I believen that both Audyssey and Dirac adjust for Phase/Timing as part of their EQ... although colloquially termed RoomEQ, both are doing more than"mere EQ" ( as defined by the traditional graphic equaliser metaphor).
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Center speaker advice: Is timbre matching real?
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DavidMcRoy
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In my experience and based on my preferences, timber matching for a center channel speaker is absolutely essential. It just "doesn't work" for me unless it is. Using Dirac Live, ART Studio, or some other good automated correction system can get you really close if things aren't ridiculously out whack. I welcome the assist because I find getting it exactly right is very difficult without it. Some listeners may not be so picky, I guess. I worked in audio-for-video production for over 30 years, so accurate voice reproduction is Job 1 for me.
Totally agree - the midrange, the vocals / dialogue - get that right and you are 90% of the way there - everything else is a bonus!
What do you mean?
The term neutrality refers to the frequency response curve of the speaker... theoretical perfection is a flat line.
All midrange and up AVR's nowadays include RoomEQ which adjusts the frequency response to a target curve (many also allow tailoring of the target curve)
Once you use the RoomEQ, whether Neutral or not, the actual response of the speaker will be determined by the RoomEQ and not the neutrality or lack thereof of the speaker (as long as the speaker frequency response is within the adjustable range of the EQ... so it does need to be at least somewhat neutral)
So the "voicing" of a speaker is no longer determined so much by the speaker designer, it is now determined by the RoomEQ (and its defaults or the adjustments made by the user to the target curve)
Then we get to resonances
Speakers are inherently the most imperfect of all our components, they are mechanical devices that move air to produce sound - and along the way they are prone to various vibrations and resonances above and beyond the desired signal... that is why speakers that achieve 0.5% distortion are considered fabulously good, where every other component in the chain would be castigated if it didn't achieve better than 0.05%
Those distortions, are by their nature, not really subject to EQ - if you reduce the response at a resonance peak, you will also reduce the desired signal... mostly we have to live with the resonances.
Those resonances / flaws therefore become the "signature" of a speaker... and we have to live with them or live with compromises made to reduce their impact... no 2 compromises are alike, and different people find different compromises they are willing to live with.
If you apply room EQ using methods that are contrary to the known best practices, either manually or let some automated software mess it up for you, then whatever the results are will be on you. By (mis)using EQ like that you can make even identical LCR speakers not timbre match.
A resonance increases the amplitude of the signal near the resonance frequency (and the "Q" of the resonance gives how wide the peak spreads out). Applying EQ to counter the resonance peak and flatten the frequency response doesn't remove (or at least minimizes) the resulting effect of the resonance? Since mechanical resonances are by nature minimum phase phenomena, their effects (both in magnitude and phase) can be effectively countered with opposite EQ filters, and thus will make the resonance disappear. No?
Fortunately we have research that help us understand at what levels of correction errors these resonances can become inaudible.
AES Journal Forum » The Modification of Timbre by Resonances: Perception and Measurement
The AES Forum is where our members get to interact with each other in between conferences and section meetings.
Sadly, I do not have access to that document... It certainly seems "on point" (from the one paragraph summary) - but without reading the paper, I cannot comment further!Fortunately we have research that help us understand at what levels of correction errors these resonances can become inaudible.
AES Journal Forum » The Modification of Timbre by Resonances: Perception and Measurement
The AES Forum is where our members get to interact with each other in between conferences and section meetings.secure.aes.org
My personal preference is to use the target curve from the Room EQ system, however I set the target curve to follow the measured in room frequency response of my main L/R speakers - and then I apply that as the target EQ to all the other speakers (surround, height).
This minimises "messing" with the native response of the speakers in the over 250Hz range.... potentially controls or mildly ameliorates, any resonances, and timbre matches the speakers to each other.
It is worthy of note also, that although not identical my front L/C/R are quite closely matched (as measured), and my surrounds from a totally different brand, also measure with a very similar F/R curve to my mains.... so we have several presumably neutral speakers, with in room profiles that are very similar, and room EQ used to further match them - the results are, I find, pleasing.
(the "odd" speakers out, are the height speakers... where the room EQ has to do a bit more work to match the frequency response profile... but I can live with that)
DavidMcRoy
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As I implied upthread, automated software can get you very close to accurate response, but you do sometimes have to do further tweaks here and there. And for psycho-acoustics reasons, some resonances can be relativity innocuous while others may stick out like a sore thumb. With a combination of automation and the human touch, we can often get adequately good correction. Also, correction software performance is liable to improve in the future (unlike some other things.) The bottom line is, all is not lost. We should take advantage of the tools at our disposal.
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Your notion reflects a common misunderstanding of resonances. What you may referi to is rub and buzz, rattling or something like that.
A resonance isn't bad per se. It can be perfectly equalized. Once the mathematics describing the transfer function of a speaker is at hand, including resonances, the case is clear. Without it's a really hard job to explain the connection, though.
But a practical argument is in order. Using a parametric equalizer you could inject a resonance to the feeding signal. Using another equalizer would happily remove it again. Same if the resonance doesn't live in the electric part, but in the mechanical part of the "energy flow".
That assumes also that the properties of that resonance mechanism are minimum phase - if they are mixed or linear phase, then it can affect phase/timing - and is not predictably fixable...
Having said that, most of the natural mechanisms that cause such resonances are in fact minimum phase.... so yes, it is theoretically correctable
■ If EQ could freely control mechanical resonances, here’s the world we’d get
✔ End of loudspeaker engineering
No need for materials science or vibration physics.
Paper cups, plastic sheets, yogurt containers —
apply EQ and they become Focal, KEF, or JBL.
✔ Extinction of acoustic designers
Crossovers and driver design become pointless.
With EQ doing everything, speaker engineers
would have to change careers and run soba shops.
✔ Infinite directivity control
A tweeter smaller than the wavelength
could control directivity like a 30 cm woofer.
Meaning:
a 1-inch dome could output perfectly uniform directivity down to ultra-low frequencies.
Physics deleted.
✔ Infinite bandwidth
Unlimited cone excursion.
No heat, no melting, no wear.
A 1 cm tweeter could play 20 Hz at 120 dB.
The Earth cracks open.
✔ Zero distortion
Cone breakup and mechanical noise
all disappear with EQ.
THD and IMD become 0%.
FFT tools start crying.
✔ Zero resonance
Even a cardboard or steel or floppy cabinet
can be perfectly corrected with EQ.
“Cabinet resonance” becomes a religious myth.
✔ Infinite SPL
Voice coils never burn.
Surrounds never tear.
Magnets never saturate.
The birth of
the “Invincible Electronic Bass Dragon.”
✔ Forums vanish
ASR, AVS — gone.
Every thread ends with “just EQ it,”
so no debates can exist.
I respect your enthusiasm. But on the engineer's toolkit:
Michael Børresen explains himself?
I don't recall KEF ever straying off the path?
www.audiosciencereview.com
Similar scheme of misconception here. The terminology gains its own life in the ecosystem of engineering and fools you, me, other once in a while and again later. Resonance is the building block that makes energy transmission. In sound it is pressure to velocity and back again to pressure and so forth, the wave itself. In light or other electromagnetic radiation: magnetic versus static electric field, and there are many other phenomena that rely on an intrinsic conversion. What you think of as free of resonance is only a special case, that has to be defined on behalf of the phenomenon. E/g wave propagation that needs concepts of interference and boundary conditions to systematize a sound perspective (pun intended).
"Resonance" is descriptive, not a natural object. Stick to its definition, and don't say it's a bad thing per se.
So what exactly are you trying to say?I respect your enthusiasm. But on the engineer's toolkit:
Michael Børresen explains himself?
I don't recall KEF ever straying off the path?
Similar scheme of misconception here. The terminology gains its own life in the ecosystem of engineering and fools you, me, other once in a while and again later. Resonance is the building block that makes energy transmission. In sound it is pressure to velocity and back again to pressure and so forth, the wave itself. In light or other electromagnetic radiation: magnetic versus static electric field, and there are many other phenomena that rely on an intrinsic conversion. What you think of as free of resonance is only a special case, that has to be defined on behalf of the phenomenon. E/g wave propagation that needs concepts of interference and boundary conditions to systematize a sound perspective (pun intended).
"Resonance" is descriptive, not a natural object. Stick to its definition, and don't say it's a bad thing per se.
I never claimed resonance is “bad.”
My point is simply that in the real physical world,
mechanical resonances cannot be eliminated by EQ.
The physical motion created by mass, stiffness, and damping still exists,
regardless of how you choose to redefine the term “resonance.”
Calling it a “concept” doesn’t change its physical behavior.
If you want to use the term differently,
then please define it properly within actual physics,
not just linguistics or philosophy.
My notion on resonance as a term referred to post #111. My education, training and professional life assure me in my usage of that terminology. Sorry, can't help.
What @Heinrich display is a classic case of "linear thinking", as if the whole world acts like linear systems.
What does a high Q resonance do? It magnifies the amplitude by many many times at the natural frequency. Can a real system do that? Probably not as it will likely go nonlinear well before it can reach the resonance amplitude as predicted by linear analyses. The differences of small signal vs large (i.e. real) signal.
Another one is diaphragm breakup. It is a case of structural buckling, and it doesn't happen until a certain critical limit is exceeded, just like a slender column buckles when the compressive load exceeds the critical buckling load. Is that a "resonance"? Depends on how you define it. Buckling is studied using modal analyses, just like room modes. Are room mode resonances?
What does a high Q resonance do? It magnifies the amplitude by many many times at the natural frequency. Can a real system do that? Probably not as it will likely go nonlinear well before it can reach the resonance amplitude as predicted by linear analyses. The differences of small signal vs large (i.e. real) signal.
Another one is diaphragm breakup. It is a case of structural buckling, and it doesn't happen until a certain critical limit is exceeded, just like a slender column buckles when the compressive load exceeds the critical buckling load. Is that a "resonance"? Depends on how you define it. Buckling is studied using modal analyses, just like room modes. Are room mode resonances?
Exactly, because resonance is a linear concept basically involving the conversion of energy forms back and forth. It doesn't have to be periodic either. It has characteristics, mathematically, that are not available in a non-linear version.
What you may think of is something else. Non-linear systems is exactly (again) what I was referring to in post #111, rub and buzz. The "audio talking" doesn't tell the truth.
The original reference was Toole saying, that resonances are the first to avoid. What he meant was freq/ response irregularities. Mind you, nothing else than that.
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Thanks, NTK.
Your explanation captures the real dividing line:
linear resonance models are useful, but actual loudspeaker behavior is governed by non-linear thresholds, breakup modes, and material limits.
Once those kick in, EQ can only shape the small-signal response — it cannot return the system to linearity.
That was exactly the point I was aiming at.
I like your post because it’s so typical. Seriousness gets completely drowned in audiological dogmas. You don’t even address the response you asked from me. You say a speaker is ruled by non-linear thresholds, breakup modes, and material limits. Well, good for you—mine isn’t. I payed for it. Btw: Did you give some numbers for any comparison?
Who mentioned non-linearities? We were talking about resonances, which, in real-world usage, are of course always linear. But as I said, typical—I kind of like that.
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