Some of you might be aware of Toole's critique of room EQ.
See:
An Enticing Marketing Story, Theory Without Measurement? | Audio Science Review (ASR) Forum
And if you look at post 386, you'll find my explanation of the psychology heuristics underlying stereo perception.
B.
See:
An Enticing Marketing Story, Theory Without Measurement? | Audio Science Review (ASR) Forum
And if you look at post 386, you'll find my explanation of the psychology heuristics underlying stereo perception.
B.
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I tried to read most of it. And what I got out of it, is that EQ works well from around 500hz and below. And this is something I see very few people argue against.
It's not the EQ itself, It's mostly a problem with measurements and interpreting the measurement in general - which can go totally wild when pushing some "auto" button in any program.
There is no free lunch - so it's still very important to understand what you do, when manipulting the signal. Just MO.
It's not the EQ itself, It's mostly a problem with measurements and interpreting the measurement in general - which can go totally wild when pushing some "auto" button in any program.
There is no free lunch - so it's still very important to understand what you do, when manipulting the signal. Just MO.
Toole's critique is that the room doesn't disappear no matter what sound you pipe into it.
When you EQ, you aren't EQ'ing the room (which you can't do by changing the input signal, eh). You are correcting the speakers. The room and its eigentones remain and do not change by EQ.
At some level of analysis, you are falsifying the recording so as to satisfy a mic placed where your head normally is but perhaps just confusing a brain that has learned and retains the schema for that room.
When you EQ, you aren't EQ'ing the room (which you can't do by changing the input signal, eh). You are correcting the speakers. The room and its eigentones remain and do not change by EQ.
At some level of analysis, you are falsifying the recording so as to satisfy a mic placed where your head normally is but perhaps just confusing a brain that has learned and retains the schema for that room.
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And I agree. My experience tells me the following 4 things - which by the way works great here at home.
1. Above around 3-500hz you measure the speaker without the room and make it work smoothly, both on and off axis.
2. Below 3-500hz you can and should use EQ according to the listening position and speaker placement.
3. Use multiple subs below around 80-100hz with EQ.
4. It helps with integration if the main speakers can manage to play deeper than the 80-100hz, where subwooferes are normally crossed - this means having an overlap from the mains to the subs, where the mains fall off slowly and the subs steeper.
Is it Schrödingers frequency, at which we like to switch over between room EQ to speaker EQ?
Anyway, I don't like to carve space for the room out of the speakers responses above this certain frequency.
Music production and reproduction are two seperate things in my book.
Listening to a studio album and an accoustic recording therefore can require different systems to my opinion. That is, if you want your room accoustics to be present more when you listen to it.
Anyway, I don't like to carve space for the room out of the speakers responses above this certain frequency.
Music production and reproduction are two seperate things in my book.
Listening to a studio album and an accoustic recording therefore can require different systems to my opinion. That is, if you want your room accoustics to be present more when you listen to it.
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Schroeder was bound to show up in this discussion, so let me offer my interpretation of his "law": at higher freq you don't need to fret about eigentones and at lower freq you do; "higher" and "lower" depends on your hearing, the room absorption, and the bounce-scope (or maybe size) of the room.
What Schroeder did was offer a rule-of-thumb with minimal parts count, nothing more. He said you take the room volume and the Sabine reverb time (-60dB) and his fudge factor. If you check the previous paragraph, you'll see that's what I said.
I don't believe it is any more helpful than the soft guidance you get from other rule-of-thumbs or rules-of-thumb.
B.
The two threads come together this way. If the room never disappears (this thread) then stereo is just a "parlour trick" (the other thread, in the Lounge) which you can cherish or dispense with, depending on your taste.
Only a small fraction of music listening (even for us audiophiles) is ears-forward and fully focussed on the stereo speakers. The rest of the time, we do dispense with stereo. But we still value the room-filling ambience that stereo speakers provide.
B.
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Going to the topic, the OP again proposes a new thread about something that is universally accepted as an evolution, that is, musical reproduction with two channels instead of just one, the stereo sound. (Ohhh, a speaker for each ear, isn't it wonderful ?)
Who can seriously object to this?
The feeling of depth and the sound stage achieved with two channels is impossible to achieve with just one. Point.
Everything else is pure blah, blah, blah, and, like the dog that spins trying to bite its tail, it leads nowhere.
Who can seriously object to this?
The feeling of depth and the sound stage achieved with two channels is impossible to achieve with just one. Point.
Everything else is pure blah, blah, blah, and, like the dog that spins trying to bite its tail, it leads nowhere.
My theory is formed on the basis, of the physics of sound propagation in gasses as a medium.
A closed box speaker can never reveal the true full sinus. Dipole can, but the other half of the sinus relies on reflection and is therfore delayed and distorted.
But when superimposing closed box speakers, all information in the recording is presented to the carrier medium and listener directly.
I've succesfully put my idea to practice.
The speakers form a superimposed Blumlein style array.
Simple to try. You need an amp, 4 speakers and a stereo source.
Try it. Why not.
A closed box speaker can never reveal the true full sinus. Dipole can, but the other half of the sinus relies on reflection and is therfore delayed and distorted.
But when superimposing closed box speakers, all information in the recording is presented to the carrier medium and listener directly.
I've succesfully put my idea to practice.
The speakers form a superimposed Blumlein style array.
Simple to try. You need an amp, 4 speakers and a stereo source.
Try it. Why not.
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Stereo is not "a speaker for each ear" and a mono recording/reproduction chain is eminently capable of producing acoustic cues that endow an impression of depth (rather an all-encompassing reproduction). Point?
Interesting you talk of cues, just like a perceptual psychologist.
Ironically, with mono there is no lateral spread because the cues to the virtual image on centre-line are so compelling (assuming your stereo speakers are matched OK). BTW, my large dipole ESLs produce as perfect a centre-line virtual image on mono as I can imagine any point-source speaker producing.
But as you suggest, and for my first impression, is that the cues to z-axis depth are about the same in mono as in stereo. But at the best, I think depth is very poorly perceived and gross, in reality and in audio systems. Stokowski moved his sections around - betcha no audiophile could tell from recordings that happened.
Visual cues to depth are pretty prominent, as would befit arboreal creatures. But grabbing a branch as you fly through the air doesn't benefit from good hearing.
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As I understand it - Schrödingers frequency, is the broad limit, where you cross over from the upper frequencies that are able to be measured in a given room, with a given Schrödingers frequency. So in my room, I measure down to around 500hz with a gated measurement and correct the speaker, so that it's well bahaved, both on and off axis. I believe Toole is correct in his talks about speakers being linear from around 500hz and up, in anechoic rooms, also makes them sound great in any normal room - works awesome here!
Lower then that(500hz) and my rooms dimension and the wavelength, dictates that the rooms reflections mix up and my measurement is no longer a direct sound from my speaker, but a product of my speaker and my room. So it's like af gray zone, where you have to be creative, use sound absorbtion, move the speakers around and think about your seated position.
Below aprox. 90hz. The room absolutely dominates and therefore opens up for the concept of multiple subs, by Geddes.
A pretty good and pragmatic debate about room correction, is presented here:
Three Acoustical Issues that Room Correction Can’t Correct
We should however distinguish between EQ with IIR or FIR. I do not find any real improvements yet, that FIR should be any better than IIR. But I'm still trying, since I'm not afraid to be challenged
It is not incorrect or correct. That doesn't change the things you hold, not Toole.
You say :
Only a small fraction of music listening (even for us audiophiles) is ears-forward and fully focussed on the stereo speakers. The rest of the time, we do dispense with stereo. But we still value the room-filling ambience that stereo speakers provide.
Wow, you need to maintain that a single source of punctual sound in the center of the room can achieve the same as a 7.1 system, to give a very exaggerated example, by the way.
I listen to just the opposite in most good recordings. Left and right images and if there is a solo voice, they usually join R&D forming a central image.
I think it's the place where singers are located, but maybe I'm suffering from strabismus or some other eye condition.
Also in live recordings I perceive comments and applause from the audience in plans that give depth to the audition, although, to be honest, the applause usually comes in a circular image, around the musicians, as if you were one of the performers . I don't agree with those approaches to recording and mixing technicians.
So I think it is easy to read articles and then comment on single paragraphs to generate polemics of never ending.
What is not simple is to hold an idea in time without contradicting each other.
How far I deduce from your interventions here, you are an advocate (for the number of times you mention it, is it logical to assume that defense, or not?) Of the room correction with DSP, which is essential if you want a "correct" sound "(if you want choose another term, it doesn't matter, precise sound, without resonances, etc, etc,) that you have to make measurements, use REW, etc, etc.
But now it seems that you change your mind and support the theory of this Mr. Toole, who seems to question all the technical paraphernalia behind the fashion of room correction.
I share that they are not just a speaker for each ear, of course.
It was only an irony, so as not to deepen or open another area of discussion, such as that a pair of headphones (although they are excellent in dynamic range, frequency response, etc.) have too much separation of channels, etc, etc. That is why there are headphone amplifiers that merge R&D at will, to make hearing more similar to reality. Don't ask me which one please, I already forgot.
Bold highlighting is not shared by the writer, however. Not at all.
Point and coma is better ?
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It is what I hold ......
Conclusion
I hope you have found this article educational and that you now have a good understanding of the three acoustical problems a room correction product cannot fix. Room correction is not a magical cure-all that can rid us of the sound quality ills given to us by our rooms. It cannot solve phase interaction issues such as speaker boundary interference that cause audible bass suck-outs. Nor can it solve long reverberation times and strong early reflections that degrade imaging, sound staging and clarity. These issues can only be solved by good acoustic design, treatment and system setup techniques.
What do you think about the role of room correction in a modern high quality sound reproduction system? Did you realize that room correction can’t fix all the acoustical issues of our listening rooms?
For those who speak English exclusively here, and could not deduce the following, I make a clarification:
When I talked about I+D it is not Investigation and Development, it is left channel and right channel
izzquierdoo y deerechooo in Spanish, OK ? Dee acueeerdo ?
(I have to cheat GT writing like this)
When I talked about I+D it is not Investigation and Development, it is left channel and right channel
izzquierdoo y deerechooo in Spanish, OK ? Dee acueeerdo ?
(I have to cheat GT writing like this)
I share that they are not just a speaker for each ear, of course.
It was only an irony, so as not to deepen or open another area of discussion, such as that a pair of headphones (although they are excellent in dynamic range, frequency response, etc.) have too much separation of channels, etc, etc. That is why there are headphone amplifiers that merge R&D at will, to make hearing more similar to reality. Don't ask me which one please, I already forgot.
Bold highlighting is not shared by the writer, however. Not at all.
Point and coma is better ?
But in a well-engineered recording and reproduction chain, a sense of depth (of source position in the recording space) is perceived. The key are the patterns of early reflections. It is not perfect but it is there. Spatial and temporal information are not distinct entities in our perception.
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