If one defines fidelity as when the output of the acoustical waveform matches what the signal is... Then it seems like it cannot happen to be correct until the time and phase response is correct. All things being equal, it will will not hurt.
A lot of people believe that we hear in the frequency domain. It is certainly easier to describe a system’ s frequency response in the frequency domain.
it is also also easy to describe a "system response" using the transcient response.
But a lot of scientific work suggests that in reflective spaces, Phase is not the primary issue.
Maybe swap your red and black wire on both the left and right speakers and test whether it sounds any different when the signal is reversed in phase... (some people easily hear it and some people do not.)
|
the powered KEF 50 use DSP to correct the passive KEF 50 impulse response...somebody at KEF thought that a worthwhile thing to invest effort into....hmmmmmmmmm....
All the DIRAC like systems doing phase and time correction make for a largely time and phase coherent system.
I suppose DIRAC would not exist, outside of the physics and math useage, if the majority of speakers had nice impulse response right out of the box?
|
If I have to pick the most important factor in sounding live it's linearity. Double the input then the output should double. Triple and etc. And it's true in the entire system, not just speakers. I recall Bud Fried's speakers were linear phase and roughly time aligned but it was their linear changes in sound pressure level that made the sound real. And There are non linear phase and non time aligned speakers that sound real like ATCs and again it's linearity that makes it happen.
Why stop there? (one should be able to rank them maybe using Floyd's book)
But I think I agree with you, as non linear systems have a lot of harmonic distortion and IMD.
We can talk about the frequency response as the thing the translates best statistically to "being perceived as being good".
So if one had a speaker that was not time/phase correct, but had good frequency response, no cabinet resonances, and a good pattern, then they would sound better than a time/phase aligned speaker with bad FR.
If one uses a DSP to make the FR good, then we get a different fight.
If one uses a different DSP to also do impulse response (phase) EQ, then it is different again.
However a DSP cannot remove cabinet resonances , harmonic distortion, IMD, and port noise, and compression.
If you got ^those^ good however, one could do the rest in the specific few DSPs that allow it.
|
Ever hear a group of unamplified musicians playing spread apart on a stage...anywhere? No phase or time allignment occurs. Hmmm...
Not true...
For instance, say a single French horn player is playing a note that has the fundamental in the woofer, and harmonics in the midrange, and even higher harmonics in the tweeter.
Do you want those harmonics to all be related to each other?
Or do you want the midrange to have the phase flipped?
|
For Thiel (and Vandersteen) time and phase coherency is their marketing hook but in both cases their designers combined a range of good practices to make their speakers sound great.
He list I heard was: Dunlavy, Quad, Spika, Thiel, Vandersteen
And we pretty much have the majority of posters here talking about their T/P aligned speakers.
https://www.stereophile.com/content/measuring-loudspeakers-part-two-page-3
|
I learned this past year how much diffuser panels helped with imaging. Diffusers on the back wall brought the imaging into much sharper focus. The next step was putting my speakers on springs. That not only improved the bass but also increased detail and focused the soundstage even more. Controlling room reflections has a big impact on imaging. The springs isolate the speakers from the floor and reduce speaker cabinet ringing. I saw the difference with accelerometer FFT plots. As minor as that seems it makes an audible difference. And remember, the Thiel speakers have a mineral front baffle that is very rigid but still benefitted with isolation.
What does ^that^ have to do with time/phase alignment in a speaker?
It is almost implying that a speaker which is not time/phase correct only need springs and wall treatments.
Or another spruiking of the springs for the Nth time.
|
|
...my statement refers to aiming for a perfectly flat measured speaker response as a sonic end point
But the thread is about the time domain performance of a speaker.
One cannot change that too much with DSP. The impulse response can be cleaned up somewhat. But in the edges of the crossover bands it is not really possible to do much in a passive system compared to an active one.
Once the non-time/phase aligned system and the time/phase align systems are in place, then either/both can have the frequency response dialed into what ever is asked for.
And the question then that the OP sort of asked is, "will they sound different?"
|
Room treatments do not add to coherency. Room treatments subtract. The speaker must produce a time or phase coherent sound field in order to produce that astonishing three dimensional soundstage. The reflections- both airborne and the mechanical interaction between the speakers and the floor (as well as to the amps and other components) though small they may be smear the sound. The room treatments remove those reflections to restore coherency and detail as well as bring more clarity to the bass. That is my experience.
Good for you, but the topic was time and phase... so you are out of sync.
Past attempts at DSP were abysmal failures, but perhaps significant gains have been made in the past few years. Funny I still dont consider DSP a viable option which is probably not wise. Just dont like the idea of DSP at a fundamental level.
So you were bit biased?
I phase and time align every concert venue I mix (hundreds overe decades) , and my home rig also. I never said phase and time don't matter, I simply was pointing out that live music with no sound reinforcement is never specifically adjusted for time and phase, and it still sounds great. Musicians hopefully play in sync and in tune, but not always perfectly and it can still like magic.
The signal from a person playing or singing is, by definition, time/phase aligned.
If there is no speaker reinforcement, then why are you there?
|
Little snarky there holmz...I was referring to the sound of multiple musicians playing the same music with space between them. I attend concerts I don’t mix, and ones I do mix I listen to unamplified sound from various areas during sound check including right in front of or on the stage. If you can’t understand my posts, why are you here?
I am not always the model of all things Buddhist, which is also why I asked the question ending in the question mark.
As there no way to adjust non sound reinforced music it also is hard not to be snarky. The only thing that really needs adjustment anyhow are the speakers. The rest is time-n-phase correct.
Appolgies for the tone, in any case.
|
I suppose if someone in Washington state or Alabama had a set of Thiels then they could be tested on a Klipple.
Then would have something objectively interesting.
|
@mijostyn I would like to be a Buddhist, but that is about as far as I got. But I do know enough to know that snarkiness is not a positive attribute.
I am pretty sure that the phase is usually more critical with bass than timing.
Our ears and brains are good at getting the direct path, and depending on the speakers directivity and echoyness of the walls, then reflections usually affect the frequency response.
The more delayed echos, can add some ambiance.
I agree it gets complicated in a room.
|
@mijostyn lets say we have two wide band speakers.
And we time align them in the 10-20kHz region.
One has a 12dB/octave HPF slope at 2.5 kHz.
The other has a 24 dB/octave slope also at 2.5 kHz.
The phase between those two will look different in the DC to ~5kHz region.
Then lets say we have time aligned a woofer and sub at 120 Hz.
The sub is in a bandpass box, and the woofer in a sealed.
as the frequency goes towards DC the two will deviate in phase from each other.
We could address both of the phase in the first case, and the group delay in the second case with a DSP to correct the phase, or at least in the tweeter case, some XO magic can be done to better align them in phase in the ~2.5 kHz region. (I cannot do it in solder, but many can).
Usually the time alignment is done, in a “minimum phase” sense… and it is done somewhere where the phase is not swinging wildly from say, group delay.
So they are tied at the elbow, but they’re distinctly different once we talk about more than a single frequency. At any given frequency they are effectively able to give the same correction.
|
The last paragraph in the stereophile review of the meridian dsp 8000 JA asks why the speaker wasn’t time aligned since they could basically do it for free and the reply was that specific xover design sounded better without it. The new dsp 8k’s are time aligned with the ability to switch it off and on with the remote and tbh I don’t think I can hear any difference.
I guess if we discount the waveform, then not having speakers time aligned makes sense if we just trust our ears?
They do look like some expensive speakers.
And it makes it a bit difficult to try other cables being a fully built active speaker.
|
I was looking at a step function response the other day, and there was as much energetic below the axis as above it.
I was thinking a silencer maker would be blessed with that as the wind they needed to suppress… but real life doesn’t work quite like that.
|
