Does Time alignment and Phase coherency make for a better loudspeaker?

I agree with Millercarbon. Phase and tme alignment is critically important, but when it compromises other aspects, then you will get a less than desirable effect.

BTW, absolute phase and time alignment is IMPOSSIBLE to achive for the entire spectrum of 20Hz-20kHz. Phase correct means only that the crossover regions are not out of phase.

Time alignment also applies only to limited frequency ranges... 

Nevbertheless, when a manufacturer is aware of these parameters, and stirves not to make blatant errors in these areas, it does make for vastly better speakers compared to those where the manufacturer is unaware of these issues.

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actually phase accuracy in the rest of the chain is difficult and requires an engineer with ears deeply involved in the listening and design process... Charlie at Ayre comes to mind... No global negative feedback.... think thru what NFB is, how it works and what positive and negative aspects it can have.... Of course we owe Dr Otalla a debt of thanks for derailing the THD crowd.... The T in TIM is all about time... ( a quiz of sorts ). I have a variable NFB amp ( RIP Roger, you were a genius )... Assuming level matching, the changes to stereo image across various NFB is apparent.

Carry on ! enjoy the music.

I learned this past year how much diffuser panels helped with imaging.

So many have spoken out about room treatment, and I was convinced to try some out for myself. I finally manged to complete and install some quadratic diffusers from plans, and I am surely glad I did.

With absorption and diffusion, (and I have a lot of scope to dial it in much better) the presentation is giving me a better understanding of the advice and benefits shared here in Agon

@tomic601 , An engineer does not need ears to develop a phase coherent loudspeaker, just a measurement microphone.

In order to be accurate (I did not say sound good) a speaker has to start with a flat frequency response and be time coherent which as unsounds relates assures phase coherence. Unfortunatly, for speaker designers this has to include the room the speakers are set up in. For state of the art accuracy one has to be able to adjust frequency response so that the speakers are flat from 20 Hz to 20 kHz. This also assures that both channels have exactly the same frequency response which is very important for imaging. If a subwoofer is added one has to make sure they are time coherent with the main speakers. The only way all of this can be done is with digital signal processing. Afterwards the frequency response can be adjusted so the system sounds good to the owner. I like mine up 5 or 6 dB at 20 Hz and down 6 dB at 20 kHz. Done this way the difference between speakers is based on the way they radiate into the room and what kind of source they are point vs line.

Generally, speakers with controlled radiation patterns sound better because they cause less room interaction. Horns, dipoles and line arrays come to mind. Omnidirectional speakers require much more room treatment and produce a smaller soundstage like sitting at the back of the hall. This can sound quite natural depending on the recording. 

@mijostyn ^that^ is all well put.