If that trough falls within the plus and minus 3, I seriously doubt you would hear much if any difference between the two sweeps.
Our ears just aren't that good at discerning small level changes at different frequencies.
Even at the same frequency, most people can't discern less than about 3db of difference even when listening intently.
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Yes it was. You twice demanded that I explain why I wanted room sweeps...
See the start of this thread.
AND ... I did give you a rather comprehensive answer.
3dB is commonly quoted as a small but noticeable change, with 1dB being about the smallest difference Average Joe can perceive.
I did a few tests and found I could reliably tell 0.5dB changes, but anything smaller than that was a guess. My digital mixing desk allows 0.1dB steps.
Chris
So you want me to believe you can hear the difference in level between (lets say) a 500hz tone at 70db and a 1200hz tone at 70.5db?
Or are you suggesting that you can hear the difference when you take a single tone and turn it up or down .5db ... with someone else administering the board.
Nobody's ears are that good.
The latter.
Here's the site I used to test: Blind Testing a 1 dB Level Difference
Last time I did it, I could detect 1dB changes very reliably, 0.5dB pretty reliably (something like 85%), but couldn't manage 0.2dB - it came out to be guesswork.
I do live sound and recording for a living, so I have reasonably well-trained ears.
Chris
Here's the site I used to test: Blind Testing a 1 dB Level Difference
Last time I did it, I could detect 1dB changes very reliably, 0.5dB pretty reliably (something like 85%), but couldn't manage 0.2dB - it came out to be guesswork.
I do live sound and recording for a living, so I have reasonably well-trained ears.
Chris
The reason for seeking a flat response is so that you are listening to your source recordings without coloration... as they were intended to be heard.
Now if that doesn't suit your personal taste, that's fine, tweak away. But in my experience, most people want fidelity not personality.
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don't room modes, reflections,resonances and echos exist because of time? sorry if don't understand this correctly but if time is running aren't all frequencies in the domain rotating in their phase?
Sure did .. didn't hear a thing, even on studio quality headphones, and I've been at this a long time, more than 40 years.
The thing is that some of us, myself included, are inclined to over-estimate our prowess as a result of experience and we need to be careful not to assume others can pull the same feats we think we can.
Self-deception is a very poor replacement for test equipment and training.
The plain truth is that, by and large, people don't actually care the backside of a rat about sound or even music quality. They listen to the music without ever questioning the equipment and they are perfectly happy with that. These fine discernments we make, or think we can make, are completely lost on them.
Yep, that's about where most people will begin noticing the change.
I can hear that clearly.
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Okay... I think we need to clarify what we mean by phase...
First off, phase is a relationship. It is not an absolute anything.
Phase relationships can exist only between sounds/signals of the same frequency or that are harmonically related by frequency.
Those that are not related, have no phase relationship whatsoever.
That is you can have a phase relationship between two 500hz tones, between a 500hz and a 1000hz tone ... but not between a 300hz and a 500hz tone.
This is to say that a woofer producing a 300hz tone and a tweeter producing a 2000hz tone have no real phase relationship, the rise and fall of the waveforms do not coincide in any meaningful way. But a woofer producing 300hz and a tweeter producing 2,400 hz tone (a harmonic of the woofer frequency) can and do have a phase relationship in that if they start together they will periodically coincide.
Now we need to understand that within a fixed system... a speaker cabinet or a room, in this case... these phase relationships are going to be stable and measurable in the frequency domain as the waves mix and then add or subtract at various frequencies.
Thus we can look at frequency response to deduce phase relationships, where a relationship exists.
In a speaker, the phasing of various drivers only really matters at the crossover points, where you have a brief segment of the frequency spectrum where two drivers are reproducing the same information. If they are properly in phase, the crossover should happen seamlessly, but if they are not you will get a dip, as the out of phase signals tend to cancel one another.
In a room, where reflections and echos mix together phasing is only critical at what they call a room node... at one of the resonant frequencies of the room. These effects are fixed and behave more or less reliably, so we can see them in the frequency domain as peaks and dips in the response level.
Does that help?
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With an average speaker listening 'flat' will give you near 100 percent direct treble with the midrange and bass a mix of direct response plus room reflections. This sounds wrong, leading to a thin, harsh presentation of the source material. If that's what floats your boat good luck to you. In no way does it sound accurate or natural, or indeed as they were intended to be heard.
Floyd Toole explains this much better than I can in 'Sound Reproduction,Loudspeakers and rooms'
I'm not about to get into a protracted discussion of perception. It's different for every person.
I've sat in quite a few sweet spots over the years and I'm pretty sure that once you have a reasonably flat response --including all the room crap-- you're going to get a very clear and robust sound that, at least to my ear, definitely does not lack in bass.
10/10 99.99% @ 1db
Easy to hear and have partial loss in one ear, too.
edit: just did it @ .5db .... 10/10 99.99%
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From Floyd Toole (my bolding):
"A preference for a downward tilting steady-state room curve is the result of two things:
1. beginning with my very first double-blind listening tests in the late 1960s, through the detailed tests in my 1985-86 JAES papers, continuing to this date, the highest rated loudspeakers have had the smoothest, flattest on-axis anechoic response. This is the direct sound.
2. The normal forward-firing configurations of drivers inevitably start out as omnidirectional at low frequencies, becoming progressively more directional at higher frequencies. The rising bass energy yields a steady-state room curve with a downward tilt.
A fundamental problem has been the incorrect assumption, made long, long ago (in the age of RTAs), that the audio rule "flat is beautiful" should apply to steady-state room curves, not the direct sound. It corrupted the movie industry and its problematic "X-curve" (Chapter 11 in my book), and the rest of audio in its application to the ITU-R BS.1116-3 and EBU Tech 3276 standards, unfortunately still used by at least some. broadcasters and monitor manufacturers. Turning back the clock is difficult."
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