate the effect of room acoustics from the speaker itself. Also, like a blind person must learn to navigate, we too can learn the characteristics of the spaces we listen in based on reflections, but most people do not. This phenomenon shows the 'sound' we associate with a room is due to the reverberant field, not the direct sound.
As shown in this video and in sometimes quite elaborate ways variable acoustics is being done in concert halls. It is also done in studio tracking spaces especially, and often achieved by sliding diffusers or absorbers to cover reflective surfaces. One can make a room highly reverberant, live but diffuse, or fairly dry by the proper blend of reflective, diffusive or absorptive panels. Properly setting these up for specific types of music tracking takes practice, but a good engineer can become accustomed fairly quickly.
Cheers!
Howie
FWIW, the term "Sumiko Method", is just a catch all phrase used in some audio forums that has no real explicit meaning as there is nothing established as to what it actually is.
Sumiko's training seminars are called MASTERS, an acronym for the program. I tend to think it is likely quite similar to what Stirling Trayle does, as I think it's a reasonable assumption. But I could be wrong too.
What I do is similar to what the video guy does. And what he does is take the training he received at the Sumiko seminars along with what he learned from Rod Tomson, and came up with what he called it Rational Speaker Placement. Rod Tomson calls his method Master Set. Master Set and RSP are most likely just abbreviated versions of MASTERS so as to enable a less time consuming process for completing the task.
From my conversations with Rod Tomson long ago I learned that few participants from the seminars really did anything with the training. The training was required in order to be a Sumiko dealer, so they had to attend. Rod was one of the few who really took hold of it.
If you do a google search you do get a bit more information now than say 10 years ago, but there still is limited information and it mostly comes from just a couple posters who are certified in MASTERS.
I think it's pretty hard to get much of an understanding of what goes on by just reading incomplete information or watching a video explanation. I was fortunate to have heard the results before I even knew anything. The sound was extraordinary and I then wanted to know how it was done and sought out information as best I could.
I have attended numerous Melbourne Symphony concerts in Hamer Hall. The recent renovations, as shown in the video, have really improved the orchestra sound of the hall. It's a wonderful place for a concert!!
Coincidentally, do you have references on specifically the difference in reflective properties between wood and brick?
You are probably right. (probably because i'm not in the others'mind;-)
I believe too the way we listen is highly "cultural".
My question about the interest of adapting a different *control room* for different kind of music was because this idea surprised-me.
If we are supposed to create the good climat, the good distances in our mixs according to the type of music and taste of their public, we are supposed to mix for an average listening room in the houses our the listener (and their cars ;-). And listeners do not change their rooms with the records they play, do they ?
For the studios itself and theaters, of course. The problem, in recording studio (where the musicians are playing) is to get enough air to give some life and the good presence, playing with the distance and the brightness of the room, and to get rid of too much reverberation, because, if it is easy to add-it during mixs, it is not really possible to remove the acoustic ones that are captured by the mic.
Agree ?
I think you can find somme tools on internet that can answer your question, like calculate the reverberation time depending of the size of the walls etc, based on the absorption coefficient of different known materials at each frequency and their relative surfaces and position.
Look for RT60.
It is a world of infinite complexity, like the way different surfaces absorb, diffuse and reflect the light at different wave lenghs. And, if we can watch the lights and the colors as long as we want to analyse-it, the sound is passed when we hear-it ;-)
I think too that hhoyt is lot more qualified than me to answer precisely to your question. I'm far, far to be an acoustician. And those guys afraid-me like magicians working in the world of invisible with no right for error because their art is ... so expensive. ;-)
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Maybe that seemed like a very basic question, but I've been thinking about it. Both wood and rock/glass have a much higher acoustic impedance than air. As far as I can tell for that reason they reflect sound in much the same way, although with a significant difference coming from how they are constructed as wood walls have significant gaps and rock walls have a different texture than wood.
So if wood is not so much worse a reflector than glass, then is there any real reason beside cosmetic to for instance use wooden reflectors in an orchestra hall where glass reflector panels are sometimes used to improve the acoustic?
So if wood is not so much worse a reflector than glass, then is there any real reason beside cosmetic to for instance use wooden reflectors in an orchestra hall where glass reflector panels are sometimes used to improve the acoustic?
http://www.linkwitzlab.com/AES123-final2.pdf
"When the precedence effect operates, the combination of direct and reflected sounds is heard as a single entity, and the perceived location of the entity corresponds to the direction of the direct sound. Reflections add a sense of 'space filling' and loudness to the sound as a whole, but the reflections are fused with the direct sound."
Of course most rooms and set ups do not support the precedence effect, but as you say it could be possible to "tune out" the room psychoacoustically to a degree. SL suggests we do this automatically, when we first walk into a room we are aware of its acoustics but after a while we tend to ignore them
Wood is a lot more flexible than concrete. Its flexibility will absorb some frequency ranges a different way. Think to their own resonance (that you can hear, hitting their surfaces). It depends on the kind of the wood used, think to cork, as an example.
Hhoyt will keep-me corrected, but I believe softwood, in general, will produces a warmer acoustic atmosphere (better absorption of the treble) not forgetting the visual warmness.
The good studios that I know use damping materials (foams , glass wool, moving panels, heavy curtains), and both wood and bricks geometrically arranged in such a way they will diffuse the reflexions. Each one with its own character.
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Okay, but when the acoustic impedance is already >> the acoustic impedance of air, the amount of sound reflected is 90%, only the remaining 10% (or less) has any interaction with the resonance of the material (depending on the material thickness). This is not the same as striking a board or a violin where all of the sound energy is transmitted via vibrations of the wood.
There is two things.
What I tried to say (My scientific knowledge in acoustic is near 0, but i have some practical experience) is: I believe that if you can manage to send a pink noise signal to some surface that will not be heard by the mic, and mesure the response curve of its reflexion, this response curve will vary depending of the material.
Resonance in sympathy of the panels is an other issue.
May-be i'm wrong ?
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