I have to say, I believe the whole concept behind this EQ-solves-all discussion to be seriously flawed. It's all fine mathematically, but not acoustically, and doesn't even take into account what the presence and performance of the equalizer brings to the table. Nothing good, usually.
Through my recording and mixing in a variety of studios along with assisting in design of same, I learned from several different mentors a basic theme: that the basic aural characteristic of any room where recording or serious listening is to take place should be as neutral as possible before any electronic assistance is applied. The reasoning, most important during recording, is to not allow the room characteristics to influence negatively the character of the instrument(s) being recorded. But the same can be said about influences a room has on the playback as well.
The waterfall plots (including those with the natural room noise correctly superimposed) show the resonant decay of any given frequency. The length of that decay at each significant frequency influences all sounds produced in that room, regardless of their level. Long decays in a frequency center (the result of a room mode) will extend its audible time, and that by itself gives an entirely different character to how an instrument falling in that frequency range will sound. In the event a resonance is very low level, it may be lost at the bottom of the dynamic range of the room.
Think of it like this. You have a room with a large resonant peak at 70hz, and want to record an upright bass or cello. The room will significantly modify the character of the bass/cello by resonating with it at that resonant frequency. Eq later during mixing will not correct the problem; that note or range will always sound different than the neighboring frequencies. You can lower its level, but the character remains the same. The same thing would be true if you were in the middle of a room null produced by mode cancellations, and were recording an instrument. At certain notes the cancellation itself will have a unique decay which could not be recovered entirely by eq in the problem area.
The same issues apply in a listening room. Unless you acoustically treat the room to eliminate or significantly reduce (at least major) aberrations, the eq will only be a partial solution: level of the frequencies, not the perceived character of them.
The notion that you lose bass when using bass traps also seems faulty. You only lose what shouldn't be there in the first place -- resonances in the room. The actual bass produced by the speakers does not diminish.
Maybe I'm missing something? I don't know, but this all seems wrong to me.
--Bill
Well, let's take a look at this graph where it shows the frequency response of the identical speaker but from different seating positions:
Which line is most faithful the recording below transition frequency? The blue, red or green? What if I changed the room? Would the lines change?
I think the obvious answer is that the room that we put the speaker in completely changes the character of the sound that is coming out of the speaker in low frequencies. It can create swings of up to 30 db. That is 6X different level perceptually (and far more as far as measurement is concerned).
Now, the point you are making is that during recording there were also such peaks. That is very correct. Alas, we don't know what that curve looked like. Not from one venue, or the other million that is used to produce music. So in no way can we ever match what was heard during the recording. All we can do is be faithful to the groves or the bits on the source. That faithful reproduction says don't have your room make up its on "EQ" and change the tones. Because when it does, it doesn't sound right. Somehow as humans we are able to tell that. When I was testing the sub and I played guitar music into it, I could easily tell it was "wrong" when the peaks were there. When I took them out, it sounded much more like a guitar string without the overhang and boominess and seemed to come and go. From Dr. Toole:
"Since the true nature of the original sound cannot be known to listeners one cannot say “it sounds as it should.” But listeners routinely volunteer opinions on scales that are variations of like-dislike, which frequently have a component of emotion. Descriptors like pleasantness and preference must therefore be considered as ranking in importance with accuracy and fidelity. This may seem like a dangerous path to take, risking the corruption of all that is revered in the purity of an original live performance. Fortunately, it turns out that when given the opportunity to judge without bias, human listeners are excellent detectors of artifacts and distortions; they are remarkably trustworthy guardians of what is good. Having only a vague concept of what might be correct, listeners recognize what is wrong. An absence of problems becomes a measure of excellence. By the end of this book, we will see that technical excellence turns out to be a high correlate of both perceived accuracy and emotional gratification, and most of us can recognize it when we hear it."
As to whether EQ is a natural or unnatural fix, I can't agree
. There is no magic in an acoustic material that makes it more right than anything else. Acoustic material can also shape the sound just like an EQ. Here is a simulated absorber:
Clearly the absorption rate varies with frequency and there is even some ringing/vestiges of "comb filtering." Who says that is a good way to get rid of the energy in the room? Maybe it is more natural that we don't energize the room to start than to try to absorb it later!
To be honest, yes, an EQ can be poorly implemented and cause its own set of problems. Graphic EQs are one such example. But DSP is pretty cheap these days and we can do a very good job.
Hope I didn't miss your point
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